Re: They land back to earh requires an ungodly amount of fuel
TFW you remember the first time your read about "Delta-v" in the novelization of "2001 - A Space Odyssey" back in the 70s.
"At the moment my closest approach is sixty miles; it will increase to about a hundred as Japetus rotates beneath me, then drop back to zero. I'll pass directly over the thing in thirty days – but that's too long to wait, and then it will be in darkness, anyway.
"Even now, it's only in sight for a few minutes before it falls below the horizon again. It's damn frustrating – I can't make any serious observations.
"So I'd like your approval of this plan. The space pods have ample delta vee for a touchdown and a return to the ship. I want to go extravehicular and make a close survey of the object. If it appears safe, I'll land beside it – or even on top of it.
"The ship will still be above my horizon while I'm going down, so I won't be out of touch for more than ninety minutes.
'Tm convinced that this is the only thing to do. I've come a billion miles – I don't want to be stopped by the last sixty."