Science
Proposals sought for satellite experiments Consortium of universities will assist scientists in engineering, funding for experiments aboard NASA earth-orbiting satellites Are you a scientist who hasn't previously participated in space research but nevertheless is interested in experiments involving space chemistry, lubrication technology, polymerization, hydrolysis, radiation damage, materials processing in space, cell biology, space physics, solar physics or, for that matter, any other work that either utilizes or studies the environment surrounding an orbiting spacecraft? If that is the case, you might be just the type of investigator that the Universities Space Research Association (USRA) is seeking to aid in getting a "free ride" for your experiment on a new scientific satellite that will be launched by the National Aeronautics & Space Ad-
ministration sometime late in 1979 or early in 1980. Called LDEF—Long Duration Exposure Facility—the new satellite will be able to carry more than 70 experimental packages. It will be transported into space by the Space Shuttle where it will be left to orbit earth for six to nine months. Then, another shuttle will bring LDEF back to earth so that experiments may be returned to their developers. Several LDEF missions are planned. LDEF offers several unique opportunities: It provides a way in which experiments can be exposed to radiation fluxes and low gravity for a long time; it allows experiments performed in space to be returned and analyzed on earth; and it opens the way for space experiments to be conducted routinely by a variety of investigators rather than rarely by only a selected few. Indeed, with LDEF, any scientist having a good experimental idea now has a fairly reasonable chance of actually getting his or her experiment "to fly." Although all research proposals must go through a peer review system, several
routes exist for being selected to participate in an LDEF mission. Technological experiments that complement and support research programs of NASA's office of aeronautics and space technology may be chosen directly. Applying through NASA Announcements of Opportunity is another possibility. Proposals submitted in response to the first LDEF announcement were due Nov. 11. However, it is expected that additional announcements will be made on a yearly basis to obtain new experiments. For inexperienced investigators who might hesitate considering a space experiment because of unfamiliarity with bureaucratic application procedures or special engineering knowledge needed to design the experiment, yet another way remains. These workers may submit an idea to USRA—an international consortium consisting of more than 40 universities active in space research and headquartered at Rice University in Houston. Under NASA sponsorship, this group vigorously is seeking proposals in widely diversified subject areas from both the
Experiments in space will be exposed to these conditions Environment
Minimum
Nominal
Maximum
Comment
10~ 6 G continuous
Acceleration
3 X 10~8 torr
Ambient pressure
Will be modified by LDEF interactions (outgassing, surface chemistry)
Ambient atmospheric number density
108/cc
Major component is atomic oxygen (0). Will be modified by LDEF interaction (outgassing and surface chemistry)
Ambient atmospheric ion particle density
105/cc
Major component is singly ionized atomic oxygen (0+). Will be modified by LDEF interactions
High-energy particle flux (electrons)
10 8 /sq-cm day
3X10 9 /sq-cm day
Flux is for energies greater than 0.5 meV. Orbit is free of electron radiation 86 % of the time
High-energy particle flux (protons)
10 6 /sq-cm day
2 X 107/sq-cm day
Flux is for energies greater than 5.0 meV. Orbit is free of proton radiation 83 % of the time
Magnetic field intensity
0.2 gauss
0.6 gauss
Value varies as a function of LDEF position relative to earth
Solar radiation
Meteoroid fluxes and corresponding masses
10%
25%
Percentages are referenced to the direct continuous solar radiation at normal incidence integrated over one year for a 28.5° orbit inclination (excludes albedo effects). The limits will vary with the mission duration and the launch time of the year
10~14/sq-m second for masses of 10~1 gram 10~ 5 /sq-mi>econd for masses of 1 0 - 9 gram
Source: National Aeronautics & Space Administration
Dec. 6, 1976C&EN
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ORGANIC INTERMEDIATES FROM SWITZERLAND dyestuffs pharmaceuticals agrochemicals perfumes photochemicals CH3
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170 Mason-Street, Greenwich, Conn. 06831 Phone: 203TO9-3088 Samples for commercial trade only Agents in other countries : Please inquire
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academic community and industrial ex perimenters willing to work with aca demics. "We are particularly interested in encouraging potential experimenters who haven't had previous experience in space research," says Dr. Milford H. Davis, program director of LDEF for USRA. Because of this interest, previous experi ence with NASA programs, institutional size, and similar factors will be given less emphasis than is perhaps often the case. Applicants may be foreign as well as from the U.S. and eventually may include high school and college groups. Unfortunately, NASA's office of aero nautics and space technology, which runs the LDEF program, is not providing funds for developing and analyzing ex periments submitted under the USRA program (called LDEF/USE for Univer sity Space Experiments). However, NASA has promised a "free ride" on LDEF for those experiments that both have been approved under the USRA program and can be funded from a source other than NASA. Additionally, NASA will provide for preflight testing and in tegration of the experiment. USRA thus has assumed the role of a coordinator, Davis observes. It will ac tively assist experiments approved under its program in securing funding from other government agencies or private sources. At present, most proposals must be handled on a case-by-case basis, but, he says, USRA hopes that in the future it may develop general sources of funding for LDEF experiments. In addition, USRA will arrange for engineering assis tance in developing experiments. The procedure for getting an experi ment accepted under the USRA program will resemble that for publishing an article in a journal, he explains. The USRA pro gram is not designed to merely accept or reject ideas, but to create good experi ments. If a proposal is incomplete, or needs improvement, USRA is interested in working to enhance the proposal. Then, once accepted, approved as safe by NASA, and ready to fly, an experiment will be launched on the first LDEF that can accommodate it.
LDEF will travel around the earth in a circular orbit at an altitude of about 300 nautical miles. It will be gravity-gradient stabilized so that the same face of it al ways points toward earth. The body of LDEF itself actually is a structural framework about 30 feet long and 14 feet wide with a cross section of a 12-sided regular polygon. Experiments will be mounted in trays that will be furnished by NASA and that will be attached to the circumferential surface of the LDEF structure. These trays—about 38 inches wide and 50 inches long—will be of variable depths and able to hold experiments weighing up to 200 lb. On the end frames of LDEF, a few smaller trays also will be mounted. The experi ments may occupy a fraction of a tray, or, in some cases, they may exceed the di mensions of a tray and be heavier than 200 lb. LDEF will not have a central power source or systems for handling data. These features must be incorporated by investigators into individual trays for those experiments that require them. At present, the LDEF project office is de signing a small experimental data and power system that can be used individu ally for just such experiments. The data system under consideration will record data on a removable cassette cartridge, and the power system will provide raw, unregulated direct current power having an output capacity of 10 to 30 amp-hours at 75° F. Thus, experiments that are rather passive and simple in design are most suitable for LDEF. For example, one ex periment already selected will examine the effects of orbital environments on new coatings being developed to control the temperature of spacecraft. Other experi ments will study the damage done to materials by space meteoroids, the effects of the space environment on lubricant oils, and the performance of solar cells in space compared to their performance in laboratories on earth. Reflecting on the passive nature of LDEF, Davis observes that launching it will be something like "putting a raft into orbit." D
