Comments on: Interstellar Colonization is Really Difficult

By: James Nicoll

James Nicoll — Sat, 23 Jun 2007 17:18:36 +0000

I used to have a program called Swing By Calculator from jaqar and it’s amazing what you can do with relatively modest impulses if you start in space and are not afraid of some !Xtreem! Oberth manuevers as well pushing the envelope on aerobraking at the end.

By: Geof F. Morris

Geof F. Morris — Sat, 23 Jun 2007 16:31:43 +0000

Sorry, James … I mentally went from the “How do we get stuff to orbit?” problem to the “How do we go from planet-to-planet quickly enough so our crew’s bodies don’t completely fail them?” problem without signifying the leap. The error is mine.

By: James Nicoll

James Nicoll — Sat, 23 Jun 2007 14:27:15 +0000

Whoops, I was wrong: some designs for orbital towers can lob payloads out as far as Saturn on minimum energy orbits.

By: James Nicoll

James Nicoll — Sat, 23 Jun 2007 03:08:45 +0000

“Space elevators just get you to orbit. That doesn’t even address the whole planet-to-planet thing.”

Actually, they do, kind of. Out by the counter-weight, the elevator will be moving faster than orbital velocity. Drop something off the end and not only does it avoid paying the 8 km/s to get into orbit but it gets a bit of the delta vee needed to reach wherever.

By: Geof F. Morris

Geof F. Morris — Mon, 18 Jun 2007 17:30:27 +0000

Oh, I agree—if we can handle the engineering details of the space elevator, it makes a lot more sense than chemical propulsion for Earth-to-orbit operations. Just think how much more smoothly this weekend would have gone if all that was needed to fix those pesky ISS computer problems was jetting over to the other end of the elevator to pick up some spares. Even if you only use a space elevator for cargo and never for personnel transfers, it’s a win.

[I say "... and never for personnel transfers ..." because I know how pesky man-rating anything is. ]

See, and I don’t think Apollo was wrong in doing that regard, but I do think that a lot of mistakes were made in the post-Apollo era [which I would start in 1968, because by then, we were practically there]. Once we won the race to the moon, no one had a crisp answer for “Quo vadis?”—no one that got funding, anyway.

By: Stephen

Stephen — Mon, 18 Jun 2007 14:05:48 +0000

Yes, but as the first step, a space elevator is probably the way to go, and once you’re to orbit, power-wise, you’re more than halfway there.

I’m certain Nixon and Vietnam played their parts, but the underlying problem was that we did nothing sustainable in the early exciting days. Everything was focused on getting a person on the moon, not on getting people into space on an ongoing basis.

By: Geof F. Morris

Geof F. Morris — Mon, 18 Jun 2007 10:29:59 +0000

Space elevators just get you to orbit. That doesn’t even address the whole planet-to-planet thing. [Color me skeptical about our ability to get that done. It's a far, far better idea than single-stage-to-orbit, but that's not saying much for it.]

We did the headlong leap for Apollo, and look where that got us.

Whatchu talkin’ ’bout, Willis? I’ve always blamed the post-Apollo doldrums on Nixon’s attitude towards manned spaceflight and Vietnam.

By: Stephen

Stephen — Mon, 18 Jun 2007 01:27:27 +0000

Yeah. Though that’s not what people are focusing on, except for LiftPort, and as Charlie noted in comments, LiftPort is busy working on the elevator part and not the fullerine cable (or equivalent tech), and are in danger of going bust. If they’d focused on the cabling first and were successful, they’d have a product that has a terrestrial market and thus the potential for bootstrap funding for the next steps. So I’d like to see the one step at a time be a manageable step instead of a headlong leap. We did the headlong leap for Apollo, and look where that got us.

By: Jota

Jota — Mon, 18 Jun 2007 01:08:32 +0000

I dunno. All this says to me is, “build a space elevator first; you can figure out the next part once you get into orbit”.

One step at a time. Just one step at a time.