In May, NASA is scheduled to launch a probe to study Mercury. The spacecraft’s name, MESSENGER, is short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging. (Note: Mercury was a messenger of the Roman gods.) MESSENGER will make five planetary flybys, three at Venus and two at Mercury to slow it down enough to get it into orbit around Mercury. It will take five years to slow it down enough for a safe survey orbit. The survey mission will take one Earth year, or four Mercurian years.

MESSENGER will measure the geochemistry of surface rocks from orbit to help learn about the origin of Mercury. It will measure the magnetic field to better understand Earth’s magnetic field. From it’s polar orbit, MESSENGER will “sniff” the ever-shadowed polar craters for hydrogen leakage that would suggest water. A lack of hydrogen could indicate the radar-reflecting deposits are made up of sulfur. MESSENGER will be protected from solar heating by a ceramic cloth sunshade. It will need ten times more protection while at Mercury than at Earth. Flight controllers will have strict rules never to turn the craft’s solar panels directly at the sun.

Most interplanetary missions have been controlled from NASA’s Jet Propulsion Laboratory in California, but MESSENGER will be controlled from John Hopkins University’s Applied Physics Lab in Maryland. The same team that conducted the very successful NEAR mission to the asteroid Eros will be in charge of the mission to Mercury.

MESSENGER’s results will help the European Space Agency (ESA) plan their mission to Mercury. In about ten years, ESA plans to launch BepiColombo to orbit Mercury. MESSENGER will have completed its entire mission by then.