Re: Mars expeditions (was Re: Proposed sample return mission to Phobos)

henry@xxxxxxxxxxxxx (Henry Spencer) wrote in
news:JDonHF.8FG@xxxxxxxxxxxxx:

In article <45d24e52$0$25943$ba4acef3@xxxxxxxxxxxxxx>,
jacob navia <jacob@xxxxxxxxxxxxxxxx> wrote:
This is 32 months, i.e. around 2.5 YEARS in no gravity or
in very low gravity. Note that NO HUMAN has been more
than 13-14 month (I do not remember the record but it is
in this range) in space. And the guy was seriouslly ILL after
that trip.

Uh, no, Valery Polyakov walked off the plane unassisted in Star City
after 14 months on Mir. (The doctors had conniptions, but being an MD
himself, he wasn't intimidated...)

The transit time isn't a big deal, especially since it's not
formidably difficult to provide artificial gravity while in transit.
The difficult question is whether Mars gravity is enough to keep
people in reasonable shape, since a relatively long stay is desirable
and artificial gravity isn't very practical on the surface.

All human technology can do NOW is to put around 500 Kg in Mars.

Uh, no. You're confusing what can be done with off-the-shelf hardware
and what can be done with today's technology. If you are willing to
use orbital assembly, there's no question that we've had the
technology for a manned Mars expedition for about 40 years now.

To sustain several people for 16 MONTHS we would need
TONS and TONS of supplies!!!

Circa half a ton per man-year, if you can recycle wash water
adequately and you don't need too many spare parts. (The
dehumidification that you must do anyway can supply enough water for
drinking and food preparation, and you can electrolyze a bit of the
water for oxygen, but you *must* recycle the water used to wash
dishes, clothes, and people -- there's too much of it.) This is
substantial, but not a huge barrier.

In fact, you can make a passably good argument that it's cheaper to
make the mission heavier, and accept the extra launch costs, than to
spend a lot of engineering man-years making it really light. The one
"lightening" technology that probably *is* worth the trouble is
wash-water recycling.

And there is a strong possibility that they have significant water
content, in which case their resources might be quite important to
future transportation to and from Mars. (And elsewhere -- in energy
terms, they are closer to Earth orbit than the surface of the Moon
is.) Of course, that's not relevant to a flags-and-footprints Mars
mission... if that's all you care about.

This is a pipe dream. No humans will go to Mars within the next 30
years.

So? The possible resources of Phobos and Deimos remain of interest no
matter what the detailed schedule is.

WE DO NOT NEED TO GO THERE. The mars rovers have demonstrated that
we can send virtual beings controlled by us safely here, that can do
the SAME exploration that a human would do but for much longer
periods.

No, they can do *some* of the same exploration that a human could, but
*stretched out* over much longer periods. The total mileage on
Opportunity at the moment, after three Earth years, is roughly that of
the first day's rover activity on Apollo 15. The people running the
rovers say it takes them a day to do what a human field geologist
could do in half a minute. And that's for the things they can do at
all -- for example, no rover now *planned*, never mind launched, can
drill a core sample as deeply as the Apollo 15 astronauts did on their
second day. (Sure, you could build a rover which could -- although
it's not as easy as it looks -- but that's far from the only thing on
the list.)

If you ask any of the geologists on the MER science team, they'll tell
you that properly solving many of the mysteries is going to take human
field geologists on the surface. The rovers are clumsy stopgaps, not
full substitutes.

The only point I'd quibble with is that once we (US) are ready to send a
person to Mars, we'll probably be able to construct rovers competely
capable of doing anything a person can do. Such rovers might not be self-
motivating, but a simple declarative sentence will suffice to initiate an
action.



The mars rovers are working now for more than 3 years and they go on
and
on!!!

They've been lucky... and neither of them is 100% functional any more.

.

Relevant Pages

  • Lecture of the Week: Part VII: Astrobiology
    ... "If Mars be capable of supporting life, there must be water upon his ... for, to all forms of life, water is as vital a matter as air. ... rovers were sent to Mars to be the robotic hands and eyes of geologists ... landed on the floor of Gusev Crater, which was found to have been dry ...
    (sci.bio.evolution)
  • Re: Improved lunar landing architecture
    ... Mars orbit without taking a look at the two small moons. ... Kind of like a comet that lost 99% of its water due ... Phobos is losing orbit by 1.8 meters per century. ... Because of its ellipsoidal shape alone, the gravity on Phobos' surface ...
    (sci.space.policy)
  • Mars expeditions (was Re: Proposed sample return mission to Phobos)
    ... difficult to provide artificial gravity while in transit. ... a manned Mars expedition for about 40 years now. ... Circa half a ton per man-year, if you can recycle wash water adequately ... first day's rover activity on Apollo 15. ...
    (sci.space.policy)
  • Something NASA did well
    ... the Spirit and Opportunity rovers on Mars ... further evidence about water or water vapor once present on the ... initial ISS orbit correction maneuvers," he said. ...
    (sci.astro.amateur)
  • NASA Grant Will Fund New Research on Mars with the Spirit and Opportunity Rovers
    ... Opportunity Rovers ... rovers on Mars are giving some real competition to the pink bunny from ... further evidence about water or water vapor once present on the ... Oded Aharonson, assistant professor of planetary science at Caltech, ...
    (sci.space.news)
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