After losing contact with its helicopter, NASA put the Mars mission on hold | Hacker News Reader

After losing contact with its helicopter, NASA put the Mars mission on hold

arstechnica.com

119 pointsStevvo62 comments

Just getting (relative) closeups of the discarded landing stuff will probably improve reliability of the next missions all on its own. Knowing what broke, what didn't, how it broke, etc means they can hopefully allow for narrower tolerances and fewer redundances to pack more stuff into the science mission. The next helicopter can check up on its predecessor's remains to make its successor even better.

https://mars.nasa.gov/resources/26696/debris-field-from-pers...

https://mars.nasa.gov/resources/26694/rovers-backshell-seen-...

https://mars.nasa.gov/resources/26695/rover-landing-gear-see...

It's very expensive to send a science mission to check on the remains of a previous mission. Odds are the next helicopter will be sent somewhere far away from the original.

Maybe Musk can plan his summer house there and post some pics to Twitter?

    2030: After losing contact with his summer house, Elon Musk put the Mars mission on hold.

> It's very expensive to send a science mission to check on the remains of a previous mission.

Apollo 12 intentionally landed within walking distance of Surveyor 3 [0].

[0] https://en.wikipedia.org/wiki/Apollo_12

Wow, that's really banged up! Wasn't that the thing the parachute was attached to? I would have thought that with a parachute the landing would be softer.

Oh wait, Mars is almost a vacuum and the parachute is really just used to slow the lander as it's traveling at ridiculous speeds. Now I wonder what the terminal velocity was-- certainly higher than it would be on Earth, even with 1/3 the gravity?

I wonder if there are good pics of the part of the delivery system that used rockets and didn't have a parachute? Did it fare worse?

The caption for that first image says that it impacted at "approximately 78 mph (126 kph)".

Mars's lower gravity, lower-density atmosphere, and different speed of sound (atmosphere mixture & temperature) happen to combine to similar aerodynamics in the high-subsonic region as the stratospheric region around 40 km altitude on Earth.

I.e., a plane that can fly up there on Earth could fly on Mars at low altitude.

Because gravity times travel distance is constant for constant aerodynamic efficiency and constant engine ISP, and Mars is both smaller than Earth and has significantly lower gravity, a hydrolox fuel-cell (driving electric props) flying wing should be able to do a "half-way around the planet" trip with reasonable cargo, followed by re-fueling oxygen, and flying back to the other place, before running out of hydrogen.

(Alternatively, at less than 50% cargo capacity loss, it could collect the water exhaust from the fuel cell, to recover the hydrogen.)

The main issue of such a plane would be that the lift-off speed on the runway would be about half the speed of sound. Maybe use the electric motors to drive fuel pumps and run hydrolox rocket engines for lift-off? Sounds like that could allow VTOL.

The amount of absolutely insane engineering that happens on these mission is outstanding all on its own- then you go and add stunts like this, and it makes you realize something: The folks doing this stuff are just like the rest of us. They're hackers, but they have billion dollar stuff to hack on. And, they're likely far better at it than the rest of us. Still, we're cut from the same cloth. Love it.

If they're simultaneously just like us and far better at it than the rest of us I believe there is a mutual exclusion here ...

Same class != Same level. I think most math people feel a sort of kinship with mathematicians past and present, but I can't pretend I'm any good

Likewise, it can also be difficult to recognize just how good someone is unless you are bad/average at the same thing.

Dunno, sometimes they screw up in dumb ways too:

https://en.wikipedia.org/wiki/Mars_Climate_Orbiter

I don't think a Mars mission compares in any way to what most SV hackers do, whether they do it for profit (especially the ignoble kind, ad revenue) or for the common good (open source dev). Not just in scale and timeframe and budget, but in how the organization (or lack of organization in the case of many open source projects) operates.

Also, your application of the word "hacker" to their simply having to adopt to circumstance or be able to update priorities and approaches pretty much takes all the meaning out of the word, because your loose meaning pretty much applies to any endeavor, from business to war to parenting to love.

Put on hold for a day*

Almost thought they lost it

Yea, what a click bait headline. Was also worried.

the engineering team commanded Perseverance to halt all of its ongoing science activities for a full day to essentially sit there and listen intently for Ingenuity's call

That sounds like a nerve-racking bit of troubleshooting!

I hope Ingenuity can survive the Martian winter, but even if it does not, it has been a massively successful mission. Everybody who contributed to it must be incredibly proud of how well it has done!

> 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.

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

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.

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.

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.

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.

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.

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.

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

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.

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.

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 ..

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.

My understanding is that the dust is incredibly sticky. You can't "just" vibrate it off. Even the occasional dust storm only blows some of it off. It's electrostatically attracted to the panels I think

That makes sense .. but I'm guessing they have to solve the problem sooner or later anyway, I don't see how a Mars colony is going to get over this problem unless of course we ship all those useful telephone dusters up there ..

IIRC it _has_ shaken off dust, but it obviously can't remove all of the dust, and even a little accumulation can reduce solar panel effectiveness enough to be a problem when you're on a pretty thin margin.

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.

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.

Not to mention Mars has a 3rd of Earth's gravity

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.

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

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

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.

Sorry for the offtopicness, but could you please email hn@ycombinator.com? I want to send you a repost invite.

This is probably a silly question - but what are the complications of mitigating dust sticking to devices like solar panels on mars?

My inexperienced mind thinks of things like windshield wipers, maybe some electronics to oppose the static forces of dust sticking to the panels?

We sure can't send someone over there every 6 months to wash the panels off, that's for sure.

The helicopter is already outside its original mission parameters. It was only supposed to make 5 flights - probably the engineering team didn't want to invest money or weight or complexity in something they knew wouldn't be an issue during their originally scheduled timeframe.

Yeah, I've been thinking electrostatics.

> They had been closely monitoring the health of their tiny spacecraft, particularly the charge state of its batteries.

Is Ingenuity a spacecraft? I thought it was an aircraft/helicopter... is the Martian atmosphere not characterized as containing air?

> The achievement of powered flight on another world is one of the great spaceflight feats of the last decade.

Really? Could someone with more knowledge about this outline how different the Mars copter is from a run of the mill quad copter?

Such a great story about ingenuity completely shooting past all that we thought it would be able to achieve. I also like the usage of plucky to describe it. Against all odds...

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