Closest and furthest pairs of unmanned space craft Options

[tasp]

Ok, obviously, furthest separation of spacecraft would be Pioneer 10 and depending on when we check, Pioneer 11, and later Voyager 1 and/or Voyager 2.

But what is the closest 2 craft have come on seperate missions ??

Were there any close approaches of Magellan to any Soviet orbiters at Venus ??

Has there any been a Soviet Lander on Mars close to either Viking ?? Any chance of the Halley armada vehicles being particularly close to each other during their missions ??


I would mostly be interested in active mission encountering each other, but a live mission 'checking out' a prior 'dead' one closely (Apollo 12 and Surveyor 3 type encounter for example, but keep in mind Apollo 12 was manned and not applicable here) would be interesting too.

[nprev]

Wouldn't have been appropriate for the MERs with just 90-day nominal missions. Thinking of 20+ year surface surveys, which definitely are beginning to look achievable in the near future. For example, if we were to fly rovers to Titan in 2030, I'd put a pair in one place & a pair in another (deep, deep pockets and/or very inexpensive yet reliable designs assumed, of course...)

[centsworth_II]

I'd put a pair in one place & a pair in another...

I think most would agree that it would still be better to put them in four different
places. I don't see how the advantage to sending a rover as a buddy to another
rover could possibly outweigh the advantage to having a look at an entirely different
location. Even with a different science payload on each of two rovers, the use of two
sets of roving hardware (wheels, chassis, etc.) sent to one location would be an
extravagant waste of payload budget.