It seems like we’ve been preparing for the Phoenix mission for such a long time – and now it’s finally close to landing day! T-6 days according to our countdown clock! Things are getting pretty crazy here, and I thought a little overview of how the HiRISE team is supporting the Phoenix mission would be useful.

We’ve been imaging the northern plains for Phoenix since we started our mission (here’s a bunch of reconnaissance images on our website). The first images we got back showed lots of scary boulders (a close-up of one of our Transition images shown to the right), so we sampled other areas and searched for a relatively boulder-free landing spot. The area the Phoenix team finally chose is being called the “Green Valley“, not because of the “green light = safe to go” connotation, but rather because some geological maps made of the area happened to use green as the color for the valley. Perhaps coincidentally, Green Valley is also a town near Tucson, where both Phoenix and HiRISE are based. Whatever the reason, I like that the name has a lovely calm, comforting feel.

Once the Phoenix team picked out their landing site, we worked on a high-resolution mosaic of the entire 3-sigma landing ellipse (”3-sigma” means there is a 99% probability it will land within this area; see this great blog entry on landing ellipses at the Planetary Society). The Phoenix landing ellipse is shown to the left, along with the footprints of a number of HiRISE images. (This was before we were quite done with the mosaic.) These images have helped the Phoenix team characterize the regional geology and assess the safety of the landing site.

In addition to scouting landing sites, we’re also going to be involved with Phoenix during its prime mission on the ground. We’ve been planning and practicing several different ways of cooperating: (more…)

To conclude our exploration of the pipelines that take raw channel files and create a beautiful, unmapped mosaic, let me introduce the Stitch pipelines: HiStitch and HiccdStitch.

The HiStitch pipeline combines the matching HiCal products for the same CCD into one more-or-less lined up CCD cube file. HiccdStitch combines these HiStitch cubes into RED, IR, and BG mosaics.

Both pipelines take some time, as overlapping pixels are accounted for and brought together. After these mosaics are created, additional steps create smaller jpeg files for easier viewing, and full-sized jpeg2000 files. We use these jpeg2000 files for validating our images.

There are later pipelines, but we first validate the HiccdStitch products: Did the previous pipelines work correctly? Did the uplink team command the camera correctly? Is there haze or clouds obscuring our view of the surface?

If everything looks good, and we have received the correct reconstructed SPICE ephemeris data, then the geometry pipelines are invoked. These pipelines project the images mathematically to a model of Mars and add geometry data to the images so that each pixel becomes a point on Mars with latitude and longitude coordinates.

Some of you out there may be asking: what happens to a HiRISE image between the time that it is taken and the time that it is released to the public? Well, I’d like to give a summary here.

(more…)