Re: reusable motors

In article <1132437662.710913.179790@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
<lifeform1@xxxxxxxxxxxx> 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.

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. Or by bringing the rock in to be analyzed by a lab spectrometer,
which will be faster and better than a lightweight mobile instrument.

>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. 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.

>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. 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 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.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. | henry@xxxxxxxxxxxxx
.

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