Spacesuit Integrated Carbon Nanotube Dust Mitigation System For Lunar Exploration

Lunar dust proved to be troublesome during the Apollo missions. The lunar dust comprises of fine particles, with electric charges imparted by solar winds and ultraviolet radiation. As such, it adheres readily, and easily penetrates through smallest crevices into mechanisms. During Apollo missions, the powdery dust substantially degraded the performance of spacesuits by abrading suit fabric and clogging seals. Dust also degraded other critical equipment such as rovers, thermal control and optical surfaces, solar arrays, and was thus shown to be a major issue for surface operations. Even inside the lunar module, Apollo astronauts were exposed to this dust when they removed their dust coated spacesuits. This historical evidence from the Apollo missions has compelled NASA to identify dust mitigation as a critical path. This important environmental challenge must be overcome prior to sending humans back to the lunar surface and potentially to other surfaces such as Mars and asteroids with dusty environments. Several concepts were successfully investigated by the international research community for preventing deposition of lunar dust on rigid surfaces (ex: solar cells, thermal radiators). However, applying these technologies for flexible surfaces and specifically to spacesuits has remained an open challenge, due to the complexity of the suit design, geometry, and dynamics. The research presented in this dissertation brings original contribution through the development and demonstration of the SPacesuit Integrated Carbon nanotube Dust Ejection/Removal (SPIcDER) system to protect spacesuits and other flexible surfaces from lunar dust. SPIcDER leverages the Electrodynamic Dust Shield (EDS) concept developed at NASA for use on solar cells. For the SPIcDER research, the EDS concept is customized for application on spacesuits and flexible surfaces utilizing novel materials and specialized design techniques. Furthermore, the performance of the active SPIcDER system is enhanced by integrating a passive technique based on Work Function Matching coating. SPIcDER aims for a self-cleaning spacesuit that can repel lunar dust. The SPIcDER research encompassed numerous demonstrations on coupons made of spacesuit outerlayer fabric, to validate the feasibility of the concept, and provide evidence that the SPIcDER system is capable of repelling over 85% of lunar dust simulant comprising of particles in the range of 10 m-75m, in ambient and vacuum conditions. Furthermore, the research presented in this dissertation proves the scalability of the SPIcDER technology on a full scale functional prototype of a spacesuit knee joint-section, and demonstrates its scaled functionality and performance using lunar dust simulant. It also comprises detailed numerical simulation and parametric analysis in ANSYS Maxwell and MATLAB for optimizing the integration of the SPIcDER system into the spacesuit outerlayer. The research concludes with analysis and experimental results on design, manufacturability, operational performance, practicality of application and astronaut safety. The research aims primarily towards spacesuit dust contamination. The SPIcDER technology developed in this research is however versatile, that can be optimized to a wide range of flexible surfaces for space and terrain applications-such as exploration missions to asteroids, Mars and dust-prone applications on Earth

Feasibility study of long-life micro fuel cell power supply for sensor networks for space and terrestrial applications

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, June, 2010."May 2010." Cataloged from PDF version of thesis.Includes bibliographical references (p. 87-90).Sensor networks used for activities like border security, search and rescue, planetary exploration, commonly operate in harsh environments for long durations, where human supervision is minimal. A major challenge confronting such devices is providing adequate and reliable power supply required for long durations. This research considers the feasibility of a miniature Proton Exchange Membrane (PEM) fuel cell system coupled with battery to supply power for long life missions. The focus of this research is to prove the feasibility of long-life, self-contained power-supplies using miniature fuel cells for low-power distributed sensor networks. In this research, the performance of fuel cell power-supplies weighing not more than a few hundred grams is studied. The performance of the PEM fuel cell is modeled, analyzed and validated using experimental results. The feasibility of the fuel cell power systems are studied for two reference missions - one on the lunar surface and the other in the desert regions of Negev, Israel. This research analyzes the use of passive methods to achieve thermal, air and water management for PEM fuel cells supplying power to these field sensors. The results of this study suggest that the proposed fuel cell power system is capable of providing power to sensor modules in challenging field conditions with operational lives extending from many months to years. The scope of this concept can be extended to power devices such as micro-robots and small unmanned aerial vehicles operating in extreme environmental conditions for sustained periods of time.by Kavya Kamal Manyapu.S.M