back to article NASA will send tiny helicopter to Mars

NASA has announced that its Mars 2020 mission will include a small helicopter. The appeal of a ‘copter is obvious: it’ll be faster than a crawling robot, see further and should be less likely to be stuck in sand. While Bernoulli’s Principle holds on Mars, the red planet’s atmosphere is vastly thinner than Earth’s so a copter …

  1. Tom 64

    Why?

    It may be a nice way to look around the red planet, but unless they change that design, the first larger than average gust of wind is going to topple it.

    1. Sorry that handle is already taken. Silver badge

      Re: Why?

      On a planet with an atmospheric pressure 0.6% of Earth's?

    2. werdsmith Silver badge

      Re: Why?

      but unless they change that design

      Where can I look at the engineering details of the design please?

      1. Tom 64

        Re: Why?

        > "Where can I look at the engineering details of the design please?"

        Here is NASAs info. Including a lovely video based on what I assume to be an initial design:

        https://www.nasa.gov/press-release/mars-helicopter-to-fly-on-nasa-s-next-red-planet-rover-mission

        Do you always have someone google for you?

        1. werdsmith Silver badge

          Re: Why?

          Thanks Tom, but that's just the PR spin.

  2. Paul 129
    Coat

    Killer Dust Bunnies

    I put my money on the dust being fine enough to kill it before any accidents/wind events.

    1. werdsmith Silver badge

      Re: Killer Dust Bunnies

      I put my money on the dust being fine enough to kill it before any accidents/wind events.

      I think NASA should offer you a job right now because none of the engineers working at JPL would have thought to consider the effect of dust.

      1. Anonymous Coward
        Anonymous Coward

        Re: Killer Dust Bunnies

        You say none of the engineers have thought of that... but some of them never thought to check orientation, or even if imperial/metric measurements are being used.

        I joke. But in reality, sometimes a bad idea gets railroaded into production "because". It will be a first though, if it works. I'm having problems visualizing a 6% atmos heli though. Seeing one working in their giant vacuum chamber would be a blast!!!

        1. Anonymous Coward
          Anonymous Coward

          Re: Thanks for the downvotes!!!

          But there actually is a video of it :)

          https://youtu.be/qtaGQuVyp90?t=1m39s

          Wow, my eyes still are confused in how they got it working in such a low atmosphere pressure.

  3. Martin Budden

    DRAMATIC MUSIC!!!

    I was expecting menacing killer robots with huge frikkin' lasers from the music in that vid. But no, just a cute little whirlychopper.

    1. Mark 85 Silver badge

      Re: DRAMATIC MUSIC!!!

      There's just one going at this point. If we ever put a second one up there, then DroneWars!!!!!

    2. Little Mouse

      Re: DRAMATIC MUSIC!!!

      @MB - Let me guess - I bet you preferred Airwolf to Blue Thunder...?

      1. Chozo
        Coat

        Re: DRAMATIC MUSIC!!!

        Airwolf had the better theme tune

        1. John Brown (no body) Silver badge

          Re: DRAMATIC MUSIC!!!

          "Airwolf had the better theme tune"

          ...which is now running through my head. Thanks guys!!!

          (no idea what the Blue Thunder tune sounded like though, despite watching the show back in the day)

    3. Voyna i Mor Silver badge

      Re: DRAMATIC MUSIC!!!

      Well, think about it like this.

      The gravity of Mars is about one third that of the Earth and its atmosphere is about 160 times less dense. In very rough terms that means that helicopter blades have to be designed in such a way that on Earth they would have 50 times the lift they do on Mars.

      That means, again in rough terms, that if we could have a blade 5 times the lift and rotating 10 times as fast as for a terrestrial helicopter, it would do the job. The power needed, of course, should be much less because of the reduced gravity.

      The limitation on a rotating wing is the point at which the wing tips reach the speed of sound, which on Mars is about 240m/s.

      At 3000 rpm (50 revs/sec) the wing tips reach the speed of sound for a circumference of about 5 metres which means a blade length of 0.8 metres. So if we started with a Chinook with its 9 metre blades, limited to around 300rpm on Earth... it's only going to reach around 220 rpm on Mars. The blades, in fact, would be too small and slow by a factor of around 600.

      So, if I've understood it right and my back of envelope approach is even within an order of magnitude, no practical Martian helicopter is ever going to be more than a few kilos.

      1. Alan Brown Silver badge

        Re: DRAMATIC MUSIC!!!

        "The limitation on a rotating wing is the point at which the wing tips reach the speed of sound, which on Mars is about 240m/s."

        On an _individual_ rotating wing.

        You can increase the number, increase their surface area or even move to multiple rotor planes.

        All have been done in the past on earth

        My money's on the dust though. considering 6% atmosphere it has to be incredibly fine to be lifted in the kinds of quantities we see, even with 1/3 gravity.

  4. Chozo
    Alien

    appeal of a ‘copter is obvious

    NASA suspects the natives are hiding behind rocks waiting for lumbering the rover to pass.

    1. Swiss Anton

      Re: appeal of a ‘copter is obvious

      "NASA suspects the natives are hiding behind rocks waiting for lumbering the rover to pass."

      I suspect the natives will be hiding behind rocks, armed with a shotgun, waiting to blast the drone from the sky!

      1. hammarbtyp Silver badge

        Re: appeal of a ‘copter is obvious

        "NASA suspects the natives are hiding behind rocks waiting for lumbering the rover to pass."

        "I suspect the natives will be hiding behind rocks, armed with a shotgun, waiting to blast the drone from the sky!"

        I think you're getting confused with Mars, Pennsylvania

  5. Blockchain commentard

    Wonder if they've thought of using a rechargeable Dremel to power the rotors? 15,000 RPM should do nicely.

    1. Anonymous Coward
      Anonymous Coward

      Wonder if they've thought of using a rechargeable Dremel to power the rotors?

      Nope - this is a real mission. It's not a drill.

      1. Anonymous Coward
        Anonymous Coward

        If they want to drive the craft using some sort of power tool, they'll have to Makita powerful one.

      2. John Brown (no body) Silver badge

        "Nope - this is a real mission. It's not a drill."

        Congratulations! You just won Teh Internetz!

      3. Anonymous Coward
        Anonymous Coward

        yes, but the last drill they sent broke......

    2. Voyna i Mor Silver badge

      "Wonder if they've thought of using a rechargeable Dremel to power the rotors? 15,000 RPM should do nicely."

      See my other post. The rotor tips can't exceed the speed of sound.

  6. This post has been deleted by its author

  7. Phil Kingston Silver badge

    "the first powered flying machine and the first human-designed heavier-than-air vehicle to visit another planet".

    If not humans, who else is designed flying vehicles for other planets? That's some Area 51 shit going on. What does El Reg know that we don't?

    1. Mark 85 Silver badge

      What does El Reg know that we don't?

      I don't think we want to know because if they told us then they would probably have to kill us.

      1. Tom 7 Silver badge

        RE What does El Reg know that we don't?

        not again.

  8. AZump
    Alien

    Ummm...

    "...and the first human-designed heavier-than-air vehicle to visit another planet".

    So the Mars rovers are lighter than air? Well then, I guess it's a good thing the atmosphere is so thin; Otherwise, the buoyancy would have them floating off the surface. Can't have that. ...or is the implication the rovers were designed by chimps, dolphins, or E.T.s?

    Maybe they mean heavier-than-air FLYING vehicle. No, no. The Register never makes errors. It must be true, so the question is now who has NASA hired to do the design work and are they being paid a fair wage.

    Oh, what am I saying. We all know the earth is flat and all this outer-space stuff is nonsense filmed in a studio somewhere. :)

    1. Anonymaus Cowark

      Re: Ummm...

      the mice got paid a fair wage ... in cheese

      1. Pedigree-Pete Bronze badge
        Joke

        Re: Ummm...

        I think you find the mice got a fair "wedge". :)

    2. Anonymous Coward
      Anonymous Coward

      Re: Ummm...

      Of course it's all nonsense, clearly if the air is thin you would just have thicker blades.

    3. John Robson Silver badge

      Re: Ummm...

      And of course the sky crane they used for landing one of the recent missions was also a heavier than air flying vehicle. Even if it was a single use one...

      1. DuncanL

        Re: And of course the sky crane they used for landing

        That wasn't flying - it was falling... with style!

        1. annodomini2 Bronze badge
          FAIL

          Re: And of course the sky crane they used for landing

          No it hovers to lower the vehicle onto the surface.

          Then flys off some distance before crashing.

          1. Martin Budden

            Re: And of course the sky crane they used for landing

            I don't think rocketing is the same as flying. Semantics, yes, but everyone loves a pedant here at El Reg ;-)

  9. John Smith 19 Gold badge
    Coat

    It's a tough one at 1/160 Earth sea level pressure.

    I'd guessed really big blades moving quite slowly.

    But obviously not.

    Looks like one of those things you can get on eBay for when you're bored round the office.

    Likely somewhat more expensive though.

    1. handleoclast Silver badge

      Re: It's a tough one at 1/160 Earth sea level pressure.

      Looks like one of those things you can get on eBay for when you're bored round the office.

      My thoughts exactly.

      In fact, I was thinking of one of these (having purchased one of these eyeball-removers from a different seller last year).

    2. SkippyBing Silver badge

      Re: It's a tough one at 1/160 Earth sea level pressure.

      'I'd guessed really big blades moving quite slowly.'

      No, if you take the lift equation

      Lift = Coefficient of Lift * Density of the atmosphere * V squared * the reference area

      You've decreased the Density of the atmosphere, so to still get the same lift you need to either increase the area of the wings 160 times or the V squared*. Or some compromise between the two, although in this case I'm guessing there was a limit on how big they wanted the rotors to get. For an accurate answer you have to consider Reynolds number as well but that's the broad picture.

      The next problem you've got is that the rotors are now moving much closer to the speed of sound which is not ideal.

      *There's a limit to what you can do with the Coefficient of lift, if you could increase that 160 times we'd do it on Earth and airliners would have tiny wings.

      1. Michael Habel Silver badge

        Re: It's a tough one at 1/160 Earth sea level pressure.

        The next problem you've got is that the rotors are now moving much closer to the speed of sound which is not ideal.

        Ahhh yes but, what is the speed of sound on Mars. Surly its a different value than Earths or?

        Weight, to make them spin quick enough to still take off they need to be strong and strength adds weight. Especially as larger blades would exert more force on the rotor head needing more strength and weight. It's a vicious cycle.

        Again isn't Mars considerbly smaller (in Mass), to that of Earth, wouldn't the Gravity be a bit less over there then it is here?

        1. AS1

          Re: It's a tough one at 1/160 Earth sea level pressure.

          The speed of sound on Mars is around 240 m/s. A bit lower than the 340 m/s on Earth.

          Gravity on Mars is about 2/5 that on Earth (3.7 m/s² vs 9.8 m/s²). However, in this case, the mass is important as it's rotational, rather than the weight due to gravity (semantics on the part of the original post). In the same way, a satellite in zero gravity can spin itself apart if the control systems malfunction.

          1. Anonymous Coward
            Anonymous Coward

            Re: It's a tough one at 1/160 Earth sea level pressure.

            I may well be wrong - but the speed of sound is basically proportional to temperature (and gas composition) not pressure. It's slower because it's colder.

        2. Sgt_Oddball Silver badge

          Re: It's a tough one at 1/160 Earth sea level pressure.

          You don't need the strength to support the weight of the whole shebang but to stop it failing due to to angular momentum caused by swinging bits around at high speed. Newtonian physics still applies on other worlds last I checked.

      2. John Brown (no body) Silver badge

        Re: It's a tough one at 1/160 Earth sea level pressure.

        "You've decreased the Density of the atmosphere, so to still get the same lift you need to either increase the area of the wings 160 times or the V squared*."

        So, maybe something like DaVinci's design them?

    3. Sgt_Oddball Silver badge

      Re: It's a tough one at 1/160 Earth sea level pressure.

      Big blades have 2 problems;

      Size... they're big. You said so yourself. That means they take up more space and weight more. Not a good thing where every gram counts.

      Weight, to make them spin quick enough to still take off they need to be strong and strength adds weight. Especially as larger blades would exert more force on the rotor head needing more strength and weight. It's a vicious cycle.

      However if the air is thin then the sound barrier isn't such an issue so smaller, faster blades can do the job. Especially since strengthing them to go faster would require at lot less weight to reinforce them for higher speeds.

      1. SkippyBing Silver badge

        Re: It's a tough one at 1/160 Earth sea level pressure.

        'However if the air is thin then the sound barrier isn't such an issue so smaller, faster blades can do the job.'

        It's less of an issue in terms of the dynamic force on the blade, however it will still cause issues with flow over the blades breaking down leading to a loss in lift. Roughly speaking you'll get a shock wave forming somewhere on the upper surface first* rendering the area of blade behind it ineffective.

        *Where ever the relative flow is fastest.

      2. Alistair Silver badge
        Coat

        Re: It's a tough one at 1/160 Earth sea level pressure.

        Big blades have 2 problems;

        I like big blades, and I cannot.........

        Hey! If yer gonna throw produce at least make it the fresh stuff!

        (The plastic raincoat will do nicely)

  10. wsm

    Maybe...

    If they send this thing over the face on Mars, they can see if it blinks!

    https://science.nasa.gov/science-news/science-at-nasa/2001/ast24may_1

  11. Anonymous South African Coward Silver badge

    Airwolf - the Mars chapters

  12. Fruit and Nutcase Silver badge
    Black Helicopters

    Hold that Chopper!

    Wait for me! Says Ginny

    If only! Says IBMers

    1. Fruit and Nutcase Silver badge
      Alert

      Re: Hold that Chopper!

      At some point, once humans have made contact with intelligent extra-terrestrial life, no doubt big corp will be looking at offshoring offplaneting services.

      1. Michael Habel Silver badge

        Re: Hold that Chopper!

        At some point, once humans have made contact with intelligent extra-terrestrial life, no doubt big corp will be looking at offshoring offplaneting services.

        So that'll be like the whole Austrailia thing over agin would it?

      2. onefang Silver badge

        Re: Hold that Chopper!

        "At some point, once humans have made contact with intelligent extra-terrestrial life, no doubt big corp will be looking at offshoring offplaneting services."

        Ah but which will us earthlings be, the ones paying offworlders low wages, or the ones being paid low wages by offworlders?

  13. Doctor Evil

    Coolest. Video. Ever.

    Footage from the first flight over the surface of Mars. Now that will be a moment worth waiting for!

  14. Kaltern Silver badge

    I didn't know so many better-than-NASA engineers posting here at El Reg.. we're so lucky to have such knowledge available for us to read. And for free too!

    NASA should really come here and read up on why everything they do is doomed to failure. Dust! Who would have thought huh?

  15. Nano nano

    Spring clean

    Well at least it won't have the problem of dust building up on the solar array like earlier vehicles ...

  16. Aladdin Sane Silver badge
    Black Helicopters

    Get to da choppa!

    The link between Predator and Total Recall finally becomes clear.

  17. Nano nano

    WTF

    What boggled me, was the BBC announcement of this, as being a tiny "**unmanned**" helicopter.

    What prompted them to say that ? "Drone" would have done ..

    Mind you, they should have included a Lego mini-figure, made out of aerogel for weight.

    1. SkippyBing Silver badge

      Re: WTF

      It makes you wonder at their target audience.

      If it was a manned helicopter on Mars you'd expect they'd have led with a slightly different angle...

  18. mix
    Trollface

    Dust

    Won't the rotors blow the dust away?

  19. Bronek Kozicki Silver badge

    Bernoulli’s Principle

    You realize the myth that Bernoulli law has anything to do with flying has been busted very long time ago?

    Also, RC helicopters do exceed 2000 RPM sometimes, so 3000 RPM for a helicopter this small is not that much of a feat. What is (going to be) remarkable achievement though, is a stable landing from which said helicopter can start again without human intervention.

    1. SkippyBing Silver badge
      Joke

      Re: Bernoulli’s Principle

      'What is (going to be) remarkable achievement though, is a stable landing from which said helicopter can start again without human intervention.'

      Oh I don't know, a lot of times it's the human intervention that means the helicopter never starts again!

    2. imanidiot Silver badge

      Re: Bernoulli’s Principle

      Bernoulli's law isn't the only component to explaining aerodynamic lift effects, but it's certainly involved. Pressure differences due to changes in speed DO occur around certain wing/chord profiles, they're just not the only effect involved. Newtons 3rd and Coanda effects are important too, among others.

  20. ForthIsNotDead Silver badge
    Alien

    I do have to wonder...

    ...why all this interest in Mars? What about our moon? Why is NASA not working on colonising our moon? We're spending a lot of money, man-power, and human intelligence on sending vehicles to Mars, when we have the moon on our doorstep, cosmologically speaking.

    1. Anonymous Coward
      Anonymous Coward

      Re: I do have to wonder...

      "why all this interest in Mars?"

      Well, you can send a tiny helicopter to the moon if you want, but don't plan a party to celebrate because it won't have any atmosphere...

    2. John Robson Silver badge

      Re: I do have to wonder...

      It's not nearly as much further to go to Mars than the Moon as you'd think...

      Getting to earth obit is the vast majority of the work...

      You can actually get to Mars for less dV than it takes to get to the moon (RRS Kerbal dV map assumed correct):

      http://i.imgur.com/AAGJvD1.png

  21. Triumphantape

    More likely we will see complaints from the Martians about the drones invading privacy.

    1. Doctor Evil

      "More likely we will see complaints from the Martians about the drones invading privacy."

      Do Martians have shotguns?

  22. Anonymous Coward
    Anonymous Coward

    Rover to Heli

    Are we an effective team?

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