Sampling Mars Surface???

My first thought that comes to mind is."how important is it to have our
two landers move around at this time"? They have 6 wheels,and that
means 6 motors,plus a lot of engineering. Why not a stationary
plate form that can lift itself off the surface 10 feet with a periscope
camera that can go up another 10 feet. 20 feet up of viewing rather
than moving about. Instead of all those wheels and motors a strong motor
under the landers belly to core down and analyze core samples for
underground water. Going down 20 feet. It could be made with a larger
arm to drill into rock,near by. It makes for good TV viewing moving
about,but is it really worth it. Here on earth landing say in Ohio has
the same terrain for a million square miles. This has to be true or even
truer on Mars. Best it comes down where its aimed,like inside a very
large crater. The thought I'm trying to get across is" the grass can't
be that much greener from one end of a crater than the other end."
Bert

Bert posted:

My first thought that comes to mind is."how important is it to have our
two landers move around at this time"?

It is VERY important, as any geologist will tell you. The rocks rovered-to
and analyzed by the Sojourner rover were sometimes different from each other.
You can't analyze what you can't get to.

They have 6 wheels,and that
means 6 motors,plus a lot of engineering.

6 wheels means multiple redundancy in case one motor fails or one wheel get
hung-up on something. The engineering is based on Pathfinder rover technology
which worked pretty well last time.

Why not a stationary
plate form that can lift itself off the surface 10 feet with a periscope
camera that can go up another 10 feet.

That sounds half-baked (too heavy). Again, unless you can go to something you
can see, you won't know anything more about it than what it looks like.

Instead of all those wheels and motors a strong motor
under the landers belly to core down and analyze core samples for
underground water. Going down 20 feet.

That would require a substantial lander (and heavy). Again, it would not tell
you anything more than what was 20 feet directly under the lander. If the
lander landed in a spot where there was no water 20 feet down, but there was a
water-bearing layer not far away, there would be no way to get to it.

It makes for good TV viewing moving
about,but is it really worth it.

Yes it is, as was proven by the Sojourner rover at Sagan Station.

Here on earth landing say in Ohio has
the same terrain for a million square miles. This has to be true or even
truer on Mars.

No, it is not. The overall terrain shape might be similar, but the rocks are
different depending on where you *go*. It is the difference and where the
various rock types are found which tell the story of the geologic history of
the planet.

The thought I'm trying to get across is" the grass can't
be that much greener from one end of a crater than the other end."

It can be "greener" in that on one side of the crater Gusev (where MER-1 is
targeted) there is a volcano, and on the other side is a breach in the wall
where the outflow channel Ma'adim Vallis begins. That makes for a heck of a
difference in what might be found on the crater floor.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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David as I sit here reading your post my wife handed me this week"s
TIME mag.and handed it to me opened to page 60.(now I'm an expert.)
Right off I don't like its wheels.(to small) 5-ft rovers to big and
heavy. Fast reading size of a golf cart.(would it be cheaper to use a
golf cart?) Cost 625 million(was that wholesale?) Can travel 131 ft
per day Here I see the next probe will just stay in one place,and do
its research(not roving). Well David its all a point of view.
Drilling down 20 feet vertically to find water,and with camera 20ft
above the surface seeing at great distance horizontally is nice. Lets
just hope all goes well. I like this better than NASA putting people
in space to go round and round.in a Rube Goldberg shuttle. I don't care
David if all does not go well. It is only time and money lost. The most
important thing we are discovering a new world,and history of man tells
us that is his destiny Bert

Bert posted:

I sit here reading your post my wife handed me this week"s
TIME mag.and handed it to me opened to page 60.(now I'm an expert.)

Hardly. Try going to http://mars.jpl.nasa.gov/mer/ and reading what is
there. I have seen TIME produce articles which are oversimplified and, in
some cases, a bit inaccurate.

Right off I don't like its wheels.(to small)

That is too bad, because they are about the right size (10 inches in
diameter). Too large and they would not fit in the lander package. Too small
and they might not function under the weight of the rover or allow it to go
over some rocks.

5-ft rovers to big and heavy.

You need size to carry things like the multiple instruments, the solar panels,
the computers, the cameras, the masts, the arm, ect. Its not very big, and
under the weaker Martian gravity, it should do fine.

Fast reading size of a golf cart.(would it be cheaper to use a
golf cart?)

Yea, right, using a golf cart on Mars. Talk about a stupid idea. This is a
scientific mission to a dangerous world, not an 18 hole jaunt down some smooth
grassy fairways!

Cost 625 million(was that wholesale?)

That is the entire development and construction cost, and not just the cost of
the hardware.

Can travel 131 ft
per day

It may travel that much (or somewhat more, as its maximum daily "range"
(barring stops for obstacles) is close to 100 meters), and then again, if
there is a small area that has a lot to be investigated, the rover may not
travel very far during a particular day.

Here I see the next probe will just stay in one place,and do
its research(not roving).

The next probe to Mars will be an orbiter (Mars Reconnaissance Orbiter) and
not a lander. The next landing attempt *may* be another attempt to fly a
modified version of the backup spacecraft from the Mars Polar Lander Project,
now deemed "Phoenix", to the polar regions of Mars.

--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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David They used the relation that the size and weight is like a golf
cart. Do the probes have a drill to go into Mars surface? That could
tell how deep the sand is in that area. IWhen it hits the solid crust
and analyzes the composition of the crust that could be very
interesting. Just to see the dust and sand sticking to the rovers arm
has a lot to tell us. The way things stand with NASA,and our country
going into red this year by another 500 billion dollars,and if these
probes just disappear the engineers at NASA might end up selling
oranges. Bert

David The rover could come down in a rather deep sandy area,and the
nearest rock could be 1.8 miles away. Those wheels don't look like they
could push 5 hundred pounds through fine 16 inch deep sand. I posted I
like tracks. Sand is like water,and it will hold objects up and the
bigger the area the better. That is why snow shoes were invented. David
I don't want you or other readers to think I'm negative. Mars is so far
away we don't want the rocket to leave until we thought every thing out.
What I have seen on its surface it looks a lot like the moon,but has
more small rocks,and sand. Bert. .

Bert posted:

The rover could come down in a rather deep sandy area,and the
nearest rock could be 1.8 miles away.

Bert, have you ever actually *looked* at the pictures from Viking or
Pathfinder? There are rocks EVERYWHERE.

Those wheels don't look like they
could push 5 hundred pounds through fine 16 inch deep sand.

It isn't 500 lbs. Its 190 lbs (remember, Mars gravity is 0.38 that of Earth).


--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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David I did see the pictures,and that is why I posted Mars has a lot of
small rocks(yes?) Read my post again(please.) True Time Mag gave its
earth weight as over 500 lb Keep in mind David that its "MASS" stays
the same. Keep in mind David that the depth of the sand and
dust is a variable. I see their wheels with no push to them. I see them
to small,and they still have to push the mass inertia of the rovers over
rocks(hopefully that are not that bigl) The rocks may be
small,but they won't be pushed out of the way(they have their mass
inertia as well) Going over them with fine dust acting like a lubricant
is what I'm worried about. David I don't call NASA about this
because no lives are put in harms way.. Bert

Bert posted:

I did see the pictures,and that is why I posted Mars has a lot of
small rocks(yes?)

There were also a number of BIG rocks. There is no need to go "1.8 miles
away" to find a rock.

Keep in mind David that its "MASS" stays
the same.

Irrelevant. The rover won't get stuck for just being too heavy as you imply.
The rover has been tested under conditions which are a close match to those
on Mars. Its basic roving design is based on the successful Pathfinder rover.
It should work on Mars at least as well (if not better) than the Pathfinder
rover did.

Keep in mind David that the depth of the sand and
dust is a variable.

The Pathfinder rover (with similar but smaller wheels) had no trouble moving
around the surface of Mars. It moved over low dust dunes, over surfaces with
small rocks, and over flat compacted soil. Where it encountered bigger rocks,
it either drove around them, or stopped and called home for instructions. The
wheels are wider than the wheel an Earth vehicle is, and the wheel is
specifically designed to perform well on the Martian surface.

I see their wheels with no push to them

Its not the wheels that give the "push". Its the electric drive motors, and
they are more than adequate for the job. If the rover can drive around on the
Earth's rough surface (as engineering models were shown demonstrating their
abilities), they can easily do so on Mars. The lunar rovers couldn't drive on
Earth (without assistance), but they did a very nice job of it on the moon.
They needed bigger wheels due to the speed which they needed to travel over
the surface. The Mars Exploration Rovers don't need to go fast, they just
need to "go".
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
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Bert posted:

True Time Mag gave its
earth weight as over 500 lb

TIME is incorrect. The lander has a mass of 170 kg (weighs about 375 lbs on
Earth, but only 142 lbs on Mars). It is smaller than many golf carts. The
tallest segment is the Pancam Mast Assembly (containing cameras), which, when
deployed, will stand about 1.4 meters above the ground (about 4.6 feet). The
rest of the rover is less than half this high.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
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