Phoenix Final Descent Trajectory Options

[dmuller]

As for "recontact," ... It crisply captures the idea of "to collide with, at any speed, but after separation."

No doubt it is very precise language. Just imagine the press conference if the backshell did actually "recontact" with the lander on the ground!
Official: Ahm we've had an anomaly during landing as the backshell deviated from its nominal trajectory and recontacted the lander on the ground. We're currently working on the issue
Bewildered reporter: Huh, you mean the backshell crashed into the lander on the ground?
Official: It seems that an unplanned recontact was made and we're working the problem. We will update you during the next press conference (which I hope I wont have to attend ...)

[dmuller]

Building on VikingMars' work, assumed wind (straight line from lander to backshell-impact to backshell) and having Phoenix fly into the wind, heatshield impact and heatshield, and assuming that North is NOT straight up in the pic, the ground track could look like this:

(Sorry for the quality of the drawing ... I dont have any decent software, still using Windows Paint )

EDIT: image reworked ... ignore this one and see post further below

[ugordan]

Dmuller, doesn't that north vector contradict with the observed orientation of the solar panels?

[djellison]

The vehicle intentionally rotated during terminal descent to put the arrays left right.

[ugordan]

Quite. If anything, I'd say north is about 12 degrees clockwise from up judging by solar panel orientation.

[dmuller]

Dmuller, doesn't that north vector contradict with the observed orientation of the solar panels?

Yes of course, overlooked that piece of evidence Yellow line up is North.

Assuming that the heatshield went straight into the ground (i.e. was not blown to the South by the wind), it would have about followed the blue line (as the landing ellipse went from NW to SE). So Phoenix would not have steered much to the North (into the wind), and the parachute made quite a trip South even though the atmosphere and hence the wind effect wasn't quite a hurricane as we know from Earth So the dark bulge to the SE of Phoenix would be windblown, and the bulge to the SW caused by the thrusters. It also looks like the backshell did hit the ground with quite some horizontal (N to S) speed judging from the ejectile and distance between first impact and backshell. The heatshield came in more vertical but bounced off to one side.

Even though all the debris is close to Phoenix, the landing design worked out very smart with all the relative movements and deviations. Great stuff

[dilo]

Agree, Daniel. I reached same conclusions looking to pictures...
Anyway, I made this wallpaper from HiRes picture (eliminating pixelization from enlarged insets). North is almost up...

Attached thumbnail(s)

 

[Adonis]

Is anywhere information about the final landing chronology, specially the retro-phase ... I mean high versus time data?

Thanks

[MahFL]

The project manager said it would take several months to put the edl sequence together from the data.

[ahecht]

There is an updated version of the EDL movie that was uploaded a couple days ago. While it doesn't appear to have ALL the EDL info in it (such as the creation of Holy Cow), it does show the partially-deployed parachute state as it was captured by HiRISE. I would've loved to see Heimdal in the background, but I guess a video like that will come once they have all the EDL numbers crunched.

http://www.jpl.nasa.gov/news/phoenix/phx-20080611.php

[cndwrld]

MEX Failed To Image The Descent

I'm not sure it was in this thread, but I read that people did not know if Mar Express managed to image anything during the descent. And the answer is No, unfortunately. The information was posted, but it was in a place that many people did not see it. If you are interested, it is at:

http://www.esa.int/SPECIALS/Mars_Express/SEMAWQ1YUFF_0.html

Old news, but just for those who were curious.

[01101001]

The MRO team has given the Phoenix-on-parachute pixels another whack, and they might have spotted the falling heat shield:

Phoenix Descent with Color and the Heat Shield in Free-Fall

[Pertinax]

Kudos again to the MRO team and a Mars bar to T-Man et.al ( http://www.unmannedspaceflight.com/index.p...st&p=116143 )

-- Pertinax

Reason for edit: fixed link

[jmknapp]

With the imaging by HIRISE, is there a definitive location (latitude, longitude) for Phoenix, to several decimal places?

[Pertinax]

With the imaging by HIRISE, is there a definitive location (latitude, longitude) for Phoenix, to several decimal places?

And altitude?

-- Pertinax