After the final selection of the principal experiments to fly on NASA’s 2020 Mars Rover, consideration must be given to what else might productively be placed onboard [“NASA Selects 7 Science Instruments for Sample-caching Mars 2020 Rover,” Aug. 4, page 5].

I would strongly recommend that the Mars Rover have a significant LDEF-like component.

LDEF, the Long Duration Exposure Facility, was placed in low Earth orbit by the space shuttle in 1984 and belatedly retrieved by another shuttle in 1990. LDEF was a 14-faced spacecraft that hosted 57 individual scientific experiments, many of which were mounted as small flat panels on the outside faces of the spacecraft. As a result, valuable data were accumulated on the effects on many materials of long exposure to the hostile space environment.

Mars rovers have had lots of flat or gently curved areas that were in view or reach of cameras or other instruments. On Mars 2020, very small samples of materials (for example, alternative spacesuit cloths; alternative visors or window materials; different solar cells; duct tape; different metals, plastics or composites) could be affixed to various surfaces of the rover without interfering with any of the main experiments. 

Such samples are likely to be so thin they would not interfere with the Rover’s landing, deployment or operation. Their cumulative weight, even for a spacecraft on which every gram is significant, would likely be so small that samples could be accommodated in the final rover design. 

The data to be obtained, how those materials hold up in the harsh martian environment (radiation, dust and thermal changes), could be crucial in designing future Mars missions (robotic and crewed). They would be well worth their incremental weight. Better to do these tests now before they are incorporated into future spacecraft, rovers, tools and habitats, which get their field tests only after they arrive on Mars, when it will be too late to change. 

NASA should be encouraged to follow up on these LDEF-like opportunities.

Jeffrey Liss