Demonstration of Critical Systems for Propellant Production on Mars for Science and Exploration Missions

Abstract

A Mars hopper has been proposed as a Mars mobility concept that will also demonstrate and advance in-situ resource utilization. The components needed in a Mars propellant production plant have been developed to various levels of technology maturity, but there is little experience with the systems in a Mars environment. Two systems for the acquisition and compression of the thin carbon dioxide atmosphere were designed, assembled, and tested in a Mars environment chamber. A microchannel sorption pump system was able to raise the pressure from 7 Torr to 450 Torr or from 12 Torr to over 700 Torr in two stages. This data now provides information needed to make additional improvements in the sorption pump technology to increase performance, although a system-level analysis might prove that some amount of pre-or post-compression may be a preferred solution. A mini cryofreezer system was also evaluated as an alternative method for carbon dioxide acquisition and compression. Finally, an electrolysis system was tested and successfully demonstrated start-up operation and thermal stability of all components during long-term operation in the chamber. Nomenclature ISRU= in-situ resource utilization MACS = Mars Atmospheric Chemistry Simulator PEM = proton exchange membrane PLC = programmable logic controller RGA = residual gas analyzer TSA = thermal-swing adsorption

Towards synthetic biological approaches to resource utilization on space missions

“…Reference [92] reported a high of 96% methane offgas concentration in a continuous stirred tank reactor with Methanobacterium thermoautotrophicum, strain Marburg, producing methane at 530 mmol l 21 h 21 [90], which corresponds to a production rate of 204.1 g of methane per litre per day. Electronic supplementary material, table S4 summarizes the Mars ISRU mass cost of these organisms when a flow rate constraint of 3000 g of water h 21 is imposed by incorporating a 6 kg electrolyser that was recently validated in [93]. Significant reductions in the mass of methane-oxygen production-plants are indicated.…”

Capability and Technology Performance Goals for the Next Step in Affordable Human Exploration of Space

“…Subscale units have been demonstrated in a relevant environment at about 1/1000 th scale necessary for human-scale missions. 36 Ionic liquids can be tailored to selectively adsorb CO 2 from a mixed-gas stream, and there is significant research in this area for cleaning up flue gas effluents. 37,38 Initial promising results in this industry have drawn the attention of the in-situ resources community, who have begun to investigate whether the ionic liquids can be a viable method to extract and compress the CO 2 from the atmosphere in a similar temperature-swing sorption/desorption cycle as described above for the rapid cycle sorption pump.…”

Liquefaction and Storage of In-Situ O2on the surface of Mars

“…In order to reduce the initial mass needed for a human trip to Mars, oxygen can be produced on the surface of Mars. Oxygen production through the electrolysis of carbon dioxide using a high temperature solid oxide electrolyzer is currently being investigated by NASA and appears to be the leading technology for in-situ production of oxygen 3 . However, for it to be available for propulsion and other end users, the oxygen needs to be cooled, liquefied, and stored for durations up to two years, either in the actual Mars Ascent Vehicle propulsion tanks or in a separate tank.…”

“…While the oxygen production has been developed over the last several years, the cryogenic systems for operation on Mars have not been heavily invested in or studied 3,6,7 . Many of the cryogenic fluid storage technologies needed are similar to in-space technologies developed over the years 8 , but the liquefaction systems such as demonstrated for zero boil-off, would operate under different parameters.…”