Re: Why NASA should focus on the Moon, not Mars - Henry Spencer

On Nov 26, 7:20 pm, Brian Thorn <bthor...@xxxxxxxxxxxxxx> wrote:
On Tue, 25 Nov 2008 20:41:05 -0800 (PST), Totorkon

<aertr...@xxxxxxxxx> wrote:
What if it is a shorted wheel motor or broken gear on a field
expedition. Humans can't repair it without parts or in a clumsy
pressure suit.  Loss of a machine mission to faulty equipment is a
setback far better than the first corpses on mars.

Right. Spare parts cannot be carried. Designing the rover to have
easily replaceable critical parts like the Hubble Space Telescope is
never going to happen, and its is totally impossible to have a
redundant rover on standby back at the base in the worst case
scenario. Oh, wait...

Pheonix offers an example of an automated lab.

Which wasn't much of a lab by terrestrial standards and barely worked.

A crewed mars mission was part of the Bush VSE.

Only by Bush 43 saying "and eventually to Mars" in his VSE
introduction speech. Otherwise, no details whatsoever, and the
emphasis was hugely on the Moon. There is no Mars expedition in the
planning stages.

Think of what a lunar rover robot with solar wings or an rtg could
do.  It could easily cover half the moon in a year.

Whiskey Tango Foxtrot, over? We already know what solar powered rovers
can do. Spirit and Opportunity have done a few miles between them in
nearly five years. The RTG-powered Mars Science Laboratory is being
designed with expectations of a 12 mile excursion, and that's for two
years.

The Moon is not an easier destination. In fact, it may be harder due
to harsher nightime conditions and 100% vacuum.

It could dwell at
interesting selenological sites sending back millions of pictures at a
full range of magnifications.  It could send back more than a ton of
samples for a landed weight equal to one lem.

One LM was 33,000 lbs.

Mars Science Laboratory will be about 2,000 lbs and is running $1.9
billion so far. You do the math. These wonderful robots ain't cheap.

Given a $100B pricetag for iss (closer to twice that),

It's somewhere around $30 billion, actual hardware costs to date. Add
in another $3 billion a year for the Shuttle launches and we're in the
$50-75 billion range (depending on whether you count the entire
Shuttle budget to ISS, despite Hubble missions and the like). Clinton
capped its budget at $24 billion, and of course it blew past that,
causing Bush 43 to cut things like the Hab module and CRV (that's why
he put O'Keefe the beancounter in charge of NASA.)  

The oft-reported "$100 billion" cost figure originates in NASA
forecasts back before Columbia, but included Station and Shuttle
support through 2015, the original ISS end of mission. Of course, with
Shuttle retiring in 2010, a big chunk of that high cost will be
reduced after 2010.

Why do so many critics keep throwing around dishonest numbers like
"$200 billion"? Scare tactics when all else fails to sway bystanders
to your side?

estimates range up to $1T to put a crew on mars.  

Cite? Even the outrageous Space Exploration Initiative under Bush 41,
which included everything and the kitchen sink, was "only" $500
billion. And NASA was laughed off of Capitol Hill, with Administrator
Truly eventually quitting because of that debacle. There is no chance
anything that huge will ever come close to Congressional approval.

Zubrin, on the other hand, was promising manned Mars missions for
$30-50 billion in his 1990s Case For Mars heyday.

NASA is forecasting the new lunar program to cost around $105 billion,
and that includes something like a 15% cushion for busted budgets.
(And when you see $100 billion or $200 billion thrown around, remember
that Congress just handed Wall Street $700 billion free and clear.)
The Mars missions will eventually be able to use much of the lunar
infrastrure (Ares V and the Orion ferry, or under alternative
architectures, improved EELVs and orbital propellant depots) so some
of it will already be paid for.

Good luck selling that to a nation
nearing a depression.

We're not nearing a depression. Scare tactics again?

Brian

If my intent were to provoke an articulate argument for a crewed mars
landing... mission accomplished.

If international contributions are included, the pricetag of the
completed iss will exceed $100B. That $T for mars has been thrown
around, albeit by critics. Zubrin's estimate is a quarter of the
apollo program cost, which does seem overly optimistic.

The mer rovers in their prime could generate almost a kWhr/day, even
with the high incident angle of the sunlight. Careful design of solar
'wings' could quadruple that. At an average 1mph for ten hours a day,
circumnavigation of the planet would take less than four years, a
rover lifespan that has already been exceeded.

Expanded robotic exploration does have some things going for it.

Commertial spinoffs of technology development are likely to be greater
than the manned alternative.

The process can be piecemeal, building on experience and following up
on discoveries made by previous missions.

The missions can be carried on smaller launchers, with the potential
for competition.

The most efficient, but too slow for lifeforms, solar powered ion
propulsion, would benefit the developement of the lightest and longest
lasting space solar panels.

Dependable Mars adapted machinery will be essential for human
survival. Field testing makes perfect.

The more information the public has about mars, the more excitement
that can be generated, the greater the support for a second planet
with people.

The emphasis should be on the water, CO2, near earthly length of day
and radiation shielding. If the mission is configured so that most of
what's needed to survive comes from the resources in place, there
might be a lot more support for a wayout outpost of human
habitation.
.

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