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

Abstract

The In-Situ production of propellants for Martian and Lunar missions has been heavily discussed since the mid 1990's. One portion of the production of the propellants is the liquefaction, storage, and delivery of the propellants to the stage tanks. Two key technology development efforts are required: large refrigeration systems (cryocoolers) to perform the liquefaction and high performance insulation within a soft vacuum environment. Several different concepts of operation may be employed to liquefy the propellants based on how and where these two technologies are implemented. The concepts that were investigated include: using an accumulator tank to store the propellant until it is needed, liquefying in the flow stream going into the tank, and liquefying in the flight propellant tank itself. The different concept of operations were studied to assess the mass and power impacts of each concept. Additionally, the trade between insulation performance and cryocooler mass was performed to give performance targets for soft vacuum insulation development. It was found that liquefying within the flight propellant tank itself adds the least mass and power requirements to the mission.

Investigation into Cryogenic Tank Insulation Systems for the Mars Surface Environment

“…An Earth vacuum jacket would allow for simpler options than SEMOV, however, first order magnitude calculations based on the ASME Boiler and Pressure Vessel code, Section VIII suggested that the mass for each tank would be over 600 kg for each tank. 4 Based on this mass alone, (~2400 kg for the set of four tanks) the concept was thrown out as too heavy.…”