This week MESSENGER will become the first spacecraft to orbit Mercury, the closest planet to the our sun. Messenger stands for MErcury Surface, Space ENironment, GEochemistry and Ranging.
This Thursday at 20:45 (8:45pm) EDT, MESSENGER will execute a 15-minute maneuver that will put it into Mercury’s orbit. This orbit will be a year-long science campaign to understand the planet. In the years time that it will spend orbiting around Mercury, it will fly around it 730 times.
The MESSENGER mission is an effort to study the geologic history, magnetic field surface composition and other mysteries of the planet. This mission is led by NASA, the Applied Physics Laboratory at Johns Hopkins University and the Carnegie Institution. With more and more rocky planets being discovered in other solar systems there are hopes to broaden our understanding of rocky planets. Mercury is only slightly larger than our Moon and it’s core should have solidified. However, the presence of a magnetic field suggests the planet’s insides are partially molten.
During MESSENGER’s journey toward Mercury it had passed the planet several times, filling in the imaging gaps left by Mariner 10, which performed three fly-by maneuvers between 1974 and 1975. With Mariner 10’s images and MESSENGER’s images it has images the entire planet with an exception of about 5 percent. Previously Mariner 10 had only taken images of one side of Mercury leaving the other side a mystery. Once MESSENGER is in place it will focus it’s cameras on getting the best possible images of the remaining portions which is mostly in the polar regions.
The Applied Physics Laboratory at Johns Hopkins will be airing a live webcast (also follow the link for the MESSENGER mission website) about the orbit insertion maneuver starting at 19:55 (7:55pm) EDT on Thursday, March 17.