Re: reusable motors


Henry Spencer wrote:

> >> Because, to quote the chief scientist for the rovers, Steve Squyres: "The
> >> rovers... do in a day what a skilled field geologist can do in 30 seconds."
> >
> >Let's crunch the number then ... let's see ... 100 billion in 15 years...
>
> Better get that calculator checked, it's dropped a decimal point. If we
> figure an 8-hour day on the surface, that's 480 minutes, so the manned
> expedition's productivity advantage is almost exactly a factor of 1000.
> The MER primary mission was budgeted at $820M, call it $850M total with
> extensions. So for comparable cost/results, a manned mission gets to
> spend $850 billion.

Which is just about what it will cost.

> Could it be done for that? Sure it could; you could do a long series of
> manned missions for that. Especially if you didn't repeat ISS's mistakes
> by hiring Boeing and Lockheed Martin and having them "supervised" by
> Johnson Space Center.
>
> >...So you say a field geologist can do spectroscopy?
>
> Sure, the same way the rovers can: by holding a spectrometer up to a
> rock.

So you are going to send a field geologist all the way to the surface
of Mars just to hold a spectrometer up to rocks. When shall I quit
laughing. By doing spectroscopy, I mean interpreting the results.

Or by bringing the rock in to be analyzed by a lab spectrometer,

Oh, that's better.

> which will be faster and better than a lightweight mobile instrument.

Right, we can all wait another 30 years, no problem, we've all waited
30 years already.

> >The rovers have been on Mars for ... over 600 days, for about 1 billion
> >including operations, and should last another several hundred days.
> >That's enough certainly to get down into the East Basin, and over to
> >Victoria. What may we find there?
>
> Good question. A manned expedition landed at the same time would have
> known long before now.

But it didn't, because there is no infrastructure, i.e. - heavy lift
launch capability, celss, habitats, they are throwing away progresses
filled with trash, for christ sakes!

> There is no question that the rovers are doing
> good work, but if you assess them by dollars per result, they are the
> expensive way of doing things.

It's only paper, they can print more, right?

> >What will the state of rover and spectroscopy technology be in 2020?
>
> Better, but most of the advances will benefit manned expeditions too. A
> manned expedition won't be just scooping up rocks to bring home, as Apollo
> did. Given the much longer transit time, the sensible way to do a manned
> Mars expedition is a long surface stay with serious lab equipment on hand.
>
> You can't make a manned expedition look *better* by making it shorter and
> less ambitious; that's not the way the economics work. The manned
> expedition's advantages grow dramatically as the surface activity plans
> get longer and more ambitious.
>
> >There is simply no credible case for putting people on Mars in the
> >foreseeable future...
>
> There's plenty of benefit to be had; manned expeditions are much more
> cost-effective than unmanned ones, and that is not going to change soon.
> The problem is the much greater minimum mission size.

Here we disagree, and I am certainly not going to take Squeers offhand
remark as the fundamental basis of your cost effectiveness claim. Mars
is a gravity hole, and the moon is hell. We've got far more important
things to do, places to go, people to see. George Bush, Michael Griffin
and NASA have become an embarrassment to the republic. The first two
have to go, the latter has to be seriously reformed.

> They become
> politically feasible only if the cost can be reduced greatly... which
> *does* look feasible, but not if it's a business-as-usual B/LM/JSC
> project.

I agree, and it won't involve SRBs either.

> >...I would be all for a Mars Direct mission
> >just to get samples, if it didn't involve the moon at all. That is a
> >completely nonsensical diversion...
>
> No, it's simply irrelevant. Going back to the Moon first makes all kinds
> of *sense*, but the purpose is to resume exploration of the Moon, not to
> somehow prepare for Mars.

Funny that's not what George Bush and Michael Griffin originally
claimed.

Are they lying to US, or what?

I suggest everyone read this :

http://www.speakeasy.org/~donaldfr/ssme.htm

http://webpages.charter.net/tsiolkovsky/rocket.htm

.

Relevant Pages

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