New Horizons at Io |
New Horizons at Io |
Feb 24 2007, 07:53 PM
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Senior Member Group: Moderator Posts: 3242 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Since the New Horizons Jupiter Encounter thread is already getting pretty long, I decided to create a thread dedicated to New Horizons' observations of the most interesting object in the solar system: Io. Info on upcoming observations comes from the jupiter_timeline_static.xls document john_s posted, and the preview images are from Celestia (note that each image is scaled so that the pixel scale is ~correct, and represents a smaller FOV than LORRI)
Today, February 24, New Horizons conducts three observations of Io with the LORRI camera as well some observations of Io's atmosphere with ALICE. These observations have the lowest phase angle for Io of the entire encounter. Phase angle continues to increase as NH approaches Jupiter and Io. The first observation, ISunMon1, shows Io's sub-Jovian hemisphere (Clat=5.5 S, Clon=340.2 W) from a distance of 7,856,307 km. The resolution with LORRI would be 38.8 km/pixel. Pele is on the limb at lower right and Masubi is on the limb at lower left. Ra Patera is near center. The second observation, ISunMon2, also shows Io's sub-Jovian hemisphere (Clat=5.5 S, Clon=15.1 W) from a distance of 7,575,510 km. The resolution with LORRI would be 37.5 km/pixel. The Tvashtar plume might be poking above the limb at upper left. The third observation, ISunMon3, shows Io's leading hemisphere (Clat=6.0 S, Clon=84.7 W) from a distance of 6,627,459 km. The resolution with LORRI would be 32.8 km/pixel. The Zamama plume might be visible just above center on the left limb. It only gets better from here. Not sure how NH downlink works, but there is a DSN window right after the last Io observation, hopefully at least one frame from each observation will be returned. Maybe they can do the Huffman window right around where Io is... Tomorrow contains four more observations of Io, highlighting Pele and an eclipse. -------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Feb 28 2007, 01:38 AM
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Member Group: Members Posts: 447 Joined: 1-July 05 From: New York City Member No.: 424 |
I'm surprised that the reference images of Io are still from Voyager rather than Galileo. I realize that Galileo returned only a heartbreakingly small fraction of the high-resolution images of which it was capable, but I would have thought that it repeatedly covered Io at better than Voyager resolution.
I found this helpful page by volcanopele, which maps high resolution imaging, but doesn't address low resolution coverage. TTT EDIT: I thought some more about volcanopele's comments and put on my thinking cap. Io is gravitationally locked with Jupiter, and managing radiation levels was a challenge, so I guess most Galileo observations of Io took place outside Io's orbit and thus didn't cover the Jupiter facing hemisphere. [google, google] I'm not finding a handy orbit by orbit summary of the Galileo mission, the sort of thing that Emily does for us now. Did Galileo every observe the pro-jovian hemisphere of Io? This post has been edited by Tom Tamlyn: Feb 28 2007, 03:35 AM |
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Feb 28 2007, 03:03 PM
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#3
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Member Group: Members Posts: 153 Joined: 14-August 06 Member No.: 1041 |
EDIT: I thought some more about volcanopele's comments and put on my thinking cap. Io is gravitationally locked with Jupiter, and managing radiation levels was a challenge, so I guess most Galileo observations of Io took place outside Io's orbit and thus didn't cover the Jupiter facing hemisphere. [google, google] I'm not finding a handy orbit by orbit summary of the Galileo mission, the sort of thing that Emily does for us now. Did Galileo every observe the pro-jovian hemisphere of Io? The Galileo news archive, including weakly status reports, is a pretty good source: http://galileo.jpl.nasa.gov/news/archive.c...=21&Incr=10 Galileo made several close passes of Io and had a real hard time: Every time the probe approached the moon it balked and dived into safe-mode...edit: well, not quite every time - there was at least one full science pass: http://galileo.jpl.nasa.gov/news/display.cfm?News_ID=1163 |
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