When watching the insight landing I saw this map: enter image description here

Now all these missions had to have their own power supply(and more). Why did NASA not send up a kind of energy hub that is fixed where multiple rovers can attach to and branch out from there?

The benefit would be that not all rovers need to bring their own power/solar panels but would just use a battery and could charge up at the hub. The drawback would of course be that they could all only explore a region around the hub. But since it seems that a lot of missions are at similar latitudes and I would assume similar latitudes bring similar possibilities to explore? Of course you would want one around the poles and one around the equator and maybe one in between.

Has this been considered? Is it not useful because each location is so very unique and a different question could only be answered by this location that was selected? Or is it technically too difficult to maintain such a hub or what drawbacks are there that this was not done already?

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    $\begingroup$ Highly related yet distinct question: space.stackexchange.com/q/4332/58 $\endgroup$ – called2voyage Nov 28 '18 at 20:52
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    $\begingroup$ The distance for a trip from energy hub to exploration spot and back to the hub would be too much limited by the small battery capacity. Too much rover time would be wasted during the trip to exploration site and back. If the hub fails, the rovers are lost without power. $\endgroup$ – Uwe Nov 28 '18 at 21:05
  • $\begingroup$ Is it not useful because each location is so very unique and a different question could only be answered by this location that was selected? - > yes. $\endgroup$ – Hobbes Nov 29 '18 at 6:54

Relying on a hub for power not only limits the area that rovers related to a single hub can cover, but it also adds an extra layer of complexity and risk to an already risky endeavor. Missions are designed mostly independently to optimize the chance of success. If a self-sufficient rover mission was one point of failure, then a rover that relies on a hub can be said to have two points of failure. If either the hub or the rover has an issue, it could jeopardize the mission.

Even worse, since the power is centralized to a single hub, each mission adds to the potential losses incurred if the hub goes down. If you have 20 rovers sharing a single hub and the hub fails, then you just lost 20 missions instead of one.

That said, a hub strategy could make sense in a certain context. For example, if your goal was not scientific research but construction of a habitat, it might make sense to have several rovers that share a central hub. The rovers would operate over a smaller area, and you could have one or more rovers with the purpose of checking in on failed rovers (alluded to briefly here). You could even have a drone that could fly overhead to see if a failed rover was in an unsafe condition for retrieval.

  • $\begingroup$ Depending of how it is done one could argue the opposite, that each new mission increases the redundancy, because each new mission could help in repair of the hub/old rovers. So the single point of failure seem kinda unwarranted, but the first point of course stands strong. $\endgroup$ – Hakaishin Nov 28 '18 at 21:18
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    $\begingroup$ @Hakaishin Again, that makes sense over a small area, but exploration rovers cover a large area and make each rover less likely to be able to traverse the distance needed to be of much help. $\endgroup$ – called2voyage Nov 28 '18 at 21:19
  • $\begingroup$ @Hakaishin If you're interested in alternate power strategies for rovers, you should check out beamed power: space.stackexchange.com/a/27057/58 ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930013365.pdf. You could have multiple power-beaming satellites for redundancy. Then the only thing you have to worry about is something obstructing the power receiver on the rover. $\endgroup$ – called2voyage Nov 28 '18 at 21:25
  • $\begingroup$ @Hakaishin Here's another one: nasa.gov/content/success-story-power-beaming-challenge $\endgroup$ – called2voyage Nov 28 '18 at 21:27
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    $\begingroup$ Repair of a failed hub by a rover is very, very difficult. The rover should have all necessary tools and parts and enough remaining battery power to do the repair. All that additional weight would not help a rover doing exploration as his main task. If you want redundancy, you need several hubs. $\endgroup$ – Uwe Nov 30 '18 at 12:11

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