Being able to extract oxygen and produce Methane from the Mars atmosphere would greatly enhance colonization missions to Mars. Here we review how the obviously technical feasible technology would likely scale.
Mars In- Situ Resource Utilization Based on the Reverse Water Gas Shift: Experiments and Mission Applications by Zubrin and others in 1997
Basis for Scaling in Zubrin Analysis
The masses and power requirements of the S-E and Z-E systems in the 0.5 kg per day production rate are known with considerable accuracy from the experimental work done at Lockheed Martin and the University of Arizona. Power requirements for larger systems can also be estimated with confidence, since with all subsystems except controls, power requirement will increase linearly with production rate. Mass of sorption pump systems are estimated to increase by a factor of four for every factor of 10 increase in output rate. This is based upon a relative decrease in parasitic mass as the total sorption pump system becomes larger.
Mass of the chemical synthesis gear is assumed to be linear with respect to the roughly ~0.3 kg of actual chemical reactors contained within the 3 kg mass of the chemical reactor system required for the 0.5 kg per day production rate. This is based upon the author’s knowledge of the details of the Lockheed - Martin S-E system (0.1 kg Sabatier reactor + 0.2 kg of solid polymer electrolyte contained within the ~3 kg chemical synthesis subsystem) and reports from K.R. Sridhar of the University of Arizona of ~0.3 kg of actual Z - E cells within a ~0.5 kg per day output unit there. Control system mass and power is estimated to scale up by a factor of two for every factor of 10 increase in output.
Mass of lines and valves for all systems except the Z-E are assumed to scale up by factor of 3 for every factor of 10 increase in output. For the Z-E system, a factor of 5 increase in mass for every factor of 10 increase in output is assumed. This is because the Z-E system is composed of large numbers of small tubes. As the system scales up, more and more manifolds are required. This contrasts unfavorably with the other systems, which can simply employ larger reactor vessels as output rates are increased. Refrigerator mass is assumed to increase by a factor of four for every factor of 10 increase in output. This is based upon scaling observed in existing Stirling cycle
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Mars In- Situ Resource Utilization Based on the Reverse Water Gas Shift: Experiments and Mission Applications by Zubrin and others in 1997
Basis for Scaling in Zubrin Analysis
The masses and power requirements of the S-E and Z-E systems in the 0.5 kg per day production rate are known with considerable accuracy from the experimental work done at Lockheed Martin and the University of Arizona. Power requirements for larger systems can also be estimated with confidence, since with all subsystems except controls, power requirement will increase linearly with production rate. Mass of sorption pump systems are estimated to increase by a factor of four for every factor of 10 increase in output rate. This is based upon a relative decrease in parasitic mass as the total sorption pump system becomes larger.
Mass of the chemical synthesis gear is assumed to be linear with respect to the roughly ~0.3 kg of actual chemical reactors contained within the 3 kg mass of the chemical reactor system required for the 0.5 kg per day production rate. This is based upon the author’s knowledge of the details of the Lockheed - Martin S-E system (0.1 kg Sabatier reactor + 0.2 kg of solid polymer electrolyte contained within the ~3 kg chemical synthesis subsystem) and reports from K.R. Sridhar of the University of Arizona of ~0.3 kg of actual Z - E cells within a ~0.5 kg per day output unit there. Control system mass and power is estimated to scale up by a factor of two for every factor of 10 increase in output.
Mass of lines and valves for all systems except the Z-E are assumed to scale up by factor of 3 for every factor of 10 increase in output. For the Z-E system, a factor of 5 increase in mass for every factor of 10 increase in output is assumed. This is because the Z-E system is composed of large numbers of small tubes. As the system scales up, more and more manifolds are required. This contrasts unfavorably with the other systems, which can simply employ larger reactor vessels as output rates are increased. Refrigerator mass is assumed to increase by a factor of four for every factor of 10 increase in output. This is based upon scaling observed in existing Stirling cycle
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