Browsing by Author "Voecks, Gerald"
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Item CO2 removal system for Manned Mission beyond LEO using deep space radiators and solar heaters(46th International Conference on Environmental Systems, 2016-07-10) Paredes Garcia, Jordi; Nakazono, Barry; Voecks, Gerald; Jones, Jack; Jan, Darrell; Hogan, JohnThe current spacecraft technology to remove CO2 generated in manned missions uses mostly zeolite filters, which break down relatively easy; this has caused multiple problems over the last decades. The current solution has been to replace the defective components sending replacements form Earth, but this is only viable for missions close to Earth, e.g. ISS. Once humans require longer duration missions without Earth access, highly reliable CO2 capture needs to be implemented. There is no current technology that captures CO2 levels for long duration missions. Gaseous CO2 can be captured cryogenically, and the different solidification temperatures between water, carbon dioxide, nitrogen and oxygen become the key parameters of this system. It is important to note that human generated organic contaminants freeze at higher temperature than CO2. These contaminants will be captured prior to CO2 solidification. The medical community has determined that 5000 ppm in volume of CO2 is the maximum allowed concentration within an 8 hour working period for humans. Generally levels are required to be below 600 ppm. Every astronaut generates around 1Kg CO2 / day which needs to be removed from the cabin air continuously. This system consists of staged Two-Phase Heat Exchangers (NTR: 49561), to selectively solidify water, trace contaminants and carbon dioxide. Deep space radiators provide the required cooling power, and solar heaters deliver the necessary heat to evaporate all the solidified species, during the system cycles. This is why, for missions beyond LEO, that no power is required. The energy requirements are passively collected from space. (Only a small amount of power is needed for control valves and electronics).Item Mission-Scale MOXIE Development Driven Prospects for ISRU and Atmosphere Revitalization(2023 International Conference on Environmental Systems, 2023-07-16) Hartvigsen, Joseph; Hollist, Michele; Elwell, Jessica; Elangovan, S.; Voecks, GeraldThe Mars Oxygen ISRU Experiment (MOXIE) was a first of its kind demonstrations of in-situ resource utilization technology to produce propellant and breathable oxygen from the Mars ambient carbon dioxide. The use of Lunar and Martian resources represents a significant opportunity to reduce the cost of launch from Earth, enabling propellant production for space refueling, and allowing for life support of manned missions to the Lunar and Martian surfaces. Since developing the Solid OXide Electrolysis (SOXE) stacks for the Mars 2020 MOXIE program in 2017, the OxEon team has made significant advancements in scale and capabilities within NASA NextSTEP ISRU, SMTD Tipping Point, and SBIR projects. Newer variants have a five-fold larger cell area and a 6.5-fold increase in cells per stack, for a stack scaled 33-times the 0.5% scale of the device in MOXIE. Six of these OxEon mission-scale SOXE stacks will produce 30 tons of propellant oxygen to fuel a MAV in the 19-month window between landing an unfueled MAV pre-supply mission and the next launch opportunity for the first crewed Mars Mission, meeting target requirements for a return mission. OxEon has built and demonstrated systems with mission-scale stacks for both Lunar and Martian applications. A system for the production of propellant H2 and O2 from Lunar ice was successfully tested in a Mines cryo-vac chamber in 2022. Another mission-scale demonstration system demonstrated production of O2 and methane from Martian H2O and atmospheric CO2 at JPL in 2022. The Mars mission-scale system combines CO2-steam co-electrolysis with a methanation reactor. Aligned with the DOE and Naval Research Laboratories target production of liquid fuels with a Fischer-Tropsch synthesis back-end in place of methanation. This work will be presented showing the advantage of a -CH2- product (Fischer Tropsch) over a CH4 product (Sabatier) for ECLSS recovery of oxygen from respiration byproducts.