Mars Ingenuity helicopter mission extended by NASA | Hacker News Reader

Mars Ingenuity helicopter mission extended by NASA

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187 pointsTarragon58 comments

This business of we've only planned 4-5 flights in the main mission but will extend by 30 more days seems like intentional under-committment to me. NASA seems to have done this with most of the previous rover missions as well - all of them significantly extended missions.

Maybe there's politics around funding. I wouldn't be surprised if the major costs are people costs over months and sometimes years to support the science vs. the actual core mission costs but it may be a big sticker shock to ask the Congress at one go. So possibly they ask funding for a short under balled-mission (which no one really scrutinizes) and then keep getting funding extensions citing opportunity costs (the probe is already on Mars, we can get extended value etc). I can imagine there's massive politics here, so it maybe is the only smart game to play

I think it's probably to be careful with expectations. They didn't know how well it would really work, or if they'd kill it on a landing.

NASA has been making it very clear that everything more that it does from now on is a bonus.

If you keep it framed like that, it's more exciting to have a successful mission & likely to continue to get funding, than if you set high expectations and fail.

> If you keep it framed like that, it's more exciting to have a successful mission & likely to continue to get funding, than if you set high expectations and fail.

This seems to be the more plausible reason. You keep the bar for success low so you keep getting funding for subsequent missions. Isn't that pretty much how every organization with public funding sets goals?

I mean the low bar is that they fly three robots to Mars and two of them land safely and one of them makes multiple flights on the surface of another world so it’s a pretty high low bar!

I mean sure it's cool but I think the point is they've been so consistently spectacularly successful in blowing past mission objectives that it's a bit hard to imagine achieving this wasn't the "expected result" (maybe we can cut a bit of slack for Pathfinder/Sojourner which was the first complex mission after the Climate Orbiter debacle and over-delivered only 12x).

The issue here is that there's a mismatch between the probability distribution and result. In reality, either the equipment will fail some time on entry/initialization and won't be able to complete any missions, or it will work for one and thus probably work for a hundred of them.

If you promise one run and fail to complete it, it's a disappointment, but eh, it was a high-risk mission anyway. If you promise a hundred runs and fail to complete even one, you'll catch a ton of flak. If you promise one and complete a hundred, you're a hero.

The math checks out that way, especially when one single mission is good enough to get the funding anyway. Everything else is literally a bonus, why promise ten when they're paying you for one?

Yes - there's clearly an incentive misalignment in setting & communicating realistic mission risks & expectations which is not too surprising given the politics behind how NASA is funded.

What happens over a period of time in any organization if you consistently under-commit & over-deliver is that people stop believing in your "official" under-committed number ("It's just on-paper") and start creating their own informal "realistic" expectations (which are possibly different across stake-holders) and start taking (possibly mis-aligned) decisions based on these. As you may imagine, such situations tend to blow up from time to time.

Isn't this the exact same everywhere else?

Your boss wants to know how long you'll spend on a job; if you tell him 30 days and spend 30 days you're just good at estimation.

If you do it in 20, you're a star for doing it under budget!

If you're smart, that's how your private organization sets its goals, too. Under-promise and over-delver keeps stakeholders happy.

It's both a PR/optics thing, as well as a real engineering thing.

Say you have 5 critical components, any of which fail, you are no longer able to complete your entire mission (which in this context is a set of scientific experiments that you've pitched and believe that if you get nothing but that data back, that your entire mission cost was worth it). If you need X time to finish your mission, and say... you want a 95% (I have no idea what the real model number is) chance of finishing the entire mission. This will require you to push the reliability of your individual components up a lot. Say your failure rate model is uniform - your probability of failing in any given period of time is the same as any other given period of time (so you're in the bottom of the bathtub curve).

Very roughly you'd need like a maximum of 1% chance of any given component failing over X period to reach your reliability goal. If X is something like month, that translates into a mean time to failure that is not suddenly measured in years. Very quickly you can see how the constraint that N=1 MUST survive for X period will naturally lead to many instances where that N=1 CAN survive for much longer.

Now say that you can withstand component failures, and still continue with degraded performance (that would have impeded your original mission), then you can stretch things out even more.

They realized the helicopter link to the rover is quite good and can can communicate up to a km. So the rover will continue its missions while the helicopter is far away. Maybe once a week they will do a helicopter flight. The helicopter is also fast so it can quickly catch up with the rover. After a month they will evaluate if the helicopter can continue to be used without impacting the primary mission. However the helicopter was not designed to handle the thermal extremes of the Martian night/day for a prolonged period so its only a matter of time before a solder joint or camera fails.

Ingenuity's mission proposal makes sense here; It was developed as a tech demo as opposed to an operational one. A significant part of the drone was using COTS components (namely a Snapdragon 801 of all things) that weren't even rad-hardened and was exposed to all sorts of radiation for an extended period of time in space. With most missions the tradeoff is typically between risk and reliability, and even one flight on this thing involves a very large risk - 4 initial flights seems relatively reasonable.

Met a few engineers involved with the project, they did mention they ran into a lot of issues internally since the teams on Perseverance gave significant pushback to make sure that it didn't jeopardize the mission. Ingenuity's only a second priority on Mars 2020

There is a book called the grand tour about the coyager program. I cannot find the exact quote, but they couldn't get funding to design the mission they wanted to do the grand tour; they could only get funding for Jupiter and Saturn. They developed a mantra of something like "don't plan for a long mission, but also don't make any decision based on a short mission life".

I suspect we see a similar process play out with nearly every probe mission. They couldn't get funding to build something that'll work with a REALLY HIGH probably of working for a year, but they made trade offs to get them a high probably of it working for a year.

I read it as under promise- over deliver...

NASA's funding is determined by politicians, who care a lot about politics and think in those terms.

It's how the Great Game is played. It's never been a secret.

Here's the press announcement from NASA directly. It has even more information:

https://www.nasa.gov/press-release/nasa-s-ingenuity-mars-hel...

I'm honestly more interested in the failure mode that ingenuity eventually meets. Something lame like a human error in flight planning? Cosmic ray annihilating a critical component? Or maybe even martian dust destroying its delicate surfaces and bearings. So many new problems after only having stationary/wheeled rovers for so long

When it comes to stomping out working robotics on Mars, the 1-2 punch of cold and dust always gets the job done. With a tiny battery and 2400RPM blades, its just a toss up on which one will be the crippling punch for Ingenuity.

It'd be adorable if when Ingenuity gets cold, Perseverance rolls over to shelter the little helicopter and even warm it a little with that nuclear heater the rover uses for power.

To be fair, I'd imagine that the air turbulence should keep the solar panel reasonably clear...

My guess is it will be a bad landing that eventually ends the mission. As they start landing on new terrain, they're eventually going to get unlucky and tip it over on landing.

If its blades aren't damaged (prop strike), the rover might be able to right it with a nudge from its arm.

The rotors are 1.2m in length and spin up to 2500rpm.

This gives circa 160m/s (560km/h) linear speed of the rotor tip.

Pretty much impossible for the rotors to survive touching anything at that speed.

The rotors are probably already designed with absolute minimum margins. Not only the rotors are part of the package to deliver to surface of Mars, then they have to be lifted in thin atmosphere, but they also need to be spun up to very huge speeds and then quickly controlled to keep the craft stable. The mass of those rotors is critical to how well the craft can be controlled.

They have stated they have no intentions of using the rover to do so. I would think given this is now “extra credit” doing so becomes even less likely.

I don't know if the actual design can do this, but theoretically it would be able to right itself by spinning the bottom prop slowly and the top one fast, so the bottom one lifts it up enough that the top one can help it take off enough to attempt another landing.

That's probably something they didn't test for or implement, though.

Wouldn't you think the rover would be able to drive over and right it if it were not too far away?

Ingenuity has already fulfilled its mission with overwhelming success, and anything extra now is just a bonus.

Perseverance is still early in its mission. There's no way they would ever have it attempt to push Ingenuity upright, simply from a risk perspective. Why risk any complications with the primary mission, just so you can squeeze out a little more science from the expendable secondary experiment?

Technically, both are expendable.

But I think it is not possible for Ingenuity to survive tipping over. Even if the rotors somehow survive 500km/h strike onto ground (which I find extremely unlikely) they are constructed to be perfectly balanced which is extremely important at that speed. Even slightly bent they are completely useless.

It is obvious the team understand this and will not waste time on fruitless rescue mission.

The blades will likely break if tipped over. The whole things was designed to be super lightweight. Secondly the rover has a 2 year primary scientific mission it much proceed with.

If there's a prop strike with the props going hundreds of miles per hour, probably not?

It'll probably get blown away in a storm and buried in sand.

There really isn’t enough of an atmosphere to present a risk of blowing Ingenuity away, or even toppling it over - same thing with depositing enough material to bury it. More likely it could be covered in a thin film of dust that would render the solar panel nearly useless, like what happened to Opportunity.

I'll add a guess for not able to keep charging it's batteries and having enough solar energy to keep it going in the cold.

They mention that thermal cycling is a big issue. It get s super cold at night. Eventually some soldering joint fails. Other issue is the CPU is not rad hardened so there might be a fault. Also a mechanical failure like the blades breaking or tipping over.

I imagine the batteries aren't liking the thermal cycling a lot either - they are normal (albeit rather high-quality) 18650 Li-Ion cells, that are usually quite sensible to storage and operating temperatures and will tend to lose usable capacity and power output after being stored and used in the cold.

I recall reading somewhere the majority of the power consumed by the helicopter is used for heat to prolong the life of the battery cells.

Does NASA just set very limited goals for public performance/political reasons? As most missions seem to amazingly blow past these initial expectations.

I get that NASA has some brilliant people, but I struggle to believe that the initial mission times that NASA gives are genuine estimates of what is achievable. Everything always exceeds expectations. Maybe that is just the prevailing culture as we expect everything to exceed expectations.

Quite the contrary, I believe NASA is very serious about meeting their goals. If the goal was to fly for 30 days, then they'd have a huge challenge in over-engineering the mission to ensure 30 days. This way, they can get the initial proof done (hooray!) and then run the robot to failure (which itself will be interesting.) It might fail in 30 days. It might not.

Another benefit of this approach is, as with Spirit & Odyssey, they can use off-the-shelf components if they meet the initial goal.

Inversely, I blame congress and general population to be more critical on a mission failure (non-life threatening) than they need to. Rocket science and operating toys on another planet isn't easy.

The way it is now, it's a feedback loop that's working for everyone.

Why would NASA intentionally plan to end the mission? Why not continue flying this thing until it breaks?

You set your initial goals low, so you can achieve them, especially if you’re depended on public funding.

It’s a great successes story, if they flew and met all their original goals, and then just try to extend it. It’s much different story, if initial plan would be for example for 20 flights, but it’ll break after 15th. Then you have failure, people questioning why we spent so much money on failed mission, etc.

Plus, it’s easier to ask for $x billion dollars for the mission, meet all the goals and then ask for few extra $ to support extending already proven and successful mission, then to ask for higher amount from a start.

This. The two MER rovers were supposed to last 90 Marsian days but instead made it to 10+ years.

At least part of that was dust storms unexpectedly cleaning the solar panels.

I suspect, but don't know for sure, that this is related to funding for staffing in command centers and such. "Fly it until it breaks" means that somebody must approve an uncertain and ongoing expense without any results to show for it.

If you re-frame it as an initial experimental mission, it's a smaller and more defined budgetary request. You can outline potential extra-time scenarios, but presumably those are a lot easier to get approval for after the initial window is a success.

edit: It also occurs to me that framing it as a series of smaller phases with well-defined goals and benefits also makes it easier to communicate a straightforward message to the broader public about the mission.

Helicopter requires rover to be near by as means of communications as helicopter itself can not directly communicate. Thus, it originally had a limited time as the rover needs to move on to other activities.

But it's a Helicopter.

Whenever the rover moves on, the helicopter can move to a new landing spot within range.

Yes, that is the plan now. It was not the original because…we’ve never flown on another planet before. It was successful so they are changing the parameters after learning more. SCIENCE!

How far can it fly on one charge?

About 600m per flight. Actually it's flight time is limited by motor heat buildup, not battery capacity.

If they want to scout each landing site, that requires doing a round-trip one day to get photos and flying out the next day, which limits it to a maximum range of 300m every two days.

The previous rover, Curiosity has driven an average of 8m per day (usually stopping for a few days to to science then driving in bursts of ~30m/day) Ingenuity should be able to keep up.

I can definitely envisage future rover missions having a helipad, of sorts.

It would also allow the helicopter to charge directly from the rover, rather than from a clumsy solar panel.

Couldn't this increase the chance of a collision though?

Planning and funding come in chunks, you get X set of people for Y months/years with access to Z resources to accomplish goals A,B,C,etc. If it's successful you're likely to get more time and some subset of the resources if there's still interesting science to be done (and there usually is, our questions are nearly endless compared to the resources available on the rovers). Doing it on an open ended mission doesn't really match how government funding works.

Time; perseverance has had to stay close by; using our most precious resource in space —- time.

It is also all about a cost benefit using the team here to plan missions; rather than shift into a new project.

Basically what this says is, this little machine can still teach us something.

I believe perseverance is now going to move further away; but they have proven more reliable communication links so believe they can stretch the envelope.

Don’t learn a lot of this stuff until your on another planet.

Because NASA knows valuable it is to under-promise and over-deliver.

> The plan [...] to take 60 black-and-white images and five colour images

Why black and white? Why not all colour? What constraint are they working around? Storage? Camera speed?

Black and white pictures are generally much more precise. There's a lot of image manipulation involved in consumer grade color images (which the copter has).

More info:

https://youtu.be/Wah1DbFVFiY

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