Mars Exploration Rovers (MER)

Mad Grad Student · 2005-05-15 20:25:41

This problem Opportunity has worked herself into reveals how utterly awful robots are at exploring. Your average human would come up to a foot-high sand dune, maybe think "no biggie" and step right over it, while your average rover will work itself into a jam that takes weeks to get out of. It will be impossible for planetary exploration to be achieved to its fullest until we start putting people on those far-flung worlds.

That said, I sincerely hope Oppy manages to get out of this fine mess and keeps on trucking for a good long time. I've managed to become emotionally attached to these robots enough to refer to them as feminine rather than gender-neutral objects (something I ordinarily never do) when I'm being playful, and though I realize that they've already outlived their warranties by over a year it will be very sad when they bite the rusty Martian dust. Hopefully Opportunity will be out of this in no time and be back on her way to Victoria. Come on, Oppy, let's see what's on the other side of that sand dune. :;):

REB · 2005-05-16 06:51:09

I wonder if Opportunity’s underbelly is stuck on the crest of that dune?

I figure worst case scenario they’ll use the instrument arm boom to push Opportunity off the dune.

C M Edwards · 2005-05-16 14:17:10

I figure worst case scenario they’ll use the instrument arm boom to push Opportunity off the dune.

I don't know... So far they haven't even used it to look at what they're stuck in.

The composition of the dust is of interest. Look at the hazard camera images. Except where it was churned up by all the wheel spinning, the loose dust is mostly confined to the wheel track. Photos of earlier trenching efforts show mounds of displaced soil, but not here. Opportunity hardly displaced any dust cutting into that dune, even where it dug in four inches deep.

Their current simulant mixture is the first thing the ground crew has come up with that the MER couldn't hop right out of, even when they bottomed it out. That's one tough little RC car. Preliminary tests with Opportunity (on Mars, not the sandbox model) have shown that they can get it out, so the panic is over and we're just waiting for the mission plan to catch up.

Still, it seems a shame to leave without taking a look down...

Palomar · 2005-05-16 14:51:15

http://www.spacedaily.com/news/mars-mers-05zy.html]Oppy begins careful rollout

*For the first time since being stuck, Oppy rotated its wheels; this occurred on Sol 463. As commanded, the wheels made aprox 2-1/2 rotations.

Oppy moved 1.1 inch forward, 0.19 inch sideways and 0.18 inch downward. Not much, but it's given mission planners a confidence boost.

During "stuck time," Oppy's been obtaining a color panorama of its surroundings. The area is being called "Rub al Kahli."

There's been an energy boost too:

During sol 456, power engineer Eric Wood happily recognized a cleaning event. Winds removed some dust from solar panels and Opportunity's daily energy supply increased to about 650 watt-hours, from a recent range of about 620 to 630 watt-hours.

More in the article as well. Go Oppy!

--Cindy

Shaun Barrett · 2005-05-17 01:38:35

CM:-

The composition of the dust is of interest. Look at the hazard camera images. Except where it was churned up by all the wheel spinning, the loose dust is mostly confined to the wheel track. Photos of earlier trenching efforts show mounds of displaced soil, but not here. Opportunity hardly displaced any dust cutting into that dune, even where it dug in four inches deep.

I've read your post twice and I'm still not sure what you mean. Which Hazcam images are you referring to? And I'm sure you have a further hypothesis in mind about the dune in question, though I can't fathom what it might be.
I don't understand what you mean by "displaced dust" as opposed to "displaced soil".
Excuse me being obtuse but could you elucidate? ???

Palomar · 2005-05-17 05:22:09

http://www.space.com/imageoftheday/imag … l]Twilight on Mars: Photo by Spirit

*Says the bluish glow WOULD be visible to us, if we were there. Cool!

Twilight can last for up to 2 hours on Mars (before sunrise/after sunset).

These kinds of images are beautiful and evocative, but they also have important scientific purposes. Specifically, twilight images are occasionally acquired by the science team to determine how high into the atmosphere the Martian dust extends, and to look for dust or ice clouds.
...The long Martian twilight compared to Earth's is caused by sunlight scattered around to the night side of the planet by abundant high altitude dust.

Says clouds over Gusev during Spirit's mission have been rare.

--Cindy

C M Edwards · 2005-05-17 07:34:54

CM:-
[...] Which Hazcam images are you referring to? And I'm sure you have a further hypothesis in mind about the dune in question, though I can't fathom what it might be.
I don't understand what you mean by "displaced dust" as opposed to "displaced soil".

I was just using "dust" and "soil" interchangeably. The important point involves the amount of dust kicked up.

The front and rear hazard cameras are giving the best views of Opportunity's wheels and tracks.

Heres]http://marsrovers.jpl.nasa.gov/gallery/all/1/f/024/1F130314566EDN0400P1111L0M1.HTML]Here's a sol 24 view of a trench Opportunity dug in Eagle Crater.

Note the tread marks in and around the trench. Opportunity's front wheel was revved while being moved back and forth to dig a trench. This worked that wheel in as deep as it is currently buried. You can see the tread marks in the trench from the last pass where Opportunity rolled its wheel out and turned to use its microscopic imager. Adjacent tracks from the other wheels are covered by dust flung out of the trench. Those tread marks are wiped out next to the trench because material was flung out of the trench - displaced - and landed on top of them.

http://marsrovers.jpl.nasa.gov/gallery/ … .HTML]This is an image from sol 445.

Opportunity backed away from a soil target and got stuck just as deeply as it had dug down on sol 24, only with all six wheels this time. However, even with all six wheels churning, there is only a fraction of the soil displacement seen on sol 24. Later efforts to dig out involved repeated wheel revving and turning, just like sol 24, but still with less displacement. Almost all the loose soil is confined to the trench.

I believe that I can see evidence of cracking in the soil surface just adjacent to the trench. This would imply that the soil surface was not just settled, but set - adhering together and not simply loose grains. Unfortunately, the hazcam resolution isn't high enough to confirm this. It could just be a trick of the light, or packed material flung off by Opportunity's wheels.

They need to use the !#@$&! imager.

Shaun Barrett · 2005-05-18 03:39:55

Thanks, CM, for the clarification.
I see what you mean now.
And you're right. They need to use the !#@$&! imager!

Palomar · 2005-05-19 05:04:50

http://www.spacedaily.com/news/mars-mer … ]Animation of Oppy...

*...trying to get unstuck.

If all else fails, we'll just -have- to send a manned mission to push Oppy out of whatever it's stuck in.

--Cindy

REB · 2005-05-19 06:51:41

Once they get Opportunity free, then what? Will they keep going all out, figuring if they get stuck again they can get out again, or will they take it very slow? Perhaps there is a way for them to program Opportunity to steer clear of such dunes.

I was thinking they could have Opportunity run parallel with the dunes, and then do a perpendicular cross over when needed.

SpaceNut · 2005-05-19 09:28:12

Getting these rovers stuck would be a definite poison pill for Nasa. Especially since a large sector of the public, is only in favor of robotic missions due to much lower cost and risk.

C M Edwards · 2005-05-19 14:24:30

When does Spirit exceed the "Mars Direct" surface stay time?

Shaun Barrett · 2005-05-19 17:03:31

Spirit landed on the 3rd of January 2004, so it's been on the surface 503 days.
They always talk about Mars Direct as having a surface stay of ~500 days, so I suppose Spirit's already done a full 'Mars Direct Surface Mission'.

Michael Bloxham · 2005-05-20 00:06:46

Once they get Opportunity free, then what? Will they keep going all out, figuring if they get stuck again they can get out again, or will they take it very slow? Perhaps there is a way for them to program Opportunity to steer clear of such dunes.
I was thinking they could have Opportunity run parallel with the dunes, and then do a perpendicular cross over when needed.

Where are they heading anyhow?

REB · 2005-05-20 06:42:29

I believe they are heading (Hopefully not where heading, in the past tense) to a large and very eroded crater called Victoria.

Palomar · 2005-05-23 07:25:48

http://www.spacedaily.com/news/mars-mer … tml]Spirit drives to "Larry's Outcrop" // Oppy makes small moves

*Yeah, small...but at least it's moving. :-\ Not sure -why- they set Oppy for a 39-foot drive on Sol 470 when it's barely budging out of that dune?

-*-

Spirit done with "Reef." Now checking out "Davis" on "Jibsheet." Two Sols spent driving to Larry's Outcrop. (Is that the same as Larry's Outlook? Have I been reading it wrong all this time?). Spirit in excellent health.

--Cindy

P.S.: SpaceNut writes:

Getting these rovers stuck would be a definite poison pill for Nasa. Especially since a large sector of the public, is only in favor of robotic missions due to much lower cost and risk.

I disagree. The MERs have already outlived their original 3-month warranties 5-fold. Sure, the "large sector of the public" can be ignorant and apathetic; but if they were to bemoan (if they're even paying attention, which is highly doubtful) Oppy's current circumstance, all the other factors (longevity, overall good health, discoveries/findings) could be easily presented to counterbalance any undue criticism. It'd be like someone complaining their car got a flat tire after 120,000 miles of superb and flawless performance. Sure, some folks might still complain; but they'd look silly for doing so.

C M Edwards · 2005-05-25 14:11:38

Check out these microscopic imager photos:

http://marsrovers.jpl.nasa.gov/gallery/ … 4.html]Sol 494 at Larry's Outcrop

It looks like just another rock, but according to the corresponding day's forward hazcam images (showing where the image was taken), this looks like a soil target. It's part of the soil layer that appears to be clinging under the outcrop.

It's holding together remarkably well for a bunch of dust, don't you think?

Shaun Barrett · 2005-05-25 17:52:07

Cindy:-

It'd be like someone complaining their car got a flat tire after 120,000 miles of superb and flawless performance. Sure, some folks might still complain; but they'd look silly for doing so.

:laugh: Good analogy!

Shaun Barrett · 2005-05-25 17:53:34

CM:-

It's holding together remarkably well for a bunch of dust, don't you think?

Thinking of brine? ???

C M Edwards · 2005-05-26 08:29:13

I would not object to brine. :;):

However, it's more likely the formation is dry. It might be similar in grain structure to the dune where Opportnuity is bogged down, and possibly formed by a similar process.

But, without imager photos from Opportunity, the rover team aren't the only ones spinning their wheels...

aldo12xu · 2005-05-26 12:06:14

If anyone is interested I just completed a video flyby over the polar volcanoes that Mars Express photographed last February. The video is 4 min long and is basically an animation of the ESA perspective photo.

Hope you like it,

Aldo.

Palomar · 2005-05-26 13:35:45

If anyone is interested I just completed a video flyby over the polar volcanoes that Mars Express photographed last February. The video is 4 min long and is basically an animation of the ESA perspective photo.
Hope you like it,
Aldo.

*Hi --

We have a separate thread http://www.newmars.com/forums/viewtopic.php?t=1569]for Mars Express articles/items.

--Cindy

aldo12xu · 2005-05-26 19:59:12

OK, I'll post it there.......I went back about 4 pages and didn't notice anything on Mars Express.

Rxke · 2005-05-26 23:47:57

Regardless of aldo being off-topic or not, be sure to check out his site, his movies are utterly awesome.

and... in fact his post wasn't that offtopic, he has pretty spectacular movies of the rovers too!

I'm sooooo glad I rediscovered this site, thanks aldo!

Shaun Barrett · 2005-05-27 01:46:12

From what I've seen of the site so far, I have to agree with Rik. It's a very worthwhile site and I add my thanks to Rik's - thank you Aldo! :up:

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