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Spot the difference: Spirits solar panels collected a lot of dust in two years (NASA/JPL)

Despite Dust Storms, Solar Power is Best for Mars Colonies

20 Nov , 2008

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Dust — a solar panel’s worst nightmare.

Is sending solar-powered robots to the Red Planet a bad idea? Mars is a very dusty planet, and Mars dust sticks to everything, especially solar arrays. After all, Phoenix’s death was probably hastened by a Sun-blocking dust storm, and rover Spirit was battered by the combined solar panel-coated dust layer plus dust storm, nearly draining its batteries (as can be seen in the comparison above, after two years on the Martian surface, Spirit’s dusty layer was already an acute problem).

However, a NASA-sponsored MIT think-tank has weighed up the future energy needs of a manned settlement on Mars and arrived at an interesting conclusion…

It sounds like the “nuclear space debate” continues. Thinking back to when Galileo was launched toward Jupiter in 1989, or when Cassini was sent to Saturn in 1997, huge protests erupted from critics, Cape Canaveral neighbours and anti-nuclear organizations. The argument was that should there be a launch accident, the radioactive material contained inside the radioisotope thermal generators (RTGs) could be scattered through the atmosphere and over a wide area on the ground (i.e. death and destruction). While this is a scary thought, NASA engineers were very quick to point out that RTGs are virtually indestructible, even under extreme conditions during an explosion and atmospheric re-entry.

The motivation for sending plutonium (non-weapon grade Pu238) on board missions to Jupiter and Saturn has even been called into question, spawning wild conspiracy theories such as “Project Lucifer.” Therefore, it seems only sensible that NASA should want to carry out an in-depth study of all energy production techniques before committing to a potentially unpopular (and therefore politically damaging) nuclear source for future Mars colonies.

With the help of energy specialists from the Massachusetts Institute of Technology (MIT), NASA commissioned a study of how future manned Mars settlements can be powered. Will nuclear generators need to be constructed? Or can solar panels fulfil our proto-colony’s energy needs (regardless of the dust situation)?

Interestingly, if positioned in the correct location, solar arrays might function just as well, if not better, than the nuclear options. Solar panels could provide all the energy a fledgling colony needs.

The MIT researchers assessed 13 different energy generation systems and compared solar and nuclear options. In a presentation last month at the International Astronautical Congress in Glasgow, MIT engineer Wilfried Hofstetter compared nuclear fission reactors, RTGs, Sun-tracking solar panel arrays and non-tracking thin-film solar arrays laid atop the Martian landscape.

Like any space travel endeavour, efficiency is paramount; astronauts will need to utilize every last energy-generating ounce of equipment sent to Mars (including back-up systems).

It would appear that a large solar panel array can match nuclear generators, only if they are situated at a latitude of 0-40° north of the Martian equator. Southern latitudes have much less solar energy available for most of the year.

So what’s the best plan of action? According to Hofstetter, a Mars mission should be able to transport several 2 metre-wide rolls of thin-film solar panel arrays. Rolling out an array of these thin-film rolls could supply ample energy to a colony. For example, if the array is positioned at 25° north, measuring 100×100 metres, 100 kilowatts can be generated. The MIT researchers even calculated it would take two astronauts 17 hours to construct the array (alternatively they could get a robot to do it).

Commenting on this Mars energy solution, Colin Pillinger, planetary scientist with the Open University, UK (and head Beagle 2 scientist) said the solar array’s old foe — dust — shouldn’t be too much of a problem after all. “Dust storms tend to start in well-known places in the southern hemisphere as it warms up, so it shouldn’t be too difficult to avoid them,” he said.

So the skies may be clear for solar energy on Mars after all. Even though dust storms causes problems for our robotic explorers, manned expeditions may be able to avoid them all together. Besides, I don’t see why astronauts couldn’t pack some brushes to wipe down the arrays should dust become a problem…

Source: New Scientist


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Stig Bjorge
Member
Stig Bjorge
November 20, 2008 9:17 PM

Why on earth (or mars really) aren’t the land based mars explorers equipped with some kind of vacuum cleaner for the solar panels? It shouldn’t be that hard to keep the panels free of dust, should it?

jason
Guest
jason
November 20, 2008 9:35 PM

well a colony would be able to squeege the panels, and i think the rovers could add an extra ounce of weight and have a little windshield wiper system to wipe of the dust. they could live 100x the mission goal

Astrofiend
Member
Astrofiend
November 20, 2008 10:24 PM

jason Says:
November 20th, 2008 at 9:35 pm

“…they could live 100x the mission goal”

Sadly, I think congress would cut funding for them long before then. In fact, that almost happened just last month to our intrepid little explorers.

As for the main article – exactly! Solar panels would be great for colonies because they can be maintained – wiped down, repaired etc. RTG’s are super reliable too, so really it comes down to what is easier to get there and safest to have around for the amount of energy produced by each.

I could envisage that both technologies would have a part to play in any future colony as requirements and circumstances dictate.

Damien
Guest
Damien
November 20, 2008 10:27 PM

Personally I think nuclear energy , wind and solar energy are great ideas for planets like mars. As far as I can see without going into other sources of energy that we experiment with, the nuclear option would be one of the best ideas for power on mars, at least used to power a command center.

leafguy
Member
November 20, 2008 11:40 PM

Solar is the best route up until Ceres, after that, the distance / energy relationship of the sun doesn’t provide enough energy to reach furthur out. Nuclear would likely be for the places like the Galilean moons and beyond.

Mike Jackson
Guest
Mike Jackson
November 20, 2008 11:48 PM

I agree with Damien about nuclear energy and I’m reluctant to trust “scientific” think tanks and committees now that scientists have shown themselves to be as open to ideological bias as any of the “soft” fields of study.
The global warming debate has been an eye opener, with scientists calling for “denialist” colleagues to be decertified by their professional organizations and so on. Nauseating.
Nuclear power is not as clean as solar power but for the power requirements needed for a safe productive colony (or mission) nothing else is close.

M83
Guest
M83
November 21, 2008 12:13 AM

It seems that dust on the photovoltaic cells would be a minor problem for a Mars colony. NASA could either A. Devise some sort of automated system to periodically blow or wipe the dust from the panels, or B. Just have some of the colonist wipe them off occasionally.

Seems simple enough, but I could be wrong…

Either way I agree that solar power is the best option to juice a future colony.

Christopher Farmer (Adealide, South Australia)
Guest
Christopher Farmer (Adealide, South Australia)
November 21, 2008 12:27 AM

You know I think they might have overlooked the whole windscreen wiper thing.

Does anyone know for sure?

Allan
Guest
Allan
November 21, 2008 12:28 AM

The windscreen wiper idea sounds O.K. but would be improved by using a rotating brush in place of a squeegee type wiper……….Solar power sounds wonderful, but how is the generated power stored for use at night ?Surely the weight of batteries needed to supply a manned colony would be far in excess of being an acceptable payload to the detriment of being able to carry other more essential supplies……..food…..water…..air….habitat…..etc

DCTECHGUY
Member
DCTECHGUY
November 21, 2008 4:20 AM

Solar Power plus battery weight plus eventual demise of the rechargeable batteries makes an RTG (nuclear) power source in my humble opinion a no brainer. No silly wipers, no EVAs to “wipe” (how often do you do that in a storm?). The two Vikings used them until congress ordered them turned off. Voyager still uses them (launched over 30 years ago) and will be operating further decades into the stars. Lets design an all purpose excellent 50 year RTG and make enough of them so these silly solar toys can be put to rest. So what is there to figure out?

jtagg
Guest
jtagg
November 21, 2008 4:27 AM

Why not use some kind of windshield wipers for the solar panels?

jtagg
Guest
jtagg
November 21, 2008 4:27 AM

whoops…I should have read before posting. sorry.

outcast
Member
outcast
November 21, 2008 6:54 AM

Something we seem to forget is the energy density of solar is really low. 100 meters by 100 meters is 10 KM^2……..that’s a lot of solar panels. So it would take that much to just get 100 kilowatts with solar, while the reactor on a modern navy ship can produce 100 times that at least. I’m sorry but given the amount of money it costs get stuff there and the trouble with martian dust, solar just doesn’t cut. Long term, there is really nothing but nuclear. It’s unfortunate that some people just don’t get that.

ShadowDancer
Member
November 21, 2008 7:13 AM

I am actually more curious about the “Lunar Dust Buster” concept for the solar panels. Do we know if NASA is actively looking into this as a possible solution for solar panels on the Moon or Mars? (http://science.nasa.gov/headlines/y2006/19apr_dustbuster.htm)

Dark Gnat
Member
Dark Gnat
November 21, 2008 7:29 AM

I’m thinking a can of compressed air would probably work very well. Less mechanical devices than a motorized brush – which would also drain the battery. Just blast the dust away.

maudyfish
Guest
maudyfish
November 21, 2008 7:51 AM

How many cans of compressed air do you think they will need, Dark Gnat?

Did I understand correctly that we should build some type of nuclear generator that would last 50 years? So what do we do with the waste product? We know nothing about the planet and we are already contaminating it!!

Solar energy is a “store-type” system, right?
Why do they need to do an EVA for dusting in a dust storm?

outcast
Member
outcast
November 21, 2008 8:07 AM

[quote]Did I understand correctly that we should build some type of nuclear generator that would last 50 years?[/quote]

Yes you did, because other than fossil fuels there is nothing else with a high enough energy density and reliability (granted in space reliability isn’t the problem, but on practically any planet or moon it will be) to be useful.

[quote] So what do we do with the waste product?[/quote]

Reprocess it for reuse in the reactor and what cannot be reprocessed perhaps can be reused as RTGs.

But really, modern reactors don’t make that much waste. Yes, the waste storage pools in american reactors are full, but that took more than 30 years for this to happen and that was without reprocessing.

Maxwell
Member
Maxwell
November 21, 2008 8:27 AM

We need a combination.
Solar panels for the main power, a few RTG’s to serve as backup (and booster for when experiments require the extra power).

By the time theres enough colonists and waste to worry about, mars bases should be self sufficient.

Tim
Guest
November 21, 2008 8:28 AM
I can’t believe NASA never thought of dust being a factor when they built these robots! It just goes to show that sometimes we get caught up in the technical details without considering practicality. I agree that Nuclear could be a solution, but it takes anything from 6 to 12 years to get a reactor fully functional. And like the others have said – what happens to the radioactive waste? We’ve already created enough waste on Earth. We shouldn’t start spreading it all over the solar system now. The idea of compressed air is an idea, however, how will it be refilled? I think all the solutions to cleaning the panels are a start, but they all have… Read more »
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