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How NASA Designed a Helicopter That Could Fly Autonomously on Mars

spectrum.ieee.org

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Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#71

Post by tkinom »

ryan_j_naughton wrote: post #52

Can someone who understands aeronautical engineering explain why they went with a helicopter over a winged aircraft? My guess is that takeoff would be too difficult for a traditional winged aircraft and VTOL was way too complicated. But given the thin nature of the atmosphere, a helicopter seems even more difficult to get lift than a winged aircraft. Can someone explain or link to the science between lift and air den…

Wonder the same thing, I have the impression that Quad or Hex copter would be more stable/reliable with more redundancy build in.

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#72

Post by zokier »

amelius wrote: post #42
gambiting wrote: post #39

Earlier quoted context omitted.

I do remember reading about this - a balloon would work, but it would be absolutely enormous, far larger than anything we can bring into Mars currently. Maybe some day.

Another thing I'm wondering: the drones can probably carry only a small (light) camera, whereas a satellite can carry much more and thus also a much better camera. Wouldn't a satellite+camera be a better option?

You mean like HiRISE:

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

or HRSC:

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

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#73

Post by carabiner »

tkinom wrote: post #71
ryan_j_naughton wrote: post #52

Can someone who understands aeronautical engineering explain why they went with a helicopter over a winged aircraft? My guess is that takeoff would be too difficult for a traditional winged aircraft and VTOL was way too complicated. But given the thin nature of the atmosphere, a helicopter seems even more difficult to get lift than a winged aircraft. Can someone explain or link to the science between lift and air den…

Wonder the same thing, I have the impression that Quad or Hex copter would be more stable/reliable with more redundancy build in.

Quad/hex would be less efficient and heavier for the same performance (range, speed, service ceiling), but yes, more stable. In this mission, I suspect minimizing weight (as a rocket payload to be sent through space) and maximizing range (hop flights on Mars on a limited power source) were a priority. This is also why full size helicopters are almost all single main rotors with a TR.

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#75

Post by nharada »

amelius wrote: post #17

If you just want images from a different angle, why not tether it to the rover? Also can't you use a kind of balloon instead to save power?

There actually have been airship proposals for Mars, but as you'd expect because of the tiny atmosphere they're... different: https://www.nasa.gov/directorates/spacetech/niac/2017_Phase_...

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#77

Post by trhway »

teraflop wrote: post #68
nynx wrote: post #59

Earlier quoted context omitted.

I'm a little surprised they didn't go for three separate computers and compare them for every operation, or something like that, but I'm sure they have their reasons.

I've never seen an off-the-shelf processor that has hardware support for doing that kind of cross-checking on every instruction. And doing it in software would probably add so much overhead that the error-checking would be much more likely to fail than the application code. If you're willing to relax your real-time constraints a bit, and risk a brief period of incorrect behavior before the error is caught, the proble…

>off-the-shelf processor that has hardware support for doing that kind of cross-checking on every instruction.

it is usually done with COTS CPU by either running the CPUs in lockstep (the simpler early generations of CPU) or by inserting hardware checkpoints at various points like branches, by number of instructions, etc. A recent such commercial system was the triple Itanium from Tandem/NonStop(HP).

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#78

Post by MayeulC »

MayeulC wrote: post #47
secondcoming wrote: post #22

Could they use it to try blow dust off the Opportunity rover's solar panels to see if it'll boot again?

I guess the atmosphere would be too tenuous to try to blow dust away with it (max pressure should be a bit more than Ingenuity's mass/rotor surface, so not much). How long before a commercial autonomous helicopter-based solar panel dusting service on Mars, I wonder?

s/mass/weight/

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#79

Post by jack_h »

teraflop wrote: post #68
nynx wrote: post #59

Earlier quoted context omitted.

I'm a little surprised they didn't go for three separate computers and compare them for every operation, or something like that, but I'm sure they have their reasons.

I've never seen an off-the-shelf processor that has hardware support for doing that kind of cross-checking on every instruction. And doing it in software would probably add so much overhead that the error-checking would be much more likely to fail than the application code. If you're willing to relax your real-time constraints a bit, and risk a brief period of incorrect behavior before the error is caught, the proble…

There are the ARM Cortex-R series of processors which have two cores running in lockstep for fault tolerance.

Re: How NASA Designed a Helicopter That Could Fly Autonomously on Mars

#80

Post by tpmx »

> With all this in mind, getting Ingenuity to Mars in one piece and having it take off and land even once is a definite victory for NASA

Sorry, slightly off-topic: Not a native English speaker. Isn't this sloppy writing? Seems like declaring victory ahead of time?

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