[X] My Assistant

[Guest_Myran_*]

It impacted! Hurray hurray! And happy july 4 for the USA guys in this forum.

[Bob Shaw]

Mariner 6 and 7 had brief extended missions as they flew out into the inner fringe of the asteroid belt.  They'd been launched on fast-trajectory Mars flybys and had extra encounter speed and got a mild gravity assist from Mars during the flyby.  The did engineering tests, post encounter and fired the midcourse engines a second time and watched the exhaust cloud's spectra with the short wave channel on the infrared spectrometers.  No interplanetary science instruments onboard, so they couldn't do much else.

Any idea of their final orbital parameters? I always assumed they were in classic Hohmann transfer orbits and *just* grazed Mars at their apogee - it never struck me before that they were in fast solar orbits. Still, maybe that explains the high energy Atlas-Centaur combo (rather than the Atlas-Agena for Mariner 4) despite still being relatively small spacecraft.

[edstrick]

There's orbit info in the JPL TR series final mission technical report on Mariner 69, but I don't have those volumes. They got more or less out to the inner edge of the asteroid belt. They were the furthest from the sun on solar power till <maybe/probably> Near or certainly Stardust.

The spacecraft were too heavy for Atlas Agena and too light (in effect) for Atlas Centaur. Some, I think 900 lb vs 450 or so lb for Mariner 4 and nearly 1 ton for Mariner 9, which was almost the same spacecraft, but with fuel tanks and an orbit-insertion engine added.

[jaredGalen]

Just threw this together to give myself a bit of a context shot of where the impactor most likely hit.
Hope we get some good shots of the crater from underneath that bright ejecta cone.

[jaredGalen]

Teased some more detail from on the great image of the comet.
ImageShack isn't cooperating so have to upload it here

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[um3k]

An animation made from an impactor image and a deconvolved hi resolution camera image:


I used a demo version of the "FocusFixer" filter for photoshop for the deconvolution, which is the reason for the watermarks on that image.

[4th rock from th...]

A mosaic of several impactor images.
It's a little big but this way you can see the context of the impact area.

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[edstrick]

This evening, I grabbed "tif" versions of press release images from the Planetary Photojournal site and did bandpass filtering enhancements on the images. I've spotted things that haven't been commented on and am posting 3 sets of images with some comments.

Note: A lot of the so-called TIF images on the photojournal apparently were initially generated as jpg's and were then turned into tifs, complete with jpg artifacts. Enhancing those tends to result in a mess with the jpg artifacts being strongly enhanced with other small low contrast details.

Pia02127 is a whole-comet image from the impactor, and is the best single-frame view of the nucleus I've seen. The nucleus is divided into at least 3 "regions" with well divided curving borders separating them. Region 1 is the top half of the visible nucleus, Region 3 is the bottom, lower left and lower right edges. Region 2 is sandwiched between 1 and 3, but the borders between 2 and 3 curves up and 2 pinches out in a triangular "cusp" between the borders of 1 and 3. 1 and 3 both give the impression of overlapping 2, with features and texture patterns in 2 stopping abruptly at the borders. In both the region 1 border and the lower right border of region 3 against 2 and against 1, there are features sub-parallel to the border behind the border, giving both borders a very substantial width of a couple hundred meters.

The whole impression is of plastically deformed bodies that were gently "smushed" <very technical geological term, there> together to form one body, which is now being "etched" as ices ablate and crust disintegrates and blows away into space, shownig internal traces of how it was assembled. This is not a "rubble pile", but I get the impression of an assembled object, put together with ultra-low-speed collissions.

The top half of region 1 is very irregular, above the "pitted plains" that are nearly at the center of this view of the nucleus. The large depression with strong shadows on its wall to the right seems floored with very irregular material, and the sharp edges on the right and bottom sides disappear on the upper left. Above it is a smooth plains unit with little texture above the noise and artifacts in the image, and to the depression's upper left is another depression, shallower, but also vaguely circular, filled or floored with extremely irregular material which may have a raised edge compared with the irregular textured material on the uppermost part of the nucleus. Some possible lobes of the smooth plains seem to extend up to a very obliquely viewed facet or depression at the top edge of the nucleus. The plains seem superimposed on the rough terrain with in places locally sharp boundaries.

Another plains unit is present on Region 2, with well defined escarpments as edges. There's faint textures within this feature, but it's surface is remarkably uniform and smooth in all images I've seen.

The different regions have distinctly different populations of surface features. The bottom half of region 1, above the thick border with regions 2 and 3, has multiple rimless crater-like pits, resembling those on Comet Wildt as seen by Stardust. In contrast, Region 2, other than the superimposed smooth plains, seems to have an abundance of dark rimmed features with light spots or patches in the centers. The most prominent is the thing everybody's seeing and saying "impact crater", and I think it probably is... but ... there are many other smaller dark spots with light centers you can see in the next pair of images I'll post. The dark "rims" indeed appear to be raised, both on the "crater" and the smaller spots, as though they're erosion resistant relative to the lighter material outside the spots. Perhaps these are indeed impact craters, with altered, maybe compressed or heated and sintered crater walls and near-wall material resisting erosion. Why these are so different from the flat floored rimless craters in region 1... go figure!

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[edstrick]

These images are press-released and enhanced versions of image PIA02135, from the impactor, showing most of region 2, it's border with region 3, and the smooth plains superimposed on region 2.

The smooth plains have weak textures converging into it's center from the upper right and lower right edges, but is remarkably smooth and flat. The escarpment at it's edge seems pretty uniform in height over much of it's length. Scattered bright spots are visible for a ways to the right and below the edge of the smooth plains. Some of these appear to be real albedo features, rather than sunward facing slopes.

Further to the right, region 2 seems smoother, but has the scattered dark spots, many/most with light centers, as described in the previous posting. Light patches seem decidedly less common.

The border of Region 3 and 2 forms a well defined topographic break on the surface of region 3, but seems to descend into a hummocky "badlands" as it transitions into region 2. Much of the border below and to the lower right of the topographic break is fairly smooth, but the rest of region 3 all the way down to the the limb is extremely rough and "hackly" Some vaguely elliptical features give the impression of obliquely viewed crater-form depressions in the rough terrain, but resolution is not good enough to clearly tell if this is so.

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[edstrick]

Pia02130 is a cleaned up but not deconvolved hirez camera image of the impact. The enhanced version clearly shows the defocused blur pattern of the high contrast sun-facing wall of the sharp depression at the terminator. The picture is badly out of focus, but at least this file does not have JPG artifacts introduced before it was turned into the TIF I downloaded.

The images is labled "Moment of Impact". The caption says, in part:

"When NASA's Deep Impact probe collided with Tempel 1, a bright, small flash was created, which rapidly expanded above the surface of the comet. This flash lasted for more than a second. Its overall brightness is close to that predicted by several models. After the initial flash, there was a pause before a bright plume quickly extended above the comet surface. The debris from the impact eventually cast a long shadow across the surface, indicating a narrow plume of ejected material, rather than a wide cone."

In the enhancement, the bright part of the flash is *NOT* saturated in the press release image, and has a very well defined sharp edge, beyond which there is diffuse glow which progressively gets fainter beyond the edge. I cannot tell if the edge is real, or an artifact of the imaging system or data processing, but if it's real, it's clearly an important feature of the expanding plasma and vapor cloud.

Low contrast mottled features are visible within the edge of the bright spot, in particular, there is a dark smudge at the bottom of the ejecta plume's shadow, apparently shadow visible through the bright "blob". The ejecta plume is not itself at all clearly visible or recognizable. Of particular interest, not otherwise noted yet that I've seen.. the shadow is *DOUBLE*.. with a darker portion on the right, and parallel to it a fainter portion on the left. This *might* suggest an irregular, maybe keyhole shaped hole punched in the surface layer of the comet with the high angle early ejecta emerging in a double plume.

I've tried enhancing later post-impact images. In the versions on the planetary photojournal, the brighter portions of the eject plume are saturated and contain no detail. Elswhere, there are strong vertical stripe and some horizontal stripe artifacts that have not been cleaned up from the totally raw data before the images were deconvolved, and they really degrade the enhancement. Image Pia02123 is the best of the 4 (2 of the 4 are the same data). The ejecta streamers are not perfectly radial to one point, but they do converge on a not-saturated part of the image just above a main saturated area and to the left of a smaller saturated bright spot. Texture is faintly visible in this area behind the strong vertical and several horizontal stripes from the camera artifacts, but no feature I'm inclined to interpret as a crater is evident above the noise and artifact level.

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[Guest_Sunspot_*]

WOW.........the HRI images look almost useless.......

[jaredGalen]

WOW.........the HRI images look almost useless.......

It's wonderful what the deconvolution can do though.
Even looking at um3k example animation of the impact a few post up
shows the potential for some cool final results I'd say.

BOOOOOOOM

[Guest_Sunspot_*]

Did they plan on taking colour images with the MRI too?... I'm sure I read that somewhere.

[jaredGalen]

In looking at the MRI's I noticed these two frames.
I think you can see a radial shock wave extending around the impact site.

Or maybe it's just the beginning og the plume and it's really low.
Not sure.
It's cool though

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[edstrick]

The HRI image of the flash has been pretty well cleaned up.. very few streaks, etc. Just the blur of the de-focus. The DECONVOLVED HRI image shows much sharper details, but it hasn't been cleaned up, so the artifacts and streaks are horribly exaggerated. The focus problem is a real shame, but they're gonna be able to produce deconvolved clean images that are several times sharper than the MRI images, with some grain from bosting fine details during deconvolution, much the way my bandpass filtering boosted grain from single pixel random noise.