Ingenuity- Mars 2020 Helicopter, Deployment & Operations Options

[Andreas Plesch]

The latest news item has a youtube clip which shows a plot of the flight:



Assuming that y is N-S and x is E-W, it shows the main S component of the flight but also about a 22m component to the E or W. On the other hand, x returns to close to 0m but the ZCAM image shows that it landed about 10m East of the starting position. Perhaps the internal position tracking drifted during the long flight, in E-W direction only.

If positive x means to S, and negative z up, then positive y would mean to W, I think, in a regular right-handed system. Staring at the Hazcam picture I thought maybe Ingenuity is to the E, closer to the rover not that it is really possible to tell.

I went ahead and sketched out W and E options for a possible flight path in this map:



What is interesting that adding a sight line to Ingenuity on the Hazcam image using the hill in the background (long arrow), leads to an intersection really only with the E option. So the circled area is a possible location for Ingenuity on the Hazcam image. It would mean it was close to its destination at 12:34:13. Presumably we will soon know when more images from the flight are released.

[Dig]

Great news!. The helicopter has been a total success.
It would be good if, after the 4 successful flights and the extension of the mission, they enabled a new category in the RAW images section or on the "Mars Helicopter" website with the images made by the helicopter during the first four flights.
According to the plans that they had and that they have been publishing for flights three and four, I suppose they will have many images that have not yet been published.

[neo56]

Video of Ingenuity 4th flight in approximately real time:



Speed x2 and squeezing of the period when Ingenuity is not in the field of view:

[Andreas Plesch]

Here timestamped animations for flight FOUR using the right ZCAM sequence, clipped to the in-frame action (click for mp4):



lossless webp:

http://bit.ly/Flight4Lossless

workflow:

roverpics -> wget -i -> rename for use in labeling: for a in *png; do cp -n $a labels/`echo $a |
sed 's/Z.*_0069_//' | sed 's/ECV.*/\.png/' | sed 's/_/\./'`; done

determine average ms per frame: ls | sed 's/.png//' | awk '{print $1 - prev; prev = $1}' | awk '$1 < 0.2 {sum += $1; i += 1; print sum/i}'

select frames

label with imagemagick: convert selection/*.png -enhance -gravity South -annotate +0+10 '%t(s)' -gravity SouthEast -annotate +10+10 'Attributions' allFrames.tiff

convert to mp4: convert -delay 144x1000 allFrames.tiff -quality 100 animation.mp4
convert to webp with gimp

[Andreas Plesch]

Since the left ZCAM camera captured lift-off and landing, I combined it with the right camera using the timestamps:




lossless webp: http://bit.ly/Flight4LosslessLeftRight (large, will play at proper speed the second time)

One could transition between the cameras more smoothly, or combined left and right frames for a wider view, with a lot of work (>500 frames).

[Andreas Plesch]

Contrast stretching and speeding up reveals how Ingenuity kicks up dust on lift off and particularly on the return trip where she descends through her own dust cloud and disturbs it during landing.




There appears to be a southerly breeze (blowing to the north).

[MarkL]

Contrast stretching and speeding up reveals how Ingenuity kicks up dust on lift off and particularly on the return trip where she descends through her own dust cloud and disturbs it during landing.

Thanks Andreas. This is a great set of images from both cameras that really contextualizes the majority of the flight.

Whatever dust is kicked up is ephemeral. You can't even detect it without significantly boosting the signal in the images. The nadir-pointing camera on Ingenuity shows very little dust also, so far.

[Art Martin]

One thing to think about in regards to dust kicked up by Ingenuity is that the takeoff site I believe was a bit scoured of dust by Perseverance's landing so, even though the rotors are much closer to the surface there, there's little dust to kick up. It makes complete sense to me that mid flight you may see more dusting effects even from higher altitude.

[Andreas Plesch]

A recently posted, right MCZ image sequence for sol 74, 15:19:38 to 15:19:53, looking at a portion of the flight path of flight FOUR, shows no activity for that time (click for mp4):




(auto white balanced)

Unlikely that the video was planned for another flight attempt since nothing was announced. Perhaps a preparatory test recording, since in parallel the left ZCAM recorded a wide field of view, with some processing issues.

auto white balance:

gimp: color - levels - auto input: note input levels for each channel, convert to percent
convert: convert 0673520*.png -fill gray90 -gravity South -annotate +0+10 '%t(s)' -gravity SouthEast -annotate +10+10 'NASA Mars2020/JPL, converter' -channel R -level 9%,99.6% -channel G -level 4.3%,94.1% -channel B -level 0%,77.6% allFramesC.tiff

[PaulH51]

Details of flight 5 announced LINK

[Tom Tamlyn]

From the update article that PaulH51 linked to above:

[O]n the fourth flight, we actually scouted for a landing zone over 100 meters (328 feet) away. The digital elevation maps put together by the Ingenuity team gave us confidence that our new airfield is flat as a pancake – a good thing when you have to land on it.
***
Our helicopter is even more robust than we had hoped. The power system that we fretted over for years is providing more than enough energy to keep our heaters going at night and to fly during the day. The off-the-shelf components for our guidance and navigation systems are also doing great, as is our rotor system. You name it, and it’s doing just fine or better.

[Tom Tamlyn]

Helicopters do not scale up well.

Beyond the obvious thrust challenge in the thin Martian atmosphere (i.e. classic momentum theory, and the Mach/Reynolds aerodynamic issues common to all aeronautics), there are some other rotorcraft-specific issues that actually are rather challenging for Ingenuity that one only confronts when one gets into the real details of design and test.

First is heat transfer. The thin atmosphere gives almost no cooling. The Ingenuity motors have parts made of beryllium to act as a heatsink, but even then I think overheating is actually the limiting factor on flight duration, not battery energy.

Second is aeroelasticity. There's a similarity parameter called the Lock Number (that I hadn't heard of until I started working with rotor people on Dragonfly) that is important in assessing the structural damping of blade flexing. Again, the thin atmosphere is the problem, it provides no damping so blade oscillations can build up.

Both of these issues get worse as you scale up. So at the NIAC / Powerpoint / student-final-year-project level, yes you can mock out neat-looking hexacopters and stuff in the 10-20 kg range and they look like they should fly, but once you really start poking into the thermal and mechanical design, I bet even those would not work out.

At the April 30 press conference, https://www.youtube.com/watch?v=BAlXe-U0ws4 at about the 78 minute mark, J (Bob) Balaram, Ingenuity chief engineer, made a couple of comments that speak to one of the issues raised by Ralph in the fascinating quoted post and several followups.

First, Balaram confirmed that vehicle heating rather than power availability was the factor constraining flight duration. Second, he noted that "[s]ince we were a technology demonstration designed for short flights, all the waste heat in the motor actually gets absorbed in the motor, and the motor temperature raises by about one centigrade for every second of operation." For what it's worth, and yes, it's just an offhand remark at a press conference for a general audience, I hear that as not ruling out the existence of techniques that might permit the next generation of Mars helicopters to shed enough waste heat to allow longer flights.

Incidentally, does anyone know the eponym of Lock's Number (also called Lock's Constant)? I've traced the following citation, Lock, C., “Application of Goldstein’s Airscrew Theory to Design,” Aeronautical Research Committee, RM 1377, Nov. 1930, but haven't found any biographical information for "C. Lock."

[Andreas Plesch]

Details of flight 5 announced LINK

Based on preliminary mapping of dunes and rocks, I believe the highlighted area in this flight 4, aerial image was the destination for flight 4, and could be the targeted landing area for flight 5:

[Explorer1]

Microphone on SuperCam worked!
https://www.youtube.com/watch?v=y5niGi4k9vQ

[Xerxes]

Incidentally, does anyone know the eponym of Lock's Number (also called Lock's Constant)? I've traced the following citation, Lock, C., “Application of Goldstein’s Airscrew Theory to Design,” Aeronautical Research Committee, RM 1377, Nov. 1930, but haven't found any biographical information for "C. Lock."

Finding this information was extraordinarily difficult, and I think underlines the importance of not omitting material when writing because "everybody who cares already knows what this means". Here we are a hundred years later, and nobody living remembers what this meant. I think the man's name was Christopher Noel Hunter Lock, based on this link: https://www.google.com/books/edition/The_Wa...=1&pg=PA121

I found some biographical notes in this study of the Lock family history:

Thursday 13 March 1924, page 17: forthcoming marriages: MR. C. N. H. LOCK AND MISS GILLMAN. The marriage of Christopher Lock, Fellow of Gonville and Caius College, Cambridge, son of the late Rev. J. B. Lock, Fellow of Gonville and Caius College, and Mrs. Lock, with Lilian, daughter of Mr. A. W. Gillman, O.B.E., and Mrs. Gillman, of Streatham, will take place at the end of April.

Tuesday 29 March 1949, page 1: deaths: LOCK.—On March 27, 1949, suddenly, at 49, Park Road, Hampton Hill, Middlesex, CHRISTOPHER NOEL HUNTER LOCK, M.A., of the National Physical Laboratory, Teddington, aged 54.