Dusty Mars Rovers

[brellis]

It was reported that 'dust devils' had swept away martian dust that had acumulated on the solar panels of Spirit and/or Opportunity. Has this on-the-job experience affected the design for prototypes of future mars rovers? <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[JonClarke]

I haven't seen anything specifically, but I think it increases people's confidence in solar power on Mars, at least for low latitude areas with high wind frequencies. This is important for furure rovers like ExoMars which is solar powered.<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>

 

[Philotas]

One wonders if the MER rovers will hold out longer than MSL thanks to their solar power. When MSL use all its plutonium(or what it uses) it will stop the mission no matter how good(or bad) in shape the vital electronics ought to be; while at MER it`s the wealth of the onboard electronics that`s going to decide it. <br />Ironically, MSL is planned to last twice as long as MER, so its expected lifetime increases every day... <div class="Discussion_UserSignature"> </div>

 

[brellis]

i just got the MARS special issue of Astronomy mag. apparently only Spirit in March 2005 had the benefit of a dust-devil dustoff. these rovers and their operators are amazing!<br /><br />especially considering the planned duration of future missions, i wonder if they're giving any thought to methods of removing dust. perhaps a martian maid service <img src="/images/icons/smile.gif" /> <br />seriously, what if the equivalent of the 'rock abrasion tool' on the current rovers could sweep off the dust from the solar cells? now i'm probably sounding like a neat freak, which couldn't be farther from the truth, hehe <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[JonClarke]

Interesting possibility. I wonder if it could be tested in a wind tunnel?<br /><br />The problem with cleaning systems is the mass. But it would probably work for very large arrays, associated with human missions, because the mass as a fraction of the overal mission will low.<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>

 

[yurkin]

Of course on a manned mission the astronauts could go and sweep the panels. <img src="/images/icons/smile.gif" /><br /><br />I think I remember reading something about the extreme cold changing the polarity of the dust. So that the morning wind will just blow it off. Something like this may have happened to Oppy.<br /><br />If I was designing a mars rover I would still much rather have an RTG. Oppy was getting pretty close to empty and had a couple cold sleeps before its panels got cleaned. If the MERs didn’t have those extra fold back solar panels it probably wouldn’t have made it. Its hard to say whether wind cleaning is reliably enough to be taken into account for the mission parameters or if the rovers have just been getting really lucky.<br />

 

[chmee]

Actually both rovers had cleaning events on their solar panels, though now there is some doubt that it was dust devils in Spirit's case. The current thought is that unusually high winds caused the cleanings.

 

[JonClarke]

Certainly a garanteed source of power would make for better sleep. Steve Sqyres said this at a conference I was at in answer to a question. If you want to explore high latitudes for an extended period (at the MERs show that rovers can last for extended periods) there isn't really an alternative.<br /><br />But a RTG brings its own hassles of complexity, cost, mission risk, interference with other instruments, thermal management, and technological immaturity. So it's horses for courses, depending on many factors.<br /><br />But the fact that dust has not been a terminal problem, in the face of all predictions has certainly showed that solar power is much more viable, for many applications, than had been considered.<br /><br />One point that is almost never considered is that RTGs are also effected by dust. They generate a lot of waste heat, and this has to be shed. Unfortunately radiator surfaces also collect dust, which effects their efficiency. Because of their complex shape, may trap dust more effectively than solar panels.<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>

 

[the_ten]

<font color="yellow">"Actually both rovers had cleaning events on their solar panels, though now there is some doubt that it was dust devils in Spirit's case."</font><br />------<br />Of course it wasn't a 'dust devil'. It was the martians trying to help our mission to their planet last longer.