>You don't need to get the entire mass of the elevator down initially. Just the harpoon and cable.
That's what I said. The trouble is there's no "just" about it. A cable long and strong enough is going to be extremely heavy, never mind the "harpoon". In a traditional "harpoon" the cable is a small fraction of the total mass - you can't really afford that kind of design (shoot heavy thing, drag negligible thing behind) so it's not clear how the orbital dynamics would work. You'd be looking more along the lines of little tug rockets spaced along the length of the cable.
>Many of the ideas for visiting other planets could and should be tested on earth first.
Quite. This Mars stuff is completely pie in the sky. Let's see a self-sustaining habitat in a desert on Earth, never mind even the moon. As an incidental benefit of solving this we would be able to perform sustainable agriculture anywhere on Earth.
The harpoon could be a big heavy thing. Perhaps we crash an astroid into Mars that is trailing a cable. That doesn't really jive with the planetary protection principals but it might be the kind of thing we need to consider to get the job done.
> As an incidental benefit of solving this we would be able to perform sustainable agriculture anywhere on Earth.
True. Although sustainable on Earth usually also means economical. I would like to see a sustained habitat on the moon.
That's what I said. The trouble is there's no "just" about it. A cable long and strong enough is going to be extremely heavy, never mind the "harpoon". In a traditional "harpoon" the cable is a small fraction of the total mass - you can't really afford that kind of design (shoot heavy thing, drag negligible thing behind) so it's not clear how the orbital dynamics would work. You'd be looking more along the lines of little tug rockets spaced along the length of the cable.
>Many of the ideas for visiting other planets could and should be tested on earth first.
Quite. This Mars stuff is completely pie in the sky. Let's see a self-sustaining habitat in a desert on Earth, never mind even the moon. As an incidental benefit of solving this we would be able to perform sustainable agriculture anywhere on Earth.