Re: An alternative to Orion/Constellation?

Hi Jeff,

Some brief responses...

Jeff Findley wrote:
There are arguments for a lunar base and against a lunar base when you claim it's a first step to Mars. As an example, man has spent precious little time actually on the moon and it will provide a way to gain EVA experience on a body other than earth. How well the *particulars* translate to a Martain EVA is what's debatable. The atmosphere on Mars is thin, but does complicate cooling. The gravity is higher than the moon, making lightweight suits and life support critical. Abrasive dust (like the moon) may not exist on Mars due to wind erosion.

There are countless other ways that a moon base could help us learn how to live and work in space before we attempt a Mars mission. But in the end, Mars isn't the moon...

Agreed.

Instead...

We should be focusing on building what I call a 'traveling space habitat'.
Something on the order of a very small space station that can be sent out
of low Earth orbit (LEO) on orbital exploration missions. First to the moon,
then maybe Venus, and eventually Mars. It would be self-sufficient and fully
reusable and capable of supporting a 6 person crew nearly indefinitely. Such
a vehicle would get us well past the moon, but could be effectively used in
a lunar exploration program as well as giving us a pathway to the planets.

We can do "spam in a can" missions in LEO. That's what ISS is for.

Hmmm. As a destination now that it is (almost?) finished I agree. During its construction
NASA was the one claiming that the Shuttle was indispensable to accomplishing
that task. Do you think 'spam in a can' could have *built* the ISS?

Changing the venue to lunar orbit or Martain orbit doesn't make much of a difference in terms of the engineering, science, or even public interest. Actually setting foot on the moon, an asteroid, or Mars is completely different.

I think I spot a difference of opinion between you and Derek Lyons. Derek thinks there
are huge engineering obstacles to overcome going each step of the way, each
gets harder than the other. LEO, Lunar Orbit, Interplanetary Transit, (and
for the heck of it since Derek didn't mention it) Planetary Orbit. I feel I
have to agree with Derek, these are all significant problems to overcome. I differ
with Derek in that I think we should get started on them now.

In terms of public interest, I think you over estimate the value of 'boots on
the ground' as it were :-). The journey itself will be enough to capture the
public imagination. That is why I think a Venus orbital mission would be a good
pre-cursor to Mars. There are significant advantages to going to Venus before
Mars in terms of distance and logistics. Having a manned orbital laboratory in
Venusian orbit to conduct experiments over the better half of a year would lead
to invaluable planetary science benefits. In terms of atmospheric science and
climate change, maybe even more so that a Mars mission.

Besides, if you're going to pay the delta-V to send your habitat to Mars, leaving out the landing part is pretty silly. You're 90% of the way there, why not go that extra 10%?

Oh absolutely. There would be no point to going to all the trouble of outfitting
for a manned Mars mission that would not include manned surface landings.
If I implied that, it was wrong. I did not mean to imply that.

We need not another moon capsule but a better shuttle and the ability to
construct stuff in low Earth orbit (LEO). The moon can wait IMO. Colonization
should be left up to the private sector when there is sufficient economic
reason to do so. That's the only way it will ever be sustainable.

Meh.[1]


Reusability would be a good thing, if the flight rate was higher. Starting with a reusable first stage is where I'd start. A reusable capsule won't save money if the flight rate is going to be very low due to using expendable launch vehicles (the latest Ares I proposal is to delete the Ares 1-Y test flight and delete SRB recovery to save development costs and get it flying sooner). NASA is definitely going away from reusability in its panic to keep Ares I and Orion funded.

Jeff

Which implies what? A low flight rate, correct?

[1] Meh.

:-)

Dave
.

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