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How NASA Designed a Helicopter That Could Fly Autonomously on Mars
- dataflow 6y agoObligatory Veritasium video link: https://www.youtube.com/watch?v=GhsZUZmJvaM https://www.youtube.com/watch?v=GhsZUZmJvaM
- inetstarrrrrr 6y agoWhat's the point of flying a helicopter on Mars? What scientifically relevant data do you get? Its fun and cool but why?
- hoseja 6y agoWell, you may be able to get places a rover can't. But as they say in the article, this is just a demonstrator to show if they can fly on Mars at all.
- shatnersbassoon 6y agoI would have thought atmospheric data that you can't get elsewhere - you'd be able to learn things about pressure and wind at altitudes that rovers can't get to.
- inetstarrrrrr 6y agoI don't think it will fly that high to make a measurably difference to ground level. It only flies for 90 seconds. How high can you get in that time?
- aero-glide2 6y agoThis is a tech demo. This will help design future Martian drones.
- simonh 6y ago* Scouting possible destinations or routes for the rover. * Imaging areas from above with higher fidelity than possible from orbit, and from angles not possible from a rover. * Retrieving samples from areas inaccessible for a rover.
- BelenusMordred 6y agoIt's just a demonstrator but can travel 100m in each 90 second flight. For comparison, the Curiosity rover has travelled 23 km over 8 years.
- virtue3 6y agomain thing I've seen on mark rober's youtube is that it allows you to really scout out locations with a speed unheard of for rovers. Also, you can't really(easily) get a helicoper stuck on rocks :)
- Daniel_sk 6y agoTo test the technology for next missions. This is just a proof of concept.
- arethuza 6y agoPerhaps we could eventually get things like a video of a drone flying over the 4km high cliffs of Echus Chasma: https://apod.nasa.gov/apod/ap080723.html https://apod.nasa.gov/apod/ap080723.html There is a whole new world out there!
- pengaru 6y agoI find it hard to believe you genuinely asked yourself this question and came up empty before posting this vacuous comment.
- fudged71 6y agoThe article covers this. In the future maybe they can fly with LiDAR to get more accurate surface details for the rovers to navigate with, and finding interesting features
- holoduke 6y agoBecause exploring is our nature. And because it will be the first test or flying something in an alien atmosphere. Tons of data alone from the first 5 seconds is very interesting. It's the first step to commercial airliners on Mars :)
- sdoering 6y agoI find, besides all the extremely exciting, technical challenges, the following sentence incredibly fascinating: > "This [is] the first time we’ll be flying Linux on Mars." But regardless of that, I find it so incredibly cool and inspiring that during my lifetime, a human flying vehicle will fly on Mars. I was a space nut in my childhood and youth and love to see this.
- neurostimulant 6y agoLinux flying on Mars and Electron regularly launched to LEO. What a time to be alive :)
- retSava 6y agoSo many interesting details in this article. Snapdragon 801-based hw running Linux, sensor fusion from three sensors whereof some bought COTS from sparkfun (who make breakout boards for sensors, basically the sensor datasheet recommended design). 3 flights planned, but potentially more which will be planned after the three first. 30 day lifetime window, due to dependecy on the rover, which needs to conserve resources. I would looooove to know more more more about this. What did dev of this look like (eg simulators)? What's the flight envelope? What are the most important risks and how are they mitigated? What internal discussions took place (do this, prio that, don't do X etc). Just so much interesting stuff! Can't wait :) edit: from wikipedia: "Each flight is planned to be at altitudes ranging from 3–5 metres (10–16 ft) above the ground.[1] In up to 90 seconds per flight, it could travel as far as 50 metres (160 ft) downrange and then back to the starting area". "The helicopter uses counter-rotating coaxial rotors about 1.2 metres (4 ft) in diameter". Etc. Recommend the wiki page on it: https://en.wikipedia.org/wiki/Mars_Helicopter_Ingenuity https://en.wikipedia.org/wiki/Mars_Helicopter_Ingenuity
- RapidFire 6y agoThis is the coolest part of the mission IMO. My big question is where does it land? Does it dock with the rover? It seems to power itself via a solar array. About 100 days into the mission they plan on launching the helicopter for the tiny lifespan window. I think the limit on its lifespan is really, "How long until destroyed by wind/dust". And then how long until it cannot charge its own batteries/sustain itself.
- foobarbecue 6y agoI agree, this is the coolest part, but the most useful part for humanity is MOXIE. It lands on the ground. And yes, dust on the panels is a big concern. (I work at JPL but not on Perseverance / Ingenuity)
- RapidFire 6y agoThat's really cool; thanks for your work!! I cant wait to see how Y'all figure out how to get those rock samples back to earth; that's gonnna be nuts XD
- protoman3000 6y agoUnfortunately the article does not talk about how this helicopter would fare in a sandstorm. Are the winds strong enough to tip it over?
- londons_explore 6y agoThere is practically no wind on Mars. The wind speed is super high, but the air density is so low it won't impact anything more than dust.
- spaetzleesser 6y agoThis is really interesting to think about. On Venus it’s the opposite. Any kind of wind speed will have a huge impact.
- SubMachineGhost 6y agoMars has 1% of earth's atmosphere, so it will not affect the vehicle, The answer comes from an interview with the engineers here : https://youtu.be/GhsZUZmJvaM?t=534 https://youtu.be/GhsZUZmJvaM?t=534
- londons_explore 6y agoSeems shortsighted to end this mission after 30 days. I imagine it's purely for mission planning complexity reasons. But a more sensible approach seems to be to say "after 30 days you have to limit comms to 100 bytes/sec back to earth and stay 100 meters from the rover". In the future I could imagine the more modern processor on the helicopter might become handy... Some neural network based navigation system might run on it but not the rover main cpu... Also the helicopter might be able to get very good aerial photos that could be turned into 3d models to figure out the best spots to do science. It should be able to see much better than orbital radars.
- pridkett 6y ago> Seems shortsighted to end this mission after 30 days. At this point, NASA is getting rather famous for this. Opportunity had a 90 day mission that survived for nearly fifteen years. Curiosity, a much bigger and more complicated machine, is still doing science 8.5 years later.
- throwaway0a5e 6y agoThe official mission length is just how long they have to wait before calling it a success. They expect it to last much longer. Since this is primarily a technology demonstrator once it's a "success" more options open up for actually experimenting with tactics and the limits of the device. It's like how you wait until you've left the parking lot to do a big smokey burnout and see how fast a rental goes in 1st gear.
- amelius 6y agoIf 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?
- deleted 6y ago[deleted]
- coldcode 6y agoI would think the atmosphere is too light to support a balloon.
- gambiting 6y agoI 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.
- amelius 6y agoAnother 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?
- rtkwe 6y agoFor a given aperture there's a limit to the angular resolution you can get which means you can only see objects above a certain size from orbit. The highest resolution we had in 2013 had a resolution of ~.3m/pixel. That's too large for anything beyond rough mapping for things like landing or a vague plan for driving. TL;DR a decent camera at <1km is hard to beat from >100km no matter how good the satellite camera is. https://space.stackexchange.com/questions/1140/whats-the-highest-resolution-camera-orbiting-mars-as-of-2013 https://space.stackexchange.com/questions/1140/whats-the-hig...
- zokier 6y agoYou mean like HiRISE: https://en.wikipedia.org/wiki/HiRISE https://en.wikipedia.org/wiki/HiRISE or HRSC: https://en.wikipedia.org/wiki/High_Resolution_Stereo_Camera https://en.wikipedia.org/wiki/High_Resolution_Stereo_Camera
- zeristor 6y agoOne thing that I have been wondering, if the atmosphere is so thin, then how does the RTG cool? I seem to have nerd-sniped myself. It needs a temperature differential to generate electric current and it looks to have fins for convective cooling but the atmospheric pressure is a few % of that of sea level Earth.
- gbrown 6y agoI believe the fins are primarily radiators. Conduction, convection, radiation.
- pengaru 6y agomars is freezing cold, it's like dust covered ice ball.
- iso1631 6y agoBut the heat still needs to leak into the environment, and a thin atmosphere means little convection, so it's still just radiation - same problem as in a vacuum.
- nkrisc 6y agoSpace is cold and yet getting rid of waste heat is a challenge for any spacecraft. The ISS has giant radiators to dissipate heat. It doesn't matter how cold Mars is if it's difficult to transfer the heat away, such as in a very thin atmosphere which has less capability to carry away heat than Earth's atmosphere. There needs to be some kind of medium for the heat to transfer away (aside from radiation), regardless of ambient temperature. It's why a vacuum-walled thermos can keep things warm even in a cold environment. That's what they were asking about. Heat can be conducted away by contact with another object, probably not what you want if you're using an RTG to power your spacecraft, you don't want your RTG to heat it too much. It can be convected away, which is more difficult in a thin atmosphere like Mars has. Or it can be radiated away by blackbody radiation, which some certainly is, but that is limited and isn't much.
- trhway 6y ago
- secondcoming 6y agoCould they use it to try blow dust off the Opportunity rover's solar panels to see if it'll boot again?
- kam 6y agoNo, it's not going to land anywhere near Opportunity. https://mars.nasa.gov/resources/24729/map-of-nasas-mars-landing-sites/ https://mars.nasa.gov/resources/24729/map-of-nasas-mars-land...
- MayeulC 6y agoI 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?
- MayeulC 6y agos/mass/weight/
- f6v 6y agoImagine how far the technology could go had we sent 10 times the missions we do now.
- nemof 6y agotechpod did an episode recently with the engineering camera payload uplink lead from nasa jpl doug ellison. it was very cool. from the episode summary: > "Friend of the podcast Doug Ellison from NASA's Jet Propulsion Lab stops by to give us the lowdown on the newest Mars rover Perseverance, which will be landing on the red planet in just a few weeks, plus all kinds of fun info about Lagrange transceivers, making oxygen out of thin air, flying helicopters on other planets, and recording home movies at mach 25." https://techpod.content.town/episodes/71-curiosity-and-perseverance https://techpod.content.town/episodes/71-curiosity-and-perse...
- BorisTheBrave 6y agoCan someone explain the phyics of flying a helicopter in such low density atmosphere? It must be less efficient than on earth, but evidently efficiency isn't proportional to density or else it could not fly at all.
- lmm 6y ago> It must be less efficient than on earth No it mustn't. You'd expect efficiency to be higher, all else being equal, since there's less drag to overcome - aircraft can generally fly more efficiently at high altitude on Earth (up to a point). The limiting factor is that helicopter flight only works while the rotor tips are subsonic, so as the air gets thinner the "IAS" that a pitot tube on the rotor (that's going as fast as you safely can) would experience gets lower and lower, and so the flight dynamics will be like a helicopter with a slow rotor, but speeded up. But for a small helicopter the square-cube law is on your side and so a low "IAS" is quite doable.
- ldargin 6y agoSee https://www.wired.com/story/a-helicopter-ride-over-mars-nasas-about-to-give-it-a-shot/#:~:text=As%20far%20as%20physics%20is%20concerned%2C%20flying%20a,pull%20air%20downward%20fast%20enough%20to%20generate%20lift https://www.wired.com/story/a-helicopter-ride-over-mars-nasa....
- aero-glide2 6y agoThe blades spin much faster to generate the required lift (lift proportional to density). Mars having lower gravity also helps.
- drone_aero 6y agoUsing actuator disc theory, accounting for 38% gravity and 1.2% air density, Ingenuity would need about 2.1x more power to hover on Mars. But it's not that simple. The reynolds number which Ingenuity's blades are operating on Mars is extremely low, 10,000 to 20,000. This makes the airfoils less efficient compared to what you might design on Earth. Compare to a Trex 450 (30% heavier weight equivalent) helicopter on Earth, it's got 10+ minutes of endurance and has a smaller diameter rotor, whereas Ingenuity has a 90 second stated endurance, although that is probably limited by navigation too.
- 4gotunameagain 6y agoI wish we could have more information on the terrain relative navigation implementation..
- jshier 6y agoI had the opportunity to speak with one of Ingenuity's engineers in the NASA pavilion at the EAA Fly In in Oshkosh, WI in 2017 (or perhaps 2016). This was before it had been accepted for the Rover2020 mission but just after they had proven the concept flight capable. I asked him about flight conditions on Mars and what they had to do to get their design airborne in such a thin atmosphere. He made a few points. 1. Given the thinness of the atmosphere, the counter rotating blades are balanced among thickness, length, and rotation speed. They're essentially as big as they can spin with the power they have at a speed where the tips are just under the Martian speed of sound. 2. I asked if wind was an issue. He said that it wasn't an issue for the stability of the craft (Martian wind moving much of anything is a movie trope) but the turbulence it caused could be a major issue for the blades, as they're essentially small wings, like a helicopter. The turbulence of a cross breeze could disrupt the flow of air over the blades and cause them to lose lift. 3. The design of the craft was essentially locked once they confirmed it could fly. They would keep most of their original hardware and software, rather than rebuild anything, which I found surprising. Given this was before they were accepted on the mission I'm not sure if anything changed. It does appear to be pretty equivalent to what we saw there.
- DAlperin 6y agoHere's one of the referenced software frameworks (if I understand correctly) used for the ingenuity control systems: https://github.com/nasa/fprime https://github.com/nasa/fprime
- ryan_j_naughton 6y agoCan 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 density and it's relation to helicopters and winged aircraft? Thanks!
- NikolaeVarius 6y agoit needs to fit inside the fairing. also what do winged aircraft use to fly?
- aero-glide2 6y agoNo runways on Mars, so takeoff could be difficult. Maybe we could do that once we have well prepared surfaces. Helicopters can also hover and are much more manoeuvrable than fixed-wing. Lift is proportional to density. L = Cl x .5 x rho x v^2 x S (L is lift, Cl a non-dimensional coefficient which depends on wing shape, rho is density, v is speed and S is surface area of the wing). For fixed wing aircraft, v is speed of aircraft. For helicopters its the speed of the blade (when its in hover. When its moving forward its a bit more complex). Haven't done the math but the aircraft has to be going pretty fast ('v' in the equation) to generate the required lift. This also means longer runway lengths.
- interestica 6y ago> But given the thin nature of the atmosphere, a helicopter seems even more difficult to get lift than a winged aircraft. Easier to speed up a helicopter's wings (rotors) than speeding up an aircraft which would need more and more runway.
- tkinom 6y agoWonder the same thing, I have the impression that Quad or Hex copter would be more stable/reliable with more redundancy build in.
- 6y ago
- tpmx 6y ago> 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?
- happy-go-lucky 6y ago> It’s kind of an open-source victory, because we’re flying an open-source operating system ... That is in reference to Linux. I think it can be a proud moment for Linus Torvalds and the team.
- Animats 6y agoI'm amazed they were able to pack enough energy in the thing to get the props to go fast enough to work in Mars's barely there atmosphere. Keeping it upright is standard equipment in even low-end quadcopter drones.
- tomas789 6y agoI implemented a visual-inertial navigation based on the algorithm called MSCKF. It would be really interesting to know what kind of algorithm they are using. They mentioned state propagation in the article. This might indicate they are using an algorithm based on extended kalman filter. It takes quite some care to make those algorithms robust. Even when you run in an environment covered with diverse visual features. The state divergence is a real thing which essentially means the copter is falling from the sky (Do they call it like that on Mars?).
- blt 6y agoProbably MSCKF.