7

I see on the interwebs that the lander Insight is about to land on Mars and the NASA PR describes the solar panels as producing 600-700W now and 200-300W when covered in dust.

Is there any reason why some sort of cleaning apparatus can't be installed on the lander to keep the dust off the solar panels? Or, why was it decided not to install some sort of apparatus to keep the panels clean?

I like the mental image of a robot arm with a feather duster but there are probably more practical solutions.

ConcernedOfTunbridgeWells
  • 189
  • 7
  • This is a good question, and it's puzzled me as well. It seems ESA's current thinking is to hope for the best, take what comes, but not to expect the worst. How will the ExoMARS Rover keep it's solar panels dust-free and collecting maximum power? – uhoh Nov 26 '18 at 17:15
  • I would turn lemons into lemonade, and use an anemometer to drive an electric generator. After all, the dust gets there by the wind! – DrSheldon Nov 26 '18 at 18:01
  • No real sources to give a good answer, but ... I feel like all the reports of dust and solar on Mars comes down to 'Dust on the panels is a minor nuisance, it clears itself with time.' I don't think missions are lost to dust on panels - they're lost to dust in the air for so long that things get too cold. Hard to justify the extra mass for cleaning systems if they aren't necessary for mission performance. – Saiboogu Nov 26 '18 at 19:28
  • 1
    @Saiboogu: A dust storm in June 2018 covered the solar panels of the Opportunity rover and forced it into hibernation. The dust storm cleared about a month ago, and NASA tries at least once a day to re-establish contact. I just saw such an (unsuccessful) attempt about an hour ago on DSN Now. So, missions can most certainly be lost by Martian dust. – DrSheldon Nov 27 '18 at 05:09
  • I'd consider changing the question to "why (the heck) haven't dusters been used..." – uhoh Nov 27 '18 at 05:17
  • I'm pretty sure it's lighter, simpler, cheaper and faster to simply add enough solar panels that it has enough power even when covered in dust. – Nathanael Vetters Nov 27 '18 at 05:52
  • Have a look at this question: https://space.stackexchange.com/questions/3487/is-vibration-useful-in-shaking-off-mars-dust I also remember another answer somewhere which made a list of possible solutions to clean the rovers (and showed them to be unpratical) - but I can't find it now. – BlueCoder Nov 27 '18 at 12:40
  • Actually what I was looking for is in answer of the question linked by uhoh. "Tilting and shaking the rover could work, but it would be complicated and possibly damaging to sensitive instruments. Other methods involve washing them (which requires liquid), using an electrostatic charge (still requires tilting the panels, and could also damage sensitive electronics), and blowing them off (requires moving a high-powered fan across the panels). " – BlueCoder Nov 27 '18 at 12:42
  • 1
    Anyway, as reminded here (https://space.stackexchange.com/a/3491/25067), Opportunity worked fine for more than 10 years without any means to remove dust... So this in itself may answer why dusters aren't installed (you don't really need the added complication) – BlueCoder Nov 27 '18 at 12:44
  • 1
    @DrSheldon Opportunity wasn't lost because it was unable to clean it's panels. It was lost because it couldn't get enough sunlight to keep itself warm enough to prevent the batteries from being destroyed by the cold. Even if opportunity had had perfectly clean solar panels the entire duration of the storm, it still wouldn't have gotten enough power. – Dragongeek Nov 27 '18 at 14:50
  • @Dragongeek: I disagree. Opportunity had survived several other dust storms and recovered. The decrease in solar panel output in this and previous storms is well-documented. There are also pictures of dust on the solar panels before and after previous storms. Perhaps you are thinking of Spirit? – DrSheldon Nov 27 '18 at 15:07
  • 1
    @DrSheldon I don't agree with your assumption that dust storms 'killed' Opportunity. It is my understanding that incidents like that happen when the sunlight reaching the surface is too low for too many days for the rover to keep it's electronics warm, and to build enough power for a return from hibernation. After days or weeks of unpowered cold soak, things break and the rover doesn't wake up. This may be a mistaken impression, I'm watching for answers here.. – Saiboogu Nov 28 '18 at 15:42
  • Reading more comments - past dust storms were survived because the hardware was newer. Ever leave the lights on in your car overnight? You can get a jump and move on with life, usually -- Unless your battery has been through too many deep cycles, and it has been damaged. Eventually storage capacity is harmed. Similar principals with the rovers on Mars, repeated deep drains coupled with deep cold mean eventually the returning sun cannot wake them. – Saiboogu Dec 02 '18 at 17:15

1 Answers1

4

Could dusters be installed on solar panels on a Mars lander?

Yes.

Is there any reason why some sort of cleaning apparatus can't be installed on the lander to keep the dust off the solar panels? Or, why was it decided not to install some sort of apparatus to keep the panels clean?

Dust removal systems must meet stringent requirements, as must anything that goes into space. There are size, weight, power efficiency, ruggedness and reliability considerations and NASA doesn't use the same type of solar panels as are used on Earth.

It's easier to do initial trials on Earth with conventional panels, but the results must be retested on the same type of panels under similar conditions to what they would face on Mars - all that testing takes many years.

See the article: "Self-Cleaning Solar Mirrors Using Electrodynamic Dust Shield: Prospects and Progress" from the ASME 2014 8th International Conference on Energy Sustainability, by Malay K. Mazumder, Mark N. Horenstein, Jeremy W. Stark, John N. Hudelson, Arash Sayyah, Nitin Joglekar, Julius Yellowhair and Adam Botts:

"Prototype EDS-integrated solar collectors including second-surface glass mirrors, metallized acrylic film mirrors, and dielectric mirrors, were produced and tested in an environmental test chambers simulating desert atmospheres. The test results show that frequent removal of dust layer can maintain the specular reflectivity of the mirrors above 90% under dust deposition at a rate ranging from 0 to 10 g/m2, with particle size varying from 1 to 50 μm in diameter. The energy required for removing the dust layer from the solar was less than 10 Wh/m2 per cleaning cycle. EDS based cleaning could therefore be automated and performed as frequently as needed to maintain reflection efficiency above 90% and thus reducing water usage for cleaning mirrors in the solar field. A comparative cost analysis was performed between EDS and deluge water based cleaning that shows the EDS method is commercially viable and would meet water conservation needs.".

CSP Solar Panel Electrodynamic Dust Removal System

Developed at Boston University the "Electrodynamic dust removal would not require water and could be operated as frequently as needed at a miniscule cost. The BU team is now one step closer toward achieving its goal after the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy and the Massachusetts Clean Energy Center (MassCEC) awarded grants to support this research. The DOE will provide \$955,340 for solar mirrors for photothermal energy conversion while MassCEC will give another \$40,000 that will be used toward developing self-cleaning photovoltaic solar panels."

Robotic and electrostatic methods appear to be the two most promising avenues for self-cleaning of desert solar power systems, but the technology is developing all the time and several projects are still very much in development. Applications for use in space remain a number of years away.

Rob
  • 3,266
  • 1
  • 15
  • 36