Report on the U.S. Program for the International Geophysical Year: July 1, 1957 - December 31, 1958 (1965)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

X ROCKETRY PROGRAM Research Rocket Being Fired from Launching Site at Fort C h u r c h i l l , Canada

ROCKETRY PROGRAM Page A. Organization of Technical Panel on Rocketry 421 B. Summary o f Panel Actions 423 C. Project Objectives and Results 425 10.1 State U n i v e r s i t y of Iowa Rockoon & Small Rocket Program 426 10.2 Naval Research Laboratory Aerobee Program - White Sands 429 10.3 Naval Research Laboratory DAN Program - Solar Flares 433 10.4 Geophysics Research D i r e c t o r a t e Aerobee Program - Holloman 435 10.5, 10.19 - Naval Research Laboratory Aerobee Program, Ft. C h u r c h i l l . . 437 10.6 Geophysics Research D i r e c t o r a t e Rocket Program - Ft. C h u r c h i l l . . . 441 10.7 Signal Corps - Un i v e r s i t y of Michigan Aerobee Program, Fort C h u r c h i l l 442 10.14 B a l l i s t i c s Research Laboratories Nike-Cajun Program, Fort C h u r c h i l l 445 10.16 Meteorological Support, Ft. C h u r c h i l l 448 10.17 Rocket Ionospheric Data Reduction . . . . . 449 10.18 Rocket Measurements i n Guam 450 10.20 Alphatron - Sphere Experiments 453 10.21 Naval Research Laboratory P a c i f i c Solar Eclipse Expedition 459 420

ROCKETRY A. Organization of Technical Panel on Rocketry 1. Establishment of Panel. L e t t e r s were sent i n l a t e 1954 to s c i e n t i s t s engaged i n upper atmosphere research using rockets, i n v i t i n g them to membership on the Panel. Representatives of c e r t a i n other USNC panels were also i n v i t e d to serve on the Rocketry Panel to insure coordination between the appropriate s c i e n t i f i c d i s c i p l i n e s and the rocket group. J.A. Van A l l e n convened the f i r s t meeting, at which F.L. Whipple was elected chairman and H.E. Newell, J r . , vice-chairman. The Upper Atmosphere Rocket Research Panel (UARRP - an u n a f f i l i a t e d panel of s c i e n t i s t s engaged i n research rocketry, which was organized to provide a channel of communication between such workers and to provide a s c i e n t i f i c forum f o r the discussion of experiments and r e s u l t s ) was i n v i t e d to recommend a d d i t i o n a l candidates f o r member- ship to the USNC Panel. Several consultants were appointed to the Panel and represen- t a t i v e s from Department of Defense agencies were appointed as l i a i s o n members. 2. Composition of the Panel. ( A f f i l i a t i o n at time of appointment) Panel Members F.L. Whipple, Chairman H.E. Newell, J r . , Vice-Chairman W.W, Bernmg W.G. Dow E.L. Eaton N.C. Gerson Bernhard Haurwitz W.J. O'Sullivan S.F. J.W. W.G. J.A. P.H. Singer Townsend, J r . Stroud Van A l l e n Wyckoff Smithsonian Astrophysical Observatory Naval Research Laboratory B a l l i s t i c s Research Laboratory U n i v e r s i t y of Michigan Geophysics Research D i r e c t o r a t e (AFCRL) Geophysics Research D i r e c t o r a t e (AFCRL) New York U n i v e r s i t y National Advisory Committee f o r Aeronautics Un i v e r s i t y of Maryland Naval Research Laboratory U.S. Army Signal Eng. Lab. State U n i v e r s i t y of Iowa Geophysics Research D i r e c t o r a t e (AFCRL) b. Consultants and L i a i s o n K.A. Anderson L.M. Jones Hilde K. Kallmann R.M. Slavin N.W. Spencer Eaton E. Duff L.G. Smith Peter Watras D.P. Wencker O.E. Hearn State U n i v e r s i t y of Iowa Uni v e r s i t y of Michigan U n i v e r s i t y of C a l i f o r n i a , Los Angeles Geophysics Research D i r e c t o r a t e (AFCRL) Un i v e r s i t y of Michigan Geophysics Research D i r e c t o r a t e (AFCRL) U.S. Army Ordnance Corps U.S. Array Signal Corps U.S. Navy U.S. Navy Secretariat (IGY S t a f f ) G.F. S c h i l l i n g (To June 1956) John DePue (To July 1957) John Hanessian (To June 1958) P.J. Hart (From June 1958) 421

ROCKETRY 3. Panel Meetings. Nine meetings of the Panel were held. F i r s t Meeting Second Meeting T h i r d Meeting Fourth Meeting F i f t h Meeting S i x t h Meeting Seventh Meeting Eighth Meeting Ninth Meeting 4. Working Groups. January 22, 1955 February 4, 1955 A p r i l 28, 1955 June 3, 1955 January 27, 1956 March 1, 1956 September 20, 1957 A p r i l 3, 1958 November 25, 1958 Washington, D.C. Azusa, C a l i f o r n i a Washington, D.C. Washington, D.C. Ann Arbor, Michigan Washington, D.C. Cambridge, Mass. Washington, D.C. Washington, D.C. a. SCIGY. The UARRP had established a working group to make recommendations f o r the U.S. IGY program; the group was c a l l e d the Special Committee f o r the IGY (SCIGY). At an ea r l y meeting, the USNC Technical Panel on Rocketry adopted SCIGY as i t s working group to plan the d e t a i l s of the rocket program. As the working group of the USNC Panel, SCIGY was also known as the Working Group on Rocket Program Operations. The extremely d i f f i c u l t task of SCIGY was t o provide l i a i s o n between the t e c h n i c a l groups and the m i l i t a r y operational groups i n the preparation, f i r i n g , and c o l l e c t i o n of data from s c i e n t i f i c rockets. The remarkable effectiveness of t h i s group accounts i n large measure f o r the success of the U.S. program i n research by rockets. Eight special sub-committees of SCIGY were organized to study various aspects of the rocket program, such as small rockets, Dan rockets and launching f a c i l i t i e s , p u b l i c a t i o n s , communications, impact p r e d i c t i o n , data centers, and the f i n a l SCIGY rep o r t . During the period October 1954 to June 1959, SCIGY held some twenty-eight meetings. SCIGY Membership H.E. Newell, J r . , Chairman J.W. Townsend, Exec. Secretary W.W. Berning L.M. Jones F.B. McDonald (To 1957) K.A. Anderson (From 1957) W.G. Stroud P.H. Wyckoff (To 1957) R.W. Sla v i n (From 1957) N.W. Spencer Naval Research Laboratory Naval Research Laboratory B a l l i s t i c s Research Laboratory U n i v e r s i t y of Michigan State U n i v e r s i t y of Iowa State U n i v e r s i t y of Iowa USASCEL; NASA Geophysics Research D i r e c t o r a t e Geophysics Research D i r e c t o r a t e U n i v e r s i t y of Michigan SCIGY followed w i t h much i n t e r e s t the development of new rocket v e h i c l e s and incorporated the Nike-Cajun, Nike-Asp, Aerobee 300, Aerobee 25 and Loki I I - D a r t sys- tems i n the program. Technical d i f f i c u l t i e s w i t h some of the rockets also received much a t t e n t i o n and by the opening of the IGY, most of the rocket systems had been successfully t e s t - f i r e d . Undertaken by SCIGY, scheduling of f i r i n g s a t the various ranges was a complex task. An e f f o r t was made to schedule experiments to provide a sampling at various seasons and times of day, as w e l l as to coordinate some f i r i n g s w i t h the IGY World Meteorological I n t e r v a l s and Regular World Days. While the schedule had to be read- just e d many times as a r e s u l t of weather, range problems, or instrumental d i f f i c u l t i e s , the program was successful i n obtaining seasonal and d i u r n a l observations, and a l l but a few of the scheduled rockets were f i r e d during the IGY period. Thirty-one f i r i n g s were made i n the pre-IGY t e s t period, 189 f i r i n g s were made during the 18- month IGY period, 5 rockets were f i r i n g m the post IGY months, and one rocket f i r i n g was postponed i n d e f i n i t e l y . 422

ROCKETRY b. LPR Sub-committee. At the Second General Assembly of CSAGI i n Rome, 1954, m view of the advanced state of rocket technology, a r e s o l u t i o n was adopted c a l l i n g a t t e n t i o n to the tec h n i c a l p o s s i b i l i t y of placing instrumented e a r t h s a t e l l i t e s i n t o o r b i t f o r the IGY. I n response to t h i s CSAGI recommendation, the USNC requested the Technical Panel on Rocketry t o e s t a b l i s h a sub-committee t o make a f e a s i b i l i t y study o f t h i s question. W.H. Pickering, M.W. Rosen and J.W. Townsend prepared a report on ve h i c l e c a p a b i l i t i e s f o r the Rocketry Panel and t h i s group discussed the s a t e l l i t e proposal w i t h members of the Panel. The name LPR ( f o r 'long-playing' rocket) was given to the proposed program, meetings and reports of the LPR group were considered p r i v a t e u n t i l the f i n a l recommendations were approved by the government. A new Technical Panel was organized f o r the s a t e l l i t e program a f t e r an o f f i c i a l government announcement was made on July 29, 1955, that the United States would attempt to place s c i e n t i f i c i n s t r u - mented s a t e l l i t e s i n t o o r b i t f o r the IGY program. The a c t i v i t i e s of t h i s panel and the d e t a i l s of the program are described elsewhere i n t h i s r e p o r t . B. Summary of Panel Actions 1. O r i g i n a l Program. The UARRP began planning f o r the rocket program i n A p r i l 1953 and by ea r l y 1954 had developed a program c a l l i n g f o r 30 Aerobee and 50 Rockoon or Rockair f i r i n g s at White Sands and Thule, Greenland and at a proposed new f a c i l i t y at Fort C h u r c h i l l , Canada. This new launching l o c a t i o n was proposed i n order to provide f o r extensive soundings of the atmosphere i n the A r c t i c . The f a c t that the Northern Auroral Zone encompasses Fort C h u r c h i l l made t h i s l o c a t i o n h i g h l y desirable f o r auro- r a l , magnetic and ionospheric experiments. Through the cooperation of the Canadian IGY Committee and the Canadian government, arrangements were made f o r U.S. Army u n i t s t o construct a launching f a c i l i t y and range t r a c k i n g i n s t a l l a t i o n at Fort C h u r c h i l l . Canadian IGY i n s t a l l a t i o n s at C h u r c h i l l were of importance i n providing group l e v e l c o n t r o l information f o r the rocket f l i g h t s . The UARRP proposed rocket program, as submitted t o the USNC, was founded on several assumptions: a) various agencies undertaking rocket research would c o n t r i b u t e t h e i r normal programs and budgeting to the IGY e f f o r t ; b) IGY experiments would be based on proven and f a m i l i a r techniques; c) the program should conform w i t h CSAGI recommenda- t i o n s ; d) f i r i n g s would be coordinated w i t h planned World Days and World Meteorologi- c a l I n t e r v a l s ; and e) the Department of Defense would provide the l o g i s t i c support needed f o r the f i r i n g s of rockets i n remote areas. 2. Development of the Program. By June 1955, the SCIGY had added t o the basic UARRP program a series of pre-IGY t e s t f i r i n g s at White Sands and the new f a c i l i t y at Fort C h u r c h i l l as w e l l as from a Navy ship i n the P a c i f i c o f f San Diego to see whether rocket observations could be obtained of energetic r a d i a t i o n from e a r l y phases of so- l a r f l a r e s . The o v e r a l l rocket program included instrumentation f o r a) atmospheric st r u c t u r e and composition; b) r a d i a t i o n and p a r t i c l e studies; c) ionospheric studies, and d) geomagnetic observations. 3. L i a i s o n w i t h Other Panels. a. Meteorology. The Panel on Meteorology requested the Rocket Panel to advise on the f e a s i b i l i t y of conducting atmospheric s t r u c t u r e observations i n the A n t a r c t i c . I n view of the need f o r elaborate support equipment and funds, the Panel recommended against such a program; various rocket agencies indi c a t e d t h a t they would not be able to extend t h e i r program to include such work. The p o s s i b i l i t y was also discussed of ozone observations, and i t was again decided that agencies already planning programs could not include such obsejrvations. 423

ROCKETRY b. Geomagnetism. The Panel on Geomagnetism requested the Rocket Panel to include f i r i n g s f o r the study of e l e c t r i c currents. The Panel noted that NRL planned f i r i n g s m the A r c t i c and A n t a r c t i c , (the a n t a r c t i c observations were dropped from the program at a l a t e r date) but t h a t no observations were planned i n the e q u a t o r i a l regions. Dr. Van A l l e n noted that the SUI program could include f i r i n g s i n the e q u a t o r i a l r e - gions and that t h i s would be considered f o r i n c l u s i o n i n the program (see p r o j e c t 10.1), c. Planning Document f o r Other Panels. I n order to f a m i l i a r i z e the other panels w i t h the planned rocket program, a document was prepared l i s t i n g the schedule of rocket f i r i n g s , the experiments, i n c l u d i n g appropriate d e s c r i p t i o n s ; and o u t l i n i n g the scien- t i f i c requirements f o r support observations i n the various d i s c i p l i n e s covered by the experiments. This document was sent to other appropriate panels f o r t h e i r i n f o r m a t i o n and response as to how other programs would be r e l a t e d to rocket experiments. 4. Manuals. I n response to CSAGI recommendations concerning p u b l i c a t i o n of manuals i n the various IGY d i s c i p l i n e s , the Panel discussed t h i s matter and recommended th a t t e c h n i c a l manuals i n rocketry would not be required. The Panel f e l t , however, t h a t descriptions of experiments and equipment would be useful f o r other workers. 5. Publications. On behalf of the Panel, the SCIGY studied the d e s i r a b i l i t y of pub- l i c a t i o n of d e s c r i p t i v e m a t e r i a l on the IGY program, and several a r t i c l e s were prepared £jr jo u r n a l s such as S c i e n t i f i c Monthly and National Geographic. I n a d d i t i o n , through the cooperation of the White Sands Signal Support Agency, three 16 mm sound motion pi c t u r e s were produced: a. "Springboard to Science," construction a c t i v i t i e s at C h u r c h i l l b "Prelude to IGY," pre-IGY rocket f i r i n g s at C h u r c h i l l c. " F r o n t i e r Beyond the Sky," the geophysics of the IGY rocket program 6. Data. a. Exchange of Rocket Data. The SCIGY recommended that a f t e r each rocket f l i g h t , a f l i g h t summary be prepared describing the experiment, the rocket performance, and gi v i n g a preliminary assessment o f the r e s u l t s . A form was developed f o r t h i s purpose. This form was subsequently shortened and used by the various groups. A f t e r discussion of the exchange of raw or reduced rocket data, i t was decided that I t would be i m p r a c t i c a l to exchange anything but f l i g h t summaries and te c h n i c a l reports or papers m the professional j o u r n a l s . The CSAGI Rocket and S a t e l l i t e Re- porter proposed an exchange which c a l l e d f o r submission of te c h n i c a l papers discussing the rocket experiments as soon as possible a f t e r the f l i g h t . The SCIGY recommended accepting t h i s plan w i t h the q u a l i f i c a t i o n that the submission of papers be no l a t e r than f i v e years a f t e r any given f l i g h t . b. World Data Centers. The SCIGY p a r t i c i p a t e d i n the study made by the USNC i n planning the establishment of one of the IGY World Data Centers i n the United States - World Data Center A. I t had been o r i g i n a l l y recommended that the Rocket sub-center be established at the State U n i v e r s i t y of Iowa, but the USNC l a t e r decided that the rocket and s a t e l l i t e centers should be combined and located i n the National Academy of Sciences i n Washington. The Panel was asked to comment on the Rocket Report Series published by WDC-A and recommended that t h i s series should not be l i m i t e d to preliminary reports or pa- pers not suited f o r formal p u b l i c a t i o n . I t was suggested that the report series could render a valuable service i n c o l l e c t i n g r e p r i n t s or a r t i c l e s appearing i n the regular j o u r n a l s . 424

ROCKETRY 7. Post IGY Programs. a. IGC-1959. The Panel agreed that inasmuch as the IGC-1959 had been formalized at a l a t e date no special rocket program could be planned, but th a t the U.S. c o n t r i - b u t i o n could include postponed IGY rockets and f i r i n g s r e g u l a r l y scheduled by the various agencies. b. Fort C h u r c h i l l . The Panel expressed concern that the f a c i l i t i e s at Fort C h u r c h i l l might go out of service i f rocket programs should not continue. The Panel urged that DOD support be continued f o r rocket programs at C h u r c h i l l to insure the continued a v a i l a b i l i t y of t h i s important f a c i l i t y . C. Project Objectives and Results 1. Summary of Program. The rocket program was based on the assumption that the Department of Defense would supply an important f r a c t i o n of the l o g i s t i c support and tha t agencies would c o n t r i b u t e r e g u l a r l y scheduled rocket programs to the U.S. e f f o r t . The p r o j e c t s t h a t f o l l o w were f o r the most part funded by the special IGY appropria- t i o n s ; a few pr o j e c t s are also included that were contributed by agencies. A l l pro- j e c t s , however, depended t o a considerable extent on the generous support of the IGY e f f o r t of the various government agencies involved i n regular rocket research programs, not only i n d i r e c t support of some o f the vehicles and boosters, but f o r i n d i r e c t Items such as personnel and t r a v e l costs. F i n a l l y , i t was the wholehearted coopera- t i o n of the Department of Defense, p a r t i c u l a r l y the Army, that was responsible f o r the c r e a t i o n of the new launching f a c i l i t y at Fort C h u r c h i l l , Canada. The IGY funds supplied were, i n e f f e c t , the a d d i t i o n a l amount required i n order to transform regu- l a r l y scheduled rocket programs i n t o a major coordinated undertaking f o r the IGY. The e n t i r e rocket program at Fort C h u r c h i l l depended f o r i t s day-to-day operations on a group of men assigned by DOD to implement the plans of the SCIGY and Panel on Rocketry. An m t e r - s e r v i c e task group was established, and i t s members spent f u l l time i n the d e t a i l e d planning f o r the Fort C h u r c h i l l f a c i l i t y , a s s i s t i n g and super- v i s i n g elements of the cons t r u c t i o n , coordinating the flow o f s c i e n t i s t s , supplies and equipment to and from the f a c i l i t y , and a s s i s t i n g i n many other ways i n the opera- t i o n of the planned program. Members of the task group were also instrumental m a s s i s t i n g i n some aspects of the l o g i s t i c s support f o r the shipboard f i r i n g s i n the A r c t i c and A n t a r c t i c and f o r the eclipse expedition. 2. Order of Project Description. The proj e c t s that are described i n the f o l l o w i n g pages are i n numerical order to correspond w i t h the o r i g i n a l formulation of the pro- gram. For convenience, the proj e c t s are grouped below to r e f l e c t s i m i l a r i t y of purpose. Rockoon or DAN Program 10.1, 10.3 Aerobee Program 10.2, 10.4, 10.5, 10.6, 10.7, 10.19 Nike-Cajun Program 10.14 Meteorological Support-Fort C h u r c h i l l 10.16 A n t a r c t i c Rocket Data Reduction 10.17 Rocket Measurements on Guam 10.18 Alphation-Sphere Experiment 10.20 P a c i f i c Solar Eclipse Expedition 10.21 3. Cancelled Projects. Former p r o j e c t s bearing the f o l l o w i n g numbers were e l i m i n - ated from the program or combined w i t h other p r o j e c t s 10.8 to 10.13 and 10.15. 425

ROCKETRY Project 10.1 - State U n i v e r s i t y of Iowa Rockoon and Small Rocket Program 1. Objectives. This p r o j e c t at the Department of Physics, State U n i v e r s i t y of Iowa, provided f o r the f i r i n g of balloon-launched small rockets (rockoons) and small two- stage rockets from Fort C h u r c h i l l , Canada, from shipboard i n the A r c t i c , and from ship- board during a re-supply cruise to the A n t a r c t i c , covering a wide range of l a t i t u d e . There were three major types of programs: a) cosmic-ray observations t o look f o r f l u c t u a t i o n s above the atmosphere and f o r a l a t i t u d e survey, b) study of s o f t r a d i a - t i o n above 50 km i n the auroral zone, coordinated w i t h auroral observations; and c) detection of e l e c t r i c currents i n the ionosphere through the use of magnetometers. 2. Operations. Shipboard launchings were a l l rockoons. At land f a c i l i t i e s , Nike- Cajun, Nike-Asp and Loki-Dart configurations were used. SUI personnel assembled f l i g h t equipment and conducted launching operations, A summary of the f l i g h t l o c ations and experiments follows: No. of Rockets Fired Location 3 (Pre-IGY) Guam Experiment Magnetic F i e l d 15 Ship - N, A t l a n t i c Cosmic Rays, Auroral Part. & Soft Radiation 4 1 Ship Ship N. A t l a n t i c N. A t l a n t i c Magnetic F i e l d Test 14 Fort C h u r c h i l l Fort C h u r c h i l l Fort C h u r c h i l l Auroral Part. & Soft Radiation Cosmic Rays, Auroral Part. & Soft Radiation, Solar UV & X-rays Cosmic Ray, Auroral Part. & Soft Radiation White Sands Solar UV & X-rays, Micrometeorites Test White Sands Wallops I s . Micrometeorites Magnetic F i e l d 6 10 Ship - P a c i f i c Ship - P a c i f i c Cosmic Rays Magnetic F i e l d Ship - Subantarctic Cosmic Rays Ship - Subantarctic Cosmic Rays, Auroral Part. & Soft Radiation 8 Ship - Subantarctic Magnetic F i e l d 3. Personnel. This work was under the supervision of James A. Van A l l e n , Carl Mcllwain and L.J. C a h i l l , J r . were the p r i n c i p a l s c i e n t i s t s associated w i t h Dr. Van A l l e n . 4. Results. a. Soft-Radiation. SUI s c i e n t i s t s had discovered m 1953 the existence i n the northern auroral zone of " s o f t r a d i a t i o n " and pursued a study of t h i s phenomenon. The r a d i a t i o n e x h i b i t e d a l a t i t u d e dependence, w i t h a strong maximum at about 67° 426

ROCKETRY geomagnetic north, a s i m i l a r d i s t r i b u t i o n was found f o r the Southern Hemisphere. I t was concluded, from a comparison of absorption r e s u l t s obtained w i t h Geiger tubes and photomultiphers ( w i t h Nal s c i n t i l l a t i o n c r y s t a l s ) , that photons i n the energy range 10-100 kev were being detected. No examples of energy loss greater than 200 kev were detected outside of the expected number of cosmic-ray pulses. The l a t i t u d e dependence suggested, moreover, t h a t the photons a r i s e from brentsstrahlung from charged p a r t i c l e s , presumed to be primary electrons of energy 10-100 kev, i n t e n s i t y 10^ - 10°/sec cm^, g i v i n g an energy f l u x of 0.01 erg/sec cm . This energy f l u x i s consistent w i t h the amount of energy i n v i s i b l e auroras. The r a d i a t i o n ranged, on various occasions, be- tween about 4 and 750 times normal cosmic-ray i n t e n s i t y . One f l i g h t passed below and perhaps penetrated a v i s i b l e aurora, the s o f t r a d i a t i o n on t h a t occasion was 40 times cosmic-ray background. b. Auroral P a r t i c l e s . I n one f l i g h t at C h u r c h i l l , the rocket penetrated a Class I d i f f u s e aurora, i n another f l i g h t , the rocket penetrated a b r i g h t auroral arc. An e l e c t r o n energy f l u x of about 20 ergs/sec cm^ was measured f o r the f a i n t aurora, and an electron:proton r a t i o of 1000:1 was noted. The b r i g h t aurora showed an energy f l u x of as high as 200 ergs/sec cm^ but w i t h less proton f l u x than on the previous f l i g h t . I t I S concluded that f o r these two auroral displays the auroral emissions o r i g i n a t i n g at atmospheric levels below 120 km were produced by low-energy electrons w i t h no ap- preciable c o n t r i b u t i o n from protons. The electrons that produced the b r i g h t a u r o r a l arc d i d not have a high-energy t a i l i n t h e i r spectrum, they were e s s e n t i a l l y mono- energetic at about 6 kev, suggesting an e l e c t r o s t a t i c accelerating mechanism, or at least a mechanism i n which a s t a t i s t i c a l type accelerating process was weak. During both f l i g h t s there was a s t r i k i n g absence of electrons w i t h greater than 50-kev energy and the Geiger counting r a t e of only 1.2 times the expected cosmic-ray ra t e was m sharp contrast to what might have been a n t i c i p a t e d on the basis of e a r l i e r f l i g h t s . The t o t a l e l e c t r o n f l u x i n these auroras was s i m i l a r to that i n the outer zone of trapped r a d i a t i o n , but the i n d i v i d u a l e l e c t r o n energies of the trapped electrons are t y p i c a l l y an order of magnitude higher. c. Latitude Survey of Cosmic Radiation. Shipboard launchings of rockoons were c a r r i e d out over a range of l a t i t u d e s from 75° North to 72° South. Observations w i t h a single Geiger tube showed that the t o t a l i n t e n s i t y above the atmosphere at f a r southerly l a t i t u d e s i s w i t h i n 5% of that at f a r n o r t h e r l y l a t i t u d e s and i s about 4.3 times that at the equator, as found independently by Neher using balloons (see Project 2.4, Chapter V I I - Cosmic Rays). d. E l e c t r i c Currents Near the Geomagnetic Equator. A small proton precession magnetometer was developed f o r small balloon-launched rockets. They were successfully flown i n the v i c i n i t y of the Line Islands on the way to the A n t a r c t i c aboard the USS GLACIER. IGY magnetic s t a t i o n s i n the Line Islands, operated under the cognizance of Scripps I n s t i t u t i o n of Oceanography, provided ground c o n t r o l . The measurement of the t o t a l i n t e n s i t y of the earth's magnetic f i e l d i n d i c a t e d f o r t h i s p a r t i c u l a r time and place two d i s t i n c t layers of e l e c t r i c a l current w i t h a layer of lower current density between them. The lower boundary of the lower layer was at about 97 km, the top of t h i s layer was at about 110 km. The upper layer began at about 120 km, the rocket penetrated to only 127 km, j u s t above where the current density appeared to begin to decrease. An approximate l a t i t u d e spread was determined from several f l i g h t s . A current layer flowing i n the opposite d i r e c t i o n and of much lower i n t e n s i t y was found somewhat to the north. The d e t a i l s of the current system were unexpected and cannot be r e a d i l y explained on the basis of what i s yet known of the e q u a t o r i a l e l e c t r o j e t . e. E l e c t r i c Currents i n the North Auroral Zone During a Magnetic Storm. A rocket c a r r i e d a magnetometer to about 130 km during a magnetic disturbance. The rocket was launched at about 64° N. l a t i t u d e i n Davis S t r a i t near the coast of Greenland. The magnetic f i e l d i n t e n s i t y as measured by the rocket d i d not lead to an unambiguous ex- planation, but I t appeared that the simplest explanation requires a h o r i z o n t a l current layer flowing m a south-westerly d i r e c t i o n , w i t h a current density of about 11 am- peres/km^, at an a l t i t u d e o f about 95 to over 130 km. 427

ROCKETRY Other s i m i l a r f i r i n g s were c a r r i e d out at Wallops I s l a n d , V i r g i n i a i n 1959. One rocket apparently entered a weak current system at about 100 km, but the rocket only a t t a i n e d a peak a l t i t u d e of 107 km. C a h i l l has continued h i s magnetometer f l i g h t s under NASA auspices. 5. Bibliography. a. Papers Presented at Meetings. J.A. Van A l l e n : "Rocket Measurement of Soft Radiation." Washington Meeting, Nat. Acad. Sciences, (published i n Proc. NAS. v o l . 43, 1957, p. 57) and Vth Gen. Ass. CSAGI, Moscow 1958 (published i n IGY Rocket Report Series No. 1, pp. 159-63, NAS, Washington, July 1958. C.E. Mcllwam: "Direct Measurement of Radiation Associated w i t h V i s i b l e Aurorae." Vth Gen. Ass., CSAGI, Moscow, 1958 (published i n IGY Rocket Report Series No. 1, pp. 164-68. J.A. Van A l l e n , L.J. C a h i l l : "A Latitude Survey of Cosmic Radiation." Vth Gen. Ass,, CSAGI, Moscow, 1958 (published i n IGY Rocket Report Series No. 1. pp. 208-11). L.J. C a h i l l "Evidence f o r Ionospheric Currents Near the Geomagnetic Equator." Vth Gen. Ass., CSAGI, Moscow, 1958 (published i n IGY Rocket Report Series No. 1. pp. 211-16). b. Published Papers. L.J. C a h i l l , J r . : " I n v e s t i g a t i o n of the Equatorial E l e c t r o j e t by Rocket Magnetometer." JGR, v o l . 64, May 1959, pp. 489-504. L.J. C a h i l l , J r . " "Detection of an E l e c t r i c a l Current i n the Ionosphere Above Greenland." JGR, v o l . 64, Oct. 1959, pp. 1377-80. 428

ROCKETRY Project 10.2 - Naval Research Laboratory Aerobee Program - White Sands 1. Obiectives. Three aerobee rockets were instrumented at the Naval Research Labora- to r y f o r study of u l t r a v i o l e t solar r a d i a t i o n s . The experiments included u l t r a v i o l e t spectrographs and a monochromatic camera to photograph the sun i n Lyman-a. 2. Operations. A high r e s o l u t i o n spectrograph was flown on September 17, 1957. The dispersing element was an echelle g r a t i n g ruled w i t h 73 Imes/mm, and used m orders ranging from 75 at 3000 A to 112 at 2000 A. Quartz and LiF o p t i c s were used, s e t t i n g the u seful short wavelength l i m i t at about 2200 A. A si d e r o s t a t ( p h o t o e l e c t r i c a l l y operated servo-system) held the sun's image on the s l i t , compensating f o r rocket r o l l and yaw. The resolving power of the instrument i n the laboratory was approximately 0.04 A. F l i g h t of ,the two remaining rockets was postponed to e a r l y 1959. One of these rockets c a r r i e d a Lyman-a camera m the form of a double monochromator using two 40 centimeter gratings 600 lines/mm i n the f i r s t order arranged so that the dispersions were a d d i t i v e . The f i r s t g r a t i n g was mechanically deformed to compensate f o r a s t i g - matism, w i t h the r e s u l t that a stigmatic image of the sun, i n Lyman-a, was obtained. Images were obtained w i t h exposure times as short as l/50th of a second, thus providing high r e s o l u t i o n , i n s p i t e of the presence of some j i t t e r i n the p o i n t i n g c o n t r o l . The sun was photographed at the same time from the ground i n white l i g h t , hydrogen-a and calcium K w i t h the cooperation of the Mt. Wilson, McMath-Hulbert, Naval, and Sacramento Peak Observatories. A vacuum u l t r a v i o l e t spectrograph employing a 40 centimeter r a - dius 600 line/mm t r i p a r t i t e r e p l i c a g r a t i n g was also c a r r i e d on t h i s rocket. The r e - solving power of t h i s spectrograph was approximately 0.6 A. The f i n a l rocket of t h i s series, flown on July 21, 1959, c a r r i e d a high r e s o l u t i o n spectrograph to study the p r o f i l e of the Lyman-a l i n e of hydrogen. The instrument em- ployed a 50 cm 1200 line/mm g r a t i n g i n the t h i r t e e n t h order. The system was arranged to be stigmatic r e l a t i v e to the sun, the dispersion was 2.6 mm/A and the r e s o l v i n g power 0.03 A. 3. Personnel. Richard Tousey was the p r o j e c t d i r e c t o r , associated w i t h him were J.D. P u r c e l l and D.M. Packer. 4. Results. The echelle spectrograph experiment, even though rocket performance was low, produced a usable spectrum of the Mg I I absorption-emission complex at 2800 A. The r e s o l u t i o n was approximately 0.1 A during f l i g h t . The spectrum showed that the Mg I I resonance l i n e s , l i k e the calcium H and K l i n e s , have three components. The second or emission components showed a small doppler s h i f t shortward, and the t h i r d or absorption component cut i n t o the tops of the emission l i n e i n a fashion s i m i l a r to calcium H and K. The p r i n c i p a l d i f f e r e n c e was that the emission l i n e s r i s e to a f a r greater height i n Mg I I than i n Ca I I . The Lyman-a camera produced a series of excellent spectroheliograms. They showed that the Lyman-a l i n e emission i s intense from plage regions and that the p a t t e r n of emission resembles calcium K more than the hydrogen-a. I n Lyman-a the r a t i o of i n t e n - s i t y between b r i g h t and dark features i s even greater than i n calcium K and the p a t t e r n has a coarser s t r u c t u r e than does calcium K or hydrogen-a. The images show d e t a i l down to about 1 minute of arc, which i s believed to represent the true Lyman-a d i s - t r i b u t i o n . The instrument had a resolving power of approximately 1/3 minute. The e x t r e m e - u l t r a v i o l e t spectrograph flown on March 13, 1959 produced spectra showing more d e t a i l s m the solar spectrum than had been seen p r i o r to t h i s date. Ap- proximately 50 emission l i n e s were i d e n t i f i e d . V i s i b l e were several members of the Lyman series of hydrogen as w e l l as the Lyman continuum. At an a l t i t u d e of 200 km 429

ROCKETRY the Lyman- l i n e of hydrogen was completely absorbed by molecular nitrogen although higher members of the s e r i e s were present. Also v i s i b l e were absorption bands pro- duced by N 2 w i t h i n the Lyman continuum. Perhaps the most important r e s u l t of t h i s spectrum was the d i s c o v e r y of the resonance l i n e s of Ne V I I I which i s the f i r s t def- i n i t e proof of the e x i s t e n c e of neon i n the sun. Also photographed were the resonance l i n e s of Mg X which are produced i n corona. These l i n e s of neon and magnesium are the f i r s t resonance l i n e s to be discovered i n the true corona. P r e v i o u s l y , l i n e s known to be coronal were produced by t r a n s i t i o n s of a forbidden nature. The high r e s o l u t i o n Lyman-a spectrograms obtained on J u l y 21, 1959 gave a p r o f i l e of t h i s l i n e showing a weak c e n t r a l depression w i t h a sharp strong absorption core ( F i g u r e 1 ) . A n a l y s i s of the core i n d i c a t e d that i t was produced by hydrogen between the e a r t h and the sun at a temperature between 800 and 2100° K. The t o t a l v e r t i c a l hydrogen above the 100 km l e v e l was derived as approximately 2 x 10 atoms i n a column one square centimeter i n c r o s s s e c t i o n s . The Lyman-a emission l i n e was approximately 1 A broad at h a l f maximum, wi t h wings extending to about 1 A on e i t h e r s i d e . The weak c e n t r a l depression i s s i m i l a r to the t h i r d component i n the c a l c i u m H and K and Mg I I l i n e s , and o r i g i n a t e s i n the s o l a r atmosphere. The width of the emissiksn l i n e was l e s s i n plage regions than for the quiet sun. Much of the hydrogen producing the nar- row absorption core must be of a geocoronal nature. F i g u r e 1. High-Resolution S p e c t r a l Image of the Lyman-Alpha L i n e and i t s Microphotometer T r a c i n g . The absorption core i s the dark area i n the very c e n t e r of the s p e c t r a l image. 430

ROCKETRY Bibliography. a. Papers Presented at Meetings. J.D. P u r c e l l : "Use of a Bent Grating i n a Spectrograph f o r Lyman Alpha Solar Disc Photography." O p t i c a l Society of America, October 17-19, 1957. P.J. Mange, J.D. P u r c e l l , R. Tousey: "A Di r e c t Determination of Neutral Hydrogen Between the Earth and the Sun." American Astronomical Society, December 1957 (Cleveland). J.D. P u r c e l l , A. Boggess I I I , and R. Tousey: "A High Resolution U l t r a v i o l e t Spectrograph of the Sun." Vth Gen. Ass. CSAGI, Moscow, 1958 (pub. i n World Data Center A IGY Rocket Report Series No. 1, July 1958, pp. 198-200). R. Tousey and J.D. P u r c e l l . "Solar Spectroscopy from Rockets." O p t i c a l Society of America, Ottawa, Canada, 8 October 1958. J.D. P u r c e l l , R. Tousey, D.M. Packer, and W.R. Hunter: "Solar Disk Photo- graphs Made w i t h Lyman-a of Hydrogen." American Astronomical Society, Rochester, N.Y., A p r i l 1959. R. Tousey, J.D. P u r c e l l , D.M. Packer, and W.R. Hunter: "A New Solar Spectrum i n the Extreme U l t r a v i o l e t . " American Astronomical Society, Rochester, N.Y., A p r i l 1959. J.D. P u r c e l l and R. Tousey: "The P r o f i l e o f Solar Lyman-Alpha." American Astronomical Society, Cleveland, Ohio, December 1959. J.D. P u r c e l l and R. Tousey: "Photography of the Sun i n Lyman-Alpha and Other Wavelengths." I n t e r n a t i o n a l Astrophysical Symposium, U n i v e r s i t y de Li&ge, Belgium, July 1960. J.D. P u r c e l l , and R. Tousey: "The P r o f i l e of Solar Lyman-Alpha." I n t e r - n a t i o n a l Astrophysical Symposium, U n i v e r s i t y de Liege, Belgium, July 1960. * J.D. P u r c e l l , D.M. Packer, and R Tousey "The U l t r a v i o l e t Spectrum of the Sun " F i r s t I n t Space Science Symp of COSPAR Jan I960, Nice, France (pub i n WDC A IGY Rocket Report Series No 6, Nov. 1960, pp 191-98) * J.D. P u r c e l l , D.M. Packer, and R Tousey "Photographing the Sun i n Lyman Alpha " F i r s t I n t . Space Science Symp , COSPAR, Jan. 1960 Nice * J.D. P u r c e l l , and R Tousey "The P r o f i l e of Solar Lyman Alpha." F i r s t I n t Space Science Symp , COSPAR Jan 1960, Nice H.W. Cooper, I.S. Gulledge, M.J. Koomen, D.M. Packer and R Tousey "Rocket Measurements of Oxygen and OH Night Airglow " I n t e r n a t i o n a l Union of Geodesy and Geophysics Meetings, H e l s i n k i , Finland, July-August 1960 C.R. Detwiler, J D P u r c e l l , and R Tousey "The Extreme U l t r a v i o l e t Spec- trum of the Sun " Tenth I n t e r n a t i o n a l Astrophysical Symposium, Li^ge, Belgium, July 1960 These papers also included i n Space Research, Proc. of COSPAR Nice Symp., H Kallmann-Bijl, E d i t o r , North Holland Pub. Co 431

ROCKETRY b Published Papers J.D. P u r c e l l , R Tousey, D.M. Packer, and W R Hunter "Photograph of the Sol a r D i s c with R a d i a t i o n from the Lyman-Alpha L i n e of Hydrogen " NRL Report of Progress A p r i l 1959. J.D. P u r c e l l , D.M. Packer, and R Tousey "Lyman-Alpha Photographs of the Sun." Nature, v o l 184, J u l y 4, 1959, p 8 ( a l s o included i n Rocket Report S e r i e s No 6) J.D. P u r c e l l , R Tousey "The P r o f i l e of S o l a r Hydrogen-Lyman-Alpha " J Geophys Res , v o l 65, Jan 1960, pp 370-73 ( a l s o included i n Rocket Report S e r i e s No 6) R Tousey "Le Spectre U l t r a v i o l e t L o i n t a i n du S o l e i l " Science et I n d u s t r i e s Photographiques, 2° S e r i e , v o l 31, I960, pp 303-307. J.D. P u r c e l l and R Tousey "Photography of the Sun i n Lyman-Alpha and Other Wavelengths " M̂ m de l a Soc Roy des Sciences de Lifege, Tome IV, 32, 1960, 274 J.D. P u r c e l l and R Tousey "The P r o f i l e of S o l a r Lyman-Alpha." Mem de l a Soc Roy des Sciences de Lifege. Tome IV, 1960, 283 C.R. Detwiler, J.D. P u r c e l l , and R Tousey "The Extreme U l t r a v i o l e t Spec- trum of the Sun " M̂ m. de l a Soc Roy des Scienc e s de Lifege, Tome IV, 1961, 253 C.R. Detwiler, D.L. G a r r e t t , J.D. P u r c e l l , and R Tousey "The I n t e n s i t y D i s t r i b u t i o n i n the U l t r a v i o l e t S o l a r Spectrum " Ann de Geophys , Tome 17, July-Sept 1961, 9. H.W. Cooper, I . S . Gulledge, M.J. Koomen, and D.M. Packer " A l t i t u d e D i s t r i b u t i o n of Night Airglow Emissions by Rocket-borne Photometers." J Geophys Res , 65, 1960, 2484 R Tousey "The Sol a r Spectrum i n Space " ( S o l a r R a d i a t i o n i n Space), A s t r o n a u t i c s , 32, J u l y 1961 R Tousey " U l t r a v i o l e t Studies from Rockets " Georgetown Observ Mono- graph No 14, 45, published by Georgetown U n i v e r s i t y , 1960 R Tousey "Discovery of the U l t r a v i o l e t Spectrum of the Sun " Naval Res Rev P-510, 16, November 1960 R. Tousey " S o l a r Research from Rockets " Science, 134, no 3477, August 1961, 441 432

ROCKETRY P r o j e c t 10 3 - Naval Research Laboratory DAN Program - S o l a r F l a r e s 1 Ob.iectives T h i s p r o j e c t of the Naval Research Laboratory was a c o n t i n u a t i o n of the i n v e s t i g a t i o n that was begun i n a pre-IGY t e s t of r e l a t i o n s h i p s between Lyman-a and X - r a d i a t i o n during s o l a r f l a r e s Rockets were to be held m r e a d i n e s s to be f i r e d upon n o t i c e of a s o l a r f l a r e 2 Operations I n the pre-IGY t e s t , conducted with balloon-launched r o c k e t s (rockoons) from shipboard about 300 miles S.W. from San Diego, rockoons were launched each day, the rocket to be f i r e d upon n o t i c e of a f l a r e I n the event a f l a r e did not occur, the rocket was f i r e d by sunset. The period was one of r e l a t i v e l y low s o l a r a c t i v i t y but through a s e r i e s of fortunate circumstances, n o t i c e was r e c e i v e d on board ship of the occurrence of a f l a r e s l i g h t l y smaller than C l a s s I The rocket reached i t s peak some 10 minutes a f t e r the i n i t i a l d e t e c t i o n of the f l a r e and so missed the " f l a s h " phase The maximum Lyman-alpha was not s i g n i f i c a n t l y d i f f e r e n t from i t s value on the preceding day but the X-ray f l u x , of 10*-^ erg/sec cm^, over a range of wavelengths down to 3A, was s u f f i c i e n t to have doubled, approximately, the normal e l e c t r o n d e n s i t y of the D-region between 75 and 95 km T h i s was the f i r s t d e t e c t i o n of s o l a r X r a d i a - t i o n at such short wavelength and at such a low l e v e l of the ionosphere The t e s t period, thus, led to the program covered by t h i s p r o j e c t Two-stage s o l i d f u e l rockets (Nike-Deacon combination, c a l l e d DAN's) had become r e l i a b l e enough, however, to permit a simpler experimental procedure These r o c k e t s could a t t a i n the a l t i t u d e d e s i r e d , they could be instrumented i n advance and held ready to f i r e , await- ing n o tice of a f l a r e , and not be wasted i n the event no f l a r e occurred The launch- ings were c a r r i e d out at the Pt Mugu/San Nicholas I s l a n d Navy F a c i l i t y , C a l i f o r n i a Twenty rockets were launched i n 1957/58 The f e a s i b i l i t y of command f i r i n g was proved Two rockets were launched during one f l a r e w i t h i n twelve minutes of each other proving the p o s s i b i l i t y of extending coverage of a s o l a r event T h i s question had e s p e c i a l s i g n i f i c a n c e for planning the rocket e c l i p s e expedition (see p r o j e c t 10 21) 3 Personnel The p r o j e c t d i r e c t o r was Herbert Friedman, T.A. Chubb, J.E. Kupperian, J r , and J.C. Lindsay were a s s o c i a t e d with Dr Friedman 4 R e s u l t s The IGY f i r i n g s s u b s t a n t i a t e d the pre-IGY t e s t C l a s s I I and I I I f l a r e s were observed and m n e i t h e r i n s t a n c e was Lyman-a enhanced over p r e - f l a r e v a l u e s , while X r a d i a t i o n was detected at l e v e l s down to 63-77 km X-ray f l u x e s were at l e a s t 4 X 10'^ e r g s / s e c cm^ at 63 5 km (1 2 x 10'^ at 70 km) for the C l a s s I I I f l a r e and 2 X 10' at 77 km for the C l a s s I I f l a r e , s u f f i c i e n t to have caused the ionospheric e f f e c t s observed There are reasonable s o l a r mechanisms to account for the genera- t i o n of X rays down to at l e a s t 1 4A Moreover, evidence from SPA (sudden phase anomaly), an e f f e c t stemming from a sudden lowering of the lower boundary of the D- region, supports the hypothesis that X r a d i a t i o n , not Lyman-a, i s the p r i n c i p l e agent r e s p o n s i b l e for D-region solar-ionosphere e f f e c t s The SPA data i n d i c a t e that D-region lowering i s often about 16 km, i r r e s p e c t i v e of the magnitude of the f l a r e T h i s d i s - tance i s the d i f f e r e n c e i n p e n e t r a t i o n i n the atmosphere between Lyman-a and lA X rays However, i t must be pointed out that these observations have not s e t t l e d the question of the enhancement of Lyman-a i n the f l a r e " f l a s h " phase, as i n no case was the rocket i n an observing s i t u a t i o n at f l a r e onset On the other hand, i n order for Lyman-a to produce a 16 km lowering of the D-region, a f l a r e i n t e n s i f i c a t i o n of about 10^ over normal value i s c a l l e d f or, an u n l i k e l y s i t u a t i o n from the a s t r o p h y s i c a l view- point 433

ROCKETRY Bibliography a Papers Presented at Meetings. H. Friedman, T.A. Chubb, J.E. Kupperian, J r , J.C. Lindsay "X-Ray and U l t r a v i o l e t Emission of S o l a r F l a r e s " Vth General Assembly, CSAGI, August 1958, Moscow (pub i n IGY World Data Center-A - Rocket Report S e r i e s No. 1, J u l y 1958, pp 179-82, Nat. Acad S c i e n c e s , Washington) H Friedman, T.A. Chubb, J.E. Kupperian, J r . , J.C. Lindsay "X-Ray Emission of S o l a r F l a r e s . " ( i b i d , pp 182-85) J.E. Kupperian, J r , H Friedman "Gamma Ray I n t e n s i t i e s at High A l t i t u d e s " ( i b i d , pp 201-2) b. Published Papers Herbert Friedman "Rocket Astronomy " JGR v o l 64, no 1751, 1959 Herbert Friedman "Rocket Astronomy " S c i Am , v o l 200, no 6, 1959, pp 52-59 Herbert Friedman "IGY S o l a r F l a r e Program and I o n i z i n g R a d i a t i o n i n the Night Sky " ARS J , v o l . 29, 1959, p 103 "Push-Button Rocketry " A s t r o n a u t i c s , v o l 3, 1958, p 44. H Friedman, T A Chubb, J.E. Kupperian, J r , R.W. K r e p l i n and J.C. L i n d s a y "X-Ray and U l t r a v i o l e t Emission of Sol a r F l a r e s (IGY P r o j e c t 10 3) " Annal de Geophysique, v o l 14, 1958, p. 232 T.A. Chubb, H Friedman, R.W. K r e p l i n and J.E. Kupperian, J r • "Lyman-Alpha and X-Ray Emissions During a Small S o l a r F l a r e " JGR, v o l 62, 1957, p 389 T.A. Chubb, H Friedman, R.A. K r e p l i n , and J.E. Kupperian, J r "Rocket Observation of X-Ray Emission i n a S o l a r F l a r e " Nature, v o l 180, 1957, p 500 Herbert Friedman " P h o t o e l e c t r i c Measurements of S o l a r X-Rays and U l t r a - v i o l e t R a d i a t i o n . " Neuvi^me Rapport de l a Commission pour I ' l t u d e des R e l a t i o n s Entre l e s Phenomenes S o l a i r e s et T e r r e s t r e s , C o n s e i l I n t e r n a t i o n a l des Unions S c i e n t i f i q u e s , p 41, P a n s , 1957 R.W. K r e p l i n " S o l a r X-Rays." lAGA Aeronomy Symp , Copenhagen, J u l y 1960 (pub. i n Ann de Geophys , v o l 17, no 2, 1961, pp 151-161) H Friedman "Lyman-Alpha R a d i a t i o n " lAGA Aeronomy Symp , Copenhagen, J u l y 1960 (pub i n Ann de Geophys , v o l 17, no 2, 1961, pp 245-248) 434

ROCKETRY Project 10 4 - Geophysics Research Di r e c t o r a t e Aerobee Program - Holloman 1 Obiectives This p r o j e c t , supported by the Geophysics Research D i r e c t o r a t e , A i r Force Cambridge Research Laboratories, provided f o r several launchings at the H o l l o - man, New Mexico, f a c i l i t y . The U n i v e r s i t i e s of Colorado and Utah cooperated m solar u l t r a v i o l e t and ionospheric i n v e s t i g a t i o n s , r e s p e c t i v e l y 2. Operations GRD s c i e n t i s t s f i r e d one rocket (AA1.25), equipped w i t h a spectro- graph f o r the study of atmospheric composition. U n i v e r s i t y of Colorado s c i e n t i s t s instrumented a rocket (AC4 24) w i t h a b i a x i a l p o i n t i n g c o n t r o l to f i x on the sun, w i t h an u l t r a v i o l e t spectrograph The U n i v e r s i t y of Utah group instrumented two rockets (AU4 26 and AU4 27) to measure el e c t r o n density i n the D and E region, using pulsed signals from the rocket. 3 Personnel P.H. Wyckoff and R.M. Slavin were the p r o j e c t d i r e c t o r s , Adolph Jursa and James Ulwick of the Geophysics Research D i r e c t o r a t e , T V i o l e t t and W.H. Rense, Un i v e r s i t y of Colorado, and O.C. Haycock, U n i v e r s i t y of Utah, were associated w i t h t h i s work. 4 Results. a Atmospheric Composition. By means of seven absorption spectrograms, data were obtained that led to conclusions concerning the concentrations of n i t r i c oxide and molecular oxygen i n the region 60-87 km. Molecular oxygen concentration agreed e s s e n t i a l l y w i t h what would be expected assuming that atmospheric composition does not change w i t h height I t was determined that the upper l i m i t on n i t r i c oxide con- c e n t r a t i o n was 10 molecules/cm-' b U l t r a v i o l e t Solar Spectrum. Over t h i r t y - f i v e emission l i n e s were measured i n the range 1000-3000 Z The h a l f width of Lyman-a was found to be approximately 2A and that of H e l l (1640.5A) between 0.3 and 0.8A. A few new l i n e s were found m the 1600 A region. c. Ionospheric Electron Density. Electron density measurements were made to an a l t i t u d e of 200 km on AU4.27. A s i g n i f i c a n t d i f f e r e n c e was noted on these f l i g h t s when compared to previous Holloman launchings m that a spacing of 10 to 12 km of the s t r a t i f i c a t i o n i s evident w i t h l i t t l e tendency toward a f i n e r s t r u c t u r e . This f l i g h t was f i r e d at 0700 l o c a l time where previous launchings had been made closer to l o c a l noon. Data from f l i g h t number AU4.26 were too poor to analyze. 5. Bibliography. a. Papers Presented at Meetings. J. Ulwick: " S t r a t i f i c a t i o n of the Ionosphere." URSI, F a l l 1959, San Diego, C a l i f o r n i a . W. P f i s t e r : "Sporadic E I o n i z a t i o n . " AGARD, September 1958, Cambridge, England. b. Published Papers. W. P f i s t e r : "Sporadic E I o n i z a t i o n . " Agardograph 34, September 1958. 435

ROCKETRY W J E . Behring, H. M c A l l i s t e r , and W.A. Rense " U l t r a v i o l e t Lines i n the Solar Spectrum." Astrophysical Journal, v o l . 127, no. 3, May 1958. A. Jursa, Y. Tanaka, and F. Leblanc " N i t r i c Oxide and Molecular Oxygen i n the Earth's Upper Atmosphere." Planet. & Space Science, v o l . 1, 1959, pp. 161-172. Jursa, Nakamura, and Tanaka- "Molecular Oxygen D i s t r i b u t i o n i n the Upper Atmosphere." JGR, v o l . 68, no. 22, Nov 1963. 436

ROCKETRY Projects 10.5 and 10.19 - Naval Research Laboratory Aerobee Program - Fort C h u r c h i l l 1. Objectives. This p r o j e c t at the Naval Research Laboratory provided f o r twenty-one rockets to be f i r e d at Fort C h u r c h i l l , Canada, i n the northern a u r o r a l zone, f o r studies of atmospheric properties i n c l u d i n g s t r u c t u r e , composition, and i o n i c and e l e c t r o n con- ce n t r a t i o n s . Other experiments included measurement of the earth's magnetic f i e l d and solar i o n i z i n g r a d i a t i o n s . Experiments were planned to give comparisons w i t h s i m i l a r measurements at lower l a t i t u d e s and were scheduled to provide an opportunity to de- termine d i u r n a l and seasonal e f f e c t s . 2. Operations. Through p r o j e c t 10.19, a contract was arranged w i t h the Aerojet-Gen- e r a l Corporation f o r assistance i n handling, t e s t i n g , s e r v i c i n g and f i r i n g of each rocket at Fort C h u r c h i l l . The Aerobee rocket had been modified i n the pre-IGY period to increase i t s payload/altitude c a p a b i l i t i e s . A f t e r some discouraging t e s t s i n 1955-56, the problems were remedied and four t e s t f i r i n g s undertaken at the newly- established f a c i l i t i e s at Fort C h u r c h i l l , Canada. One rocket exploded i n the tower while being held f o r s u i t a b l e auroral a c t i v i t y , but the other three rockets performed s a t i s f a c t o r i l y . Two other Aerobees f a i l e d to a t t a i n a s u f f i c i e n t a l t i t u d e f o r the observations to be s i g n i f i c a n t but sixteen of the rockets performed s a t i s f a c t o r i l y , r e s u l t i n g i n the c o l l e c t i o n of a great amount of information. Near the close of the IGY, two newer rockets, Sparrobees, were launched, but they d i d not a t t a i n u s e f u l a l t i t u d e s . 3. Personnel. Homer E. Newell, J r . , and J.W. Townsend were the p r o j e c t d i r e c t o r s f o r t h i s work; the p r i n c i p a l s c i e n t i s t s associated w i t h them were H. Friedman, L.H. Meredith, H.E. LaGow, J.C. Seddon, C.G. Johnson, and J.E. Jackson. Others p a r t i c i - pating i n the p r i n c i p a l experiments were J.E. Ainsworth, R. Horowitz, E.B. Meadows, L.R. Davis, J.C. Holmes, O.E. Berg, J.E. Kupperian, J.P. Heppner, E.T. Byram, and J.A. Kane. 4. Results. These rocket f i r i n g s provided new information on the a r c t i c atmosphere. I t s density and temperature s t r u c t u r e , i t s composition, and e l e c t r i c a l c h a r a c t e r i s t i c s . Some completely unexpected features were discovered and some understanding of d i u r n a l and annual v a r i a t i o n s was gained. However, these data represent only a few points i n time and space and must not be considered representative of the upper atmosphere i n the a r c t i c . The program i n c l u d i n g f i r i n g s by other groups proved that c a r e f u l plan- ning can r e s u l t i n headway i n understanding the complexities of the upper atmosphere, but I t should be emphasized that only a s t a r t was made i n the IGY toward anything l i k e a "complete understanding" of the atmosphere. Some of the s i g n i f i c a n t f i n d i n g s of the NRL rocket program at Fort C h u r c h i l l are summarized: a. Atmospheric Pressures. Temperatures. Densities. At 200 km a l t i t u d e the a t - mosphere appears to be extremely v a r i a b l e , the summer daytime atmospheric density i s 6.6 X 10"' g/m^, which i s twice the w i n t e r daytime value. At t h i s same a l t i t u d e , the daytime density i s f i v e times the density at the same l e v e l above White Sands. The temperature of the thermosphere over C h u r c h i l l i n 1957-58 was much higher than over White Sands i n 1951. This a u r o r a l zone heating may be, i t i s i n f e r r e d , a consequence of energy t r a n s f e r from magnetically trapped charged p a r t i c l e s o f the Van A l l e n r a d i a - t i o n b e l t s , temporal v a r i a t i o n s i n solar r a d i a t i o n , or seasonal v a r i a t i o n s . I n the region from 30 km to 100 km a continuous density p r o f i l e of the atmos- phere was obtained on one f a l l daytime f l i g h t . I n the ozonosphere these density values were markedly lower than corresponding values f o r White Sands. b. Chemical Composition. I t was conclusively shown that d i f f u s i v e separation, based on measurement of argon, begins at about 110 km over C h u r c h i l l , above which l e v e l the r a t i o A/Nj decreased s t e a d i l y w i t h a l t i t u d e . I t i s i n f e r r e d t h a t the major 437

ROCKETRY atmospheric constituents above t h i s l e v e l may also be i n d i f f u s i v e e q u i l i b r i u m . I n the a l t i t u d e range of 70 to 100 km, a maximum di f f e r e n c e of 2 km was observed i n the O 2 atmosphere between two f l i g h t s m summer and winter. Molecular oxygen d e n s i t i e s between 70 and 86 km were lower i n e a r l y spring by a f a c t o r of 1.8 over density i n mid-summer. Di s s o c i a t i o n of O 2 appeared to begin near 86 km i n July and 96 km i n March. c. Ion Composition. N i t r i c oxide, although found to be a n e g l i g i b l e atmospheric co n s t i t u e n t , was, on the other hand, determined as the predominant p o s i t i v e i o n i n the E region of the ionosphere, atomic oxygen was found to be the predominant p o s i t i v e i on i n the F region. As the a l t i t u d e increases from 100 to 150 km, the order of r e l a t i v e abundance of p o s i t i v e 10ns during the daytime changes from ( O 2 + , NO"*") to (NCM-, 02"*", ,^+^ jjQ+^ 0,"*̂ . The only negative ion detected was NO,". 0^) to (0- d. Ionospheric Charge Density. The height p r o f i l e of e l e c t r o n density was ob- tained and proved to be s i m i l a r to that at White Sands. At n i g h t , less than 2 x 10^ electrons/cm-' were found up to 170 km and spread-F was observed above 190 km, where the atmosphere was found to be turbu l e n t and i r r e g u l a r . No v a l l e y m the daytime elec- t r o n density curves was found between the E and F regions. Electron c o l l i s i o n f r e - quencies i n the 60-80 km region were found to be a f a c t o r of three lower than previously believed. e. Auroral P a r t i c l e s and Magnetic Fields. Energetic electrons i n c i d e n t on the upper atmosphere were determined to be the primary source of au r o r a l luminosity and i o n i z a t i o n . Energetic 10ns were also found to be in c i d e n t on the upper atmosphere, both outside and w i t h i n v i s i b l e auroras. E l e c t r i c currents coincident w i t h v i s i b l e auroras were found at a l t i t u d e s of 95 to 120 km. 5. Bibliography. a. Papers Presented at Meetings. A great number of papers, too numerous to be l i s t e d here, were given by NRL s c i e n t i s t s at the X l t h General Assembly, lUGG, Toronto, September 1957, X l l t h Gen. Ass., lUGG, H e l s i n k i , August 1960, at various meetings of the URSI, AGU, APS, IAS; and at special meetings i n the U.S. and abroad. b. Published Papers. Many of the papers presented at meetings were published and are l i s t e d below. J.W. Townsend, J r . : "Atmospheric Structure Above Ft. C h u r c h i l l . " (Vth Gen. Ass., CSAGI, Moscow, July 1958), IGY Rocket Report No. 1. p. 11, Nat. Acad. Sci., Washington, 1958. H.E. LaGow, R. Horowitz, and J. Ainsworth: " A r c t i c Atmospheric Structure at 250 km." CSAGI Symp., Moscow, July 1958, IGY Rocket Report No. 1. p. 38, Nat. Acad. Sci., Washington, 1958. J.W. Townsend, J r . , C.Y. Johnson, J.C. Holmes, and E.B. Meadows: "Atmospheric Composition at A r c t i c High A l t i t u d e s . " CSAGI Symp., Moscow, July 1958, IGY Rocket Report No. 1, p. 131, Nat. Acad. Sci., Washington, 1958. J.C. Seddon and J.E. Jackson: "Rocket A r c t i c Ionospheric Measurements." CSAGI Symp., Moscow, July 1958, IGY Rocket Report No. 1. p. 140, Nat. Acad. Sci., Washington, 1958. 438

ROCKETRY L.H. Meredith, L.R. Davis, J.P. Heppner, and O.E. Berg: "Rocket Auroral I n v e s t i g a t i o n s . " CSAGI Symp., Moscow, July 1958, IGY Rocket Report No. 1. p. 169, Nat. Acad. Sci., Washington, 1958. E.T. Byram, T.A. Chubb, H. Friedman, and J.E. Kupperian, J r . : " I n t e n s i t y of Solar Lyman Alpha and Adjacent U l t r a v i o l e t Emission Lines." CSAGI Symp., Moscow, July 1958, IGY Rocket Report No. 1. p. 190, Nat. Acad. Sci., Washington, 1958. J.E. Kupperian, J r . , E.T. Byram, H. Friedman, and A. Unzicker: "Molecular Oxygen Densities i n the Mesosphere Over Ft. C h u r c h i l l . " CSAGI Symp., Moscow, July 1958, IGY Rocket Report No. 1. p. 203, Nat. Acad. Sci., Washington, 1958, and J. Atmos. Terr. Phys.. v o l . 16, October 1959, p. 174. J.W. Townsend, J r . , and E.B. Meadows- "Density of the Winter Nighttime A r c t i c Upper Atmosphere, 110 to 170 km." Ann. Geophys., v o l . 14, 1958, p. 117 and IGY Rocket Report No. 1. p. 14, Nat. Acad. S c i . , Washington, 1958. H.E. LaGow, R. Horowitz and J. Ainsworth: "Rocket Measurements of the A r c t i c Upper Atmosphere." Ann. Geophys.. v o l . 14, 1958, p. 131 and IGY Rocket Report No. 1, p. 26, Nat. Acad. Sci., Washington, 1958. E.B. Meadows and J.W. Townsend, J r . : " D i f f u s i v e Separation i n the Winter Nighttime A r c t i c Upper Atmosphere, 112 to 150 km." Ann. Geophys., v o l . 14, 1958, p. 80 and IGY Rocket Report No. 1. p. 107, Nat. Acad. Sci., Washing- ton, 1958. C.Y. Johnson, J.P. Heppner, J.C. Holmes, and E.B. Meadows: "Results Ob- tained w i t h Rocket-Borne Ion Spectrometers." Ann. Geophy^., v o l . 14, 1958, p. 475 and IGY Rocket Report No. 1. p. 123, Nat. Acad. Sci., Washington, 1958. J.C. Seddon and J.E. Jackson: "Ionosphere Electron Densities and D i f f e r - e n t i a l Absorption." Ann. Geophys.. v o l . 14, 1958, p. 456 and IGY Rocket Report No. 1. p. 149, Nat. Acad. Sci., Washington, 1958. C.Y. Johnson, E.B. Meadows, and J.C. Holmes* "Ion Composition of the A r c t i c Ionosphere." JGR, v o l . 63, 1958, p. 443 and IGY Rocket Report No. 1, p. 120, Nat. Acad. Sci., Washington, 1958. R. Horowitz and H.E. LaGow: "Summer-Day Auroral Zone Atmospheric Structure Measurements from 100 to 210 km." JGR. v o l . 63, 1958, p. 757, also, IGY Rocket Report No. 6. p. 1, Nat. Acad. S c i . , Washington, November 1960. J.A. Kane: " A r c t i c Measurements of Electron C o l l i s i o n Frequencies i n D-Region of the Ionosphere." JGR, v o l . 64, 1959, p. 133, also IGY Rocket Report No. 6, p. 127, Nat. Acad. Sci., Washington, November 1960. J.E. Jackson and J.A. Kane: "Measurement of Ionosphere Electron Densities Using an RF Probe Technique." JGR, v o l . 64, 1959, p. 1074, also IGY Rocket Report No. 6, p. 109, Nat. Acad. Sci., Washington, November 1960. R. Horowitz, H.E. LaGow, and J.E. G i u l i a n i - "Fall-Day Auroral-Zone Atmos- pheric Structure Measurements from 100 to 188 km." JGR, v o l . 64, 1959, p. 2287, also IGY Rocket Report No. 1, p. 19, Nat. Acad. Sci., Washington, November 1960. 439

ROCKETRY E.B. Meadows and J.W. Townsend: "IGY Rocket Measurements of A r c t i c Atmos- pheric Composition Above 100 km." F i n a l Report (COSPAR F i r s t I n t . Space Science Symp., Nice, January 1959), IGY Rocket Report No. 6. p. 87, Nat. Acad. Sci., Washington, November 1960. L.R. Davis, O.E. Berg, and L.H. Meredith: "Direct Measurements of P a r t i c l e Fluxes I n and Near Auroras." (COSPAR F i r s t I n t ' l . Space Science Symp., Nice, January 1960), IGY Rocket Report No. 6. p. 143, Nat. Acad. Sci., Washington, November 1960. H.E. LaGow, R. Horowitz and J. Amsworth: "Results of IGY Atmospheric Density Measurements Above Fort C h u r c h i l l . " COSPAR F i r s t I n t . Space Science Symp., Nice, January 1960; also IGY Rocket Report No. 6. p. 51, Nat. Acad. Sci., Washington, November 1960. C.Y. Johnson and J.C. Holmes: "Ionospheric P o s i t i v e Ions." COSPAR F i r s t I n t . Space Science Symp., Nice, January 1960, also IGY Rocket Report No. 6, p. 83, Nat. Acad. Sci., Washington, November 1960. J.W. Townsend, J r . : "Composition of the Upper Atmosphere." Second I n t . Conf. on Physics and Medicine of Atmosphere and Space, San Antonio, Nov. 1958, 0.0. Benson and H. Strughold, ed., Wiley, 1960, also IGY Rocket Report No. 6. p. 61, Nat. Acad. Sci., Washington, November 1960. J.A. Kane: "Re-evaluation of Ionospheric Electron Densities and C o l l i s i o n Frequencies Derived from Rocket Measurements of Refractive Index and Attenuation." Radiowave Absorption Symp., Athens, June 1960, also IGY Rocket Report No. 6. p. 135, Nat. Acad. Sci., Washington, November 1960. C.Y. Johnson: "Aeronomic Parameters from Mass Spectroscopy." lAGA Aeronomy Symp., Copenhagen, July 1960 (pub. m Ann, de Geophys., v o l . 17, no. 1, 1961, pp. 100-108). J.E. Ainsworth, D.E. Fox, and H.E. LaGow: "Upper Atmosphere Structure Measurement Made With the P i t o t - S t a t i c Tube." JGR, v o l . 66, 1961, pp. 3191-3212 (Also IGY Rocket Report No. 7. National Academy of Sciences, p. 1, Washington, D.C., A p r i l 1963). J.W. Townsend, J r . : "U.S. Pre-IGY Rocket Program - 1956." Annals of the I n t e r n a t i o n a l Geophysical Year, v o l . 6, 1958, pp. 103-107, Pergamon Press, London. John W. Townsend, J r . : "Rocket Exploration of the High Atmosphere f o r the IGY." Advances i n A s t r o n a u t i c a l Sciences, v o l . 4, Proceedings of the Vth Annual Meeting of the AAS, Nov. 1958, AAS P u b l i c a t i o n . 440

ROCKETRY Project 10.6 - Geophysics Research D i r e c t o r a t e Rocket Program - Fort C h u r c h i l l 1. Obiectives. This p r o j e c t at the Geophysics Research D i r e c t o r a t e , AFCRL, provided f o r p a r t i a l support of a>comprehensive program of atmospheric i n v e s t i g a t i o n s using Aerobee, Spaerobee, and Nike-Cajun rockets. S c i e n t i s t s from the Geophysics Research D i r e c t o r a t e , and the U n i v e r s i t i e s of Utah and Michigan p a r t i c i p a t e d . The objectives of the measurements included information on e l e c t r o n d e n s i t i e s i n the D, E, and F regions, measurement of pressure and density, and detection of micrometeorites. A measurement of airglow l i n e s was planned, but was deleted from the program because of instrumentation d i f f i c u l t i e s . 2. Operations. The Un i v e r s i t y of Utah group instrumented three Aerobee nosecones f o r e l e c t r o n density measurements. The f a b r i c a t i o n of s i x Cajun nosecones and two Aerobee nosecones w i t h alphatron gauges f o r pressure measurements was c a r r i e d out by the group at the U n i v e r s i t y o f Michigan under N.W. Spencer. This group also prepared two nosecones (one Nike-Cajun and one Spaerobee) f o r ionosphere measurements using a bi- p o l a r Langmuir probe. These l a t t e r experiments were under a j o i n t BRL-GRD program. Four Nike-Cajun rockets were instrumented by a second group at the Un i v e r s i t y of Michigan under L.M. Jones. This experiment used the f a l l i n g sphere technique f o r the measurement of density. GRD s c i e n t i s t s flew three Nike-Cajun rockets using the f a l - l i n g sphere experiment. Two of these three f l i g h t s also c a r r i e d the alphatron experi- ment f o r a comparison of techniques. Four Nike-Cajun and two Spaerobee rockets were flown by GRD s c i e n t i s t s f o r the det e c t i o n of micrometeorites. 3. Personnel. P.H. Wyckoff was the pr o j e c t d i r e c t o r f o r t h i s work; GRD s c i e n t i s t s associated w i t h him were R.M. Slavin, W. P f i s t e r , Murray Z e l i k o f f , J. Ulwick, R. Minz- ner. At the U n i v e r s i t y of Michigan, L.M. Jones and N.W. Spencer were d i r e c t o r s of two rocket groups; at U n i v e r s i t y of Utah, O.C. Haycock d i r e c t e d the work. 4. Results. As an example of the kind of r e s u l t s obtained, the micrometeorite ob- servations can be c i t e d . From one f l i g h t , ninety-nine acoustic signals were received, a l l of which were generated by p a r t i c l e s of momentum greater than 0.3 x 10"-̂ gm cm/sec; ten of the signals could have been generated by p a r t i c l e s o f momentum greater than 30 x 10"^ gm cm/sec. Another micrometeorite rocket was f i r e d during an occurrence of Es and a weak aurora. No c o r r e l a t i o n w i t h these phenomena i s evident from the data. One hundred t h i r t e e n signals were received, which could have been generated by par- t i c l e s of momentum greater than 0.3 x 10"^ gm cm/sec but no signals were received that could have been generated by p a r t i c l e s of momentum greater than 7.5 x 10"^ gm cm/sec. During a l a t e r f l i g h t , three signals were received t h a t could have been gen- erated by p a r t i c l e s of momentum greater than 120 x 10"^ gm cm/sec. Considering a l l the measurements, the rocket data corroborate information from s a t e l l i t e experiments. The r e s u l t s of the U n i v e r s i t y of Utah f i r i n g s , AU3.07, AU3.10 and AU3.il are described under p r o j e c t 10.17. Results o f the U n i v e r s i t y of Michigan f i r i n g s are described under p r o j e c t 10.20. 5. Bibliography. See pr o j e c t s 10.17 and 10.20. 441

ROCKETRY Project 10.7 - Signal Corps - Un i v e r s i t y of Michigan Aerobee Program - Fort C h u r c h i l l 1. Objectives. This j o i n t p r o j e c t of the Evans Signal Laboratory, U.S. Army Signal Research and Development Laboratory, and the Department of Aeronautical Engineering of the U n i v e r s i t y of Michigan was organized to undertake measurements of upper atmos- phere temperature and winds, using sound ranging techniques and explosive grenades ejected from rockets. 2. Operations. The Aerobee rocket instrumentation ( c o n s i s t i n g , f o r each nose cone, of about eighteen two- or four-pound grenades, timers, DOVAP and radar beacons, etc.) was prepared and handled at Ft. C h u r c h i l l by s c i e n t i s t s from the U n i v e r s i t y of M i c h i - gan. The sound ranging equipment and i n s t a l l a t i o n at Ft. C h u r c h i l l was c a r r i e d out by s c i e n t i s t s from the Signal Corps. On the ascent leg of the rocket f l i g h t , the grenades were ejected by small charges, i n a sequence determined by a pre-set timer. A lanyard was attached t o the f i r i n g p i n of each grenade, and thus the grenade was f i r e d at a f i x e d p o s i t i o n w i t h respect to the rocket. The rocket was tracked by DOVAP (Doppler v e l o c i t y and p o s i t i o n ) ; grenade detonation caused an e a s i l y recognizable a l t e r a t i o n i n the DOVAP signa l and thus gave the detonation time. The e r r o r i n l o c a t i o n of grenade bu r s t , a r i s i n g from the f a c t t h a t rocket aspect was not measured and sometimes the lanyard d i d not unwind completely before detonation, are thought to have been n e g l i g i b l e . Sound pulses from the grenades were received by an array of ground microphones. The times of a r r i v a l and angles of the sound waves enabled the average temperatures and winds to be computed. The series of explosions, then, allow the computation of temperatures and winds averaged through the layer between explosions. For each rocket f i r i n g , meteorological information was obtained from ground s t a - t i o n s and through the release of high-performance radiosonde balloons (provided f o r under p r o j e c t 10.16). 3. Personnel. This work was under the supervision of W.G. Stroud of the Signal Corps and F.L. Bartman of the U n i v e r s i t y of Michigan. W. Nordberg, W.R. Bandeen and P.A. Ti t u s were also associated w i t h the work. 4. Results. From the f i r i n g of ten Aerobee rockets during November 1956, July, August and December 1957, and January 1958, one hundred and f i f t y measurements of temperatures and winds were made. Each measurement represents the average temperature and wind of an atmospheric layer of about 3 km thickness. The r e s u l t s show a seasonal v a r i a t i o n : m summer the average temperature at the stratopause (about 50 km) was 275°K whil e i n w i n t e r i t was 260''K; at the mesopause (about 80 km) the average summer temperature was 170°K, while i n winter i t was 245°K (see Figure 2 ) . No appreciable d i u r n a l v a r i a t i o n was found. I n sunmier, temperatures at 50 km and below at C h u r c h i l l (59°N) were higher than at White Sands (33°N), above 65 km the C h u r c h i l l temperatures were lower. This p i c t u r e i s reversed i n w i n t e r . P r e v a i l i n g winds m the summer above 25 km were from the east and were usu a l l y less than 50 m/sec, but i n winter the winds were from the west, usually between 50 and 100 m/sec i n speed although they frequently exceeded 100 m/sec. The measurements i n d i c a t e t h a t the summer a r c t i c atmosphere i s very consistent from measurement to measurement between 50 and 90 km, i n contrast to a very a c t i v e dynamic and v a r i a b l e medium during December and January. A breakdown i n c i r c u l a t i o n up to 80 km i s indicated by the wind r e s u l t s of two f i r i n g s on January 27, 1958, when strong n o r t h e r l y and southerly wind components were measured. This phenomenon coincided 442

ROCKETRY w i t h the occurrence of sharp temperature increases at stratospheric l e v e l s over large parts of the Northern Hemisphere east o f C h u r c h i l l . Remarkable temperature inversions between 50 and 80 km were measured i n a l l winter f i r i n g s . These inversions r e s u l t e d m secondary temperature peaks above 50 km. On December 11, 1957, the temperature at 72 km was about 290''K. The winter v a r i a b i l i t y was demonstrated by the p a i r s of f i r i n g s i n December 1957 and January 1958. A maximum temperature peak of 290''K at 70 km on December 11 decayed to about 245°K on December 14. On January 27, 1958, a sudden warm- ing at 75 km was noted when observations from two f i r i n g s showed a temperature r i s e from 235°K at 75 km to 250°K at 80 km. This warming was, i n f a c t , p art of an "explo- sive warming," which had spread westward over northern Canada but had not reached Fort C h u r c h i l l by the day of the two rocket f i r i n g s , at least as i n f e r r e d from balloon ob- servations. The rocket observations showed th a t the warming at high atmospheric l e v e l s preceeded, at least i n t h i s case, the warming at lower le v e l s sounded by balloons. I t i s believed by the experimenters t h a t the rocket-grenade measurements show that large scale meteorological events are not l i m i t e d to the region of the atmosphere at present under s u r v e i l l a n c e by even high-performance balloons, and that the rocket gren- ade measurements would be a u s e f u l a d d i t i o n to the synoptic meteorological network, although f i r i n g s need be made only at a few s t r a t e g i c l o c a t i o n s , such as the e q u a t o r i a l and middle l a t i t u d e regions, and at several s i t e s near and inside the polar c i r c l e s . During these experiments i t was noted t h a t the a l t i t u d e c u t - o f f was about 95 km f o r r eceiving sound pulses from four-pound charges, w i t h microphones of approximately 1 dyne cm^ s e n s i t i v i t y m the frequence range 8-25 cycles. Furthermore, other ex p e r i - ments a t White Sands showed th a t much la r g e r charges detonated at higher l e v e l s d i d not produce detectable sound pulses at ground. a 50 \ N \'- WHITE SANDS BALLOON DATA AVERAGES - - ROCKET DATA } AVERAGES 1 1 r 1.. . 1 , 170 190 210 230 2S0 270 290 TEMPERATURE C K ) WHITE SANDS BALLOON DATA AVERAGES - R O C K E T DATA AVERAGES SUMMER 170 190 210 230 290 270 290 TEMPERATURE (*n WINTER Figure 2. Seasonal Averages of Temperature Data from Rocket Grenade Experi- ment a t Fort C h u r c h i l l , Canada. Some White Sands data are shown f o r compari- son. 443

ROCKETRY 5. Bibliography. a. Papers Presented at Meetings. W.G. Stroud, W.R. Bandeen, W. Nordberg, F.L. Bartman, J. Otterman, P. T i t u s : "Temperatures and Winds i n the A r c t i c as Obtained by the Grenade Experiment." Vth Gen. Ass. CSAGI, Moscow, 1958 (pub. i n IGY Rocket Report Series No. 1. Nat. Acad. Sci., Washington, D.C., July 1958, pp. 58-79.) W.G. Stroud, W. Nordberg, W.R. Bandeen, F.L. Bartman, P. T i t u s . "Rocket Grenade Measurements of Temperatures and Winds i n the Mesosphere Over Fort C h u r c h i l l , Canada." COSPAR F i r s t I n t ' l . Space Science Symp., Nice, Jan. 1960 (published i n Space Research. Proc. of Nice Symp., H. Kallman- B i j l , Ed., North Holland Press, 1960). b. Published Papers. W.R. Bandeen: "The Recording of Acoustic Waves from High-Altitude Explosions m the Rocket-Grenade Experiment and Certain Other Related Topics." USASRDL Tech. Rep. 2056, 1 July 1959. W.G. Stroud, W. Nordberg, W.R. Bandeen, F.L. Bartman, P. Tit u s - "Rocket- Grenade Observations of Atmospheric Heating m the A r c t i c . " JGR, v o l . 64, no. 9, 1959, pp. 1342-3, also i n IGY Rocket Report No. 6. p. 29-30, N.A.S., Washington, D.C., Nov. 1960. W.R. Bandeen, R.M. G r i f f i t h , W. Nordberg, W.G. Stroud: "The Measurement of Temperatures, Densities, Pressures and Winds Over Ft. C h u r c h i l l , Canada, by Means of the Rocket Grenade Experiment." USASRDL Tech. Rep. 2076, 2 Nov. 1959. W.G. Stroud, W. Nordberg, W.R. Bandeen, F.L. Bartman, P. T i t u s "Rocket- Grenade Measurements of Temperatures and Winds i n the Mesosphere Over F t . C h u r c h i l l , Canada." JGR, v o l . 65, no. 8, August 1960, pp. 2307-23, also i n IGY Rocket Report No. 6. N.A.S., Washington, D.C, Nov. 1960. H. Poetzschke: "Wind Determination from an Aerobee F i r i n g . " JGR, v o l . 65, no. 1, Jan. 1960, pp. 368-79, also i n IGY Rocket Report No. 6. N.A.S., Washington, D.C, Nov. 1960. 444

ROCKETRY Project 10.14 - B a l l i s t i c s Research Laboratories Nike-Cajun Program - Fort C h u r c h i l l 1. Obiectives. This p r o j e c t at the U.S. Army B a l l i s t i c s Research Laboratories pro- vided f o r seven rockets to be added to a comprehensive program planned at BRL f o r measurements of atmospheric parameters, i n c l u d i n g water vapor d i s t r i b u t i o n , e l e c t r i c currents and photometric properties of the earth's horizon as seen from high a l t i t u d e s . I n a d d i t i o n , BRL perfected a radio t r a c k i n g system f o r rockets, i n which a beacon i s placed on the rocket and an array of receivers i s located around the launching s i g h t . Analysis of the received s i g n a l gives the rocket t r a j e c t o r y and provides the opportun- i t y to c a l c u l a t e e l e c t r o n d e n s i t i e s i n the ionosphere. This system i s c a l l e d DOVAP (Doppler V e l o c i t y and P o s i t i o n ) . 2. Operations. Six of the rockets supported under t h i s p r o j e c t were launched at Fort C h u r c h i l l , Canada. One other was launched at White Sands as a t e s t . I n a d d i t i o n , s i x other BRL rockets were launched at Ft. C h u r c h i l l and two at White Sands. Nine large balloons intended as support f o r the rocket measurements were also launched at Aberdeen Proving Ground, White Sands and C h u r c h i l l as part of the BRL c o n t r i b u t i o n to the IGY upper atmosphere program. The highest f l i g h t reached 36.9 km a l t i t u d e . From the DOVAP records of rockets launched by BRL, as w e l l as by the other groups, e l e c t r o n d e n s i t i e s were derived f o r nineteen f l i g h t s , two of which were at White Sands, the r e - mainder at C h u r c h i l l . 3. Personnel. W.W. Berning was p r o j e c t d i r e c t o r f o r t h i s work, other p r i n c i p a l BRL s c i e n t i s t s associated w i t h the program were J.C. Mester, J.M. Conley, J. Leeder, R.E. Prenatt, E.J. Pybus and J.A. Brown. 4. Results. a. Water Vapor. While the one water vapor rocket experiment was not successful (the other f l i g h t s were postponed to IGC-59), balloon measurements showed th a t on sev- e r a l occasions i n the A r c t i c and at m i d - l a t i t u d e s , the mixing r a t i o increased above the minimum value found at the tropopause. I n one instance at Ft. C h u r c h i l l , the mix- ing r a t i o at 30 km was the same as at 3 km. b. Equivalent Electron Densities i n the Ionosphere. Two methods were used to ob- t a i n ionosphere p r o f i l e s as a by-product of DOVAP tra c k i n g data. The f i r s t method, the t r a j e c t o r y comparison technique, makes use of the small ionosphere induced e r r o r i n the DOVAP coordinates; the second method i s dependent on the faraday r o t a t i o n of the DOVAP s i g n a l . Measurement of t o t a l e l e c t r o n content i n a v e r t i c a l column to rocket a l t i t u d e was made and from t h i s e l e c t r o n density p r o f i l e s c alculated. Electron density p r o f i l e s f o r the nineteen rocket f l i g h t s to which the methods were applied are a v a i l a b l e i n BRL Report No. 1198. Selected p r o f i l e s are a v a i l a b l e i n the open l i t e r a t u r e . c. E l e c t r i c Currents i n the Lower Ionosphere. Proton precession magnetometers were used to obtain v e r t i c a l p r o f i l e s of the earth's magnetic f i e l d during both d i s - turbed and quiet conditions. The f l i g h t during a very quiet period permitted, a f t e r c o r r e c t i o n f o r h o r i z o n t a l motion of the rocket, the d e r i v a t i o n of an em p i r i c a l expres- sion g i v i n g the decrease of magnetic i n t e n s i t y as a f u n c t i o n of distance away from an o f f - c e n t e r dipole a x i s . The record taken during a magnetic storm i n d i c a t e d passage through a current sheet on the upward l e g , but not on the downward le g . From both f l i g h t s , a measure of the h o r i z o n t a l gradient of the f i e l d over Ft. C h u r c h i l l was obtained. d. Photometric Studies of the Earth's Horizon. Photographs from four rockets were recovered and assembled i n t o large composite photographs by the U.S. Weather Bureau, showing cloud s t r u c t u r e as observed from an a l t i t u d e of ICQ km. 445

ROCKETRY 5. Bibliography. a. Papers Presented at Meetings. J.A. Brown: "Review of Atmospheric Water Vapor Measurements." OOR Conference, Duke U n i v e r s i t y , A p r i l 1957. J.A. Brown: "BRL Dew Point Hygrometer." New York C i t y Branch of American Meteorological Society, February 1958. J.C. Mester: "The BRL-IGY Program." Maryland Branch of the American Rocket Society, March 1958. R.E. Prenatt: "The I n t e r n a t i o n a l Geophysical Year Program at the B a l l i s t i c Research Laboratories." National Telemetering Conference, Baltimore, Md., June 1958. W.W. Berning: "Electron Densities i n the Ionosphere from Radio Doppler Tracking of A r t i f i c i a l Earth S a t e l l i t e s . " and "IGY Upper A i r Research at the B a l l i s t i c Research Laboratories." Presented at Rocket and Sate l - l i t e Symposium, Vth Reunion of CSAGI, Moscow, August 1958. J.A. Brown: "High A l t i t u d e Water Vapor Measurements by Means of a Balloon-borne Dew Point Hygrometer." F i r s t National Conference on Stratosphere Meteorology, E l Paso, Texas, October 1958. W.W. Berning: "Rocket Ionospheric Research i n the IGY." Semi-Annual Meeting of the American Rocket Society, San Diego, Cal., June 8-11, 1959. J.A. Brown: " D i s t r i b u t i o n of Water Vapor i n the Stratosphere." and "Preliminary I n v e s t i g a t i o n of Recombination Rates at High A l t i t u d e Balloon Levels." Conference on Stratospheric Meteorology, Minneapolis, Minn., September 1959. J.A. Brown: "Stratospheric Water Vapor Measurement." Baltimore Branch American Meteorological Society, October 1959. W.W. Berning: "Some Preliminary Ionosphere Rocket Measurements at Fort C h u r c h i l l , Canada." URSI-IRE F a l l Meeting, San Diego, Cal., October 19-21, 1959. b. Published Papers. W.W. Berning: "Earth S a t e l l i t e Observations of the Ionosphere." Proc. of the IRE, v o l . 47, no. 2, February 1959, pp. 280-88. W.W. Berning: "Approach to the Ionosphere." Astronautics, v o l . 4, no. 7, July 1959, pp. 26-27. R.E. Prenatt: "Faraday Rotation Measurements at Fort C h u r c h i l l . " L e t t e r s to the E d i t o r , J ^ , v o l . 64, no. 9, Sept. 1959, pp. 1340-41. J.M. Conley: "Earth's Main Magnetic F i e l d t o 152 km above Fort C h u r c h i l l . " JGR, v o l . 65, no. 3, March 1960, pp. 1674-75. W.W. Berning: "IGY Upper A i r Research at the B a l l i s t i c Research Labora- t o r i e s . " Annals of the IGY. v o l . X I . 446

ROCKETRY J.C Mester: "Upper Atmospheric Research at the B a l l i s t i c Research Laboratories." Trans. IRE - M i l i t a r y E l e c t r o n i c s Vol. M 14, No. 2 and 3, A p r i l - J u l y 1960. BRL Reports S.T. Marks and E.J. Pybus: " F l i g h t Information and Experimental Results of Nike-Cajun Rocket OB6.02." BRL Memo Report No. 1190, Jan. 1959. S.T. Marks, F.H. Poughkeepsie, R.E. Prenatt, and E.J. Pybus: " F l i g h t Information and Experimental Results of Nike-Cajun Rocket OB6.00." BRL Memo Report No. 1200, March 1959. S.T. Marks and J.M. Conley: "Instrumentation, F l i g h t Summaries and Aspect Data of Nike-Cajun Rocket OB6.04, OB6.06 and 0B6.15." BRL Memo Report No. 1214, June 1959. H. Poetzschke: "Smoke T r a i l s of Aerobee SM 105 Grenade Bursts." BRL Tech. Note No. 1264, J u l y 1959. S.T. Marks: "Summary Report on BRL - IGY A c t i v i t i e s . " BRL Report No. 1104, A p r i l 1960. 447

ROCKETRY Project 10.16 - Meteorological Support, Ft. C h u r c h i l l 1. Objectives. This p r o j e c t , under the cognizance of the U.S. Army Signal Research and Development Laboratory, provided f o r the purchase of special high-performance balloons and radiosondes to be used i n conjunction w i t h launching of rocket-grenade experiments under p r o j e c t 10.7. 2. Operations. Before and a f t e r each Aerobee rocket-grenade experiment, meteoro- l o g i c a l data were secured to le v e l s of 10 mb i n support of the rocket observations. For discussion of the h i g h - a l t i t u d e rocket observations, see p r o j e c t 10.7. 448

ROCKETRY Project 10.17 - Rocket Ionospheric Data Reduction 1. Obiectives. This p r o j e c t at the Geophysics Research D i r e c t o r a t e , AFCRL, was a GRD supported c o n t r i b u t i o n to the IGY upper atmosphere program. Ionospheric data from polar rocket f i r i n g s were to be reduced and analyzed i n order to determine general c h a r a c t e r i s t i c s of the state of the polar ionosphere. 2. Operations. Three USAF rockets carrying a pulse delay propagation experiment were f i r e d at C h u r c h i l l , Canada during the IGY. The basic p r i n c i p l e of the experiment i s the measurement of the time r e t a r d a t i o n by the ionosphere of pulsed RF signals trans- m i t t e d from the rocket to the ground. The transmitted pulse was at 8.8 Mc i n order to be somewhat higher than the plasma frequency and was m time syncronization w i t h a pulse i n the telemetry band. The delay data were recorded at three ground s t a t i o n s , Ionosphere S t a t i o n (near launching s i t e ) , Twin Lakes S t a t i o n 15 km to the south, and Digges S t a t i o n 15 km to the southwest. From the a v a i l a b l e data the e l e c t r o n density as a f u n c t i o n of height was computed on a high speed computer u t l i z i n g a r a y - t r a c i n g technique which includes the earth's magnetic f i e l d e f f e c t s but under the assumption of h o r i z o n t a l s t r a t i f i c a t i o n . 3. Personnel. Wolfgang P f i s t e r was the p r i n c i p a l i n v e s t i g a t o r . 4. Results. a. USAF Aerobee 3.07 was launched on 3 July 1958 at 1252 hours. The peak a l t i - tude was 260 km, impact was 80 km from launqh and the azimuth was 157.5 degrees clock- wise from t r u e north. Data was recorded at the Ionosphere S t a t i o n up to 260 km, at the Twin Lakes S t a t i o n up to 250 km and at the Digges S t a t i o n up to 185 km. lonosonde records i n d i c a t e a spread F c o n d i t i o n was present during the f l i g h t . b. USAF Aerobee 3.10 was launched on 6 July 1958 at 1230 hours. The peak a l t i - tude was 244 km, impact was 64 km from launch and the azimuth was 133 degrees from tr u e north. (Radar beacon track was to approximately 225 km). Data recorded at the Ionosphere S t a t i o n were i n t e r m i t t e n t throughout the f l i g h t , at Digges S t a t i o n were recorded up to 145 km w i t h data missing i n the i n t e r v a l 100 to 112 km, and no data a v a i l a b l e from the Twin Lakes S t a t i o n . lonosonde records i n d i c a t e a strong absorption w i t h no E layer trace present during t h i s f l i g h t . c. USAF Aerobee 3.11 was launched on 11 July 1958 at 0602 hours. The peak a l t i t u d e was 250 km, impact was 97 km from launch and the azimuth was 29 degrees from t r u e north. (Skin track data were av a i l a b l e to 95 km). Data were recorded up to 220 km at the Ionosphere S t a t i o n , up to 250 km w i t h data missing i n the i n t e r v a l 125 to 160 km at the Twin Lakes S t a t i o n and no recording a t the Digges S t a t i o n . lonosonde records i n - dicate s t r a t i f i c a t i o n , sporadic E and spread F conditions. The e l e c t r o n d e n s i t i e s computed f o r the d i f f e r e n t recording s t a t i o n s f o r each f l i g h t generally are s i m i l a r i n character and b a s i c a l l y not d i f f e r e n t from the r e s u l t s of pulse delay experiments m middle l a t i t u d e s t a t i o n s . They a l l show on top of a more or less normal p r o f i l e a pronounced s t r a t i f i c a t i o n at regular height i n t e r v a l s . There i s s u b s t a n t i a l agreement i n the height o f the s t r a t i f i c a t i o n s recorded at the d i f f e r e n t s t a t i o n s at least up to an a l t i t u d e of 135 km. The distance of the maxima found was about 10 km and may be compared w i t h a value of 6 or 8 km observed at lower l a t i t u d e s . I n the F region a considerable f l u c t u a t i o n of apparent e l e c t r o n d e n s i t i e s was observed which could not be i n t e r p r e t e d as h o r i z o n t a l s t r a t i f i c a t i o n . 5. Bibliography. Paper presented at the f a l l meeting of URSI, San Diego, C a l i f o r n i a , 21 October 1959. Paper presented at Rocket Panel Meeting, Washington, D.C., November 1959. 449

ROCKETRY Project 10.18 - Rocket Measurements at Guam 1. Ob.iectives. This p r o j e c t a t the U.S. Army Signal Research and Development Labora- t o r y provided f o r a series of rocket-grenade experiments at Guam. The experiments were designed to obtain atmospheric temperatures and winds from 30 to 80 km a l t i t u d e . 2. Operations. The Nike-Cajun rockets c a r r i e d ten grenades, each of one- or two- pound charge. A single s t a t i o n DOVAP system was employed rather than the more e l a - borate systems used at Ft. C h u r c h i l l and White Sands, and a b a l l i s t i c camera was used to photograph the grenade f l a s h to aid i n f i x i n g the l o c a t i o n of the bursts. This system required cloudless skies i n the v i c i n i t y o f the rocket t r a j e c t o r y and n i g h t f i r i n g s . A microphone array on the ground received the sound pulses and two i n f r a r e d - s e n s i t i v e p h o t o - e l e c t r i c (pbS) detectors were used to obtain the time of grenade ex- plosi o n . 3. Personnel. W.G. Stroud was pr o j e c t d i r e c t o r ; also associated w i t h the work was W. Nordberg. 4. Results. Nine successful f i r i n g s (6 Nike-Cajuns and 3 s o l i d propelled Aerobees) were made during November 1958, w i t h the f i r i n g s d i s t r i b u t e d as w e l l as could be ac- complished, through the night hours. a. Temperatures. The temperatures measured at Guam (F i g . 3) o f f e r some very i n - t e r e s t i n g comparisons w i t h the temperatures obtained during the previous year at Fort C h u r c h i l l , Canada. The tenq)erature maximum i n the t r o p i c s occurs c o n s i s t e n t l y below 50 km, which i s at lower a l t i t u d e s than at C h u r c h i l l . This i s to be expected i f the temperature maximum i s caused by atmospheric absorption of solar u l t r a v i o l e t r a d i a t i o n which penetrates deeper at t r o p i c a l l a t i t u d e s . The Guam temperature p r o f i l e f o r No- vember g r e a t l y d i f f e r s from the temperatures obtained at C h u r c h i l l m wintertime. The rather steep temperature decrease from 50 to 70 km at Guam corresponds more to summer conditions at high l a t i t u d e s than to winter conditions. The average value of about 270°K f o r the temperature peak near 47 km i s somewhat less than the average summertime peak but greater than the average wintertime peak temperature at Fort C h u r c h i l l which occurs near or above 50 km. Above 60 km the r e s u l t s imply a very strong p o s i t i v e temperature gradient from the equator toward the pole i n w i n t e r , which may, at higher a l t i t u d e s , lead to a breakdown of the very strong westerly c i r c u l a t i o n found below 70 km during t h i s season. The Guam temperatures also agree w e l l w i t h the r e s u l t s obtained during both summer and winter at White Sands and w i t h the grenade experiment data from Woomera, A u s t r a l i a , reported by Groves f o r both November and A p r i l , 1957. Therefore, i t i s concluded t h a t , i n the average, temperatures up to 80 km do not vary g r e a t l y w i t h seasons at low l a t i t u d e s , that i s , w i t h i n a zone of i 35 degrees of the equator. Large day-to-day v a r i a t i o n s do occur, but they seem to be independent of season. The absence during the summer of very large temperature gradients that e x i s t i n w i n t e r between the poles and the equator i s i n agreement w i t h the observations t h a t c i r c u - l a t i o n at high l a t i t u d e s i s much weaker i n summer than i n w i n t e r . b. Winds. I t i s w e l l known that over the Northern Hemisphere, c i r c u l a t i o n i s from the west i n winter and from the east i n summer, w i t h sharp reversals during the t r a n s i t i o n s . The winter we s t e r l i e s increase w i t h increasing l a t i t u d e . The weak west- e r l y winds observed over Guam i n November f i t p e r f e c t l y i n t o t h i s p i c t u r e . Further- more, L.B. Smith observed predominantly east winds during July and August 1958 over Johnston I s l a n d which i n l a t i t u d e i s comparable to Guam. I t i s concluded, t h e r e f o r e , that the c i r c u l a t i o n p a t t e r n described above f o r the Northern Hemisphere holds tr u e even at very low l a t i t u d e s . Since Grove's data at Woomera show the same p a t t e r n f o r the Southern Hemisphere, there must be a very narrow zone of calm d i r e c t l y over the 450

ROCKETRY Altitude (Km) 100 GUAM Nov. I9S8 CHURCHILL Nov 56 a Winter'57-58 WHITE SANDS 1950-1953 CHURCHILL Summer 1957 160 180 200 220 240 260 280 300 320 Temperature (°K) Figure 3. Comparison of Rocket Grenade - Experiment Temperature Results 451

ROCKETRY equator. Smith's observations also support the conclusion that i n these regions there i s a gradual reversal i n wind d i r e c t i o n between 70-80 km. This reversal was not ob- served at higher l a t i t u d e s , possibly because i t occurs at higher a l t i t u d e s where the observations are l a c k i n g . c. General Remarks. Results from the rather modest number of soundings during the period 1950 to 1958 at Guam, White Sands, C h u r c h i l l , along w i t h those of other workers, suggest that the temperature s t r u c t u r e of the upper stratosphere and the mesosphere at low l a t i t u d e s i s p r i m a r i l y determined by absorption of solar r a d i a t i o n w i t h dynamic processes only responsible f o r large day-to-day v a r i a t i o n s . A s i m i l a r s i t u a t i o n holds f o r higher l a t i t u d e s i n summer, but here day-to-day v a r i a t i o n s are much smaller than at low l a t i t u d e s . At high l a t i t u d e s i n winter, however, ^arge scale dynamic processes occur which cannot be explained by d i r e c t absorption of solar energy. Here, dynamic processes p r i m a r i l y seem to be responsible f o r the temperature s t r u c t u r e i n the upper mesosphere. 5. Bibliography. W. Nordberg: "Upper Atmosphere Rocket Soundings on the Is l a n d of Guam." USASROL Tech. Rep. 2078, 2 Nov. 1959. W. Nordberg, W.G. Stroud: "Results of IGY Rocket-Grenade Experiments to Measure Temperatures and Winds Above the I s l a n d of Guam." JGR, v o l . 66, no. 2, Feb. 1961, pp. 455-64. 452

ROCKETRY Project 10.20 - Alphatron - Sphere Experiments 1. Objectives. This p r o j e c t at the Department of E l e c t r i c a l Engineering (alphatron) and Aeronautical and A s t r o n a u t i c a l Engineering (sphere), U n i v e r s i t y o f Michigan, was planned to secure information on the s t r u c t u r e of the atmosphere through two d i f f e r e n t approaches, a) The alphatron experiments u t i l i z e d r a d i o a c t i v e i o n i z a t i o n pressure gauges i n an array on the rocket; the pressure data along w i t h i nformation on rocket v e l o c i t y (from DOVAP) provided the means to compute ambient pressure, density and temperature up to about 100 km. b) The second set of experiments made use of a fr e e - f a l l sphere, which contained a t r a n s i t time accelerometer and telemeter t r a n s m i t t e r . The d e v i a t i o n o f acc e l e r a t i o n from f r e e - f a l l i s a measure o f drag and from t h a t , den- s i t i e s could be computed. These experiments are r e l a t e d to p r o j e c t 10.6, as consi- derable support f o r t h i s work was given by GRD/AFCRL. F i n a n c i a l assistance was also given by the National Science Foundation. 2. Operations. a. Alphatron Experiments. The use o f dynamic pressure measurements t o derive ambient pressures (and hence d e n s i t i e s and temperatures) involved the consideration of the aerodynamic pro p e r t i e s of a r i g h t c i r c u l a r cone (the rocket nose-cone) moving at small angles of at t a c k w i t h respect to the surrounding medium. As a consequence of the t h e o r e t i c a l understanding of t h i s matter, i t proved possible to instrument the rocket nose-cone, and other parts of the rocket, w i t h various pressure sensing devices to provide enough information to solve the dynamic equations and ob t a i n the ambient pressures. This method, l i k e other s i m i l a r methods, i s l i m i t e d t o tha t region o f the atmosphere where the mean free path of the atmospheric constituents i s s t i l l small compared w i t h dimensions of the various sensors, or to about 90 km a l t i t u d e . Cone-wall pressures were determined w i t h f i v e r a d i o a c t i v e - i o n i z a t i o n pressure gauges, an instrimient developed f o r and used extensively during the IGY program. The instrument consists of an io n chamber, i n which a current, developed by the constant r a d i a t i o n f i e l d , i s p r o p o r t i o n a l to the number of a i r molecules, the atmosphere, i n e f f e c t , being a v a r i a b l e r e s i s t o r . The current passes through a f i x e d r e s i s t o r o f high enough value (as large as 10^2 ohms) to provide the voltage required to modulate the telemeter c i r c u i t . I n order to match impedance between the high-value i n p u t r e - s i s t o r and the low-impedance telemeter c i r c u i t , a u n i t y gain D.C. electrometer ampli- f i e r I S used, along w i t h a servo-system to change input r e s i s t o r s to maintain the desired range of output signals. A t o t a l of 8 Nike-Cajuns and three Aerobees car r y i n g t h i s experiment w i t h varying degrees of complexity were launched at Fort C h u r c h i l l . Data were obtained i n nine o f the eleven attempts. b. Sphere Experiments. An e n t i r e l y d i f f e r e n t kind of approach i n determining atmospheric d e n s i t i e s i s the measurement of drag on a f a l l i n g sphere, a 8iiiq>le aero- dynamic shape th a t can be treated r e l i a b l y through the a p p l i c a t i o n of the drag equation. The sphere i s normally ejected from the rocket at about 80 km on the ascent, from where i t coasts to an apogee of i t s b a l l i s t i c o r b i t at an a l t i t u d e of about 170 km. A small bobbin i n s i d e a c a v i t y m the sphere i s centered by r e t r a c t a b l e f i n g e r s . When the bobbin i s released i t " f a l l s , " unaffected by the e x t e r n a l medium. The sphere i s decelerated w i t h respect to the bobbin through the a c t i o n of drag i n the e x t e r n a l medium. Thus the bobbin " f a l l s toward" the sphere. The elapsed time between moment of bobbin release and contact w i t h the sphere i s a measure of the sphere deceleration and i s telemetered to ground. Test spheres were composed o f two conducting hemispheres separated by an i n - s u l a t i n g e q u a t o r i a l s t r i p and served as a dipole antenna f o r the telemeter t r a n s m i t t e r . 453

ROCKETRY I t was found t h a t the r a d i a t i o n e f f i c i e n c y f o r t h i s arrangement was too low, f o r the l a t e r spheres, a boxed-in s l o t antenna, extending over h a l f the circumference of the sphere, was used. This arrangement had a higher r a d i a t i o n e f f i c i e n c y and was easier to construct and tune. The bobbin was recycled at one-second i n t e r v a l s throughout the descent and hence the average drag of t h i n layers of the atmosphere could be derived. From the drag equation the density i s obtained and from the equation of state of the atmosphere, pressures and temperatures are derived. Ten Nike-Cajun rockets were flown, four a t Fort C h u r c h i l l , 5 from the USS RUSHMORE at l a t i t u d e s ranging from 40°N to 65"'N, and one at Wallops I s l a n d . One Aerobee was flown at C h u r c h i l l . Only three f l i g h t s were unsuccessful. 3. Personnel. a. Alphatron. N.W. Spencer di r e c t e d the group concerned w i t h these f l i g h t s , other senior personnel associated w i t h the work were R.L. Boggess, D. Taeusch and L.H. Brace. b. Sphere. L.M. Jones d i r e c t e d the group responsible f o r t h i s experiment, other senior personnel associated w i t h the work were F.F. Fischbach, J.W. Peterson, E.J. Schaefer and H.F. Schulte. 4. Results. a. Alphatron. The alphatron experiment data reduction i s being completed at the time of w r i t i n g . P a r t i a l to complete density p r o f i l e s from nine launchings c a r r i e d out at various times of the year have been obtained which show a clear seasonal v a r i a - t i o n , increasing w i t h a l t i t u d e . At 90 km the summer de n s i t i e s exceed the winter den- s i t i e s by more than a f a c t o r of 2, while at 40 km the change i s less than 507,.. (See Figure 4 ) . Mesosphere temperatures derived from the data show large excursions from the v a r i a t i o n s normally expected (see Figure 5). A t e c h n i c a l paper r e p o r t i n g the data has been published and, i n a d d i t i o n , a tech n i c a l report i n c l u d i n g instrumentation d e t a i l s has been i n i t i a t e d . b. Sphere. Upper a i r d e n s i t i e s from the IGY f l i g h t s as w e l l as some e a r l i e r ones are shown i n F i g . 6, and wintertime temperatures a t F o r t C h u r c h i l l are shown i n Fig. 7 L i t t l e seasonal v a r i a t i o n at White Sands (32°N) and Wallops I s l a n d (38°N) was found, but there were large v a r i a t i o n s i n a few winter days at C h u r c h i l l (59°N). From a l a t i - tude survey, i t was found that there i s a l i n e a r l a t i t u d e density gradient of about 2 per cent per degree of l a t i t u d e , w i t h a low a r c t i c density at 60 km a l t i t u d e . How- ever, the v a r i a t i o n s i n density, at a single northern l a t i t u d e , as shown by the group of f l i g h t s at C h u r c h i l l , i n d i c a t e that such a l a t i t u d e density gradient as measured by the shipboard f l i g h t s might or might not occur at any given time, depending on the a r c t i c d e n s i t i e s . At C h u r c h i l l the winter d e n s i t i e s were generally lower than the ARDC standard atmosphere, while there was good general agreement between t h i s model and the observations at the lower l a t i t u d e s . The temperatures at C h u r c h i l l , as calculated from the d e n s i t i e s , i l l u s t r a t e the large increase on January 27-29, 1958, m the mesosphere, noted at other locations at balloon a l t i t u d e s . This has subsequently been found to be a wel l - e s t a b l i s h e d case of "explosive warming" and has been studied i n d e t a i l by meteorologists. 454

ROCKETRY I 0 - ' -9 10 I0 - ' i 1 © pf 1 iESSUI 1 )E 6M 1 £ EX 1 PERMI 1 • )ENSI1 Y A T ; lO KIL( 3METE »S • --' . - - 1 }ENSr 1 rv AT 1 30 K I L 1 OMETE RS 10-1 10-5 I 0 - * lo-z . )ENSI1 Y AT 0 K I L 3METE RS ; - ^ : • )ENSn Y A T 6 3 K I L ( )METE re ) E N S I Y AT SO K I L ) M E T E R S i )ENSr •Y AT <• 10 K I L ) M E T E R S • )ENSr Y AT } 0 K I L OMETl RS \ : AM 6 36 In <̂ Z 4 AM 63 8 A M 63 9 1 s 4 A A 6. I6 1 9 5 8 1 9 5 7 • 8 JAN N FEB CM MAR APRIL MAY C/ JUNE XLENDi C JULY \ R DAI AUG F E SEPT OCT lO N NOV DEC 1 9 5 6 " Figure 4. Upper a i r density from alphatron experiments 455

•p- 0^ CHURCHILL IGY, AM 4 12 ONLY " E Y E B A L L " A V E R A G E , CHURCHILL DATA UJ 70 WHITE SANDS CIRA R E F E R E N C E 1961 UJ 60 B AM2 2110/23/56 0240 C ST X AM 412 10/14/58 1904 C S T ©AM 616 11/23/58 1602 C S T CHURCHILL, CANADA < 50 AEROBEE 31 10/22/52 0721 MST WHITE SANDS —EYEBALL 'AVERAGE — C I R A R E F E R E N C E BALLOON 10/23/56 BALLOON 10/22/52 5 220 240 260 280 TEMPERATURE ° KELVIN 300 320 Figure 5. Upper a i r temperatures from alphatron experiments

ROCKETRY • ROCKET DOWNLCO + BALLOONS-AT UUNCHED X eAUjOCNS-NEARBY STATIONS AROC l9Se MODEL ATMOS H T T T K 4N0V M e ISS4 ZST S7e'N.4a7«w HIT Z4T Bse'N.sejO'w 4 FT SPHERE II DEC I9S2 « P 6 ' M 4 « N A.M &09 7 m. SPHERE Z NOV 1996 IS40ZST 490*N.4a4>W| S C - Z 9 ' ° AMBIENT OCNSITY KILOGRAMS/n METER Figure 6. Upper a i r density, four wintertime f l i g h t s a t various l a t i t u d e s . AM 6.02 29 JAN 98 ISIZ CST S M Z i O 27 JAN 98 1248 CST AH 6 09 29 JAN 98 I 906CST AM 6 0 9 4 MAR 96 1330 CST BALLOON POINTS UNSHADED ARDC 1996 MODEL ATMOS ROCKET VALUES AVERAGED OVER ~ 9 KM INTERVALS "70 180 190 200 210 220 230 240~l2S6 260 270 280 290 300 JIO AMBIENT TEMPERATURE DEGREES K Figure 7. Upper a i r temperature, four wintertime f l i g h t s a t Fort C h u r c h i l l , Canada, 58.7° N. 457

ROCKETRY Bibliography. a. Papers Presented at Meetings. L.M. Jones, F.F. Fishbach, J. W. Peterson: "Seasonal and La t i t u d e V a r i a t i o n s i n Upper-Air Density." Vth Gen. Ass. CSAGI, Moscow, August 1958 (pub. i n IGY Rocket Report No. 1. p. 47, N.A.S., Washington, D.C, July 1958). N.W. Spencer, R.L. Boggess: "A Radioactive-Ionization-Gage-Pressure- Measurement System." Vth Gen. Ass. CSAGI, Moscow, August 1958. N.W. Spencer, R.L. Boggess, D. Taeusch: "Pressure Temperature and Density at 90 km over F t . C h u r c h i l l . " Vth Gen. Ass. CSAGI, Moscow, August 1958 (pub. i n IGY Rocket Report No. 1, p. 80, N.A.S., Washington 25, D.C, Jul y 1958). b. Published Papers. L.M. Jones, J.W. Peterson, E.J. Schaefer, H.F. Schulte: "Upper-Air Density and Temperature: Some Var i a t i o n s and an Abrupt Warming i n the Mesosphere." JGR, v o l . 64, no. 12, December 1959, pp. 2331-40. L.M. Jones, J.W. Peterson, E.J. Schaefer, H.F. Schulte: "Upper-Air Densities and Temperatures from Eight IGY Rocket F l i g h t s by the F a l l i n g Sphere Method." IGY Rocket Report No. 6. N.A.S., Washington 25, D.C, December 1959. L.M. Jones and J.W. Peterson: "1961 Review, Upper A i r Densities and Teiiq)eratures Measured by the F a l l i n g Sphere Method." Univ. of Michigan, O.R.A. Report No. 03558-5-T, 1961. N.W. Spencer, R.L. Boggess and D.R. Taeusch: "Seasonal V a r i a t i o n of Density and Temperature over C h u r c h i l l , Canada, During Solar Maximum." JGR. v o l . 69, no. 7, A p r i l 1, 1964. N.W. Spencer and R.L. Boggess: "A Radioactive I o n i z a t i o n Gage Pressure Measurement System." J. Am. Rocket Soc. v o l . 29, January 1959. 458

ROCKETRY P r o j e c t 10.21 - Naval Research Laboratory P a c i f i c S o l a r E c l i p s e E x p e d i t i o n 1. O b i e c t l v e s . T h i s p r o j e c t a t the Naval Research Laboratory was planned to obt a i n information on s o l a r X r a y s and u l t r a v i o l e t during v a r i o u s phases of a t o t a l e c l i p s e , using 2-stage s o l i d f u e l r o c k e t s . The o b j e c t i v e was to a s c e r t a i n the l o c a t i o n on the sun of the X-ray and u l t r a v i o l e t sources. 2. Operations. The t o t a l s o l a r e c l i p s e of October 12, 1958, was observable from a few l o c a t i o n s i n the south c e n t r a l P a c i f i c Ocean. A group of o b s e r v a t o r i e s cooperated i n planning an exp e d i t i o n f or conventional o p t i c a l and r a d i o observations of the e c l i p s e . The NRL experiment--the short-time-sequence f i r i n g of r o c k e t s , standing-by i n readiness--was added to the exp e d i t i o n plans a f t e r the s o l a r f l a r e observations ( p r o j e c t 10.3) were proven to be o p e r a t i o n a l l y f e a s i b l e . From c o n s i d e r a t i o n s of d i s - tance from l i n e of t o t a l i t y , time of t o t a l i t y , expected meteorological c o n d i t i o n s , and l o g i s t i c s , the i s l a n d of Puka-Puka was chosen f or the s i t e of the o p t i c a l obser- v a t i o n s . The rocket experiment was planned f or shipboard operation. The cooperation o f the Navy was obtained and the r o c k e t s were placed on f i r i n g stands on the deck of the USS POINT DEFIANCE. S i x r o c k e t s were to be launched as the e c l i p s e progressed. They were equipped w i t h d e t e c t o r s to measure X ra y s i n the wavelength regions 8-18A and 44-60A as w e l l as Lyman-alpha, 1216A. On the day of the e c l i p s e , information on the l o c a t i o n of a c t i v e regions was obtained from s o l a r o b s e r v a t o r i e s i n the United S t a t e s and the times of launching planned so as to study these regions as they were o c c u l t e d by the moon. Since the rocket measurements were to be made at high a l t i t u d e s , i t was neces- sary to shoot from outside the ground shadow. The t o t a l i t y r o c k e t s , f or example, entered the e c l i p s e shadow zone at about the a l t i t u d e of 200 km. On e c l i p s e day the sky was ov e r c a s t and there were r a i n s q u a l l s . Some c l e a r i n g d i d occur, but the conventional ground o p t i c a l o bservations of the other groups were clouded out. The rocket program went approximately as planned, however, w i t h the exception that some mechanical problems delayed the f i r i n g of one rocket and only f i v e were launched during the e c l i p s e . The s i x t h rocket was launched the folloxd.ng day for background measurements. 3. Personnel. T h i s experiment was supervised and c a r r i e d out by Herbert Friedman w i t h the a s s i s t a n c e of T.A. Chubb, John C. Li n d s a y and Robert W. K r e p l i n . 4. R e s u l t s . Examination of the telemetering records showed that the f i v e r o c k e t s f i r e d on the day of the e c l i p s e reached peak a l t i t u d e s of 139, 148, 152, 150, and 55 mi. The Lyman-alpha r a d i a t i o n appeared to follow the unec l i p s e d area of the d i s k very c l o s e l y and almost disappeared w i t h i n a few seconds a f t e r the r o c k e t s entered t o t a l i t y . I n strong c o n t r a s t , a r e s i d u a l f l u x o f 50A X r a y s p e r s i s t e d throughout t o- t a l i t y . Measurements before second and a f t e r t h i r d c o n t a c t s showed enhanced X ray emission a s s o c i a t e d w i t h plages. The X ray emission s t r o n g l y resembled the kind of i n t e n s i t y d i s t r i b u t i o n observed i n r a d i o decimeter wave measurements. a. T o t a l i t y Launchings. I n the t o t a l i t y launchings, an attempt was made to scan the region about the sun i n Lyman-alpha l i g h t w i t h an angular r e s o l u t i o n of about 3° of a r c . Unfortunately, the two t o t a l i t y r o c k e t s were v e r y s t a b l e and n e i t h e r de- veloped enough yaw to scan c l o s e r than 7° to the sun. At that d i s t a n c e , no Lyman- alpha s i g n a l g r e a t e r than geocoronal r a d i a t i o n was evident w i t h c e r t a i n t y i n the record. A small f l u x of s o l a r Lyman-alpha was observed on the wide angle d e t e c t o r throughout t o t a l i t y , p o s s i b l y of prominence o r i g i n . The aspect i n d i c a t o r s used i n the t o t a l i t y launchings were p h o t o m u l t l p l i e r tubes which viewed the sky through gunsight-type r e t i c l e s . The p h o t o m u l t i p l i e r s . 459

ROCKETRY which were s e t to r e c e i v e a f l u x equal to h a l f of that of f u l l moon i n the v i s i b l e spectrum, were h e a v i l y over-exposed. I t appeared that the airglow i n the t o t a l i t y cone remained very high and was r e s p o n s i b l e for s a t u r a t i n g the p h o t o m u l t i p l i e r r e - sponse. Accurate a l t i t u d e data was nonetheless obtained. b. F l a r e Data. Unexpected data were r e c e i v e d when the l a s t rocket was f i r e d , at 0839:58 on October 13. Although the shipboard group d i d not know i t at the time, a c l a s s 2+ f l a r e was i n progress. The rocket reached peak a l t i t u d e during the f l a r e s h o r t l y a f t e r a maximum of sudden cosmic noise absorption was recorded on the i s l a n d by Robert Lee, of the HAO group. The rocket performed e x c e p t i o n a l l y w e l l and good data were r e c e i v e d on X-ray f l u x e s m the 8-18 A and 44-60 A bands as w e l l as on Lyman-alpha. The l a t t e r showed no s i g n i f i c a n t v a r i a t i o n , but the X-ray f l u x e s were st r o n g l y enhanced. 5. Bibliography. a. Papers Presented at Meetings. Herbert Friedman: "Rocket Astronomy." Meeting of the American A s t r o - n a u t i c a l S o c i e t y , Washington, D.C., December 1958. (Published i n Advances i n A s t r o n a u t i c a l S c i e n c e s , v o l . 4, 1959, p. 388, Plenum P r e s s , I n c . , N.Y. T.A. Chubb, H. Friedman, R.W. K r e p l i n , R.L. Blake and A.E. Unzicker: " I . X-ray and U l t r a v i o l e t Measurements During the E c l i p s e of October 12, 1958, I I . X-ray S o l a r D i s k Photograph." Xth I n t e r n a t i o n a l A s t r o p h y s i c a l Symposium, L i ^ g e , 1960. (To be published simultaneously m Memoir^s de l a S o c i e t ^ Royale des S c i e n c e s de Lifege and as Proceedings of the Symposium. R.W. K r e p l i n : " S o l a r X r a y s . " Symposium on Aeronomy, Copenhagen, J u l y 1960. b. Published Papers. H. Friedman: "Rocket Astronomy at the T o t a l E c l i p s e of October 12, 1958." Rept. of NRL Progress, January 1959, p. 1. H. Friedman: " I n s t a n t Rocketry." A s t r o n a u t i c s . January 1959, p. 28. H. Friedman: "Rocket Observations of the Ionosphere." Proc. of IRE, v o l . 47, no. 2, February 1959, p. 272. H. Friedman: "Rocket Astronomy." JGR, v o l . 64, 1959, p. 1751. c. Documentary F i l m s . " S o l a r E c l i p s e E x p e d i t i o n to Danger I s l a n d (Pukapuka)." 16 mm, c o l o r , sound, narrated, 20 mins, p i c t u r e s and animation (NRL). 460