Microgravity Research Opportunities for the 1990s (1995) / Chapter Skim
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Microgravity Research Opportunities for the 1990s: Chapter 8
Microgravity Research Opportunities for the 1990s: Chapter 8
Pages 128-140
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From page 128... ...
Europeans, REPORT MENU meanwhile, focused their program on microgravity fluid and materials science issues using NOTICE drop towers, parabolic flights, sounding rockets, and high-altitude balloons. The Soviets took MEMBERSHIP advantage of a nearly continuous presence in space with flight experiments in microgravity PREFACE environments.
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From page 129... ...
Approaches must be devised to obtain initial feasibility data and proof of concept from simplified, economical devices before any commitment is made to the long-term development of expensive instrument systems. As much as possible, instruments should be shared among divisions, particularly between the Life Sciences and the Microgravity Science and Applications Divisions, and between NASA and the space agencies of other countries, such as the European Space Agency.
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From page 130... ...
The same is true of the level of toxicological analysis, the time required to effect minor and otherwise insignificant changes in an experiment, and the excessive amount of documentation required to achieve flight qualification. Although any, or all, of the more stringent requirements might be entirely appropriate in specific instances, they should not be broadly and indiscriminately applied.
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From page 131... ...
Such periods of weightlessness may be useful for conducting low-gravity experiments requiring somewhat longer times than are available in the drop towers and for those cases in which the quality of the microgravity environment is not critical. Parabolic flights are useful for testing experimental packages intended for later flight on the space shuttle or space station.
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From page 132... ...
High data-rate telemetry, real-time ground up-link command, and down-link video data are routinely available. Space Shuttle The operating parameters on the shuttle have been measured by the Space Acceleration Measurement System (SAMS)
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From page 133... ...
Currently, however, astronaut motion is not subject to the vibration restrictions. Clearly, there is little point in designing the structure and instrumentation of a space station to provide a microgravity environment if the movement of the astronauts introduces unacceptable disturbances.
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From page 134... ...
Procedures have been formulated to take into account broad band disturbances. An example of the analysis of the disturbance to the microgravity environment to be expected from a particular facility is given in Figure 8.3 A,B.
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From page 135... ...
The frequency dependence of these curves reflects the frequency response of the structure of the SSF to disturbances. This example is presented for the purposes of illustration only, since more recent space station plans do not yet specify allocations for the centrifuge facility.
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From page 136... ...
The mission was launched in July 1992 and flew for about 10 months. Lunar Base Experiments conducted on the Moon's surface would take advantage of an order-of magnitude reduction in the gravitational acceleration to 0.16 g.
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From page 137... ...
it is an extremely expensive process. At present, the time required from the selection of a new principal investigator to launch of his or her spaceflight experiment is 5 to 6 years for the mid-deck (noninteractive)
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From page 138... ...
Microgravity Research Opportunities for the 1990s: Chapter 8 FIGURE 8.4 Elements of the flight experiment development process. file:///C|/SSB_old_web/mgoppch8.htm (11 of 14)
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From page 139... ...
Surmounting the various hurdles to which a flight experiment is subject requires interactions with three different NASA centers: Johnson Space Flight Center, which is in control of the orbiter; Marshall Space Flight Center, which controls the spacelab; and Kennedy Space Center, which is in charge of integration and launch. The conditions imposed on the experiment and the principal investigator by the various NASA centers are not always consistent.
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From page 140... ...
Space station 30 days continuous, 180 Additional specifications for <10-6 g, f 0.1 Hz days/year complex disturbances <10-3 g, f 100 Hz f x 10-5 g, 0.1 f 100 Hz Free-flyers <10 -5 g, f< 1 Hz Several months <10-3 g, f> 100 Hz f x 10-5 g, 1 < f< 100 Hz Lunar base 0.16 g NOTE: f = frequency. file:///C|/SSB_old_web/mgoppch8.htm (13 of 14)
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