Skip to main content

Currently Skimming:

CERTAIN ASPECTS OF ONBOARD CENTRIFUGES AND ARTIFICIAL GRAVITY
Pages 331-346

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 331...
... It is not the purpose of this paper to examine these effects of weightlessness, but to examine certain aspects of imposing artificial gravity by rotation either of the entire vehicle or a portion of it to alleviate or eliminate these potential influences. These aspects encompass the anomalies or side effects of the environments imposed by rotating vehicles such as that of figure 1, or by onboard centrifuges such as shown in figure 2, as well as the effects of these environments on mission goals.
From page 332...
... Hydrostatic pressure gradients (5) Cross-coupled angular acceleration Artificial Gravity Level The fundamental purpose of artificial gravity is twofold: to eliminate or reduce the physiological adaptation to the weightless state and to allow the astronaut to function as nearly as possible as he functions in Earth gravity.
From page 333...
... etc. Manual applica>0 The ability to push parallel to the floor would vary linearly with g-level, assuming linearity tion of forces of frictional forces, and become nil at zero g.
From page 334...
... It is evident, however, that the situation tends not to be normal as the artificial-gravity level decreases and some adaptation and learning must occur. Some limited studies of walking in artificial gravity on the Langley rotating space station simulator (fig.
From page 335...
... The effects of angular motions will be discussed under the section titled "CrossCoupled Angular Accelerations." The influences of the Coriolis forces are well known, as when someone or something moves tangentially or radially in a rotating environment, a force perpendicular to the motion relative to the rotating environment exists. Relative to self-locomotion, the movement will primarily be on the floor either axially or tangentially.
From page 336...
... 0.5. Slow initiation of walking Light on feet No leg heaviness Good walking when stepping rate is 3 ft/sec Good walking condition Start and stop well Legs have heavy sensation Heavy legs Stable sensation Tend to walk on heels Not as comfortable as 0.2 g Laborious Heavy swinging leg sensation Firm heel down steps Tend to soar or float with no control Develop large tilt to initiate Good walking condition Light on feet Less tilt required than for 0.1 Easier than at 0.2 g 9, UNITS .6-ACCELERATION AT FOOT -ACCELERATION OF BODY - NOMINAL ARTIFICIAL GRAVITY 60 BO IOO RADIUS, FT FIGURE 7. -- Acceleration of the foot compared to that of the body and the nominal artificial gravity level.
From page 337...
... I00 particularly in the cardiovascular system, may have more physiological significance than the gravity gradients just discussed. The circulation of blood to the head and from the lower extremities is a significant element in man's well-being and is influenced by the hydrostatic pressures present.
From page 338...
... With the onboard centrifuge, if used as a therapeutic device to challenge the cardiovascular system, as simulated in reference 1, gravity levels up to about 4 g may be required. Because of the confinements of space, onboard centrifuges will have radii of the order of 10 feet or less.
From page 339...
... The major impact is the increase in weight of the structure, reaction control, and flight electronic systems to accommodate this additional operating mode. The total changes in dry launch weight of the laboratory/SIV -- B combination amount to 3400 pounds and require about 600 pounds of additional propellant to circularize the orbit from an initial elliptical orbit.
From page 340...
... These criteria include upper and lower limits of gravity levels, maximum tolerable rates of rotation, rotational radius, percentage change in gravity gradient, and the degree of Coriolis acceleration tolerable and cross-coupled angular acceleration. It must be first noted that the minimum amount of artificial gravity to maintain good physiological tone and to prevent or allay the reconditioning that may occur in weightlessness is not known.
From page 341...
... , FT FIGURE 13. -- Design envelope for manned rotating space vehicles.
From page 342...
... If the artificial-gravity level selected falls within the design envelope of figure 13, the environment produced will satisfy the requirements of walking, performance of everyday tasks (table 1) and, in addition, will simplify some of the mechanical systems designs needed aboard the space vehicle.
From page 343...
... An onboard centrifuge would be extremely helpful in defining the benefits of different subgravity levels, not only in preventing loss of fitness but also in restoring fitness once it is lost. It would have value in determining postural stability while standing, as a function of the-level of artificial gravity (in a rotating spacecraft)
From page 344...
... Only when these are lifted, as in weightlessness, will the true resting discharge of the otolith organs become manifest. I believe a major scientific opportunity awaits investigators in an orbiting laboratory studying vestibular problems.
From page 345...
... If the Coriolis illusion and nystagmus are present, the former will usually be the first to go during the process of adaptation. Mild symptoms of motion sickness usually disappear soon unless head movements are restricted.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.