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Full Version: Phoenix Final Descent Trajectory
Unmanned > Mars & Missions > Past and Future > Phoenix
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Langley was responsible, at least partially, for the Spirit movie of 'chute descent and RAD/TIRS firing -the file name is something of a clue.

The AMA in another filename suggests Analytical Mechanics Associates.

QUOTE (Oersted @ Aug 9 2008, 08:23 AM) *
No, they also do the visualization of actual data that comes down. See for example the MER airbag bounce movie.

Glad to know!
This image is the best match I have found so far between the MRO image and the spice kernels. It happens 273 seconds after Spice kernel startup. The Phoenix model is scaled by a factor of 20, the actual location of Phoenix is at the center of the backshell. The point of view is at MRO and the field of view is 0.5deg horizontally. This uses the MGS MOLA 128/deg topography and Emily's map at

I can't find a perfect match, I think that the image of the crater was distorted by the fact that the TDI and motion compensation was following Phoenix, not the ground.

227.825, parachute firing
228.935, first peak parachute deceleration, 82.962m/s^2
242.825, heat shield jettison
252.985, leg deploy
253.485, leg deploy
253.980, leg deploy
~273, MRO photo

This is ~45 seconds after parachute deploy, a bit later than I had heard before. Don't take my word as Gospel, it is certainly possible I made a mistake somewhere.
Version 2A

Now I've got Emily's map and MOLA topography, and illegible HUDs instead of vectors attached to the spacecraft. Trust me, the HUDs are readable at their original resolution.

I'm not done yet.
QUOTE (kwan3217 @ Aug 22 2008, 08:53 AM) *
I'm not done yet.

Terrific! Love the changing camera angles and attention to detail (the whoosh of helium, etc.).

Curious as to what the HUD polar display is showing.
QUOTE (jmknapp @ Aug 22 2008, 07:25 AM) *
Curious as to what the HUD polar display is showing.

Polar chart shows:
(Dist)ance and direction to actual touchdown point in m and degrees (all azimuths are in degrees, N=0, E=90, S=180, W=270)
(Hspd) Horizontal speed and azimuth in m/s
(FPA) Flight path angle in degrees, 0 is horizontal, +90 is straight down
(Alt)itude in meters
(Vspd) Vertical speed in m/s
(Vrel) Total ground-relative speed in m/s
(Acc) Non-gravitational acceleration (what's felt by accelerometers) in m/s^2

The vectors in the polar chart show the vector to the actual touchdown point (green) and the vector of current horizontal speed (yellow) in a logarithmic manner. Inner ring is 1m and 0.1m/s, and each next outer ring is 10x as much. Similarly the bars under altitude and vspd are logarithmic.

This is all modeled after the VTOL instrument in the Orbiter sim.

The vector ball in the upper right has bars every 45deg in latitude and longitude. It's polar axis is the local vertical. The red bar is true North. It shows the X, Y, and Z lander frame relative to the current viewpoint (red,green,blue). The local drag frame is shown with only vector arrowheads. The cyan arrowhead (mostly covered by the red vector) is the relative velocity. Assuming no wind, Drag is exerted opposite this direction. The yellow arrowhead is the "vertical" lift vector, perpendicular to the relative velocity vector and in the local vertical plane containing the relative velocity vector. The magenta arrowhead is the "horizontal" lift vector, perpendicular to both of these and as a consequence always in the horizontal plane. The orange arrow is the direction of acceleration as felt by the accelerometers (excluding gravity) and therefore registers 1 Mars G when sitting at the surface.

Upper left is a clock in UTC, spacecraft event time.

All the sound effects, as well as the music, come from the EDL HUD video published by NASA before landing. I can't take credit there. I just tweaked things to match the actual timeline, and am not done yet.
QUOTE (kwan3217 @ Aug 22 2008, 02:37 PM) *
Polar chart shows:

Thanks... did you ever find a server to host the file? How big is it? Would love to see the hi-res version.
QUOTE (kwan3217 @ Aug 22 2008, 07:53 AM) *
... I'm not done yet.

Wow! It gets better and better. smile.gif If you're not done yet, I can't wait to see the next version. That was amazing.
QUOTE (jmknapp @ Aug 23 2008, 01:38 AM) *
Thanks... did you ever find a server to host the file?

UMSF is happy to host it.
Actually I have acquired some web space of my own for this -- Kwan Astrodynamics.
QUOTE (kwan3217 @ Aug 25 2008, 09:47 AM) *
Actually I have acquired some web space of my own for this -- Kwan Astrodynamics.

Kwan, I'd love to link from my (ex-) Phoenix realtime simulation to your movie. Let me know once all the UMSFers have downloaded it and your website has bandwidth available for more visitors :-)
Arrakis teaches the attitude of the knife—chopping off what's incomplete and saying: "Now, it's complete because it's ended here."
-from "Collected Sayings of Muad'Dib" by the Princess Irulan

OK, now I'm done, because it's time to move on to a new project. Kwan Astrodynamics now has posted version 3C, version The Last.

Also, I am in the process of packing up and posting the source code for the education of anyone who cares.

Emily, djellison, dmuller, anyone else who wishes to: You may get and host any or all of the content of Kwan Astrodynamics. It will probably be gone in a few weeks.
Just brilliant!
That turn to ride behind Phoenix as she heads in and seeing where she's going to land - FANTASTIC.

"If you need Visuals that are Dramatic, call Kwan Astrodynamics" smile.gif

... STUNNING ... thank you,
Fantastic Kwan! I wondered if you'd do plasma heating effects, a friend who does CG professionally once told me flames, smoke, vapour clouds etc are one of the hardest things to get right.

The words "Phoenix has landed! Phoenix has landed! Welcome to the north plains of Mars!" brings a lump to my throat once more, because the final reveal shot pulling back from the lander and target marker to the planetary context view is the perfect complement, illustrating the scale of the achievement. That's why those simple words mean so much to us all, and your work illustrates it magnificently.

I've mentioned work this as a work-in-progress to a couple of friends, but haven't shown them it yet because you promised further developments. It was a hard temptation to resist after the first version, because it was already so good, but I'm glad I did... I'm actually looking forward to getting back to the office after my break, now biggrin.gif

I'll show them my local copy rather than sending the link, to spare your b/w, but I really hope someone can find the space for a permanent mirror - it's an all-time classic, IMHO. Many, many thanks.
QUOTE (imipak @ Aug 29 2008, 11:15 PM) *
someone can find the space for a permanent mirror

I will put it on the Space Outreach Library in due course, when I am a bit less busy.

Just out of curiosity ... would there be a "demand" for such large files to be available offline, i.e. burnt on CD and sent my snail mail, for a nominal fee of say US$x for 1 to 2 CDs to cover for postage & stationary & a bit extra for the time involved? This could be a service that the Space Outreach Library could offer, of course only with the approval of the authors of the files in question (I dont want to appear to be "selling" other people's work)
holy mother, what an amazing development since the first already stunning video! - a great work of art and science to come home to after the summer vacation. Art because you really nailed the music score, nd because of various flourishes like the final zoom-out.

Only slight thing I can't get my non-engineer mind around is showing the swinging under the parachute with the viewpoint fixed to the backshell, and not to the shared c.o.g. of the backshell-parachute combo. In my "reality" the backshell should be not just wiggling - as it seems from the movie - but swinging quite violently around as well. Just a question of visualization, I know.

Thanks so much Kwan, you well deserve the kudos heaped on you. From the Phoenix team as well no less!
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