Hi all,
It occurs to me that I never got around to posting my videos flying my ArduCopter, Cindi Lou, on Mt Erebus last December (2011). I'm at around 10700 ft, but the pressure altitude is around 0.65 bar -- the equivalent of closer to 13,000 ft at the equator. This was on a nice, warm (-15C) nearly windless day. I was pleasantly surprised how well the quad performed in stabilize and simple mode (no sonar, and loiter was unreliable).
I got my APM / Oilpan when they first came out, and that's what's flying in this video. Unfortunately I upgraded to 2.0.49 before going to Antarctica and didn't realize that flight log collection was disabled since I had the atmega 1280 version, so no logs.
This is vaguely related to my PhD research in volcanology. My job on Erebus is to map and study some ice caves that form when volcanic gases melt tunnels into the bottom of the snowpack. The BBC came out and filmed us at work and you can see it in the "Life in the freezer" episode of the BBC / Discovery series Frozen Planet if you're interested.
I'm going back to Erebus for the fourth time this November, and this time I intend to do some serious science using multirotors with APM2 onboard. Some of the caves cannot be entered due to dangerous gasses and / or unique microbiology. I'm planning to fly an autonomous quadcopter down into them, doing SLAM or at least wall avoidance, and measuring gas concentrations. Eventually I'd also like to fly a multirotor down into Erebus' crater to sample gas from the bubbling lava lake. NASA's New Mexico Space Grant Consortium has kindly awarded me a graduate research fellowship for this work, and I am considering an application to NASA NIACS.
Please let me know if you have any advice or are interested in collaborating. Major issues I need to overcome:
- Radio transmission through the snowpack: can it be done?
- Cave wall avoidance. I will probably do this with IR distance sensors, although the MIT RANGE quadcopter-mounted lidar or Kinect approach would be better if I can pull it off. RANGE said they are interested in collaborating wants me to email them again in June...
- Propeller / motor design for high altitudes. Should I be changing the blade pitch for lower pressure?
- Keeping a quadrotor running in a cold environment with acidic and corrosive condensing vapor.
Oh, by the way, I'm now flying a 3DR frame with an APM2, and an Xaircraft X650V8 also with an APM2. Thanks to all the developers, the technology has improving by leaps and bounds! As has my own flying ability...
One more question. Does anyone know of other people flying multirotors in Antarctica? Am I the first on the continent? I hope not, because it would be great to start the McMurdo RC flying club!
Cheers,
Aaron
Comments
John, you must live in a warm area of the earth. To northerners, ice crystals is just frozen water. It'll come back next year. :-)
Hey John, I'm actually more worried about the damage the crystals would do to the copter! Tthe obstacle avoidance system (IR distance sensors or LiDAR) should get reflections from the crystals and avoid them. Most of those crystals grow extremely quickly. I deployed a cable (fiber optic, for distributed temperature sensing) and it had 5cm long needle crystals all over it within two days. In the well decorated rooms you can just stand there and hear as the crystals fall off the ceiling one by one as they grow too heavy. In most of the caves it's impossible for a human to enter without destroying a fair amount of crystals-- a mulitcopter should be lower impact.
Thats great. I just finished watching Frozen Planet this afternoon and those ice caves are amazing. I kept thinking that a camera equipped multicopter would have been handy in a lot of those places, like Mt. Erebus and the moulins in Greenland. But arent you worried about your multicopter damaging the ice crystal formations in the caves?
By the way, I can't find a good reference on this, but I've been told the barometric pressure is lower at the poles than the equator for two different reasons. First I was told it's a centrifugal force effect, similar to why the earth is ellipsoidal rather than spherical. Later I was told that the centrifugal effect is insignificant and actually the entire air column is effectively compressed because it is colder on average, so you get up to the thin layers more quickly. I can't seem to find a good reference on either contention.
Er, correction, sorry. The summit is 12,447 ft, and I was thinking the Lower Erebus Hut (where the videos are taken) was a few hundred feet below, but checking the DEM it's actually more than 1500 ft down, around 10,700. Still, the pressure altitude is quite a lot higher. It is almost always between 0.60 and 0.65 bar up there. There's some spotty data here: http://erebus.nmt.edu/index.php/environmental-stations/sensors/baro... if you click on 365 day. Looks like about 0.625 when the video was taken.
Wait a minute! You're at 12000 feet above sea level? Hell, I would have thought a quad's flight ceiling would be less than that. Well done!
I meant to say that I'll get around to editing those overexposed videos and post them if you guys are interested.
Thanks, Ellison. There are more people than you might think, actually! McMurdo has around 1200 people at peak in the summer. All of the other bases are under 100 people though.
I did some flying over a more interesting landscape on Erebus, called Ice Tower Ridge where there are big towers of ice with steaming holes in the top. Unfortunately they didn't really come out-- there was too much light and the videos are too white to make out much.
Aaron, are there really so many people down there, that you don't already know them all already? ;-)
Great vids of Antartica!
Guy! Caving in borneo sounds incredible, I would love to go some day! Fun to see I'm not the only one working on a cavecopter! Can't wait to hear about your expedition.
Thanks for the warnings about sonar in the cold. I have made friends with the owner of a local supermarket and am hoping to test the thing in their -20C walk-in freezer. However, the caves I work in are volcanically heated and are almost always above 0C (actually we have one that is 38C). I am a little worried about acidic condensation though.
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