This is just a brief post from Houston to say I'm here and covering what I can from the first day of the Lunar and Planetary Science Conference. I've already taken lots of notes on the morning's session on MESSENGER at Mercury. (Here's a program and abstracts for that session in PDF format, about 6 MB.) There's nothing Earth-shattering (Mercury-shattering?) to report from the presentations given so far, but they are beginning to dig in to the details of trying to figure out the history of Mercury's geology from the wonderful new MESSENGER data set. Some of the best news of the morning was in Maria Zuber's talk on the Mercury laser altimeter. That instrument builds up topographic information on Mercury by firing a laser at the surface several times a second and watching for the return flash. They only had one profile on Mercury from the flyby, but during that profile they were able to detect return flashes from angles of up to 70 degrees off of nadir. Let me explain what that means.
Selene at the Moon (LPSC)
It’s a day of missions. I just left the MESSENGER session to sit in on part of the SELENE mission session. This new craft on the block is a Japanese produced and is returned hi resolution images and movies back to Earth as it systematically acquires topographic maps of Earth’s moon. SELENE, which is also called KAGUYA is actually three space craft: a main orbiter, a Relay Satellite, and the VRAD Satellite.
The SELENE image gallery can be found here. One of the more visually interesting things they are doing is taking images with a Hi-Def Video camera. (image credit: 2007 JAXA/SELENE, click image above for hi res image)
In addition to the scientifically not so useful (but public attracting) hi-def camera there are roughly a data taking dozen instruments ranging from a Laser Ranging system (that is conceptually similar to the Mars and Mercury Laser ranging instruments), a stereographic imaging system that has produced 3-D movies (see image 3/3 on the TC tab of the gallery), a radar sounder, and much much more (see wiki page)
So far 4.8 million shots have been fired with their Laser, with cross path resolution of 15 km as of Feb. 29. This is very preliminary results. The laser’s first shot was fired Nov. 25, 2007 and everything is still being calibrated. While the MESSENGER Mercury data is even younger, they had a chance to calibrate when they went past Venus.
With the Lunar Radar System (LRS) they are mapping subsurface boundaries. They are finding subsurface layers that weren’t detected by Apollo 17’s ALSE radar that worked at the same wavelength. The newly detected layers are “nearly a factor of 2 shallower.” This raises the question of “Um, Why?” Well, in the Q&A the answer appears to be, we don’t know, but it’s probably a mistake in someone’s analysis. The SELENE LRS data is much higher resolution and much higher quality, and the suspicion is the factor of two comes out of mis-interpretation of the Apollo data (an example of a factor of two occuring somewhere else was mentioned). Again - all preliminary, and all very tantalizing.
From the gravity experiment (RSAT), the are filling in holes in previous data sets and they are mapping out the internal mass distribution of the Moon.