I’m interrupting my story of micro Sawppy evolution today to send congratulations to the Mars 2020 entry/descent/landing (EDL) team on successful mission completion! As I type this, telemetry confirms the rover is on the surface and the first image from a hazard camera has been received showing the surface of Mars.
Personally, I was most nervous about the components which are new for this rover, specifically the Terrain Relative Navigation (TRN) system. Not that the rest of the EDL was guaranteed to work, but at least many of the systems were proven to work once with Curiosity EDL. As I read about the various systems, TRN stood out to be a high-risk and high-reward step forward for autonomous robotic exploration.
When choosing Mars landing sites, past missions had to pick areas that are relatively flat with minimal obstacles to crash into. Unfortunately those properties also make for a geologically uninteresting area for exploration. Curiosity rover spent a lot of time driving away from its landing zone towards scientifically informative landscapes. This was necessary because the landing site is dictated by a lot of factor beyond the mission’s control, adding uncertainty to where the actual landing site will be.
TRN allows Perseverance to explore areas previously off-limits by turning landing from a passive into an active process by adding an element of control. Instead of just accepting a vague location dictated by unknown Martian winds and other elements of uncertainty, TRN has cameras that will look at the terrain and can maneuver the rover to a safe location avoiding the nastier (though probably interesting!) parts of the landscape. While it has a set of satellite pictures for reference, they were taken at much higher altitude than what it will see through its own cameras. Would it get confused? Would it be unable to make up its mind? Would it confidently choose a bad landing site? There are so many ways TRN can go wrong, but the rewards of TRN success means a far more scientifically productive mission making the risk worthwhile. And once it works, TRN successors will let future missions go places they couldn’t have previously explored. It is a really big deal.
Listening to the mission coverage, I was hugely relieved to hear “TRN has landing solution.” For me that was almost as exciting as hearing the rover is on the ground and seeing an image from one of the navigation hazard cameras. The journey is at an end, the adventure is just beginning.
[UPDATE: Video footage of Perseverance landing has shown another way my Sawppy rovers successfully emulated behavior of real Mars exploration rovers.]
“Surface operations begin” signals transition to the main mission on the surface of another planet. A lot of scientists are gearing up to get to work, and I return to my little rovers.