Ceres High Altitude Mapping Orbit (HAMO), Late summer through fall 2015 |
Ceres High Altitude Mapping Orbit (HAMO), Late summer through fall 2015 |
Aug 17 2015, 01:42 AM
Post
#1
|
|
Member Group: Members Posts: 541 Joined: 17-November 05 From: Oklahoma Member No.: 557 |
DAWN arrived in its new lower mapping orbit on August 13th. The DAWN team is preparing to resume science observation tomorrow on the 17th.
From the Current Mission Status page at the DAWN website: QUOTE August 13, 2015 - Dawn Arrives in Third Mapping Orbit
Dawn completed the maneuvering to reach its third mapping orbit and stopped ion-thrusting this afternoon. This was a little ahead of schedule because the spiral descent went so well that some of the allocated thrusting time was not needed. Since July 14, the spacecraft has reduced its orbital altitude from 2,700 miles (4,400 kilometers) to approximately 915 miles (1,470 kilometers). The orbit period has correspondingly decreased from 3.1 days to 19 hours. Dawn is scheduled to begin its new observations on the evening of Aug. 17 (PDT) and continue for more than two months. First, however, the mission control team will measure the actual orbit parameters accurately and transmit them to the spacecraft. |
|
|
Aug 27 2015, 10:03 AM
Post
#2
|
|
Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
QUOTE (hendric) Definitely a head scratcher! Yess!!! That is a good decriptor-- the closer we look, the odder it looks back at us. As I have noted with some of the Rosetta-features, it looks almost M.C. Escher-esque. My preliminary take on it is that it is a "mud volcano", a deposit driven by a hydrothermal vent composed of entrained detritus and residual salts. And much akin to the Occator Spot5, and the other large spots and the many many small spots scattered about. These spots will prove to be a major feature (and enigma) of Ceres. Note, for example, the "small' 2000-meter diameter light-toned spot about 13000 meters to the southwest (to the right on the image-view) of "Tall Mtn". It was barely noticeable on the Survey Orbit images but is somewhat prominent on the initial HAMO image and who knows about future views. --Bill -------------------- |
|
|
Aug 27 2015, 01:06 PM
Post
#3
|
|
Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
Yess!!! That is a good decriptor-- the closer we look, the odder it looks back at us. It still looks like a golf divot. "Dantu's divot. An antipodal shock feature." Ever seen an elliptical water-drop-basin? You let a drop of water fall at one focus, the ripples spread and reflect, the reflections converge, and a drop of water jumps up from the other focus. Mimas has a huge crater, and at the other side the crust is broken up by a series of cracks and chasms. If you think back to Vesta, there is some interesting topography antipodal to the Rheasilvia impact basin and a few peer reviewed papers. Image of Vesta below. Basically, at Vesta, the antipodal area is uplifted with a (probably) later crater at the focus and a "splat" area where craters are missing or disrupted. At Ceres, Lonely Mountain is just about antipodal to Dantu crater. The antipodal area has valleys/faults, a crater, and the Lonely Mountain. Situation is bizarre; looks as if a chunk of crust poped out, settled back to the surface, followed by weathering to create smooth talus slopes. |
|
|
Lo-Fi Version | Time is now: 15th June 2024 - 10:04 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |