Starship Asterisk*

http://www.planetary.org/news/2009/0923_MESSENGERs_Final_Flyby_of_Mercury_Old.html wrote:
Looking forward to MESSENGER's third flyby of Mercury
21:55 UTC on September 29
By Emily Lakdawalla Sep. 23, 2009 | 14:30 PDT | 21:30 UTC

<<Here's a map showing how MESSENGER will be filling in about 5% more of its imaging coverage during this flyby, leaving only the poles un-imaged.



As MESSENGER approaches for its third flyby of Mercury, it will capture images covering the last major swath of the planet not previously imaged by any mission. On its way out, its view will be very similar to the one it had during flyby 2. After the third flyby is completed, only the poles will remain unimaged by MESSENGER.>>

http://messenger.jhuapl.edu/target_observ.html wrote:
<<MESSENGER's third flyby of Mercury offers an exciting opportunity for a type of science observation not possible during the mission's two previous encounters with the Solar System's innermost planet: targeted observations. Because the majority of the surface that MESSENGER will view during Mercury flyby 3 has been seen during the previous flybys using the spacecraft's full suite of highly capable science instruments, the MESSENGER team was able to identify features on Mercury's surface of high interest and to plan to observe these areas in unprecedented detail during Mercury flyby 3. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) will gather high-quality spectral data by "staring" at the chosen surface targets for ~30 seconds per target. Simultaneously, the Mercury Dual Imaging System (MDIS) will obtain many sets of high-resolution color images of the targeted regions using all 11 of its color filters. Together, the data from these targeted observations will provide a wealth of new information and insights into the nature and history of Mercury's surface. Some details of these exciting targeted observations are given below.>>

A 	An unnamed crater with unusual bright material on its floor.

B 	An unnamed crater with a set of young ejecta rays that are light blue in the enhanced-color view.

C (1 & 2) 	Crater Lermontov. The bright yellowish color in the enhanced-color image and the irregularly shaped depressions on its floor may be evidence of past explosive volcanic activity.

D 	North of crater Homer. An area with an interesting mix of both light blue ejecta and bright orange materials.

E 	Near crater Titian. Enhanced-color images show a region of comparatively deep blue material that is dark and of a different composition than the majority of Mercury's surface.

F (1 & 2) 	Common plains material. This target resembles a type of material that covers much of Mercury.

G 	An unnamed crater with an intriguing bright yellow-orange color in enhanced-color views.

H 	Ray material from a spectacular rayed crater in Mercury's north. The ray material appears bright blue in enhanced color.

I 	Crater Hemingway. Enhanced-color images show the crater has an orange interior and a highly contrasting dark blue central peak. The crater will be viewed by MASCS very obliquely.>>

http://www.planetary.org/blog/article/00002135/ wrote:
Map of Mercury after MESSENGER's third flyby


Following MESSENGER's final Mercury flyby before entering orbit, the map coverage of Mercury is nearly complete. Mariner 10 mapped about 45% of the planet (green outline). MESSENGER covered another 20% on its first flyby (blue outline). The second flyby nailed 25% more (red outline). The most recent flyby filled in another 5%, including the the last missing piece of the equator and mid-latitudes. Now only 5% of the planet remains unmapped, most of it poleward of 60° north and south latitude. Credit: NASA / JHUAPL / CIW

http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=331 wrote:
<< Yesterday, as the spacecraft approached Mercury for the mission's third flyby of the Solar System’s innermost planet, MESSENGER captured this striking view. This WAC image shows portions of Mercury's surface that had remained unseen by spacecraft even after the three flybys by Mariner 10 in 1974-75 and MESSENGER's two earlier flybys in 2008. In this image, just returned to Earth early this morning, the newly imaged terrain is located in a wide vertical strip near the limb of the planet (on the left side of Mercury’s partially sunlit disk). Viewing the image coverage map from before the flyby provides more information on the location of the newly seen area. This WAC image is just one of 11 taken through the camera's narrow-band color filters, and this set of images will be used to examine color differences on Mercury's surface and to learn about the evolution of crustal rocks on the planet.>>

http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=332 wrote:

<<This unnamed impact basin was seen for the first time yesterday during MESSENGER’s third flyby of Mercury. The outer diameter of the basin is approximately 260 kilometers (160 miles). This basin has a double-ring structure common to basins with diameters larger than 200 kilometers (about 125 miles). The floor of the basin consists of smooth plains material. Concentric troughs, formed by surface extension, are visible on the basin floor, similar to those seen in Raditladi basin. Such troughs are rare on Mercury, and the discovery of such features in this newly imaged basin is of great interest to members of the MESSENGER Science Team. Crater chains produced during ejecta emplacement also can be seen emanating from the basin.>>