A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs (2006) / Chapter Skim
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4 Rocket Propulsion Systems for Access to Space
4 Rocket Propulsion Systems for Access to Space
Pages 108-170
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From page 108... ...
"Mission success" is the most effective selection criterion in a total systems engineering process to establish an overall architecture and all the elements of a system. It can be defined as achieving the functional result we want, when we want it, for the price we committed to, and within the risk level profile we accepted for the 1For responsive spacelift, the Air Force Space Command's Strategic Master Plan FY06 and Beyond defines transformational capabilities as focused on rapid response, affordability, and payload capacity for warfighter operations (AFSPC, 2003)
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From page 109... ...
Therefore, the AFSPC's Strategic Master Plan FY06 and Beyond (hereinafter referred to for convenience as SMP FY06) to sustain and modernize current satellite and launch operations into the far term will be implemented primarily using the Atlas V and Delta IV vehicles along with several smaller and medium-lift vehicles that are used by the Air Force but not shown in Figure 4-1.
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From page 110... ...
Focusing Air Force resources on identifying the gaps in the critical design criteria for total systems-defined rocket propulsion elements will be crucial to success of the AFSPC Strategic Master Plan FY06 and Beyond.2 Recommendation 4-1. The Air Force should place a high priority on developing an integrated totalsystem engineering process using quantitative life-cycle mission success as the selection criterion for near-term, highly leveraged engineering technology funded by the Air Force.
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From page 111... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 111 defining justifiable total system architectures, rocket propulsion systems requirements, and critical technologies for military space transportation to support the Air Force Space Command's Strategic Master Plan FY06 and Beyond. CURRENT CAPABILITIES OF LARGE LAUNCH VEHICLES Delta IV Family of Vehicles As shown in Figure 4-2, the Delta IV family of two-stage launch vehicles utilizes a common 5-mdiameter first stage powered by a single rocket engine (RS-68)
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From page 112... ...
The RS-68 was ultimately selected to power the Delta family of EELVs developed for the Air Force by the Boeing Space Systems Company. The RS-68 is the largest LOx/LH2 engine in the world today.
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From page 113... ...
(ATK) originally developed the GEM strap-on solid rocket booster for the Delta II launch vehicle for the Air Force and Boeing.
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From page 114... ...
114 A REVIEW OF AEROSPACE PROPULSION NEEDS New solid booster technologies under the Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program and, possibly, liquid propellant booster concepts that may be developed for a new Air Force responsive spacelift vehicle might be studied for this application.
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From page 115... ...
Because the second-stage engine for both EELVs comes from a single supplier, Pratt & Whitney, the Air Force is totally dependent on this single contractor and engine for all large payload launches. Should a failure occur that involves the second-stage engine, all launches with these systems would probably be frozen until the root cause is identified and corrected, which could take a year or more.
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From page 116... ...
All of these options offer more thrust than the RL-10 engine, which needs additional capability if heavier payloads are to be placed into higher orbits. New engine design options that appear to be most suitable for the Air Force and DoD missions are compared with the existing RL10A-4 in Figure 4-4.
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From page 117... ...
The first operational mission of the Athena, an Athena I, successfully launched the NASA Lewis satellite into orbit from Vandenberg Air Force Base in California, on August 22, 1997. The first Athena II was successfully launched from Cape Canaveral, in Florida, on January 6, 1998, sending NASA's Lunar Prospector spacecraft on its mission to study the moon.
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From page 118... ...
This format for operations will be an almost mandatory part of the total system architecture of future operationally responsive launch systems. Minotaur For the Air Force's Orbital/Suborbital Program (OSP)
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From page 119... ...
Some of the vehicles initiated under FALCON are expected to transition into cost-effective commercial launchers that could replace high-cost small vehicles. Background The DARPA/Air Force/NASA FALCON program started in August 2003.
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From page 120... ...
. Together, the capabilities of placing small satellites or payloads into LEO and performing HTV missions in a responsive manner are an important step in the evolution of ORS capabilities for the Air Force (DARPA, 2004)
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From page 121... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 121 It is worth mentioning that SpaceX has its own funding. DARPA funds only the demonstration flight and making the launch operations responsive.
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From page 122... ...
DARPA should continue to fund and monitor this company to completion of the FALCON program objectives. The Air Force should evaluate the propulsion technologies to be demonstrated for the airlaunched FALCON vehicle and include them in total system studies of options for ORS vehicles.
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From page 123... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 123 FIGURE 4-6 Air-based vertical launch system (ABVL)
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From page 124... ...
The Air Force and DoD should sponsor a detailed system engineering study to fully understand the transformational potential of cost-effective, operationally responsive launch of small, micro-, and nanosatellites (particularly for large-number satellite arrays) utilizing air-based vertical launch concepts.
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From page 125... ...
As discussed above for air-based vertical launch of small launch vehicles and missiles, candidate medium to large launch vehicle configurations and their propulsion technologies would need to be optimized to take full advantage of the potential for a modular configuration aircraft to transform mission capabilities by enabling high-altitude launch. Some of the propulsion technology aspects that need to be investigated include propellant combinations capable of long on-station standby (solids, storable fuels and oxidizers, gelled combinations, hybrids)
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From page 126... ...
Some of the missions driving the ORS architecture are indicated in Figure 4-10. In the Air Force's roadmap of ORS spirals (Figure 4-1)
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From page 127... ...
Using "mission success" as the primary selection criterion for this systems engineering process provides a powerful quantitative tool for the design of low-risk, cost-effective ORS concepts for Air Force future needs. For a specific mission defined by a set of requirements issued by a user program authority, "mission success" can be defined as achieving the functional result we want, when we want it, for the price we committed to and within the risk level profile we accepted for the program.
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From page 128... ...
The result of the Air Force's current analysis is a basic architecture concept for a reusable, fly-back-to-launch-site, rocket-engine-powered first stage and an expendable, rocket-engine-powered second stage. The Air Force believes the ARES hybrid is the medium-term solution for a revolutionary spacelift capability (James, 2005)
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From page 129... ...
[The] Air Force wants to achieve its goals using the lowest risk approach practical The ARES management team uses the term technologies in the generic sense of describing the technological means to an end.
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From page 130... ...
, the services and agencies, and NASA by providing an independent evaluation of the feasibility of achieving the science and technical goals as outlined in the National Aerospace Initiative, the National Academies, under the leadership of the Air Force Science and Technology Board, will form a committee to answer the following general questions concerning the NAI: 1. Is NAI technically feasible in the time frame laid out?
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From page 131... ...
X-43D Mach 0 12 Flight Demo ( NASA/Air Force) 8 9 Space Access (ROADMAPS IN PROGRESS)
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From page 132... ...
Although funding for IHPTET has been severely limited, contractors have had considerable freedom to develop new technologies that can improve the performance and life of both solid and liquid rocket engines. Several contractors say the main difficulty is that there is no clear definition of Air Force needs.
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From page 133... ...
Air Force Research Laboratory Efforts Under IHPRPT Combustion Stability The Air Force Research Laboratory (AFRL) is planning to upgrade its combustion stability models by including more physics in their development as well as their validation.
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From page 134... ...
The more basic work seems to be of high quality, but its basic nature and not knowing where the Air Force wants to be in the future make it very difficult to set the priorities for these efforts or even determine if they are the best ones to undertake. A thorough review by outside experts might help in prioritizing the efforts.
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From page 135... ...
It further estimated that a sixfold cost reduction could be attained if critical skills and experienced staff could be retained for the next cycle of engine development programs. Rocketdyne said that a big problem was that it had no clear picture of future Air Force needs in rocket propulsion.
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From page 136... ...
136 A REVIEW OF AEROSPACE PROPULSION NEEDS · Integrated powerhead demonstrator. The objective of this program is to provide the combustion devices for the Air Force's IPD 250,000 lbf, LOx/hydrogen, full-flow staged combustion engine and test them at Stennis Space Flight Center.
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From page 137... ...
USET is a 5-year old IHPRPT program, funded and managed by AFRL at Edwards Air Force Base, and slated to end in FY08. It has the primary goal of improving the software design and analysis tools used for advanced rocket engine development.
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From page 138... ...
Additional information on USET can be obtained from AFRL at Edwards Air Force Base. USET is an important step toward achieving the ultimate vision -- computerized development of high-fidelity virtual engine designs that can be tested on a virtual test stand.
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From page 139... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 139 of Redondo Beach, California (now Northrop Grumman) offered a LOx/RP-1-fueled engine in the 1million-pound-thrust class, which it named the TR-107.
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From page 140... ...
140 A REVIEW OF AEROSPACE PROPULSION NEEDS TABLE 4-3 RS-83 Engine Key Design Characteristics Characteristic RS-83 SSME (Block II) Thrust sea level (lbf)
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From page 141... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 141 TABLE 4-4 RS-84 Engine Key Design Characteristics Characteristic RS-84 SSME (Block II) Propellants LOx/RP-1a LOx/LH2 Thrust sea level (lbf)
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From page 142... ...
142 A REVIEW OF AEROSPACE PROPULSION NEEDS Preburner and chamber LH2 supplies Single preburner Mature SSME Mature SSME are uncoupled feeds both TPAs LO2 ATD TPA LH2 ATD TPA OIV FBV OBV PFV POV EHMS FIV OTC IPS IRC FTC PEB CCV To LOXTank OB QuickTimeTM and a decompressor are needed to see this picture. PBC OB To LH2 Tank MOV LH2 regen coolant drives boost pump Nozzle gasified LOX drives Main case provides boost pump, enables secondary containment higher thrust, eliminates for inner manifold breach critical Hx failure mode RLV-146 FIGURE 4-17 COBRA engine schematic.
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From page 143... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 143 Individual thrust cells for each ramp 10 10 For a total of 20 individual thrust cells per engine. FIGURE 4-18 XRS-2200, single-engine computer-aided design and manufacturing drawing.
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From page 144... ...
144 A REVIEW OF AEROSPACE PROPULSION NEEDS offers another cryogenic upper-stage engine, designed and developed by a highly experienced Russian maker of cryogenic engines. This engine, designated the RD-0146, is manufactured by Chemiautomatics Design Bureau (CADB)
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From page 145... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 145 monopropellant hydrazine (N2H4)
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From page 146... ...
146 A REVIEW OF AEROSPACE PROPULSION NEEDS FIGURE 4-20 650,000-lb thrust TR-106 engine. SOURCE: Northrop Grumman.
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From page 147... ...
The X-34 was cancelled owing to NASA's decision to terminate all activities associated with SSTO next-generation launch vehicles. The Air Force subsequently declined to pick up or fund any follow-on work.
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From page 148... ...
When the in-house MSFC project was terminated, the turbopump assembly elements were eventually shifted for use on two current new, small, low-cost, launch vehicle development projects jointly sponsored by DARPA, the Air Force Space and Missile Systems Center, and NASA. Those two projects are part of the FALCON small launch vehicle program.
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From page 149... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 149 The turbopump for the MC-1 engine is a common shaft design with the oxidizer pump located forward, the fuel pump amid shaft, and the turbine in the aft. The oxidizer and the fuel pumps comprise an axial flow inducer followed by a radial flow impeller.
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From page 150... ...
150 A REVIEW OF AEROSPACE PROPULSION NEEDS Materials and Chamber Cooling, Pratt & Whitney Pratt & Whitney is working on advanced high-temperature aluminum alloys. Initial characterization indicates their specific strength is 2.5 times as great as that of current steel jackets at elevated temperatures.
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From page 151... ...
Both the Chinese and Indian contenders have bustling launch vehicle programs, and the Russian engineering influence is clearly seen in the product. The United States is already aware of the performance advantages offered by some rockets from the former Soviet Union, and U.S.
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From page 152... ...
The committee's rocket panel has identified two technology areas as important tools and elements of the design criteria database. Integrated Totals Systems Engineering Process Because it can determine how the DoD/Air Force technology mix should be restructured to effectively support ORS, one of the highly-leveraged critical technologies requiring immediate effort is the further evolution of an integrated total systems engineering process, with mission success as the primary selection criterion (See Recommendation 4-1)
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From page 153... ...
Performance, cost, and reliability data are especially lacking for reusable rocket engines and launch vehicles of interest to the Air Force. · Engineering level.
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From page 154... ...
The bottom line is that Air Force M&S tools are aging and are limited in their ability to support an integrated design process. M&S tools for air-breathing vehicles appear to be well ahead of those for rockets and launch vehicles.
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From page 155... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 155 NASA/University of Alabama in Huntsville Overall launch systems development cost can be substantially minimized by optimizing propulsion system components using historical engine data, a propulsion thermochemical code, and optimization tools and techniques. A joint effort between the University of Alabama in Huntsville (UAH)
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From page 156... ...
, led by UAH. As of August 2006, the CUIP consortium consists of 18 universities, led by the Johns Hopkins University Applied Physics Lab, managed by NASA, and advised by a board that includes the Air Force Office of Scientific Research (AFOSR)
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From page 157... ...
ROCKET PROPULSION SYSTEMS FOR ACCESS TO SPACE 157 University of Illinois at Urbana-Champaign Center for Simulation of Advanced Rockets The U.S. Department of Energy (DOE)
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From page 158... ...
This is a very important enabling technology. The Air Force needs conceptual vehicle design tools to conduct honest broker assessments of the system benefits of propulsion technology in a timely manner and to evaluate concepts proposed by industry.
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From page 159... ...
As the primary members of the national team, the Air Force and DoD should provide mission definitions and system requirements to interactively identify and prioritize tool capability requirements. The Air Force should establish a process for maintaining and upgrading modeling and simulation tools.
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From page 160... ...
160 A REVIEW OF AEROSPACE PROPULSION NEEDS be selected early on, since it will probably have the most influence on the operational factors involved in total mission success. Upper-Stage Engines USET is an important step in achieving the computerized, high-fidelity virtual engine designs that can be tested on a virtual test stand.
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From page 161... ...
The design of these engines should take advantage of all the engineering lessons learned during the development, certification, and extensive upgrades of the SSME. To permit the Air Force to have dual-source propulsion systems for ARES and subsequent ORS vehicles, two engine design concepts should be selected based on different propellants and configurations having functional and hardware failure modes as different as possible.
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From page 162... ...
Recommendation 4-12. DoD and the Air Force should fund a program to explore various approaches to creating storable oxidizers that would significantly enhance rocket performance with different storable fuels.
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From page 163... ...
Finding 4-13. All of these materials requirements for in-space propulsion need to be balanced against the changing and maturing Air Force and DoD needs and then adequately funded to assure a TRL level of 6 or higher by 2018.
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From page 164... ...
DoD and the Air Force should take the lead in establishing viable methods to achieve availability and assured continuous supplies of critical materials and items, including new ablative materials for thermal insulation and new materials for ITE nozzles for high-temperature and high-pressure applications.
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From page 165... ...
Some of the AirLaunch data might be leveraged to support other air launch concepts such as airborne vertical launch and multimission modular vehicles. Other small, expendable launch vehicles being developed by industry -- for example, SpaceX -- could also provide an opportunity for supplying technologies for small access-to-space vehicles for the Air Force.
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From page 166... ...
166 A REVIEW OF AEROSPACE PROPULSION NEEDS TABLE 4-10 Historical Trends in National Rocket Propulsion Funding as a Percentage of Apollo Program Peak Funding by Year Year Share of Peak Funding Comments (%) 1967 100 Apollo peak propulsion effort.
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From page 167... ...
. In the United States, the development of technology for rocket propulsion, for all spaceflight applications has significantly lagged behind that in the rest of the world since the initial certification of the space shuttle.
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From page 168... ...
for a new operationally responsive family of spacelift vehicles, starting with ARES in 2010 and ORS in 2015. DoD and Air Force commitment to fully develop these new robust launch vehicles might help rejuvenate the U.S.
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From page 169... ...
The committee's estimate of the additional focused investments needed is $50 million to $75 million annually. REFERENCES Published AFSPC (Air Force Space Command)
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From page 170... ...
2005. Small satellites and the DARPA/Air Force FALCON program.
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