On March 28, the MESSENGER spacecraft completed 40% of its 6.6 year cruise phase as measured by time traveled—and one-third of its flight distance to Mercury. DTM director Sean Solomon serves as Principal Investigator of the mission. The cruise phase has been used to commission the spacecraft systems and instruments, and to fine-tune the mission operations procedures of the team at the Johns Hopkins University Applied Physics Laboratory, ensuring that the spacecraft and its instruments will perform flawlessly at Mercury. The average speed of the spacecraft has continued to increase during the cruise phase and will reach a spacecraft record of close to 63 km per second (141,000 miles per hour) in mid-October 2008.

MESSENGER launched on August 3, 2004 and performed a flyby of Earth and a large propulsive maneuver in December 2005, setting it on track for its first Venus flyby in October 2006. MESSENGER will fly by Venus again on June 5, 2007, completing final rehearsals for three Mercury flybys. Those flybys, assisted by four deep space maneuvers, will slow the spacecraft sufficiently to enter into orbit about Mercury on March 18, 2011.

For more information, see an in-depth article at SpaceRef.com or the MESSENGER Web site. Images and a movie of MESSENGER’s Earth flyby are available on the Space Exploration Resources Page of the Arizona State University Web site.