Opportunity getting unstuck movie

They have a Quicktime movie up made up from pictures from Opportunity
showing the rover getting itself unstuck from the dune:
http://www.jpl.nasa.gov/videos/mer/0...pportunity.mov
Whoever designed those wheels the way they did should get a medal, as
the rover doesn't drive its way out, it _digs_ its way out using the
wheels like bucket-wheel excavators. one thing this movie really lets
you see is the consistency of the Mars soil, and how it behaves when
acted on by mechanical force; to me the way it behaves is a lot like I'd
expect Lunar soil to behave- it's got a decided "stickiness" to it and
stays clumped together, as well as adheres to things when compressed,
the way dry cement dust would. The appearance of the soil in the wheel
cleats makes it looks like it's extremely homogenous and fine grained,
but has a sort of fragile crust over its surface that the rover is
grinding up with its wheels, like very fine-grained sand whose surface
has been wetted and then allowed to dry.

Pat

The soil mechanics people will get a lot of data out of those movies.

I wonder if the "soil" (regolith) is representative of the whole area.

Note by definition, soil contains a biological component.
A more proper tem is "regolth"

Matthew Ota

Matthew Ota wrote:
The soil mechanics people will get a lot of data out of those movies.

I wonder if the "soil" (regolith) is representative of the whole area.

Note by definition, soil contains a biological component.
A more proper tem is "regolth"

Matthew Ota

More years ago than I care to recall, we had at our Outdoor School a
soil coucelor whose major rant was "Soil Is NOT dirt!! You can't eat
dirt!", and then would promptly eat a handful. It was the high point of
the week.

I might be a bit out of date, but in my Geo classes (late '70s West
Coast) we used "dirt" to indicate an organic component, and "soil" was
the general term. This was soom after the Apollo and Viking Missions,
when even the scientists freely used "soil" for either. Regolith was
used for the lunar surface; but it always seemed to be used as a bulk
term, and the samples (or if you got some on your spacesuit) were
always refered to as soil (or soil particles).

wrote in message
oups.com...

I might be a bit out of date, but in my Geo classes (late '70s West
Coast) we used "dirt" to indicate an organic component, and "soil" was
the general term. This was soom after the Apollo and Viking Missions,
when even the scientists freely used "soil" for either. Regolith was
used for the lunar surface; but it always seemed to be used as a bulk
term, and the samples (or if you got some on your spacesuit) were
always refered to as soil (or soil particles).

Mixing one's definitions, it follows that a Martian rover's wheel may be
very dirty and very clean at the same time.

Matthew Ota wrote:

The soil mechanics people will get a lot of data out of those movies.



They never would have tried what they ended up having to do on purpose;
but the whole icident should reveal a lot about the regolith.

I wonder if the "soil" (regolith) is representative of the whole area.



It looked to me like there was a harder under-layer that the loose stuff
that the rover got stuck in had drifted over rather like a sand dune;
when it get's fee in the movie, you can see it's not makeing anywhere
near as deep an impression in the regolith ( I never liked that term,
I'm going to call it Barsoomolith from now on) as it was when it was
when it was near the area where it got stuck.

Note by definition, soil contains a biological component.
A more proper tem is "regolth"



Well, here's hoping it's soil then. :-)

Pat

References:

http://en.wikipedia.org/wiki/Soil

http://en.wikipedia.org/wiki/Regolith

Matthew Ota