Re: A case for the eradication of unmanned Mars missions

Eugene Leitl (
Fri, 10 Dec 1999 13:40:54 -0800 (PST)

Catching is neat (you can do it with a linear mass driver as well), but each time you miss the target by a meter or two you 1) lose your cargo 2) badly wreck the catcher

The good part about teleoperated/autonomous Lunar industry is that you only have to send bits up there, when a huge material stream can be your return. If you target is Earth surface or LEO, aerobraking will do. If it's deep space, there are solar sails, ion drives or magnetic solar wind sails, ... put your favourite propulsion scheme here.

As to bungee, 1) try putting a bungee cord into a hard vacuum chamber for a week 2) make it deviate from room temperature by a 100 K in either direction 3) what is the speed of sound in bungee rubber? your delta vee be better damn small

If you really want a catcher, then better make it electromagnetic. Can even use regen braking, but why bother?

Jeff Davis writes:
> Now if the capture cable was bungi cord, with the other end attached to an
> outbound vehicle, you could catch one and launch one at the same time. :-)
> Hmmm. A bungi cord launch system? Setting aside the excessive complexity
> of a simultaneous capture and launch arrangement, I wonder if this has any
> merit. It certainly is elegant in its simplicity. I like elegant. I'll
> have to do some calcs. In fact, I'm thinking that a mass driver may be a
> bit more tech than is needed (though I'd be delighted to here of the
> elegance available in mass driver designs). I wonder what other low tech
> options are available for getting a lunar vehicle up to the
> not-very-intimidating-speed of 3745 mph. Suggestions, anyone?
> Best, Jeff Davis
> "Everything's hard till you know how to do it."
> Ray Charles