In Situ Propellant Production on Mars
- Paper number
IAC-05-A5.1.06
- Author
Mr. Gabriele Messina, Deutsches Zentrum fur Luft und Raumfahrt e.V. (DLR), Germany
- Coauthor
Mr. Massimiliano Vasile, Politecnico di Milano, Italy
- Coauthor
Dr. Andrea Davighi, Politecnico di Milano, Italy
- Coauthor
Dr. Elvina Finzi, Politecnico di Milano, Italy
- Year
2005
- Abstract
In Situ Propellant Production (ISPP) will be a key technology for future exploration of Mars, since it will reduce the mass at launch from Earth, saving the propellant mass necessary to come back to Earth. Moreover ISPP could significantly increase the chance of “living off the land”, depending on local resources and not only on materials carried from Earth. Many missions have been designed exploiting ISPP or more in general ISRU (In Situ Resource Utilization) which ISPP is a part of; as far as now ISPP needs to be certified and experimented in all its features.
The aim of this study is valuing different ways to produce propellant on Mars, selecting the more feasible and efficient plant and designing it in all its parts.
The ISRU plant is composed of the following parts:
- ISPP plant: chemical plants and devices necessary to extract raw materials and to produce propellant;
- tanks: for the storage of produced propellant;
- cryogenics: devices necessary to cool, liquefy and keep at the right conditions the propellant in the tanks;
- power source: it supplies power to both ISPP plant and cryogenic devices.
This study takes account of three kinds of propellant: H2/O2, CH4/O2, C2H4/O2. Mars atmosphere is rich in both oxygen and carbon, in form of carbon dioxide (95%); what’s difficult is to find and mine hydrogen. H2 can be found only in the small amount of water vapour in the atmosphere, in the Martian polar caps as ice, mixed with dry ice, and in the soil as permafrost. A last possibility is to carry H2 from Earth. Landing site (equatorial zone or polar cap) and chemical processes involved in the propellant production are other parameters that influence the choice of the ISRU plant.
The following processes were considered during the trade off analysis:
- WAter Vapor Adsorption Reactor (WAVAR), that uses a Zeolite bed to absorb water vapour from the atmosphere;
- Water Electrolysis and Zirconia Electrolysis (the latter to extract O2 from CO2);
- Reverse Water Gas Shift, together with Water Electrolysis to produce oxygen;
- Sabatier reactor, to produce Methane from CO2 and H2;
- Fischer Tropsch Catalysis, to produce Ethylene.
According to the mass of the payload that has to return to Earth, two different scenarios have been investigated:
- a small ISRU plant, that should be easily feasible and conservative; this plant should be considered a technology demonstrator to bring back to Earth a symbolic sample weighing about three kilos.
- a large ISRU plant, designed to bring to Earth heavier payloads, e.g. for manned missions; a 2250 kg payload mass has been chosen during the design.
For both missions the propellant is produced in one synodic year. A lot of different ISRU plants have been designed and the trade off process, based on plant mass and power request, has led to the following choices: both ISRU plants produce Ethylene landing in an equatorial zone, but, with reference to the small one, Hydrogen will be carried from Earth while, as regards the bigger one, it will be mined in situ, that is from atmosphere. Actually, for the large plant, it would be more advantageous in terms of mass using the polar caps ice, both as cold well for the nuclear reactor and as source of water. However the ice hole depth (more than 2 km) caused by ice melting decreases considerably the feasibility of the plant. In order to guarantee the saving of the mass and volume, inflatable tanks for propellant storage were expressly designed and optimized in relation to appropriate cryocoolers (where required).
- Abstract document
- Manuscript document
IAC-05-A5.1.06.pdf (🔒 authorized access only).
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