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NASA regains contact with mini-helicopter on Mars

phys.org

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Re: NASA regains contact with mini-helicopter on Mars

#11

Post by wongarsu »

mmbop wrote: post #5
wyldfire wrote: post #3

Earlier quoted context omitted.

The existing helicopter is extremely small and light, IIRC. less than one kg. So it definitely won't be picking up a 900kg rover, even if you tried to scale it up somehow. The atmosphere is just too thin to support anything but a minimal payload. But yeah having more helicopters might be feasible - for surveying the surface.

Is there a problem of scaling this up to say a 20kg payload? I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

One issue might be rotor span. Ingenuity has pretty big rotors to counter the thin atmosphere (about 4 feet top-to-tip).

On earth rotor sizes are limited by the speed at the wing-tip. Once you make the rotor too long the tips start approaching supersonic speeds, giving you all kinds of weird mach effects. To make matters worse, the speed of sound is about 30% lower on Mars compared to near earth's surface.

Re: NASA regains contact with mini-helicopter on Mars

#12

Post by jessriedel »

mmbop wrote: post #5
wyldfire wrote: post #3

Earlier quoted context omitted.

The existing helicopter is extremely small and light, IIRC. less than one kg. So it definitely won't be picking up a 900kg rover, even if you tried to scale it up somehow. The atmosphere is just too thin to support anything but a minimal payload. But yeah having more helicopters might be feasible - for surveying the surface.

Is there a problem of scaling this up to say a 20kg payload? I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

I don't know the answer to your question, but for context here are the weights of Mars rovers:

Sojourner (1997): 11 kg

Spirit & Opportunity (2004): 185 kg

Curiosity (2011): 899 kg

Perseverance (2020): 1,025 kg

Re: NASA regains contact with mini-helicopter on Mars

#13

Post by jvanderbot »

surfpel wrote: post #4
simion314 wrote: post #2

We will use more helicopters instead of rovers for new missions ? Or larger crafts would be much harder or riskier to use ? Or maybe have a helicopter that can move the rover with the equipment to different locations.

That's the goal, yes. Depending on the destination, naturally. Here's what's planned for Titan: https://en.wikipedia.org/wiki/Dragonfly_(spacecraft)

Was going to post this.

Titan is such a wonderful place for a nuclear powered helicopter. Much better than rover/submarines/floaters, IMHO. A balloon would also have been excellent, but the extra mobility from helis is going to be amazing.

Re: NASA regains contact with mini-helicopter on Mars

#14

Post by mmbop »

jessriedel wrote: post #12
mmbop wrote: post #5

Earlier quoted context omitted.

Is there a problem of scaling this up to say a 20kg payload? I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

I don't know the answer to your question, but for context here are the weights of Mars rovers: Sojourner (1997): 11 kg Spirit & Opportunity (2004): 185 kg Curiosity (2011): 899 kg Perseverance (2020): 1,025 kg

I know these are much larger - I’m just really curious about the dynamics of scaling up rotorcraft & why it is problematic. ie - do rotor physics become impracticality large or fast at some point for materials science, or is it purely a space problem for rocket launches.

Re: NASA regains contact with mini-helicopter on Mars

#15

Post by jvanderbot »

simion314 wrote: post #2

We will use more helicopters instead of rovers for new missions ? Or larger crafts would be much harder or riskier to use ? Or maybe have a helicopter that can move the rover with the equipment to different locations.

A heli that can move a rover is basically worse than a heli that has rover instruments and a few wheels. You have extra weight and parts and complexity for hitching and carrying that you can just avoid by giving a small rover flying ability.

Even the combo is probably too much complexity. A heli with good imagers, spectrometers, and the ability to cart soil samples would be fantastic.

Re: NASA regains contact with mini-helicopter on Mars

#16

Post by mmbop »

wongarsu wrote: post #11
mmbop wrote: post #5

Earlier quoted context omitted.

Is there a problem of scaling this up to say a 20kg payload? I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

One issue might be rotor span. Ingenuity has pretty big rotors to counter the thin atmosphere (about 4 feet top-to-tip). On earth rotor sizes are limited by the speed at the wing-tip. Once you make the rotor too long the tips start approaching supersonic speeds, giving you all kinds of weird mach effects. To make matters worse, the speed of sound is about 30% lower on Mars compared to near earth's surface.

Oh interesting! I can see how that would be a harder problem (although not insurmountable since some planes on earth have supersonic propellers).

Just a quick edit - wow, u didn’t realize the span was already 4ft! Anything much larger could definitely be hard to pack inside a fairing!

Re: NASA regains contact with mini-helicopter on Mars

#17

Post by mmbop »

nortlov wrote: post #9
mmbop wrote: post #5

Earlier quoted context omitted.

Is there a problem of scaling this up to say a 20kg payload? I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

In a thin atmosphere, lifting a heavier payload needs bigger rotors or increased RPM, which increases power demands and structural stress. The challenge is to keep the vehicle light enough to fly while also making it sturdy enough to carry the payload and survive environments.

Ok - this makes sense to me. Also taken into account the context that anything going to space needs to be light at this point in time. Hopefully we don’t have that restriction forever :)

Re: NASA regains contact with mini-helicopter on Mars

#18

Post by jessriedel »

wongarsu wrote: post #11
mmbop wrote: post #5

Earlier quoted context omitted.

Is there a problem of scaling this up to say a 20kg payload? I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

One issue might be rotor span. Ingenuity has pretty big rotors to counter the thin atmosphere (about 4 feet top-to-tip). On earth rotor sizes are limited by the speed at the wing-tip. Once you make the rotor too long the tips start approaching supersonic speeds, giving you all kinds of weird mach effects. To make matters worse, the speed of sound is about 30% lower on Mars compared to near earth's surface.

Yea good point. Apparently the blade tip speed on Ingenuity is Mach 0.6-0.7!

Re: NASA regains contact with mini-helicopter on Mars

#19

Post by jessriedel »

mmbop wrote: post #14
jessriedel wrote: post #12

Earlier quoted context omitted.

I don't know the answer to your question, but for context here are the weights of Mars rovers: Sojourner (1997): 11 kg Spirit & Opportunity (2004): 185 kg Curiosity (2011): 899 kg Perseverance (2020): 1,025 kg

I know these are much larger - I’m just really curious about the dynamics of scaling up rotorcraft & why it is problematic. ie - do rotor physics become impracticality large or fast at some point for materials science, or is it purely a space problem for rocket launches.

Oh for sure, it's a great question.
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