The Sample Fetch Rover (SFR) was a key element of the Mars Sample Return program, having the objective to locate, retrieve and return samples cached by the Mars 2020 (Perseverance) rover. Designed for autonomous operations and fast mobility on Mars terrains, the Sample Fetch Rover mission profile included traverse to the "depot" where Perseverance will have left the tubes containing soil and rock samples; collection and on-board storage of the tubes, and their transport back to the Mars Ascent Vehicle. A key design driver for SFR, as with any Martian mission, is keeping equipment warm during the cold Martian night, with environmental temperatures dropping to -130°C. SFR does not have any form of radioactive heating and relies entirely on electrical heating to sustain internal temperatures. As such, heat leaks to the cold environment must be minimised, with the main heat leak being via the CO2 atmosphere. This imposed a need for an efficient gas insulation design around hot zones within SFR. To achieve this a literature review of previous Martian gas testing was conducted, identifying key parameters for a gas insulation design such as maximum gap size which suppresses convection. From this, multiple designs for novel gas insulation solutions for SFR were created and a test was defined to determine empirically which design provides the highest level of insulation. This paper details the literature review, the various novel gas insulation designs and the proposed testing for design selection.
Tamkin et al. (Sun,) studied this question.