The $426 million Messenger mission is set to begin on Aug. 2 with liftoff atop a Delta 2 rocket from the Cape Canaveral Air Force Station in Florida. If there are delays, the launch window reopens each night until Aug. 14.If all goes well, the 1.2-ton craft will make 15 loops around the sun. It will swing by Earth again in August 2005, past Venus twice (October 2006 and June 2007) and by Mercury three times in 2008 and 2009. In March 2011, after a circuitous journey of 4.9 billion miles, it will slip into a nearly polar orbit of Mercury, swooping as low as 125 miles from the surface.
Messenger an unmanned, desk-sized spacecraft was designed and built at the Johns Hopkins University’s Applied Physics Laboratory near Laurel. Its scientific instruments were built at NASA’s Goddard Space Flight Center in Greenbelt, the University of Colorado and the University of Michigan. Messenger’s 7 1/2 -year mission: to go where only NASA’s Mariner 10 has gone before.Messenger will help understand the forces that have shaped the least-explored and innermost of the terrestrial planets.