Messenger Arrives

Messenger has been inserted intoorbit around Mercury and will be now adjusting its orbit from stronglyelliptical down to near circular.

We will be soon getting plenty ofclose images from the place.  This isalways neat to see.  I recall the firstorbit of the moon that gave us a rear view for the first time.

Anyway, we are there.

MESSENGER becomes first spacecraft to orbit Mercury

By NoelMcKeegan

00:52 March 18, 2011

http://www.gizmag.com/messenger-spacecraft-orbit-mercury/18170/

NASA has reported that its MESSENGER spacecraft is now in orbit aroundthe planet Mercury – the first ever mission to achieve this feat. More than 40years on from the first moon landing in the age of the Mars rovers and space tourism,it's easy to overlook just what a remarkable a feat this is. These amazingfacts might just jolt our sense of wonder – before reaching orbit on Thursdayat approximately 9 pm EDT, MESSENGER traveled for six and a half years andcovered 4.9-billion-miles in which it went through three flybys of Mercury, oneof Earth and two of Venus. After firing its main thruster for 15 minutes thespacecraft slowed by 1,929 mph (leaving around 10 percent of fuel in the tankfor orbit correction maneuvers) and it is now in a 12 hour elliptical orbitaround the innermost planet some 96.35 million miles from Earth.

MESSENGER (short for the slightly less palatable MErcury Surface, SpaceENvironment, Geochemistry, and Ranging) is the first mission to return datafrom Mercury since Mariner 10 photographed around 45 percent of the planet's surfacein 1974-75. It will stay in orbit for a year and map around 90 percent of theplanet in color.

The spacecraft is carrying high-res imaging equipment and an array ofspectrometers which are amazingly kept at room temperature by its heat shieldsdespite the proximity of the Sun. On March 23 these instruments will beswitched on and tested before the primary science phase – which will delivernew insights into the make-up of the little understood planet – begins on April4. A full run down on the MESSENGER's payload can be found here.

"Despite its proximity to Earth, the planet Mercury has fordecades been comparatively unexplored," said Sean Solomon, MESSENGERprincipal investigator of the Carnegie Institution of Washington. "For the first time inhistory, a scientific observatory is in orbit about our solar system'sinnermost planet. Mercury's secrets, and the implications they hold for theformation and evolution of Earth-like planets, are about to be revealed."