:: What's a "heliospheric orbit"?
:: You just made that up, didn't you?
:: And have no idea what you really mean by it, right?

I googled it also, fwiw. It's used in a few places, but incoherently.
Possibly Bob picked it up from some other orbital-mechanics-challenged
individual.

: Jochem Huhmann
: I think it's pretty clear that he means a relay in an orbit around the
: sun that would allow continious communications between Earth and Mars.

In which case, I conclude you need an orbit in either an earth-sun L[45]
point, or an earth-mars L[45] point. Otherwise, it's difficult to ensure
that you can always send a message without expensive fuel use. Or, naict.

: Which probably isn't worth the money, especially for aging flaky
: rovers. If something's suspect of not surviving a month of not being
: closely monitored it's probably hardly worth saving anymore.

Yes, if that's the only application.