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Opportunity's sand box....



 
 
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  #1  
Old May 13th 05, 09:45 PM
snidely
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Default Opportunity's sand box....

Here's JPL's note about working on the way out of the stuck position
Opportunity is in:
http://www.jpl.nasa.gov/news/news.cfm?release=2005-072

quote
"We choose to proceed cautiously, so we don't expect to begin actually
driving out of the dune before next week, possibly later," said Jim
Erickson, rover project manager at JPL

[...]
Last week, engineers arranged a simulated dune using sand that was
already at JPL's rover testing facility and put a test rover into a
comparably dug-in position. The test rover had no difficulty driving
away, even when sunk in belly-deep. However, that sand offered better
traction than the finer, looser material that appears to make up the
surface at Opportunity's current position. "We needed to do tests using
material more like what Opportunity is in, something that has a
fluffier texture and cakes onto the wheels," said JPL rover engineer
Rick Welch, who is leading the tests.

Experimenting with different mixtures, engineers and scientists came up
with a recipe that includes play sand for children's sandboxes,
diatomaceous earth for swimming pool filters and mortar clay powder.
Then they went to several home supply and hardware stores to find
enough bags and boxes of the ingredients to make more than 2 tons of
the simulated Mars sand for more realistic mobility tests, said JPL
rover mobility engineer Jeff Biesiadecki.

[...]
Experiments indicate that in this more powdery material, the test rover
positioned comparably to Opportunity can drive out after some initial
wheel-spinning. More testing, analysis, planning and review will
precede any actual commands for Opportunity to begin driving away from
the dune
/quote

  #2  
Old May 18th 05, 05:54 PM
snidely
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Default

Here's Ron Baalke's posting of the latest status in sci.space.news:

From:
Newsgroups: sci.space.news
Subject: Mars Exploration Rovers Update - May 17, 2005
Followup-To: sci.space.policy
Date: 17 May 2005 16:34:27 -0700

Sol 466 (May 16, 2005): Results from the sol 465 drive were good

(some
wheel cleats are clean and the rover is making forward progress), so

the
team commanded a drive that, if there were no slippage, would roll 4
meters (13 feet), consisting of ten 40-centimeter (16 inch) steps.
Opportunity gained an additional 2.7 centimeters (1.1 inch).


  #3  
Old May 18th 05, 07:41 PM
Jim Kingdon
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the team commanded a drive that, if there were no slippage, would
roll 4 meters (13 feet), consisting of ten 40-centimeter (16 inch)
steps. Opportunity gained an additional 2.7 centimeters (1.1 inch).


Sounds like they continue to make slow progress. I keep wanting to
hear "OK, Opportunity is now unstuck" but it looks like for now the
good news is going to more be a trickle of "well, we made a bit of
progress but we are still in a lot of loose sand and not moving
anywhere near full speed".

There's a nice article at
http://www.newscientist.com/article....ine-news_rss20
which talks a bit more about how they are trying to get out (retrace
their steps), and what route to take after that (undecided).

Here are some photos of the wheel moving ever so slightly (this is
from a few days ago, before some of the recent progress):

http://science.slashdot.org/article....&tid=226&tid=1
http://marsrovers.jpl.nasa.gov/galle...JP1344L0M1.JPG
http://marsrovers.jpl.nasa.gov/galle...1P1344L0M1.JPG

  #4  
Old May 19th 05, 01:30 PM
snidely
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Default

Thanks!

/dps

  #5  
Old June 4th 05, 06:57 AM
snidely
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Jim Kingdon wrote:
[...]
Sounds like they continue to make slow progress. I keep wanting to
hear "OK, Opportunity is now unstuck" but it looks like for now the
good news is going to more be a trickle of "well, we made a bit of
progress but we are still in a lot of loose sand and not moving
anywhere near full speed".


And so it goes, and so it goes...

"Since the rover began making its way out of the sand trap last month,
it has driven enough to have moved 177.2 meters (581 feet) if there
were no slippage, and has made actual forward progress of 93
centimeters (3 feet)."

thanks to Ron Baalke's posting:
Newsgroups: sci.space.news
From:
Subject: Mars Exploration Rovers Update - June 3, 2005
Followup-To: sci.space.policy
Date: 3 Jun 2005 16:33:41 -0700
Message-ID: .com


at
http://groups-beta.google.com/group/sci.space.news/msg/37977011c67c4c0b

/dps

  #6  
Old June 5th 05, 07:12 AM
Jim Kingdon
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"Since the rover began making its way out of the sand trap last month,
it has driven enough to have moved 177.2 meters (581 feet) if there
were no slippage, and has made actual forward progress of 93
centimeters (3 feet)."


Thanks. The updates are also, say, at
http://marsrovers.jpl.nasa.gov/missi...portunity.html
or
http://www.marstoday.com/news/news.html?mid=58

But more interesting, there are some cool animated GIF's of
http://marsrovers.jpl.nasa.gov/galle...20050524a.html

  #7  
Old June 5th 05, 05:06 PM
nobody
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Which direction, forward or reverse, are they trying to move? If I
drove me car off the pavement into loose sand, I would not continue in
the same direction.

"Since the rover began making its way out of the sand trap last month,
it has driven enough to have moved 177.2 meters (581 feet) if there
were no slippage, and has made actual forward progress of 93
centimeters (3 feet)."


  #8  
Old June 5th 05, 06:02 PM
Jim Kingdon
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Which direction, forward or reverse, are they trying to move? If I
drove me car off the pavement into loose sand, I would not continue in
the same direction.


According to
http://www.newscientist.com/article....ine-news_rss20
they are trying to retrace their steps as best as possible. Although
other articles say "forward", I'm guessing "forward" means the
direction they came in. For example, the photos at
http://www.spaceflightnow.com/news/n0506/04mer/ does show the tracks
dead-ending and the rover apparently exiting the way they came.
(Although I haven't seen a highly detailed description of this....)

Some of the animations at
http://marsrovers.jpl.nasa.gov/galle...20050524a.html
show them driving over undisturbed sand, so I guess that means they
aren't always able to drive in the tracks they made coming in.

Here's another article about them now being free:
http://science.slashdot.org/article..../06/04/2110235

  #9  
Old June 6th 05, 12:51 AM
snidely
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According to
http://www.newscientist.com/article....ine-news_rss20
they are trying to retrace their steps as best as possible. Although
other articles say "forward", I'm guessing "forward" means the
direction they came in.


IIRC, one of the early "stuck" reports said they were driving in
reverse, either to even wear or to compensate for a wheel concern.

I should google for the reference, but that will have to wait a little
bit....

/dps

 




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