Esa ‘huygens And Mars Express’ Science Highlights, Call to press - Paris, 30 November 2005 Options

[ugordan]

I guess the news belongs to the Mars forum as well, but since I'm more of a Huygens guy myself, I figured this is a better place:

http://www.esa.int/esaCP/SEMA96ULWFE_index_0.html

[alan]

Does this mean the Nature articles are about to be released too?

[DDAVIS]

Does this mean the Nature articles are about to be released too?

Doggone well about time. I would like to see the final image mosaics from Huygens, with color overlays from the spectral data, as we saw in the test images.

Don

[ugordan]

I would like to see the final image mosaics from Huygens, with color overlays from the spectral data, as we saw in the test images.

I wouldn't hold my breath for color mosaics like that, they would need pretty accurate reconstruction of where the spectrometer was looking at (not that it samples only a single point, rather it averages the entire FOV, IMHO). In any case, the color resolution would probably turn out very low and the whole scene uniformly colored, sort of like that one uniformly hued surface image.
I seem to remember Marty Tomasko saying that most of the spectra they've taken is very similar.

[DDAVIS]

[quote=ugordan,Nov 22 2005, 03:23 PM]
I wouldn't hold my breath for color mosaics like that, they would need pretty accurate reconstruction of where the spectrometer was looking at (not that it samples only a single point, rather it averages the entire FOV, IMHO). In any case, the color resolution would probably turn out very low and the whole scene uniformly colored, sort of like that one uniformly hued surface image.


Perhaps, but this test image, at:

http://www.lpl.arizona.edu/~kholso/images/.../mosaic_c_3.jpg

shows some resolution of color information. In addition, the quality of the images in the tests seems to be suspiciously better than the performance of the flown camera. I suppose low contrast in the Titan view provided an opportunity for compression artifacts to have a field day.

Don

[ugordan]

  Perhaps, but this test image, at:

http://www.lpl.arizona.edu/~kholso/images/.../mosaic_c_3.jpg

shows some resolution of color information. In addition, the quality of the images in the tests seems to be suspiciously better than the performance of the flown camera. I suppose low contrast in the Titan view provided an opportunity for compression artifacts to have a field day.

Not to mention that 7 years of cosmic radiation damage to the CCD had also done its job. Also, the test images were taken from a low altitude and they (the team)were able to provide complete coverage of the area beneath by rotating the camera. Huygens' descent was pretty much chaotic tumbling...

[DDAVIS]

[quote=ugordan,Nov 22 2005, 04:54 PM]
Not to mention that 7 years of cosmic radiation damage to the CCD had also done its job.

Were those CCD cameras markedly more sensative to Cosmic Rays than those used in Cassini or Galileo? I might expect distinctive defects on each and every frame of the three Huygens cameras caused by 'hits' on the CCD.



Also, the test images were taken from a low altitude and they (the team)were able to provide complete coverage of the area beneath by rotating the camera. Huygens' descent was pretty much chaotic tumbling...


Certainly, and they lost half the pictures due to a screw-up, I am not talking about coverage so much as inherent quality of the returned images. If you look at the test image mosaic, at:

http://www.lpl.arizona.edu/~kholso/images/...00_big_merc.jpg

you can see the sky at top displaying nominal gradations of brightness, which along with the rest of the image reveals little visible compression artifacting. Was the compression ratio in the earthbound tests the same as that actually used during the mission?

Don

[ugordan]

Were those CCD cameras markedly more sensative to Cosmic Rays than those used in Cassini or Galileo? I might expect distinctive defects on each and every frame of the three Huygens cameras caused by 'hits' on the CCD.
Also, the test images were taken from a low altitude and they (the team)were able to provide complete coverage of the area beneath by rotating the camera. Huygens' descent was pretty much chaotic tumbling...
  Certainly, and they lost half the pictures due to a screw-up, I am not talking about coverage so much as inherent quality of the returned images.  If you look at the test image mosaic, at:

I don't believe the CCD was more prone to radiation than other CCDs. If you look carefully at the raw images, you can clearly see a pattern of persistent noise on every frame. This can always be divided out if you have an appropriate flatfield image, but the compression artifacts make this somewhat difficult. The resolution of the CCD itself is nothing near the other cameras so the blemishes on individual pixels are more visible.
The contrast at Titan is markedly lower than the scenery on Earth so the raw images needed to be contrast-stretched quite a bit, of course also stretching and enhancing compression artifacts (which get bad with random noise introduced into the image).

[The Messenger]

you can see the sky at top displaying nominal gradations of brightness, which along with the rest of the image reveals little visible compression artifacting. Was the compression ratio in the earthbound tests the same as that actually used during the mission?

  Don

If I am interpreting the design documents correctly, there should be an index of the compression rations, jpeg schemes (and filtering) of each image; so the imaging team may have been able to bring out more details - we should know after the data release on the 30th. Don't expect miracles - Huygens was operating in very poor, virtually shadowless light. I think we stand to learn a lot more from the other instruments.

[ugordan]

Several results on Mars Express/Huygens are now available online at:
http://www.esa.int/SPECIALS/Results_from_M...ss_and_Huygens/

[SigurRosFan]

All Huygens Results (five press releases)

http://www.esa.int/SPECIALS/Results_from_M...ULWFE_0_ov.html

[elakdawalla]

Is anyone else watching the NASA or ESA TV feeds? I was looking hard for what's new in the results they were talking about. I think there were some nuggets of new-ness but I fear I'm going to have to read the actual Nature papers carefully before I will be able to write anything coherent about it. At least there are some new graphics on the ESA site:

HASI graph of impact:


Lower atmosphere wind speed and direction data from DISR:


Also, Jonathan Lunine showed the DISR team's attempt to match their mosaic to the RADAR images; I really hope that graphic shows up on JPL's website. One big difference between his stuff and René Pascal's is that the outermost tiles of the mosaic are stretched much longer, making some of those dark stripes line up with RADAR features quite neatly....

--Emily

[dvandorn]

Ought to go into one of the Mars forums, I think, Marz...

For those of you who have been watching this press conference on NASA-TV on streaming video, y'all may be interested in the fact that I'm watching NASA-TV on cable and what ESA is sending out to NASA-TV is not even a video feed. It is, itself, nothing more than a streaming video from a webcam! They have all these wonderful graphics and charts and videos -- and all of them are on a 100k (or less) Real Player stream out to NASA-TV. And it's going to black every minute or two (I imagine so that their Real Player can re-buffer the stream).

It doesn't even have enough resolution to be able to read the PowerPoint slides -- which make up 90% of the visuals they're presenting.

For those who have been defending ESA's PR effort -- you *cannot* convince me that ESA has the money to mount planetary missions but lacks the money to provide a *watchable* video feed of their "triumphant" release of Huygens and Mars Express data.

This is totally, completely lame.

-the other Doug

[JRehling]

Combining the GCMS data, I get the following atmospheric composition (which is a form I like to see this data in, but ESA refuses to do the math!)...

Incidentally, I get different results if I sum the apparent CH4 isotopes in the GCMS chart than the ESA graph which reports just N2 and CH4. They may not be counting CH4 isotopes in the latter? The table below uses the CH4 count from the time of landing (not later, when CH4 abundance rose, apparently due to the spacecraft warming the ground) and ESA's CH4 count from the N2-CH4 chart. Clearly, the levels of CH4 are variable, and are thus more like H2O in Earth's atmosphere -- highly variable, and usually not reported in atmospheric composition of "dry" air.

N2 90.4%
CH4 9.2%
H2 0.32%
Ar-40 0.011%
CO2 0.009%
C2H6 0.007%

If you discount CH4 from the total, then N2 ends up as 99.6% of the total, with the other gases getting values about 1.1 times that reported above.

[SigurRosFan]

PIA06435: Huygens Landing Site (Animation)

http://photojournal.jpl.nasa.gov/catalog/PIA06435

--- This movie shows a quick succession of multiple products of Titan's surface from the Cassini orbiter and the European Space Agency's Huygens probe. It shows Cassini imaging science sub-system images, radar images and visual and infrared mapping spectrometer images of the Huygens probe landing area. The rest of the movie consists of mosaics from the descent imager/spectral radiometer. The camera system on the Huygens probe mimics the descent profile of the probe starting at about 144 kilometers (89 miles), looking eastward throughout. It displays the Titan surface in true color. The sequence ends with a true-color surface image. The radar images of the Huygens landing site were taken by the Cassini orbiter radar instrument during the Titan flyby on Oct. 28, 2005. ---