Mars Rover Spirit Mission Update Thread

[fangsheath]

It seems pretty clear at this point that they intend to try to reach the summit of Husband Hill, after that I don't know. But they are having steering issues with the rover again, and I am not at all confident that the vehicle will make it. In any case, I think it is months away.

 

[thechemist]

This rock is Route_66, and JPL has posted a "true color" picture of the "dandellion" in Apr 16. <br /><br />The brushed area looks "bright" in a couple filters: Sol 100 <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[marslauncher]

A problem that affects the steering on NASA's Mars Exploration Rover Spirit has recurred after disappearing for nearly two weeks. <br /><br />Engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., are working to fully understand the intermittent problem and then implement operational work-arounds. Meanwhile, Spirit successfully steered and drove 3.67 meters (12 feet) on Oct. 17. <br /><br />Rover engineers are also analyzing a positive development on Spirit's twin, Opportunity: a sustained boost in power generation by Opportunity's solar panels. <br /><br />Both rovers have successfully completed their three-month primary missions and their first mission extensions. They began second extensions of their missions on Oct. 1. <br /><br />Rover engineers refrained from driving Spirit for five days after an Oct. 1 malfunction of a system that prevents wheels from being jostled in unwanted directions while driving. Each of the front and rear wheels of the rover has a motor called a steering actuator. It sets the direction in which the wheel is headed. The steering actuators are different from the motors that make the wheels roll, and hold the wheel in a specific direction while driving. A relay used in turning these steering actuators on and off is the likely cause of the intermittent nature of the anomaly. <br /><br />The relay operates Spirit's right-front and left-rear wheels concurrently, and did not operate as commanded on Oct. 1. Subsequent testing showed no trace of the problem, and on Oct. 7, the rover steered successfully and drove about 2 meters (7 feet), putting it in position to examine a layered rock called "Tetl" for several days. However, the anomaly occurred again on Oct. 13, and the problem appeared intermittently in tests later last week. <br /><br />"We are continuing tests on Spirit and in our testbed here at JPL," said Jim Erickson, Mars Exploration Rover project manager at JPL. One possible work-around would be to deliberately blow a fuse controlling t

 

[trockner]

old subject, but as far as dust accumulation on the solar panels goes I seem to remember that they early on said that dust accuumulation would exhibit an increasing upward trend in terms of power degradation...and then level off at a certain point. I'm not at all sure of why THAT would occur, though.

 

[fangsheath]

I believe that what happens is that the rate of accumulation of dust on the panels eventually equilibrates with the rate of removal by the wind. This seems to have already more or less occurred with both rovers.

 

[fangsheath]

Spirit has RATed the upper surface of the layered rock on the left, called Uchben. Not far away is a larger rock with similar morphology. I wonder if they will try to get a RAT hole into a layered portion of one of these rocks.

 

[heyo]

Hey all. Newbie here, just signed up to post this question, but look forward to staying a member since I am a space nut. Forgive me if this has already been asked/discussed, I wasn't able to find it though.<br /><br />I realize that as the rovers age, one of the things that will affect how long they last is the reduction in available power due to dust collecting on the solar panels.<br /><br />Why did they not design some lightweight squeegie type thing or some other device to clear the dust off the panels?<br /><br />Heyo

 

[anoolios]

Heyo, I think the short answer as to the various capabilities of the rovers comes down to cost, complexity, and development time considerations. Dust accumulation on the solar panels was a known factor to the MER designers, with more time and resources I'm sure they could have come up with something to mitigate the effects (there was some discussion in these forums a while ago of possible wipers or peelable layers of film on the panels). <br /><br />If "we" were more supportive of science and space exploration, oh the amazing fleets of explorerers possible with current resources... ack, I better get off the soapbox before I lose it, it makes my heart ache to think of it...

 

[centsworth_II]

<font color="yellow">"...one of the things that will affect how long they last is the reduction in available power due to dust collecting on the solar panels."</font><br /><br />It now looks like dust accumulation will NOT be the limiting factor for mission life. The rovers will make it through the worst part of winter with no serious problems in energy production in spite of whatever dust has accumulated. With the approach of spring, and the sun rising in the sky, the energy situation will only improve. No dust removal necessary! If you want to worry, worry about the eventual demise of the batteries or a catastrophic hardware, or software problem. Or getting stuck in some ground hazzard. <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[fangsheath]

We have indeed bounced around some ideas here for cleaning the panels, but any device inevitably adds some weight and cost, and keep in mind that the rovers were not designed for long life. I wonder if it would be possible to put the rover on a fairly steep slope and do a little "yaw dance," that is, quickly alternate between starboard and port spinning, jiggling the vehicle. I think that could clear a lot of dust, but I don't know what effect it might have on the instruments.

 

[centsworth_II]

<font color="yellow">"...do a little 'yaw dance'... spinning, jiggling the vehicle. I think that could clear a lot of dust..."</font><br /><br />I don't know about the dust on the rovers' solar panels, but that which settles on shelves, table tops, etc. around my house is VERY resistant to remvoval other than by strong suction or blowing, or by wiping. <div class="Discussion_UserSignature"> </div>

 

[fangsheath]

But have you tilted and jiggled?<br /><br />Uchben looks like more of the same to me - another soft, very un-basalt looking rock.

 

[yurkin]

Hi Heyo<br /><br />And welcome to the thread. Yes that question has been asked many times in many forms. It was a common question back when the rovers first landed. In fact I even asked a similar question once.<br /><br />It’s more complicated then it first appears. They’d not only need an arm and actuators for the squeegee. It’s got to be built to survive the conditions on mars and the journey to mars. It also has to fit within size and weight limitations. They also need heaters on it and code to operate it. And I suppose in this case some way to keep the squeegee moist.<br /><br />But even in the rover’s present configuration it’s more likely something else will fail long before power runs down. So there’s not much point in increasing that system’s reliability when other things could be done first.<br /><br />And again welcome to the forum.<br />

 

[trockner]

centsworth_II...I suspect also that electrostatic adhesion of dust to the solar panels might be a lot stronger than aeolian forces under 100 km/hr.<br /><br />Just a guess.

 

[fangsheath]

The RATed surface of Uchben (top) closely resembles that of Ebenezer (bottom). Sabre showed similar structure.<br />

 

[mikehoward]

What on Mars? http://qt.exploratorium.edu/mars/spirit/pancam/2004-10-26/2P151574958EFF8987P2416R1M1.JPG<br />

 

[Leovinus]

Looks like swiss cheese, or sponges, or where blueberries fell out. <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

Wow! This looks to me like a totaly new phenomenon that needs to be explained. I don't remember seeing anything like this amount of pock marking in the rocks of West Spur before. To me, it seems like these rocks came out of nowhere! <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Magnificent! It looks very much like tafoni, or honeycomb weathering. On earth this is due to salt crystalisation and wind action.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[fortytwo]

Credit:<br /><br />http://pubs.usgs.gov/of/2004/1007/volcanic.html<br /><br />"Tafoni is a type of surface weathering caused by wetting and drying of porous rocks that gives these cliffs of rhyolite tuff a "cheese-like" appearance (located in the canyon below the campground at Hole-In-The-Wall)."

 

[JonClarke]

Honey comb weathering<br /><br />http://www.ics.uci.edu/~eppstein/pix/mendocino5/lp/Honeycomb.html<br /><br /><br />http://www.uky.edu/KGS/coal/webgeoky/fieldtrip/BigSinking/Misc/misc01.jpg<br /><br />And a bit of explanation.<br /><br />http://www.gsajournals.org/gsaonline/?request=get-abstract&doi=10.1130%2F0016-7606(1999)111<1250:OOHWTR>2.3.CO%3B2<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[claerwen]

Interesting...<br /><br />I've seen the same phenomena in shells that wash up on the beach. Similar mechanism?

 

[mikehoward]

Fascinating links! Here are a couple more nearby examples. There's obviously so much more to discover... I hope Spirit can keep moving.<br />http://qt.exploratorium.edu/mars/spirit/pancam/2004-10-28/2P152196298EFF8987P2419R1M1.JPG<br />http://qt.exploratorium.edu/mars/spirit/pancam/2004-10-28/2P152196324EFF8987P2419L7M1.JPG<br />

 

[silylene old]

The pits in the large rock in the center of this photo are arranged in an approximately rectalinear pattern. If you cannot see it, I can post an illustration. The pits are non-randomly scattered over the stone surface.<br /><br />What erosion mechanism accounts for this? The rock did not appear to be significantly stratified (if at all). If the rock long ago was covered by a elephant-skin layer (polygons), which has now eroded off, could this putative ancient coating have affected the erosional surface we seee today? (I am imagining some type of natural lithography).<br /><br />http://qt.exploratorium.edu/mars/spirit/pancam/2004-10-28/2P152196298EFF8987P2419R1M1.JPG <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[JonClarke]

I don't think we really understand what controls the distrbution of such pock marks on earth. Nobody has thoght it important I suspect. People have been more interested in the process.<br /><br />Cheers<br /><br />Jon<br /><br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>