NASA’s Vision for Space Exploration calls for a return of humans to the Moon by no later than 2020. Reducing risk to astronaut safety and mission success will require technology development in a wide variety of areas. The exploration community is beginning to come to consensus with Apollo 17 astronaut Harrison Schmitt who recently declared, “Dust is the number one environmental problem on the Moon” (ref. 1). The Apollo record shows that dust caused a wide variety of problems for those missions including vision obscuration, false instrument readings, equipment clogging, radiator degradation, seal degradation, abrasion, and respiratory and eye irritation (ref. 2). Clearly,these are problems that must be understood and mitigated if humans are to establish a long-term presence on the Moon.
One source of the difficulties in understanding the interaction of lunar dust with sensitive surfaces (such as visors, radiators, and seals) in the lunar environment is that lunar dust has a structure unlike any dust on Earth, and the lunar environment is very different from any environment on Earth. This makes testing of components and systems that will be used on the Moon more difficult than one might suppose. For example, testing of radiator surfaces using real lunar dust in terrestrial lunar-simulation facilities suggested that a nylon bristle brush would be effective to remove dust from the Lunar Roving Vehicle battery radiators (ref. 3). However, in use on the actual lunar surface, the nylon bristle brushes were almost totally ineffective (ref. 4). This illustrates that there is more to accurately simulating the lunar environment than creating a good vacuum.
The Lunar Dust Adhesion Bell Jar (LDAB) was designed at the NASA Glenn Research Center to simulate the dusty lunar environment as accurately as possible. There are provisions to treat the dust by driving off absorbed water, thermal cycling the dust, exposing it to high-energy particles (simulating the solar wind) and ultraviolet light, and then applying a light coating of sieved dust to coupon-sized samples. These samples can then be further heated, cooled, and subjected to ultraviolet light. The LDAB also has a variety of diagnostic capabilities including residual gas analysis by mass spectroscopy, calorimetric measurements, and microscopic sample imaging. Capabilities to quantify the adhesive forces, lower the temperature to 40 K, and test mitigation techniques will be added in the coming year. It is expected that the LDAB will be a major asset in unraveling the web of interactions among the dust, the lunar environment, and spacecraft and that it will help to verify the effectiveness of various dust-mitigation strategies.
Artist’s cutaway drawing of the LDAB showing the principal features.
Long description of figure 1.
Last updated: December 17, 2007
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