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> But recently, the small, automated helicopter has had problems with dust accumulating on its solar panels, NASA says. This dust reduces the ability of the veh

> But recently, the small, automated helicopter has had problems with dust accumulating on its solar panels, NASA says. This dust reduces the ability of the vehicle to recharge its six lithium-ion batteries. IIRC, this dust-on-solar-panels problem has been a serious threat to all the Mars rover missions. I wouldn't make sense on a helicopter, but it seems it would be smart to include some kind of emergency-use brush to clean it from the panels as a last-ditch solution on a rover. Especially considering how greatly-"extended" missions seem de rigueur for NASA.

Rastonbury 4y ago
When reading up on this, the commonly discussed point is that they expected other parts to fail a lot before the panels are covered in dust. Although I've never found an "official" rationale
- deleted 4y ago
  [deleted]
- rtkwe 4y ago
  Modern rovers just use RTGs and avoid the problem all together. Ingenuity couldn't and had to use solar panels but was mostly planned as a test craft so the accumulation problem would happen long after it achieved it's mission goals so it wouldn't cause a mission failure. All of the rovers start with a fairly small mission and it gets extended as it provides good science and congress/NASA finds money to continue to staff the support teams and get time on the Deep Space Network.
pjc50 4y ago
This was the first ever exoplanet helicopter, I think they were only 50-50 on whether it would work at all, with a very high risk of some other issue crashing it first.
topynate 4y ago
Not for Curiosity and Perseverance, which use RTGs. NASA like RTGs for their big, power-hungry vehicles, and use solar panels on the smaller ones. I guess that one problem is that any brush or compressed air mechanism would have to be particularly light to justify itself, else you might as well design around an RTG instead of solar panels. Rotorcraft are a special case though, because they come with powerful fans attached. Maybe the next rotorcraft will have a way to direct its prop wash over its solar panels.
wrycoder 4y ago
Do it like horse race jockeys, who wear multiple pairs of goggles on top of each other, and just rip off the top one when it gets muddy. So, layers of Mylar and a way to peel back or roll away.
- jcims 4y ago
  I always wanted to get Oakely tearoffs for riding dirtbikes as a kid, but i had to put all of my money into keeping the thing running. xD I imagine there are people on this planet that could spend an entire day transfixing you with a conversation on the physical phenomena of dust collecting on solar panels on Mars. Why it happens, what's unique about the environment, what isn't. What's been tried, what will be tried next, why the current configuration was chosen vs others that might have better or worse results, what breakthroughs in materials science might make the whole thing go away, etc etc etc. Aircraft on Mars are obviously always going to be very weight constrained. I wonder if some of the microwave power transfer tech could be used to reduce the cycle time and help in situations like this. Maybe when we can start getting multi kW generators and/or fixed solar arrays on the planet it will start to make more sense.
- rtkwe 4y ago
  The tricky part is the helicopter is already one the edge of being able to fly because of the thin atmosphere and that would put more weight and it would be up high above the rotors.
- DonHopkins 4y ago
  Kind of like how Martians have enormous lower lips, which when they're startled, they can extend out in front of themselves and thrust up into the air, to hide their big eyes behind. https://www.youtube.com/watch?v=KTc3PsW5ghQ https://www.youtube.com/watch?v=KTc3PsW5ghQ
jffry 4y ago
Perseverance uses an RTG (something like 100 watts of power + heat), which is heavy but extremely reliable. For an experimental helicopter that must fly around, Ingenuity's mass budget is extremely tight. I don't know how they'd put something on the helicopter, and I imagine it's considered far too risky to have the rover have some way of cleaning the helicopter.
- throwaway0a5e 4y ago
  It's a helicopter. It basically has an onboard vibrator. Park it at an angle and spin blades until you find a resonance and then leg gravity do the rest. I'm sure there's some very specific reason this "doesn't work". Or just hope the vehicle's flight envelope is wider than the "dust's ability to stick to the panel" envelope. You're gonna lose the vehicle either way so why not try it. I think part of the problem is that the kind of people who have a lot of experience solving these kinds of problems don't really have career paths that intersect with NASA so the engineers spec'ing out the vehicle don't really know with good enough levels of certainty when they can make cheap minor tweaks to the design of the vehicle that will produce some secondary positive result. And you can't go just call up the professional specialists and ask for their input because the processes involved are too bloated and would cost too much money to invoke over small secondary features so you really need that kind of expertise in house or not at all.
  - aa-jv 4y ago
    Yeah, I really don't understand why they don't include a shaker motor to vibrate the particles off the panels .. I mean I can guess that its just one more part to throw at a very, very expensive BOM already, but it seems to me that there must be some resonant frequency, well known through tests already, that would shake the panels just so that they become functional again ..
    - jffry 4y ago
      I doubt they would add another part (which takes mass, space, and testing) to solve a problem that is far, far outside the scope of the helicopter's designed mission.
causi 4y ago
My opinion is that since they already have to use motors to unfold the panels on rovers, why not spend the extra mass to let the motors go both ways? Folding the motors halfway back up would remove the majority of the dust on a rover like Spirit/Opportunity.
- Liquid_Fire 4y ago
  I'm not sure how "sticky" the dust on Mars is. On Earth most dust (obviously very different composition) doesn't just fall off on its own when you tilt a surface sideways, you have to wipe it off applying some pressure.
  - Rastonbury 4y ago
    Not to mention Mars has a 3rd of Earth's gravity
Stevvo 4y ago
There has been some work recently on electrostatic repulsion for cleaning dust from terrestrial panels. I expect NASA will investigate if the same technology is suitable for other planets.
oktwtf 4y ago
Could the rover pick up Ingenuity and invert the lad to clear some accumulation?
myself248 4y ago
The obvious solution on the next one is to make the blades themselves out of solar panels. ;)
- somat 4y ago
  I laughed. but it made me think, I am not sure about that, have you seen the surprising amount of dust that can stick to a computer fan's blades.
  - dang 4y ago
    Sorry for the offtopicness, but could you please email hn@ycombinator.com? I want to send you a repost invite.

Rastonbury 4y ago

When reading up on this, the commonly discussed point is that they expected other parts to fail a lot before the panels are covered in dust. Although I've never found an "official" rationale

deleted 4y ago
[deleted]
rtkwe 4y ago
Modern rovers just use RTGs and avoid the problem all together. Ingenuity couldn't and had to use solar panels but was mostly planned as a test craft so the accumulation problem would happen long after it achieved it's mission goals so it wouldn't cause a mission failure. All of the rovers start with a fairly small mission and it gets extended as it provides good science and congress/NASA finds money to continue to staff the support teams and get time on the Deep Space Network.

pjc50 4y ago

This was the first ever exoplanet helicopter, I think they were only 50-50 on whether it would work at all, with a very high risk of some other issue crashing it first.

topynate 4y ago

Not for Curiosity and Perseverance, which use RTGs. NASA like RTGs for their big, power-hungry vehicles, and use solar panels on the smaller ones. I guess that one problem is that any brush or compressed air mechanism would have to be particularly light to justify itself, else you might as well design around an RTG instead of solar panels. Rotorcraft are a special case though, because they come with powerful fans attached. Maybe the next rotorcraft will have a way to direct its prop wash over its solar panels.

wrycoder 4y ago

Do it like horse race jockeys, who wear multiple pairs of goggles on top of each other, and just rip off the top one when it gets muddy. So, layers of Mylar and a way to peel back or roll away.

jcims 4y ago
I always wanted to get Oakely tearoffs for riding dirtbikes as a kid, but i had to put all of my money into keeping the thing running. xD I imagine there are people on this planet that could spend an entire day transfixing you with a conversation on the physical phenomena of dust collecting on solar panels on Mars. Why it happens, what's unique about the environment, what isn't. What's been tried, what will be tried next, why the current configuration was chosen vs others that might have better or worse results, what breakthroughs in materials science might make the whole thing go away, etc etc etc. Aircraft on Mars are obviously always going to be very weight constrained. I wonder if some of the microwave power transfer tech could be used to reduce the cycle time and help in situations like this. Maybe when we can start getting multi kW generators and/or fixed solar arrays on the planet it will start to make more sense.
rtkwe 4y ago
The tricky part is the helicopter is already one the edge of being able to fly because of the thin atmosphere and that would put more weight and it would be up high above the rotors.
DonHopkins 4y ago
Kind of like how Martians have enormous lower lips, which when they're startled, they can extend out in front of themselves and thrust up into the air, to hide their big eyes behind. https://www.youtube.com/watch?v=KTc3PsW5ghQ https://www.youtube.com/watch?v=KTc3PsW5ghQ

jffry 4y ago

Perseverance uses an RTG (something like 100 watts of power + heat), which is heavy but extremely reliable. For an experimental helicopter that must fly around, Ingenuity's mass budget is extremely tight. I don't know how they'd put something on the helicopter, and I imagine it's considered far too risky to have the rover have some way of cleaning the helicopter.

throwaway0a5e 4y ago
It's a helicopter. It basically has an onboard vibrator. Park it at an angle and spin blades until you find a resonance and then leg gravity do the rest. I'm sure there's some very specific reason this "doesn't work". Or just hope the vehicle's flight envelope is wider than the "dust's ability to stick to the panel" envelope. You're gonna lose the vehicle either way so why not try it. I think part of the problem is that the kind of people who have a lot of experience solving these kinds of problems don't really have career paths that intersect with NASA so the engineers spec'ing out the vehicle don't really know with good enough levels of certainty when they can make cheap minor tweaks to the design of the vehicle that will produce some secondary positive result. And you can't go just call up the professional specialists and ask for their input because the processes involved are too bloated and would cost too much money to invoke over small secondary features so you really need that kind of expertise in house or not at all.
- aa-jv 4y ago
  Yeah, I really don't understand why they don't include a shaker motor to vibrate the particles off the panels .. I mean I can guess that its just one more part to throw at a very, very expensive BOM already, but it seems to me that there must be some resonant frequency, well known through tests already, that would shake the panels just so that they become functional again ..
  - jffry 4y ago
    I doubt they would add another part (which takes mass, space, and testing) to solve a problem that is far, far outside the scope of the helicopter's designed mission.

causi 4y ago

My opinion is that since they already have to use motors to unfold the panels on rovers, why not spend the extra mass to let the motors go both ways? Folding the motors halfway back up would remove the majority of the dust on a rover like Spirit/Opportunity.

Liquid_Fire 4y ago
I'm not sure how "sticky" the dust on Mars is. On Earth most dust (obviously very different composition) doesn't just fall off on its own when you tilt a surface sideways, you have to wipe it off applying some pressure.
- Rastonbury 4y ago
  Not to mention Mars has a 3rd of Earth's gravity

Stevvo 4y ago

There has been some work recently on electrostatic repulsion for cleaning dust from terrestrial panels. I expect NASA will investigate if the same technology is suitable for other planets.

oktwtf 4y ago

Could the rover pick up Ingenuity and invert the lad to clear some accumulation?

myself248 4y ago

The obvious solution on the next one is to make the blades themselves out of solar panels. ;)

somat 4y ago
I laughed. but it made me think, I am not sure about that, have you seen the surprising amount of dust that can stick to a computer fan's blades.
- dang 4y ago
  Sorry for the offtopicness, but could you please email hn@ycombinator.com? I want to send you a repost invite.