Phoenix SSI Reference Material Options

[djellison]

Finally - I found an image of the Phoenix SSI with, I presume, two spare MER CCD's inside

http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2156.pdf

It's sprouted a big lump on top of the white cylinder MPF and MPL design, due, I presume, to the use of two CCDs instead of one.

Doug

[James Sorenson]

Why isn't the "Peter Pan" Mission success panorama being done at full resolution color?. I would think that they would be doing this at full resolution. Or are they gonna do that later after this pan?.

[Deimos]

Why isn't the "Peter Pan" Mission success panorama being done at full resolution color?. I would think that they would be doing this at full resolution. Or are they gonna do that later after this pan?.

This is a really good question, and like all such, it has multiple answers.

One answer is about quality. On that front, the color pan from SSI is actually closer to full resolution than, say an image from your digital camera (making assumptions here..). The difference is your camera hides that fact, SSI is open. A typical Bayer pattern CCD takes images such that the green are half-resolution and the red and blue are quarter resolution. The image is manipulated on chip or in software to predictively extrapolate to full res before you ever see it. SSI has some filters at full res, others at quarter res, and they can be upconverted even better than the Bayer-sampled images can be (see the sol 2 pan press release, based on 1 full res and 2 1/16th res filters).

OK, the pan will be full res, but why not do better? Well,there's the practical answer. We need to see the pan before it is useful to us. Finishing it on sol 150 is not an option. So, design a pan that can be acquired and downlinked in a reasonable time. This pan is a requirement for full mission success, and a useful planning tool (interpretation of immediate workspace through context, identification of interesting distant features). So you figure out how many frames you want, how many sols you have to finish, and what fraction of the downlink you can use (unlike MER, the panoramic camera is merely one of 3.5 major data hogs). Then, you land, get great comm and thermal, end up with more data. So the runout version of the pan is obsolete, and the new and improved pan is in. Another practical issue is that Phoenix has very little flash memory. The pan is the last thing saved, almost, so we cannot just take lots o' data and play it back at leisure.

Isn't it a waste to take multiple pans? Well, no. An "efficient" way to acquire a pan would be to spend the whole mission getting the best quality. That would mean on sol 45 *half* the site is unseen. Thus we plan not 2, but 3 pans. The sols 1-3 site pan, low res, for quick look. The full res color pan to sol 30(??). Then, maybe, if needed, a high res, low compression, many filter pan. But if that never happens, we're still good. (Actually we need to reacquire the low res site pan a couple times, just as pancam does, as part of an orbiter-coordinated experiment.)