[extropy-chat] MARS: Because it is hard

Spike spike66 at comcast.net
Wed Apr 14 06:03:42 UTC 2004

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org 
> [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of 
> Emlyn ORegan
> Sent: Tuesday, April 13, 2004 9:12 PM
> To: ExI chat list
> Subject: RE: [extropy-chat] MARS: Because it is hard
> It seems as though it'll be really hard to put physically 
> capable people
> on the surface of Mars, and they'll only be necessary as very flexible
> labour (putting fallen over wheeled devices back on their feet, that
> kind of thing).

Hmmm, thats not really what I had in mind for the
humans to do there.  Vehicles on the surface must
be built to be able to right themselves and not
depend on a human to come out and help.  The human
is there to make some on-the-spot judgements from
nearby, perhaps in Martian orbit.

There is a good argument for not trying to soft-land
the human cargo, for the risk and cost would be high.
The machines I have in mind to take to the Martian
surface would need to withstand the hard landing 
similar to the airbag approach used on the last two
Mars rovers.  After having looked over the weight
calculations, that approach to landing seems to be
about the most convincing.  Soft-landing humans and
all their necessary gear would be too heavy for the
Shuttle-A approach I was thinking about.

In a previous post I mentioned Shuttle-A without
any explanation.  Zubrin mentions a couple of
STS-derived technologies he calls the Shuttle-C
and the Shuttle-Z.  My Shuttle-A notion is the very 
least expensive shuttle-derived technology imaginable:
take an actual shuttle, destined to become a
museum piece after its last official trip for
NASA, then take off everything that is not needed
for re-entry and reuse: wings, wheels, tail, all
aero-control surfaces, some of the orbit maneuvering
system, the sensors, a lotta heavy stuff could
come off.  Then use the remaining orbiter with the
already-designed solids and lightweight external tank,
as a lightened truck to carry perhaps 100Mg of stuff 
directly to Mars.  

The pressurized forward section of the shuttle would be 
the indefinite home for the two ladies.  Their job,
their entire reason for going, would be to guide
and direct the surface equipment, perhaps from a
synchronous orbit.  Remote control from a fraction
of second away is far more practical than attempting
control from 2-15 minutes one-way.  If that scheme is 
used, the plan is to eventually return the astronauts
to earth.

Of course as Gene points out, there are some good reasons
to not send humans at all.  Spending two to five years 
controlling robots would not be a fun job.  Radiation
would likely be quite harmful, and all that weightlessness
would be bad, but both would probably be survivable.

Zubrin is one who has done a lot with the actual weight
calculations.  Until one takes into account weights for
mission design, going to Mars is all just so much talk.
Without the weight calcs, it is too easy to draw the
wrong conclusions about nearly every aspect of the mission.

>... then adjust again and
> fling straight back to the moon/earth. It seems like that 
> might shorten
> the trip in both directions (no slowing down) and minimize the fuel
> (whatever form) required (minimal stopping and restarting, no climbing
> down and up gravity wells)... Emlyn

I can imagine nuclear and ion propulsion being used to
haul nearly all the equipment, with chemical propulsion
being used to carry only the human cargo and related
life-support equipment.

Emlyn, Gene, Adrian, Robert, the rest of you space guys,
what we need to do is put together or look for an existing 
spreadsheet to aid Mars mission design, one that includes 
necessary delta-vees and required fuel load and tank 
size requirements.  Zubrin has already made some pretty
competent looking weight estimates in The Case For Mars.
Perhaps I need to take that on for my next project, or
look around at what has already been done.


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