Hacker News Reader

Comment by waiseristy | Hacker News Reader

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

View on HN

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.

Reply on news.ycombinator.com