The only unifying factor among the experiments discussed is that they are all unique Opportunities and/or Techniques for High-caliber Experimental Research (OTHER). Thirteen of the experiments are briefly described

Corso, George J.

Devincenzi, Donald

Duba, AL

Freeman, John W.

Lopez, Ramon

Nuth, Joseph A.

Stephens, James

Strong, Ian

Wolfe, John

English

NASA Technical Reports Server

6.0 REPORT ON OTHER PROPOSALS FOR SSPEX 
Joseph A .  Nuth (NASA Headquarters), George Corso (Northwestern University), Donald 
DeVincenzi (NASA Headquarters), A1 Duba (Lawrence Livermore Laboratory), John 
Freeman (Rice University), Ramon Lopez (Rice University), James Stephens (Jet 
Propulsion Laboratory), Ian Strong (Lm Alamos National Laboratory), and John Wove 
(San Jose State University). 
6.1 Introduction 
Unlike the previous summary reports, the only unifying factor among the 
experiments discussed in this section is that they are all unique Qpportunities and/or 
xechniques for Kigh-caliber Experimental kesearch (OTHER!). Many of the 
investigations discussed in this report were submitted to the SSPEX workshops as 
abstracts, although several additional experiments have been added as a result of workshop 
discussions. Despite the enormous diversity of the proposed investigations, several 
common concerns have emerged regarding the availability of "standard" items. 
Several people expressed a desire for one or more windows. These can be located 
either in the lab module, as a transparent hatch cover or in the habitability module. In 
general, these would not be in constant use, in fact they probably would be used only 
rarely. Windows should "look" both "upstream" and "downstream" from the station and 
should also be available for Earth and "deep space" views. Because they would be used 
only occasionally, positioning behind mobile equipment racks in the lab module could be 
considered. 
Another requirement of several of the proposed investigations is the development of 
automated tether systems; if possible, small (< 500 m) tether systems should be able to 
travel along tracks spanning much of the station. Another possibility is the attachment of 
small tethers to one or more remote manipulator arm&) or to one or more deployable 
booms. A boom which can hold a shield several hundred meters I'in front of' the station 
(or above it) in order to avoid local contamination is a necessity for several experiments. 
Of course, investigators assume some astronaut EVA time for limited servicing, equipment 
and/or sample changes, as well as deployment or retrieval of the experiment. 
One additional factor which requires thought is the degree of overlapping needs or 
use of common equipment for very different experiments. For example, the experiment 
proposed by Walker could provide a very large shield to create the ultrahigh vacuum 
required by Duba or Nuth (see abstracts). Could such an ultrahigh vacuum facility be 
useful to a larger community? Could the small tethers required by Lopez be used to deploy 
and retrieve Stephens' artificial comet? Could the rail gun proposed for the cratering 
experiments be used to fire projectiles into the atmosphere at speeds greater than 25 km/s 
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https://ntrs.nasa.gov/search.jsp?R=19890005632 2020-03-20T05:05:20+00:00Z
and thus create an artificial meteor? Could the dust collectors proposed by Corso be 
mounted on all tethered upper atmospheric research satellites? 
Along these same lines, mutual interferences among experiments with Space Station 
operation must be considered. As examples, could particles released by Strong or 
Stephens interfere with the collection efforts of Walker? How many tethers could be 
deployed around the station, and in which directions, before they constitute a navigational 
hazard? How large a disturbance to microgravity experiments would result by firing 
projectiles into the upper atmosphere (or doing cratering studies)? 
Many of the experiments described in the abstracts are in the "formative" stage of 
development. Still, all of the proposals utilize the space station environment for 
investigations which could never be performed on Earth. None are suitable for flight on 
the KC-135, although several could be developed as Shuttle experiments. In some cases 
(e.g., Strong and Williams) development of Shuttle experiments is under way. 
The following includes brief descriptions of 13 experiments; 9 of these were 
presented to workshop participants. Another is mentioned in the "Banks" Report as a 
candidate for IOC. Two more experiments were discussed by participants at the 
workshop, as an outgrowth of other experiments already under discussion. A final 
"calibration" experiment was discussed by Boynton at an earlier meeting. Considering the 
number and variety of Planetary Science experiments which keep emerging these should be 
considered as the vanguard of many more proposals. 
6.2 Specific Experiments 
Ultrahigh Vacuum Petrology Facility 
Duba proposes placing a large (> 3 m diameter) shield in front of (or above) the 
Space Station. The region behind the shield would experience a very low pressure due to 
the shield "sweeping" ambient gas away as it travels at orbital velocity (8 km/s). Pressures 
of lO-l5 torr of H and He seem possible, while atom partial pressures less than 10-20 torr 
could be obtained. In this very low pressure region Duba proposes to study the high 
temperature metamorphism of carbonaceous chondrites. In particular he proposes to 
measure the variation in the electrical conductivity of the sample as a function of both time 
and temperature in order to test the theory that the observed differences in composition of 
asteroids (as a function of their orbital semi-major axis) could be due to electromagnetic 
heating during the early history of the solar system. 
Artificial Comet-Free Flyer 
Stephens proposes placing several large "chunks of ice" into orbit in which finely 
dispersed dust particles and several radio thermometers have been frozen. The object of the 
experiments is to determine the dependence of the temperature structure within the comet on 
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both the composition and concentration of the dust. In particular, he wants to test the 
hypothesis that a significant quantity of volatiles could be trapped inside of "dead" comets 
and protected by a highly efficient insulating layer of "hardened", extremely porous dust. 
Artificial Comet - Tethered 
In this experiment Stephens proposes to tether materials similar to those described 
above in order that the "comets" can be recovered for later study on earth. In this way the 
thickness of the insulating layer, as well as its structure could be determined and correlated 
with its "insulating efficiency". An additional advantage of tethered comets is observation 
of the development of the dust plume as a function of exposure to various levels of solar 
insulation. 
Cosmic Dust Detector 
Wolfe proposed placing a relatively large (1-2 m2) acoustic impact detector on the 
space station in order to measure the long term anisotropy of the flux of cosmic dust 
particles. Using acoustic spectral analysis he feels that it is possible to derive some 
compositional information about the impacting particle as well as its directions and 
momentum. In this way, information about both the flux and composition of asteroidal, 
cometary and interstellar particles might be gained. 
Cosmic Dust Collector 
In this experiment, Wolfe proposes placing an electrostatic decelerator on the space 
station. The detector is capable of decelerating particles entering the collector with 
velocities as high as 25-30 Ws, and will simultaneously reject relatively slow moving 
debris in the vicinity of the station. Periodic return of the collector surface would allow the 
recovery of pristine, cosmic-dust samples which have not been contaminated by the Earth's 
atmosphere. Such materials would constitute an extremely valuable resource to the 
exobiology community. 
Dust Collection using Tethered Satellites 
Corso proposed outfitting satellites, which would be lowered into the Earth's upper 
atmosphere, with cosmic dust collectors. In this way he hopes to collect large numbers of 
relatively uncontaminated particles soon after their arrival. In fact, using this method it 
could be possible to determine to within a few hours the time of arrival of particular 
particles and thus correlate them with known meteor showers. Such a collection would be 
complementary to both the stratospheric and space station efforts. 
Artificial Mag ne to sp he re 
Lopex proposes suspending a strong magnet from a tether approximately 200 m or so 
above the space station in order to create an artificial magnetosphere. Diagnostic probes 
could be suspended on mobile tethers downstream from this magnet to probe its interaction 
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with the ambient plasma. In addition, ionic tracers such as barium could be released 
"upwind* at will. A series of non-tethered experiments might also be necessary to probe the 
effect of the tether on the plasma sheath. 
Micro-gravity Petrological Studies 
Williams and Lofgren have constructed a highly efficient furnace system which 
accurately controls the redox conditions under which the experiments are performed. They 
propose to fly this system aboard Space Station in order to study the effect of cooling rate 
on the resulting texture of chondrule-like materials. Efforts to study this problem in 1 g are 
frustrated by the settling of early condensates from the melt and, in some cases, by 
buoyancy driven convection. 
Slitless UV Spectrometer (Construction and Calibration) 
Wdowiak et al. have proposed the construction of a Slitless UV Spectrometer to 
obtain meteor spectra, and especially to determine the relative ratios of the biogenic 
elements in these meteors. If the cratering community (or SDI) places a rail gun (or similar 
facility) into orbit it might be possible to fire projectiles of known composition into the 
Earth's atmosphere along well determined trajectories at speeds approaching 25 km/s. Such 
a facility not only could be used to accurately calibrate the spectrometer but could also be 
used to test models of atmospheric entry phenomena. 
ODACE - Orbital Determination and Capture Experiment 
Walker proposed building a large dust collector (10 m x 10 m) with the capability to 
determine the velocity of the impacting particle. When "interesting" particles are observed 
the small cell (10 cm x 10 cm) containing the particle would be returned to Earth for study. 
At this time it might be possible to precisely determine the orbital parameters of the particle 
as well as a significant amount of compositional and structural information. A cosmic dust 
collector is mentioned in the Bank's Report as a high priority item for IOC. 
High Velocity Sputtering of Amorphous Silicates 
This experiment grew out of discussions with A1 Duba and others at the workshop. 
If we put a hole in the middle of A1 Duba's shield (which could be closed off, of course) 
then this would be an excellent source of 7-8 km/s oxygen, nitrogen, helium and hydrogen 
atoms with which to carry out sputtering experiments. It might also be possible to charge 
these atoms using an electron gun so that one could electromagnetically separate the beam 
into its atomic components. This device could serve as a useful experimental facility for 
material science experiments. In particular, Nuth wants to study the metamorphism of 
amorphous iron and magnesium silicates exposed to such a beam in order to better 
understand the processing of these materials via shocks in the interstellar medium. 
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Particle Release Experiments 
Strong and coworkers have not yet established a definitive set of particle release 
experiments to be performed from the space station, in part because they have not yet 
carried out a planned series of releases from the space shuttle. These experiments will take 
advantage of the unique observational capabilities of the AMOS Facility in Hawaii in order 
to measure various properties of the released particles such as the scattering, absorption and 
extinction efficiencies as well as the speed with which the particles become aligned in the 
Earth's magnetic field. The results of these early shuttle experiments will determine the 
particular experiments which best utilize the unique opportunities afforded by the Space 
Station. 
Calibration of Gamma and X-ray Remote Sensing Probes 
Boynton mentioned this possibility at a previous meeting and it is included here for 
completeness. He suggests that the best place to calibrate a remote sensing tool such as a 
gamma-ray or x-ray fluorescence spectrometer is in the space environment. On Earth, only 
single-line, gamma-ray sources are available for use as excitation probes for natural 
samples. Similarly, no continuous "natural" x-ray spectra are available with which to 
calibrate x-ray fluorescence detectors. Much better instrument calibrations would be 
available if one could observe transported natural samples such as basalts, granites and 
various ices - or even observe various parts of the station itself prior to launch of the 
instruments to their ultimate planetary targets. 
6.3 Conclusion 
Since the time this report was originally compiled a number of workshops have been 
convened to better define experimental concepts described above. In particular, the reader 
is encouraged to study the report "Trajectory Determinations and Collection of 
Micrometeoroids on the Space Station" (LPI Report 86-05) for a discussion of potential 
cosmic dust experiments. The report "Experimental Cosmochemistry in the Space 
Station", available from Bjorn My sen at the Carnegie Geophysical Research Laboratory in 
Washington, D.C., contains an excellent update and expansion of the geochemical studies 
discussed above as well as many experiments which were not discussed originally at this 
meeting. We expect that many more scientifically exciting experiments will be proposed 
than can actually be accommodated aboard the space station. For this reason, early 
discussion of potential experiments within the planetary science community is essential so 
that we propose only "the best" experiments possible. 
6-5 


Report on OTHER proposals for SSPEX

Report on OTHER proposals for SSPEX

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