Author Topic: Mars Helicopter  (Read 15276 times)

Offline catdlr

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Mars Helicopter
« on: 01/23/2015 01:03 AM »
New thread:
https://forum.nasaspaceflight.com/index.php?topic=45676.0

Crazy Engineering: Mars Helicopter

Published on Jan 22, 2015
JPL engineers are working on a small helicopter that could Ďscoutí a trail for future Mars rovers, but getting a chopper that could fly in the Martian atmosphere is tricky. Episode 2 of Crazy Engineering.

« Last Edit: 05/14/2018 11:17 AM by Chris Bergin »
Tony De La Rosa

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Re: Mars Helicopter
« Reply #1 on: 01/25/2015 04:33 PM »
Interesting system, although I wouldn't bet on the long-term survival of this system on Mars. A safer alternative would be to put a camera/mirror on top of a long pole stuck to the rover. With a 10-m pole you may be able to see a few km away in flat terrain.

Offline Bubbinski

Re: Mars Helicopter
« Reply #2 on: 01/25/2015 04:47 PM »
Thanks for the video catdlr.  Couldn't the mini copter be mounted on a long tether that could stabilize and wind the craft back to the rover in an emergency?  Or alternatively would it be better to mount cameras on tethered balloons?
I'll even excitedly look forward to "flags and footprints" and suborbital missions. Just fly...somewhere.

Offline MarsInMyLifetime

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Re: Mars Helicopter
« Reply #3 on: 01/25/2015 05:06 PM »
Any pole or leash would need to be ejectable in case either became snagged in the landscape, effectively tethering the rover forever. I do worry about tip-over and blade damage effectively ending the reconnaissance mission earlier than planned.
Don

Offline Moe Grills

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Re: Mars Helicopter
« Reply #4 on: 01/25/2015 05:39 PM »
Personally, I would prefer to see a fixed wing unmanned aircraft used on Mars.
Imagine one equipped with a pair of HD digital cameras and transmitting the images to an HMO orbiter relay overhead. Imagine such a craft flying through the martian grand canyon and recording and transmitting HD streaming video of such an awesome scenic flight.
« Last Edit: 01/25/2015 05:40 PM by Moe Grills »

Offline Burninate

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Re: Mars Helicopter
« Reply #5 on: 01/25/2015 09:10 PM »
Personally, I would prefer to see a fixed wing unmanned aircraft used on Mars.
Imagine one equipped with a pair of HD digital cameras and transmitting the images to an HMO orbiter relay overhead. Imagine such a craft flying through the martian grand canyon and recording and transmitting HD streaming video of such an awesome scenic flight.
The average air pressure of the Martian surface is equivalent to Earth air pressure at 36,000 meters, and the maximum is at the bottom of Hellas, equivalent to 31,000 meters.  The highest altitude achieved by an unmanned solar-powered airplane on Earth has been 29,500 meters, and that was gigantic and extremely fragile.  Exacerbating factors: the solar power at 1AU is twice as intense.  Mitigating factors: The Earth atmosphere reduces insolation somewhat more than Mars, and gravity on Mars is a third as intense.

Streaming video is something we don't have the bandwidth for now - that will require laser telecommunications orbiters.

Superpressure balloons are much more practical on Mars than airplanes, and something that we're developing into functional products for Antarctic astronomy right now.

« Last Edit: 01/26/2015 04:10 AM by Burninate »

Offline Dalhousie

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Re: Mars Helicopter
« Reply #6 on: 01/25/2015 09:14 PM »
Looks like a good idea. I suspect that the probability of reuse decays exponentially with the number.  But even a single high would be a valuable for initial mission phases, especially of future missions aim to stay in the landing ellipse.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Bob Shaw

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Re: Mars Helicopter
« Reply #7 on: 01/25/2015 09:45 PM »
The atmospheric pressure on Mars is so low that getting anything to fly won't be easy. I could *just* about imagine a super-capacitor powered lurch into the air followed by a barely controlled descent, all of which seems a bit of a reach, especially when you add any payload.

There are alternatives.

Already available on our own planet are multi-camera rigs encased in tough balls which the user simply throws into the air. Or catapults, for that matter. The cameras all snap away like mad, and you can rapidly build a full 360 degree image. No pointing, nowt except cameras really. Imagine a springy extensible fishing rod with such a camera on a tether, pulled back and then allowed to go 'sproinggggg' into the air, then rapidly recovered (perhaps wound into a baseball mitt very quickly while still in the air, so no snagged recoveries).

If little else, it'd offer good sport for passing Martians with their ever-ready ACME disintegrator rays.

Now, put a helicopter on Titan, or Venus - then we'd be talking!
« Last Edit: 01/25/2015 09:46 PM by Bob Shaw »

Offline Dalhousie

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Re: Mars Helicopter
« Reply #8 on: 01/25/2015 10:19 PM »
The atmospheric pressure on Mars is so low that getting anything to fly won't be easy. I could *just* about imagine a super-capacitor powered lurch into the air followed by a barely controlled descent, all of which seems a bit of a reach, especially when you add any payload.


There have a number of studies on the viability of Mars helicopters, so personal incredibility aside, this appears a perfectly viable concept, with useful flight times, payloads and ranges.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA480702

http://rotorcraft.arc.nasa.gov/publications/files/Young%202005Mars_Rotorcraft_IEEE_Final.pdf


"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline simonbp

Re: Mars Helicopter
« Reply #9 on: 01/25/2015 10:25 PM »
The atmospheric pressure on Mars is so low that getting anything to fly won't be easy. I could *just* about imagine a super-capacitor powered lurch into the air followed by a barely controlled descent, all of which seems a bit of a reach, especially when you add any payload.

Did you actually watch the video? Especially the part where they were testing the helicopter in the JPL vacuum chamber at Mars surface pressure conditions? The number of ~500 meters per day was based on actual analysis of the current capabilities of the design without invoking supercaps or any other exotic technologies.

In fact, given that they were able to get so much range out of a tiny (look like 10 cm2) solar cell, it really begs the question of if you could scale up the system and build a helicopter with an instrument package similar to Spirit/Opportunity. Given the issues with Curiosity's mobility system severely limiting its range, a "heli-rover" capable of traveling a km per sol (and then resting for a few sols to recharge take data) would be extremely competitive.

Quote
Now, put a helicopter on Titan, or Venus - then we'd be talking!

I don't know why you would want a helicopter on Venus. Anything at low altitudes would more like a high-temperature submersible, while at higher altitudes and Earth-like pressures, you don't want to sit still but rather move around and sample. I know for a fact that Northrop Grumman is working on a hybrid fixed-wing dirigible (think a plane with inflatable wings) to do just that.

On Titan, a helicopter would work great, but the solar flux at the surface of Titan is so low that you just could not do it solar powered. It would have to be RTG-powered, which makes the vehicle much larger...

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Re: Mars Helicopter
« Reply #10 on: 01/26/2015 07:06 AM »
A helicopter can fly over ridges and crevasses; these tend to imprison rovers.

A fixed wing aircraft will have difficulty taking off on a planet without runways.  It either has to return to the lander at night or stay in the air.  A rover and a plane are probably too heavy to send to Mars.

Offline pagheca

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Re: Mars Helicopter
« Reply #11 on: 01/26/2015 08:16 AM »
When I saw the title of this thread I thought "just another crap fantasy", given the low atmospheric pressure.

Then I read the post and found is quite a reasonable idea. It's amazing how common sense can be wrong in anything related to space...

One question: I would expect much longer blades than those. Do you know if those are due to reasonable specs for a Mars payload or they are limited by the 2400 rpm they mentioned for effective flight or any other requirement (stability? Fragility?). Any expert on helicopter basic design rules here?
« Last Edit: 01/26/2015 10:03 AM by pagheca »

Offline Bob Shaw

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Re: Mars Helicopter
« Reply #12 on: 01/31/2015 11:13 PM »
The atmospheric pressure on Mars is so low that getting anything to fly won't be easy. I could *just* about imagine a super-capacitor powered lurch into the air followed by a barely controlled descent, all of which seems a bit of a reach, especially when you add any payload.

Did you actually watch the video? Especially the part where they were testing the helicopter in the JPL vacuum chamber at Mars surface pressure conditions? The number of ~500 meters per day was based on actual analysis of the current capabilities of the design without invoking supercaps or any other exotic technologies.

In fact, given that they were able to get so much range out of a tiny (look like 10 cm2) solar cell, it really begs the question of if you could scale up the system and build a helicopter with an instrument package similar to Spirit/Opportunity. Given the issues with Curiosity's mobility system severely limiting its range, a "heli-rover" capable of traveling a km per sol (and then resting for a few sols to recharge take data) would be extremely competitive.

Quote
Now, put a helicopter on Titan, or Venus - then we'd be talking!

I don't know why you would want a helicopter on Venus. Anything at low altitudes would more like a high-temperature submersible, while at higher altitudes and Earth-like pressures, you don't want to sit still but rather move around and sample. I know for a fact that Northrop Grumman is working on a hybrid fixed-wing dirigible (think a plane with inflatable wings) to do just that.

On Titan, a helicopter would work great, but the solar flux at the surface of Titan is so low that you just could not do it solar powered. It would have to be RTG-powered, which makes the vehicle much larger...

Gosh. Yes, I *did* watch the video, but wasn't convinced.

As for Venus, that wasn't entirely serious, but ...

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Re: Mars Helicopter
« Reply #13 on: 04/02/2017 10:04 PM »
'new' video.


2-3 min flights, 600m range to 40m altitude, one flight a day.
1.1m rotors, 1kg, 220W power.
Transmits data back to a psuedo-instrument on the rover bus, which looks to the rover like any other instrument.

Blade tips are moving about half the local speed of sound.
Hard landings would be bad.

Online TrevorMonty

Re: Mars Helicopter
« Reply #14 on: 04/02/2017 10:56 PM »
Being able survey a route from air for rover should speed up exploration. NASA can download flight information and use it to plot a route for rover. Load rover with 100m route and leave it to it.

Ideal for scouting lava caves.

Offline sevenperforce

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Re: Mars Helicopter
« Reply #15 on: 04/03/2017 02:13 PM »
Yeah, the low blade length is surprising to me. Total thrust is a function of power and blade-sweep area; you can boost your thrust without increasing power usage simply by increasing the area swept out by your blades.

But then again I'm sure they had a good reason, given the tests they've done. Maybe there was a concern about materials integrity with longer blades potentially reaching transonic speeds at the tip. The altered density and pressure of Martian atmosphere means a much lower local speed of sound.

I suppose another reason to minimize blade length would be the physical size of the craft....

Offline Rei

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Re: Mars Helicopter
« Reply #16 on: 04/03/2017 03:49 PM »
Quote
Now, put a helicopter on Titan, or Venus - then we'd be talking!

I don't know why you would want a helicopter on Venus. Anything at low altitudes would more like a high-temperature submersible, while at higher altitudes and Earth-like pressures, you don't want to sit still but rather move around and sample. I know for a fact that Northrop Grumman is working on a hybrid fixed-wing dirigible (think a plane with inflatable wings) to do just that.

Indeed, VAMP.  One of the coolest things about the concept is not just how it flies around the atmosphere, but how it does atmospheric entry: without an aeroshell. It inflates in space and does a very low beta, high L/D, very large cross section (aka radiating surface area) entry.

There's no serious proposal to actually launch VAMP at this time, but I'd love to see it compete for the next flagship mission.

There are of course many types of Venus flying probe proposals, mainly superpressure balloons. For the surface, two main concepts are explored - metal bellows with a winch to control lift, and phase change balloons, where liquid is kept in a pressure vessel, flash boiled when they want lift, and recondensed at high altitudes.  The former seems to be more in favour at present, and they've validated a prototype in an autoclave. Unfortunately it looks like the first mission to validate it won't fit in a Discovery budget.

Offline Rei

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Re: Mars Helicopter
« Reply #17 on: 04/03/2017 03:50 PM »
Yeah, the low blade length is surprising to me. Total thrust is a function of power and blade-sweep area; you can boost your thrust without increasing power usage simply by increasing the area swept out by your blades.

But then again I'm sure they had a good reason, given the tests they've done. Maybe there was a concern about materials integrity with longer blades potentially reaching transonic speeds at the tip. The altered density and pressure of Martian atmosphere means a much lower local speed of sound.

I suppose another reason to minimize blade length would be the physical size of the craft....

That is indeed the constraint: size. If you wanted bigger you'd have to engineer a folding prop - more money, more risk, more mass.

Online TrevorMonty

Re: Mars Helicopter
« Reply #18 on: 04/03/2017 06:16 PM »
Current mass and size limits are so it can fit on this rover as payload. Future versions could be up to 50kg, at this size a rover could be helicopter's payload.

Ideal payload for likes of Red dragon.

Offline Tulse

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Re: Mars Helicopter
« Reply #19 on: 04/03/2017 07:38 PM »
I wonder if it would be possible to put the solar cells on the rotor blades.  This would avoid the aerodynamic problems of where it is currently, and would also likely give a larger area for the cells.

I also wonder if instead of putting panels of aerogel into the chassis for thermal protection, one couldn't simply carve the body of the vehicle out of a block of aerogel, and thus use the thermal protection as a structural component as well.  This might lower weight, and would provide a better thermal seal for the electronics as it reduces the number of seams that have to be managed.

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Re: Mars Helicopter
« Reply #20 on: 04/05/2017 07:09 PM »
I suppose another reason to minimize blade length would be the physical size of the craft....

Packaging too.
Go much longer, and you can't avoid blades being required to fold in multiple ways.
The required power may go down, in principle per watt if you increase area, but the torque also rises, meaning you need a more capable gearbox, and probably swash plate and related unreliable mechanisms.

Plus, the above can cope with expected winds - more blade, and you're going to have to fold on landing them to avoid the sail area meaning you get blown over.

Fun optimisation problem.

Offline Rei

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Re: Mars Helicopter
« Reply #21 on: 04/05/2017 10:32 PM »
So, for fun I pulled up my prop calculator spreadsheet.  Plugging in 220W, air density 0,02kg/m≥, prop diameter 1,1m, 4 blades, prop cord 6cm, prop lift coefficient 0.7, prop drag coefficient 0.03, air viscosity 1.42e-5, etc.... I get static thrust of 9,5N, versus gravity on Mars of 3,7m/s≤... so 0.6G (earth-g) acceleration. Sounds like a perfectly reasonable design spec  :)  RPM is high (20k RPM).

If we change the prop to 2m, prop chord 12cm, everything else the same, the power req for the same static thrust goes down to 120W. and RPM down to 5.8k.  Contrarily, you could hold the power constant and get 14,2N thrust, and thus 4,7N more, enough to hold an additional  1,27kg mass.

Note that this is just for static thrust.  Efficiency drops as airspeed increases.  Also, my spreadsheet isn't very good at converging for static thrust (since I don't use it for that), so it's leaving a bit of residual flight speed (so real efficiencies would be a bit higher) - about 0,15m/s.  I could tweak it to get rid of the residual but... meh.  ;)
« Last Edit: 04/05/2017 10:36 PM by Rei »

Offline as58

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Re: Mars Helicopter
« Reply #22 on: 04/05/2017 10:48 PM »
So, for fun I pulled up my prop calculator spreadsheet.  Plugging in 220W, air density 0,02kg/m≥, prop diameter 1,1m, 4 blades, prop cord 6cm, prop lift coefficient 0.7, prop drag coefficient 0.03, air viscosity 1.42e-5, etc.... I get static thrust of 9,5N, versus gravity on Mars of 3,7m/s≤... so 0.6G (earth-g) acceleration. Sounds like a perfectly reasonable design spec  :)  RPM is high (20k RPM).

If we change the prop to 2m, prop chord 12cm, everything else the same, the power req for the same static thrust goes down to 120W. and RPM down to 5.8k.  Contrarily, you could hold the power constant and get 14,2N thrust, and thus 4,7N more, enough to hold an additional  1,27kg mass.

Note that this is just for static thrust.  Efficiency drops as airspeed increases.  Also, my spreadsheet isn't very good at converging for static thrust (since I don't use it for that), so it's leaving a bit of residual flight speed (so real efficiencies would be a bit higher) - about 0,15m/s.  I could tweak it to get rid of the residual but... meh.  ;)

Blade tip speed seems to become a bit... excessive.

Offline Rei

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Re: Mars Helicopter
« Reply #23 on: 04/05/2017 11:58 PM »
Hmm, yeah, it does (the spreadsheet doesn't check for the prop going supersonic, it's just basic blade element theory). I'm sure they're not designing for a supersonic prop, so their parameters must be different somehow. Probably a different angle of attack than I used.
« Last Edit: 04/06/2017 12:02 AM by Rei »

Offline scienceguy

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Re: Mars Helicopter
« Reply #24 on: 04/06/2017 04:19 AM »
Maybe a helicopter on Mars shouldn't be called a helicopter. Maybe it should be called an ornithopter.
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Offline as58

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Re: Mars Helicopter
« Reply #25 on: 04/06/2017 01:47 PM »
Maybe a helicopter on Mars shouldn't be called a helicopter. Maybe it should be called an ornithopter.

I'm not following. Ornithopter is a completely different type of flying machine and making one work on Mars seems to me (much) harder than a helicopter.

Offline scienceguy

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Re: Mars Helicopter
« Reply #26 on: 04/06/2017 08:32 PM »
Maybe a helicopter on Mars shouldn't be called a helicopter. Maybe it should be called an ornithopter.

I'm not following. Ornithopter is a completely different type of flying machine and making one work on Mars seems to me (much) harder than a helicopter.

I was just thinking of the book Dune, where they flew around in ornithopters. The planet Arrakis is like Mars.
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Offline ChrisWilson68

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Re: Mars Helicopter
« Reply #27 on: 04/06/2017 09:05 PM »
Maybe a helicopter on Mars shouldn't be called a helicopter. Maybe it should be called an ornithopter.

I'm not following. Ornithopter is a completely different type of flying machine and making one work on Mars seems to me (much) harder than a helicopter.

I was just thinking of the book Dune, where they flew around in ornithopters. The planet Arrakis is like Mars.

Yeah, I remember that from Dune.  But "ornithopter" isn't just a made-up name.  It has an actual meaning -- it means a machine that flies by flapping its wings, like a bird, not like a helicopter.  So, in Dune, Frank Herbert was imagining a future civilization that had developed flying machines with flapping wings.


Offline ChrisWilson68

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Re: Mars Helicopter
« Reply #28 on: 04/06/2017 09:09 PM »
Being able survey a route from air for rover should speed up exploration. NASA can download flight information and use it to plot a route for rover. Load rover with 100m route and leave it to it.

Ideal for scouting lava caves.

I would agree if I hadn't already seen how detailed the pictures we can get from orbit already are, and how well autonomous vehicle driving software already works.  With today's technology, anything too small to be seen from orbit can easily be handled by autonomous software on the rover.

So, while a helicopter on Mars might have value as a rover in its own right, I don't think it has value in finding a path for a ground rover.

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Re: Mars Helicopter
« Reply #29 on: 04/06/2017 09:27 PM »
I would agree if I hadn't already seen how detailed the pictures we can get from orbit already are, and how well autonomous vehicle driving software already works.  With today's technology, anything too small to be seen from orbit can easily be handled by autonomous software on the rover.
The people who actually build and operate Mars rovers do not appear to agree with this. For current rovers, the range visible in the navcams is a significant limiting factor. It only takes a small dip or rise to completely obscure what's ahead.  Autonomous driving is much slower and less efficient. On could certainly argue that more advanced autonomy would be a better trade than longer range imagery, but it's definitely a trade.

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Re: Mars Helicopter
« Reply #30 on: 04/06/2017 09:48 PM »
In ideal terrains rover can see and travel 120m and considerable less than <120m in lot of terrain. Helicopter increases that to 400m in most terrains.

The video had great example of rover spending days finding a safe route into a crater. Helicopter survey would have saved days of precious rover time plus wear and tear in this case.

It is not just about route survey but also locates points of increase kms away.

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Re: Mars Helicopter
« Reply #31 on: 04/07/2017 12:15 PM »
So, for fun I pulled up my prop calculator spreadsheet.  Plugging in 220W, air density 0,02kg/m≥, prop diameter 1,1m, 4 blades, prop cord 6cm, prop lift coefficient 0.7, prop drag coefficient 0.03, air viscosity 1.42e-5, etc.... I get static thrust of 9,5N, versus gravity on Mars of 3,7m/s≤... so 0.6G (earth-g) acceleration. Sounds like a perfectly reasonable design spec  :)  RPM is high (20k RPM).
The quoted blade speed in the other video is 2200RPM.
Prop chord of 6cm is reasonable as a limit for a 11cm prop, but you're probably looking at more like 60cm, especially with a coax.
This drops the rotary speed a lot.

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Re: Mars Helicopter
« Reply #32 on: 04/07/2017 12:29 PM »
In ideal terrains rover can see and travel 120m and considerable less than <120m in lot of terrain. Helicopter increases that to 400m in most terrains.
The range of the helicopter is several hundred meters - but it's at ~40m altitude at those ranges.

You are going to get (over the whole flight) useful stereo images of much of the surrounding flattish terrain out to several hundred meters from the flightpath, enough to say you can probably, or probably can't navigate over it.

Combining a couple of flights, or selected images over one orthogonal to a path, you get information over a much longer baseline, but at this point, you're bumping up against orbital terrain models possibly being more useful.

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Re: Mars Helicopter
« Reply #33 on: 04/07/2017 05:24 PM »
The range of the helicopter is several hundred meters - but it's at ~40m altitude at those ranges.
Right, the higher altitude is a big deal. Some early MSL designs had cameras on a second arm to get further reach, e.g. https://twitter.com/elakdawalla/status/601596999704666113

Again, a helicopter isn't the only possible solution, but it is a solution to a problem that has a significant impact on operation of current vehicles.

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Re: Mars Helicopter
« Reply #34 on: 04/08/2017 04:03 PM »
Again, a helicopter isn't the only possible solution, but it is a solution to a problem that has a significant impact on operation of current vehicles.

Even treating it as a one-shot 'which is the best way out of this canyon' tool, it may well entirely pay off its 1kg mass budget in one flight.
I also wonder about landing.
For obvious reasons, these may not need to be on the 'soft landed' part of the structure.
What if you throw them out 500m up, before final braking, saving some on mass.

Offline Asteroza

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Re: Mars Helicopter
« Reply #35 on: 04/10/2017 12:00 AM »
Lasermotive was working on a power/data over fiber solution for tethered surveillance UAV's, which could easily fit the bill here if the UAV need not land away from the rover.

Other options include using a thick inflatable rotor blade, perhaps using a sublimating substance for inflation gas. You could get a much larger rotor than packaging would allow for fixed hard rotors.

Offline CameronD

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Re: Mars Helicopter
« Reply #36 on: 04/10/2017 06:56 AM »
Again, a helicopter isn't the only possible solution, but it is a solution to a problem that has a significant impact on operation of current vehicles.

Even treating it as a one-shot 'which is the best way out of this canyon' tool, it may well entirely pay off its 1kg mass budget in one flight.
I also wonder about landing.
For obvious reasons, these may not need to be on the 'soft landed' part of the structure.
What if you throw them out 500m up, before final braking, saving some on mass.

If that's all you're trying to achieve, use a balloon on a string.  When finished, deflate, rewind and re-use.  ::)

The helicopter idea only starts to makes sense if you're wanting to survey a long way away from the rover ..and even then I'm not so sure:

http://www.gaerospace.com/space-exploration/planetary-balloons/mars-balloons/



« Last Edit: 04/10/2017 07:06 AM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Asteroza

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Re: Mars Helicopter
« Reply #37 on: 04/10/2017 08:19 AM »
Again, a helicopter isn't the only possible solution, but it is a solution to a problem that has a significant impact on operation of current vehicles.

Even treating it as a one-shot 'which is the best way out of this canyon' tool, it may well entirely pay off its 1kg mass budget in one flight.
I also wonder about landing.
For obvious reasons, these may not need to be on the 'soft landed' part of the structure.
What if you throw them out 500m up, before final braking, saving some on mass.

If that's all you're trying to achieve, use a balloon on a string.  When finished, deflate, rewind and re-use.  ::)

The helicopter idea only starts to makes sense if you're wanting to survey a long way away from the rover ..and even then I'm not so sure:

http://www.gaerospace.com/space-exploration/planetary-balloons/mars-balloons/

Running with the evacuated theme, NIAC phase 2 had one for a vacuum airship. Deploy tethered from a rover?

https://www.nasa.gov/directorates/spacetech/niac/2017_Phase_I_Phase_II/Evacuated_Airship_for_Mars_Missions

Offline TheFallen

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Re: Mars Helicopter
« Reply #38 on: 12/20/2017 08:05 PM »
Quote
Now, put a helicopter on Titan, or Venus - then we'd be talking!

NASA just brought the Titan helicopter closer to reality (hopefully)... Go Dragonfly! :)

Back to topic, I forgot that NASA was planning to put a drone chopper on Mars 2020; I'm totally excited for it

Online speedevil

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Re: Mars Helicopter
« Reply #39 on: 02/17/2018 03:54 PM »
https://en.wikipedia.org/wiki/Entomopter
http://angel-strike.com/entomopter/NIAC_Final_Report_10-31-02.pdf



Though I question highly their choice of motive power - brushless motors and batteries have come on so enormously in the 16 years since that liquid hydrogen seems insane at a first glance.

Offline Jcc

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Re: Mars Helicopter
« Reply #40 on: 05/04/2018 12:06 PM »
How about combining with a hydrogen balloon for additional lift and stability?

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Re: Mars Helicopter
« Reply #41 on: 05/08/2018 03:50 PM »
How about combining with a hydrogen balloon for additional lift and stability?

The helicopter works well with near-off-the-shelf parts without a balloon, and can land and take off multiple times easily.
It is easily scalable by adding rotors, to get quadcopters.

If you add the balloon, you now have a ridiculously fragile envelope which can't be deflated (at least without >>>1kg machinery) and reinflated, and if you try to land without deflating it is a massive sail area.

(ridiculously fragile = for a kilo lift, you need around a 8m or so diameter balloon, with walls a tenth as thick as your average mylar party balloon)

It might be interesting as a survey probe for long distances, where you are happy with being blown randomly by the wind.

Offline deruch

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Re: Mars Helicopter
« Reply #42 on: 05/08/2018 04:00 PM »
http://spacenews.com/decision-expected-soon-on-adding-helicopter-to-mars-2020/

Quote
NASA is expected to make a decision later this month on whether to include a small helicopter as a technology demonstration on the Mars 2020 rover despite concerns by scientists that it might distract from the roverís science mission.

...

Speaking at a meeting of the National Academiesí Space Studies Board here May 1, Steve Jurczyk, NASA acting associate administrator, said the review, scheduled for late May, will also give the agency the opportunity to decide whether to include a small helicopter on the rover. That helicopter has been under development for several years, including flying it in a chamber at Mars atmospheric conditions....
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Online TrevorMonty

Re: Mars Helicopter
« Reply #43 on: 05/08/2018 05:15 PM »
Helicopter is going to prove technology not as useful add on and only has life of 30days. With lot of that time devoted to testing vehicle, how much use it will be to rover during that time is unknown.

Given most JPL vehicles live well past their use by date, they may get 3-12months from   helicopter in which case it will be valuable asset.


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Re: Mars Helicopter
« Reply #44 on: 05/08/2018 08:55 PM »
Helicopter is going to prove technology not as useful add on and only has life of 30days. With lot of that time devoted to testing vehicle, how much use it will be to rover during that time is unknown.

Given most JPL vehicles live well past their use by date, they may get 3-12months from   helicopter in which case it will be valuable asset.
The helicopter weighs around a kilo, with perhaps a hundred gram payload, and is readily stretchable to several kilos just by bolting together four as a quadcopter.

I note that off-the-shelf XRF instruments are almost in the range you might consider being able to carry one on a very modestly stretched chopper. (1.5kg, with case, and LCD and ...)


Offline Zed_Noir

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Re: Mars Helicopter
« Reply #45 on: 05/09/2018 12:31 AM »
How about combining with a hydrogen balloon for additional lift and stability?

Then it is no longer a helicopter. It is a helistat instead.

Offline Lar

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Re: Mars Helicopter
« Reply #46 on: 05/09/2018 12:35 AM »
The helicopter works well with near-off-the-shelf parts without a balloon, and can land and take off multiple times easily.
It is easily scalable by adding rotors, to get quadcopters.

Don't quadcopters require blade synchronization? I had been assuming the blades will be very large span and thus likely to interfere (even by raising the shafts of some, you are going to get blade droop that plays havoc)
« Last Edit: 05/09/2018 12:48 AM by Lar »
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online fthomassy

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Re: Mars Helicopter
« Reply #47 on: 05/09/2018 02:18 AM »
... (even by raising the shafts of some, you are going to get blade droop that plays havoc)
How much does lower gravity solve droop?
gyatm . . . Fern

Offline Robotbeat

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Re: Mars Helicopter
« Reply #48 on: 05/09/2018 02:29 AM »
They better fly that helicopter. NASA exists, in part, to do cool stuff. And that's definitely cool. And is a genuine expansion of capability beyond just a single mission that is transformative for Mars exploration. Unfortunately, sometimes risk analyzers can be too myopic to see the value in something like a helicopter. It doesn't have science advantages RIGHT NOW.

The helicopter is seed corn. NASA needs it.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online speedevil

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Re: Mars Helicopter
« Reply #49 on: 05/09/2018 11:17 AM »
The helicopter works well with near-off-the-shelf parts without a balloon, and can land and take off multiple times easily.
It is easily scalable by adding rotors, to get quadcopters.

Don't quadcopters require blade synchronization? I had been assuming the blades will be very large span and thus likely to interfere (even by raising the shafts of some, you are going to get blade droop that plays havoc)
The 'best' way to do quadcopters is to simply not overlap the blades.
Doing so, while it has minor benefits in area hurts your thrust a little, and raises obvious issues like above.

The 'Scout' helicopter mentioned above uses two contrarotating propellors at 1.1m diameter, and has a total thrust of about 0.6kg/6N (implied by the comments on weight growth) on 220W/1kg weight.
Converting to standard units used in the quadcopter community, this is 3g/W of thrust, which is basically completely standard for cheap racing quadcopters.

You need a folding structure of course, but this has to only cope with kilo loads over a meter or so moment arm - and carbon fibre is light.

A quadcopter offers benefits over Scout though:
The coaxial props are notably less efficient than one isolated prop, as they are working in dirty air.
Being able to remove the swashplate, and go to a much simpler prop design with only variable pitch simplifies the rotor construction.
Being able to isolate the props removes the possibility of blade slap as is a concern with coaxial designs.
On the flipside, it's harder to test in reduced pressure chambers.




Offline rosbif73

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Re: Mars Helicopter
« Reply #50 on: 05/09/2018 01:20 PM »
On the flipside, it's harder to test in reduced pressure chambers.

Is this just because you need a bigger chamber to test in, or is there some other issue with reduced pressure?

Offline Lar

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Re: Mars Helicopter
« Reply #51 on: 05/09/2018 06:26 PM »
I guess my concept that the blades would have to be long and overlapping is incorrect? Or at least not needed? Even in this thin atmosphere?
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online speedevil

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Re: Mars Helicopter
« Reply #52 on: 05/09/2018 06:59 PM »
I guess my concept that the blades would have to be long and overlapping is incorrect? Or at least not needed? Even in this thin atmosphere?

Overlapping is useful from a 'pack enough thrust into a given unit area' perspective, but it sacrifices power efficiency for areal.
You also lose control because the more the centres are isolated, the more control you have.

The frames can be remarkably light - somewhere I have one which would almost suit - though it's designed for 60cm, not 120cm blades.
It may or may not be desirable to use coaxial props - the reduction in area is nice, but if you have the blades folding along the spar connecting them to the main body, it can all pack pretty well into one long thin box.
Coax hurts power use, means more complex gearboxes/motors, so it's not a simple trade.

And yes, I meant on the testing purely that it's much harder to find testing chambers >> 8 feet across.

A mars quadcopter which is 3m maximum radius looks enormous from one perspective.
It looks rather less enormous when you fold up the props along the arms, fold the arms together and end up with the motors, structure, and props in something like a 5cm*5cm*1m box.

For a camera drone alone, with a total mass of 1kg, a helicopter is probably a reasonable choice. If you're thinking about growing it, multirotors have a number of advantages.

« Last Edit: 05/09/2018 07:12 PM by speedevil »

Offline CameronD

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Re: Mars Helicopter
« Reply #53 on: 05/14/2018 02:52 AM »
In the news today:

Quote
NASA has announced that its Mars 2020 mission will include a small helicopter.

https://www.theregister.co.uk/2018/05/14/mars_2020_helicopter/



With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline catdlr

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Re: Mars Helicopter
« Reply #54 on: 05/14/2018 03:58 AM »
This thread has gone from Advanced Concept to be part of the Mars 2020 rover project.  Future thread post should now go to this new thread. This thread could now be closed.

https://forum.nasaspaceflight.com/index.php?topic=45676.0
Tony De La Rosa

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