Save the 2009 Mars rover. . .

(Tom Merkle) wrote in message . com...


NASA recently took the fantastic looking diagrams and video off of
JPL's site or I'd point you that way.
_ /--\ _
//----[====]----\\ ----'crane'
| *
** | ** --rocket exhaust
* * \ * *
__\__
\____\ -----------rover

anybody else notice the pictures make the 'skycrane' strongly resemble
a Klingon Bird of Prey?

Tom Merkle

Andrew Gray writes:

You get to pick and choose the landing site, avoiding big boulders,
etc... ;-)

As a quick thought experiment, visualise the way a Viking-style lander
comes down... engine firing, legs touch, kill engine. Sits there on the
sand with a foot of clearance.

OK. But I don't see how the trapeze approach is fundamental to avoiding
boulders. If you're coming down on a cable beneath your landing rockets and see
a boulder where you intend to land, you need some extra fuel to hover while you
move horizontally to find a clear space.

With a Viking style lander and enough fuel to hover and move sideways, couldn't
you do the same thing?

Will McLean

In article ,
Paul F. Dietz wrote:
Laser power beaming?
Not unthinkable, but it'll need a fair bit of laser infrastructure somewhere.

I predict if they build a lunar base, they'll use terrestrial lasers
to power it.

It's a definite possibility. It may actually be the easiest approach for
a small base. (A number of other lunar-night-power approaches are viable
at gigawatt sizes, but scale down poorly.)
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

Subject: Save the 2009 Mars rover. . .
From: (Tom Merkle)

No, not from the budget axe or the usual suspects, but from a far more
pernicious foe: the TooMuchNewStuffAtOnceists.



I agree with much of what you wrote......MSL looks like a sure-fire failure
that ignores the lessons of the 70s and 80s.

The government funded US aerospace industry has long tended to over specify
it's programs. Even the current rovers suffer from this to some degree. For
example the RAT is probably the heaviest and most power hungry instrument on
the rover....it is also the least used......nice to have but not exactly
essential. In fact if you look at the science that has been done so far, much
of it could have been done from a fixed lander . Beagle 2 could have
photographed the outcrop from a distance, and dug holes in the soil and taken
pictures of spherules to it's heart's content. At the Gusev site it could have
told you that the rocks were volcanic and could have studied the "sticky" soil.

The key lesson from the current rovers is that you need to visit lots of places
on the surface of Mars. The science at different sites tends to be different.
Another lesson is that even a simple fixed lander can go a long way towards
characterizing a site.....as long as it has some good lightweight scientific
instruments. You don't need a 2000lb nuclear powered monster.

There were 6 landing sites on the shortlist....the Valles Marineris site rated
higher than Gusev until landing site safety considerations knocked it out.
ANother one was in a crater with a lot of layered rocks and another was an area
with signs of very recent volcanic activity. WHy not take a proven design and
fly to a couple more places? Incremental improvements could be made to the
instrumentation and to reduce the size of the landing ellipse. That last
factor, and the other landing site safety limitations, are probably the biggest
limitation the current rover design has.

Instead NASA wants to repeat past mistakes. In the 70s they flew numerous
medium sized probes, often launched in pairs, and many of them did quite well.
THen in the 80s they went to multi-billion dollar monster missions which went
far over budget, suffered numerous technical failures, and accomplished a lot
less science than hoped. Why is history repeating itself? (JWST is another
example.....but I'll save that for another time)

On Thu, 19 Feb 2004, Brian Thorn wrote:

On 19 Feb 2004 03:19:17 GMT, (McLean1382) wrote:


Theoretically, this gives the lander the ability to pick and choose
its landing site, avoiding big boulders, etc.

What is the advantage of this compared to a Viking style lander?

Look at this great big boulder visible nearby from Viking 1...

http://nssdc.gsfc.nasa.gov/image/pla...glander1-1.jpg

Had Viking 1 landed on it, the mission would have been lost.


Using the so-called "Skycrane" method also allows you to set the rover
down near some of the more interesting places on Mars that we haven't
visited because they're too dangerous for the current generation of lander
methods: namely you can land near or right inside some place like Valles
Marineris.
-Mike