Browsing by Author "Calle, Carlos"
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Item Corrosion on Mars: An Investigation of Corrosion under Relevant Simulated Martian Environments(48th International Conference on Environmental Systems, 2018-07-08) Calle, Luz; Li, Wenyan; Buhrow, Jerry; Johansen, Michael; Calle, CarlosThe goal of this research is to develop a systematic approach to understand corrosion of spacecraft materials on Mars by conducting a literature search of available data relevant to corrosion in the Mars environment and by performing preliminary laboratory experiments under relevant simulated Martian conditions. This project was motivated by the new found evidence for the presence of transient liquid brines that coincided with the suggestion by a team of researchers that some structure degradation cannot be attributed to rock scratching and may be caused by corrosive interactions of brines with spacecraft materials. An extensive literature search on data relevant to Mars corrosion confirmed the need for further investigation of the effect of the Mars environment on the materials used for spacecraft and structures designed to support long-term surface operations on Mars. Simple preliminary experiments, designed to look at the interaction between AA7075-T73 aluminum alloy and the gases present in the Mars atmosphere, at 20 degree C and a pressure of 633 Pa, showed that there is a significant interaction between the small amount of oxygen present in the Mars gas and the alloy when there is a scratch that removes the protective aluminum oxide film. There are many other important components of the Mars environment that can affect this interaction such as: the photo-catalytic effect of radiation on the oxidizing species, and the effect of salts in Martian soil. These initial experimental results provide strong justification for further investigation of the corrosion mechanism of materials relevant to long-term surface operations in support of future human exploration missions on Mars.Item Investigating the Feasibility of Utilizing Carbon Nanotube Fibers for Spacesuit Dust Mitigation(46th International Conference on Environmental Systems, 2016-07-10) Manyapu, Kavya K.; Peltz, Leora; de Leon, Pablo; Gaier, James R.; Tsentalovich, Dmitri; Calle, Carlos; Mackey, PaulHistorical data from the Apollo missions has compelled NASA to identify dust mitigation of spacesuits and other components as a critical path prior to sending humans on potential future lunar exploration missions. Several studies thus far have proposed passive and active countermeasures to address this challenge. However, these technologies have been primarily developed and proven for rigid surfaces such as solar cells and thermal radiators. Integration of these technologies for spacesuit dust mitigation has remained an open challenge due to the complexity of suit design. Current research investigates novel methods to enhance integration of the Electrodynamic Dust Shield (EDS) concept for spacesuits. We leverage previously proven EDS concept developed by NASA for rigid surfaces and apply new techniques to integrate the technology into spacesuits to mitigate dust contamination. The study specifically examines the feasibility of utilizing Carbon Nanotube(CNT) yarns manufactured by Rice University as electrodes in spacesuit material. Proof of concept testing was conducted at NASA Kennedy Space Center using lunar regolith simulant to understand the feasibility of the proposed techniques for spacesuit application. Results from the experiments are detailed in this paper. Potential challenges of applying this technology for spacesuits are also identified.Item Spacesuit Dust Mitigation-Study in Vacuum Settings Using Carbon Nanotube Fibers with Electric Fields(2020 International Conference on Environmental Systems, 2020-07-31) Manyapu, Kavya; Peltz, Leora; De Leon, Pablo; Calle, CarlosEven after 50 years since the first lunar manned missions, lunar exploration has been a significant topic of interest to advance human space exploration. With NASA working towards an eventual return to the lunar surface to set up permanent human outposts, these activities necessitate robust and reusable spacesuits to enable frequent extravehicular activities in the dusty environments of the lunar surface. Dust contamination was shown to be a serious problem during Apollo missions when the powdery dust substantially degraded the performance of spacesuits and other critical equipment. The research presented in this paper designed, developed and tested the Spacesuit Integrated Carbon nanotube Dust Ejection/Removal (SPIcDER) system. SPIcDER generates an electric field that can actively levitate and repel dust particles off the spacesuit outerlayer when energized using a multi-phase AC voltage signal. Carbon nanotube (CNT) flexible fibers, used as electrodes, are embedded within the outerlayer of the spacesuit as they provide the required resilience and flexibility required for spacesuit operations. The system leveraged the Electrodynamic Dust Shield (EDS) developed by NASA for rigid surfaces. SPIcDER applies novel fabrication methods to create a ‘smart fabric’ suited for repelling dust from flexible surfaces. Proof of concept for SPIcDER was demonstrated successfully at coupon level and a functional full-scale knee joint section of a spacesuit prototype. Our experiments with lunar and Martian dust simulants demonstrated the functionality and efficacy of SPIcDER in preventing dust contamination. The current paper details the performance of SPIcDER in vacuum conditions based on experiments conducted at the Kennedy Space Center utilizing spacesuit material coupons with CNT fibers. The research provides an assessment of both the design and manufacturing parameters influencing SPIcDER dust cleaning performance. While SPIcDER was initially developed for spacesuits, the underlying technology is versatile, applicable to flexible structures deployed during a mission in space, or on Earth.