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First full-resolution MARDI frame: Bye-bye, heat shield

Posted By Emily Lakdawalla

07-08-2012 23:50 CDT

Topics: pretty pictures, spacecraft, amateur image processing, pics of spacecraft in space, Mars, Curiosity (Mars Science Laboratory)

Well, this was a nice surprise. The MARDI images from Curiosity's descent to Mars were posted to the Curiosity raw images website several hours ago, but I didn't notice until someone on pointed out that among the nearly 300 thumbnail frames (200 by 150 pixels) there was a single full-resolution image, and it contained the heat shield far below the rover. So cool. It is still mind-blowing to think that this snapshot was taken by a spacecraft flying in the air above a different planet.

Curiosity's heat shield falling toward Mars

NASA / JPL / MSSS / Emily Lakdawalla

Curiosity's heat shield falling toward Mars
A color MARDI image from the descent sequence shows the heat shield falling far below the rover. It was taken Sol 0 (2012-08-06 05:15:39 UTC).

The raw image has some odd and distracting compression artifacts, so I did some light tweaking of the image in Photoshop to suppress them. "Compression artifacts" are features that weren't in the original image that get introduced into the image when it is run through an algorithm that shrinks its file size with some cost to the quality of the image. They have to compress the heck out of most of the images that are coming down from Curiosity right now because it's only communicating at 8 kbps right now, which is a pretty darned low data rate. It'll be wonderful when they finally get that high-speed link to Mars Reconnaissance Orbiter working and they can start downlinking at 2 Mbps.

Eventually, we should be getting back the entire MARDI descent video uncompressed, but the uncompressed frames are low in priority compared to science and engineering data, so we'll probably have to wait for some time. I thought about noodging the color and contrast a little bit to bring out more features on the surface, but when I tried that the image lost the sense of atmosphere separating the heat shield and the surface, so I decided to leave the color alone.

Related: Emily's continuing coverage of the latest images from Curiosity

See other posts from August 2012


Read more blog entries about: pretty pictures, spacecraft, amateur image processing, pics of spacecraft in space, Mars, Curiosity (Mars Science Laboratory)


Mike: 08/08/2012 03:12 CDT

I wonder if the bright spot at about the 1 o'clock position from the heat shield is the same sort of bright spot that can be seen from a small airplane on Earth, when more than about 3,000 feet above the ground? Also, is the actual landing spot visible in that image? Do we know yet exactly where the lander landed?

Borek: 08/08/2012 04:14 CDT

Yeah, that spot really looks like the opposition effect.

Harry: 08/08/2012 04:43 CDT

@Mike. I think the two white spots you see on the heat shield are calibration marks used to calibrate the brightness and color of the Mardi camera. See the first frames of the animation to get a better look of them.

MaG: 08/08/2012 04:45 CDT

What do you think about small dark spot near heatshiled? First I thought, it's a heatshiled shadow on the ground, but In opposition effect I can't find something like sahdow, maybe there is only some little darker circular feature as a shadow of parachute, but it's not so dark..

Emily: 08/08/2012 11:27 CDT

Yes, I thought "opposition effect" too when I saw that, but wasn't sure of the geometry. We asked about that dark spot on and Mike Caplinger (Malin Space Science Systems) thinks it's a "bit of crud" on the detector.

Anne: 08/08/2012 11:50 CDT

What is that square or diamond-shaped "crater" to the right and below the heat shield? It's near a more visible round crater.

John: 08/08/2012 12:34 CDT

FYI: The white spots on the back of the heat shield are visible in this picture:

Dave: 08/08/2012 04:03 CDT

I noticed the same thing Anne did. It looks like a square wall foundation. I wonder who built that? ;-)

fthurber: 08/09/2012 12:52 CDT

So do I take it that the high-gain antenna is still not working?

Don: 08/12/2012 03:41 CDT

So, they are doing the (lossy) compression on Mars (some martian algorithm?) before sending because of the slow data rate.. Does this mean when the 2mb transmissions come we get raw/uncompressed? I would presume so.. btw, what compression are they using?

Emily: 08/14/2012 11:36 CDT

Regarding the crater shape: there's a lot of degradation/modification of craters here; they're really old. It's not surprising that erosion has carved weird shapes into some of them. And regarding compression, it's just JPEG, but it has some funny effects on the Bayer-filtered images. Yes, the hope is that they will eventually return losslessly compressed versions.

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