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I was looking at the map of where Perseverance is and noticed that it is backtracking, following the path it already took, with only minor deviations. On Sol 353 for instance, it looks like it spent some driving time following its own tracks exactly. Wouldn't it make more sense to send Perseverance through new and unexplored territory, to maximize what we can learn from the mission?

How long will Perseverance keep backtracking? Why is Perseverance returning towards its landing site? And why did the Perseverance team decide to send the rover through a region it already visited, rather than exploring other areas?

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  • $\begingroup$ I don't know whether that is the case in this particular instance but have you considered the possibility that Perseverance is heading back precisely because it was sent through new and unexplored territory and found that there is nothing interesting there? $\endgroup$ Feb 17, 2022 at 12:42
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    $\begingroup$ Well, I would think that if you hadn't found new and interesting things that I would look elsewhere in new areas rather than where I had been. $\endgroup$
    – tckosvic
    Feb 17, 2022 at 16:49
  • $\begingroup$ Purely a guess I haven't confirmed, hence a comment: part of Perseverance's mission is caching samples for the subsequent sample-return mission. Maybe they're driving back to terrain thought to be more suitable for a lander to collect the samples from? $\endgroup$ Feb 19, 2022 at 12:35

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This is only a partial answer. Returning along the same route to the landing site appears to have been the plan from the beginning for this part of the mission.

From https://mars.nasa.gov/resources/25965/perseverances-first-road-trip/

enter image description here

June 09, 2021

[...]

Perseverance’s first science campaign sends the rover south and west of the Octavia E. Butler Landing Site to investigate and sample several of the deepest, and potentially oldest, accessible geologic units in Jezero Crater – the “Séítah” unit (which in Navajo language means “amidst the sand”), and the “Cratered Floor Fractured Rough.” At the completion of the science campaign, Perseverance will return to the “Octavia E. Butler” landing site on its way north, then head west toward the location where its second science campaign will begin.

I couldn't find an answer specifically about why the rover is retracing it's steps almost exactly, instead of exploring more terrain. One blog post discusses these types of decisions as "trade-off between sols and expected science return".

From https://mars.nasa.gov/mars2020/mission/status/362/almost-on-the-rove-again/

Looking forward, after we finish sampling at this location, Perseverance will move back to Artuby ridge where we’ll undertake proximity science at a location known as “Rimplas”. After that, the team is still deciding whether to reattempt a sample at Roubion, where our first sample disintegrated, and/or to take a sample of the “Chal” member rocks, which are massive, blocky rocks closer to our landing site. These decisions, as all decisions on a mission as complex and ambitious as Mars 2020, will be a tradeoff between sols (the martian days we’ll spend) and the expected science return. We’ll then begin a multi-km drive aimed at reaching the delta as soon as possible. Along the way, science observations may include investigations of the craters we pass throughout our journey to the delta. This could be particularly useful for understanding the sequence of events at Jezero crater, which may be revealed in exposures along the crater walls.

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    $\begingroup$ I think the rover is retracing its steps almost exactly because that's the fastest way to get back to the landing site and from there to the location where the second science campaign will begin. The Seitah unit is "amidst the sand" so Perseverance can't beeline and the area to the west and the north of the landing site are also impassable for the rover. $\endgroup$
    – Cornelis
    Feb 20, 2022 at 15:06

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