Comments on: Griffin on Congress, White House changes

By: Adrasteia

Adrasteia — Sun, 24 Dec 2006 13:45:21 +0000

A rover would only weigh about a hundred kilograms, I assume they’ll bolt it onto the bottom of the descent stage.

By: Paul Dietz

Paul Dietz — Wed, 20 Dec 2006 02:37:17 +0000

Heck, even the rover isn’t in the ESAS plan, is it?

By: Doug Lassiter

Doug Lassiter — Tue, 19 Dec 2006 23:25:21 +0000

“… for a known cost, with current technology and no leaps of faith”

A few *kilometers* of power cable???? C’mon. Spare me. It is NOT known cost, NOT current technology (what, rain and snow proof vinyl insulation?), and quite an enormous leap of faith. Get a grip.

By: kert

kert — Tue, 19 Dec 2006 09:26:47 +0000

I know that the “permanently lit” areas of moon are permanently questioned ( for really bitter critique, see Donald Rapp’s recent rants on http://www.mars-lunar.net/ )
Asserting that wireless power transmission is considered “too risky” technology, and putting up a lunar powersat to illuminate the solar panels in the dark is also too far-fetched ..
Given a “hopper” type of lunar lander or a good rover, how hard would it be to lay few kilometers of power cables on lunar surface around the pole ? so that you could actually get all time solar power, with different sites with panels backing you up.
It would probably take few cargo launches of the cable, but you would have the problem cracked, for a known cost, with current technology and no leaps of faith.

By: Drew

Drew — Tue, 19 Dec 2006 04:06:05 +0000

I think the mean equilibrium temperature for a grav-normal surface at the pole is more like 130K. That is still kind of cold. Had wondered how they were going to deal with that. Perhaps they will always hang out on a sun-facing hillside?

By: Doug Lassiter

Doug Lassiter — Tue, 19 Dec 2006 00:51:19 +0000

Polar bases on the Moon will place a premium on horizon visibility. This need, and the challenges that the resulting shadowing entails, is already understood as a serious problem by LAT folks. But that’s another thread.

Heat sinks are indeed useful in thermal management, but not with hot surfaces. In fact, non-polar regions of the Moon are understood to be difficult re thermal control. The hab gets hot, and you can’t dump the heat into the warm regolith underneath. That’s one advantage of polar ops (ummm, there aren’t many others). BTW, I’m looking forward to watching astronauts trying to walk around on a 100K surface! Ouch! Ouch! Wool socks maybe?

It’s actually not hard to dump heat in free space. Your radiators need to get hot (as in Prometheus-type nukes), but that works. But except for NEOs (yep, let’s dismantle a few!) you don’t have rocks to grind on up there. Ah well.

By: Donald F. Robertson

Donald F. Robertson — Mon, 18 Dec 2006 20:08:04 +0000

Here, Doug, you might benefit from thinking positively. Most asteroids rotate quickly, and (on non-tumbling bodies) the pole is a short distance away. Power should be readily available.

Likewise, a polar base on the moon, for (as I recall) a minimum of seventy percent of the time.

Moreover, rocky bodies offer an added benefit of a near-infinite heat sink in any permanent shadows. You should be able to “sink” directly to the physical surface, potentially an easier process than radiating to free space.

In both cases, this contrast between high solar temperature next to permanent cold presents ideal conditions for generating power and running many industrial processes.

— Donald

By: Doug Lassiter

Doug Lassiter — Mon, 18 Dec 2006 19:15:18 +0000

“But even more important, depending on the nature of said rocks, you can “live off the land” to a lessor or greater degree. Outside of power, you can’t do that in free space.”

Well, if this were about “living” rather than “doing”, I might accept the assertion.

Important point about power. When the Sun goes down, those rocks between your toes get kinda cold, the oxygen extraction system grinds to a halt, and the lights go off. That’s when you really wish you had the technology to make use of the 3He you’re standing on, as the wishful thinking about it doesn’t generate a lot of energy.

By: wg cannon

wg cannon — Mon, 18 Dec 2006 18:48:13 +0000

I’d rather see us going to Mars, but with the political climate now you take what you can get. And I think the moon is our only shot at getting out of earth orbit.
Through l2 destinations might be more practical but try to explain something as intangiable as a langrange point to a congressman.

By: Donald F. Robertson

Donald F. Robertson — Mon, 18 Dec 2006 18:37:37 +0000

Hey, Doug, here’s another rare moment of (partial) agreement. I don’t think that Mars must, or even should, immediately follow Earth’s moon. It’s too big a leap. Nearby asteroids and the Martian moons should both come first.

That said, there a great advantages to “rocks between your toes.” It’s a more familiar environment than free space, and we shouldn’t underestimate the importance of tacking the relatively familiar before the completely alien. But even more important, depending on the nature of said rocks, you can “live off the land” to a lessor or greater degree. Outside of power, you can’t do that in free space.

(If we didn’t already have an established political coalition for returning to the moon, I might even argue that NEAs should come before that. Notwithstanding that I think there is a lot of extremely valuable science to be done on the moon, both the scientific and resource benefits of asteroids are likely to be higher.)

— Donald