Messenger Lines Up For Its Second Venus Flyby

MESSENGER’s Trajectory Correction Maneuver 13 (TCM-13), its first since its maiden pass at Venus in October, was successfully executed last Saturday and will help keep the spacecraft on track for its second flyby of Venus on June 5, 2007. This maneuver changed MESSENGER’s velocity by 25.6 meters per second (84.1 feet per second) in a direction oriented 41.7B0 from the spacecraft-to-Sun direction.

For the first time, the burn was conducted in three parts – called “components” – to protect sensitive portions of the spacecraft from overheating by direct exposure to sunlight. Three rather than two components were required in order to maintain sufficient fuel reserves in the smallest fuel tank.

MESSENGER is now about 81.8 million miles from the Sun, but during all three components of TCM-13 the sunshade protected heat-sensitive parts of the spacecraft from direct sunlight. Mission controllers at The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., monitored the maneuver, communicating with MESSENGER through NASA’s Deep Space Network tracking station outside Goldstone, Calif. The separate components of the maneuver, lasting about 1,670 seconds, 97 seconds, and 1,640 seconds, began at 4 p.m., 5 p.m., and 10 p.m. EST, respectively.

With TCM-13 complete, the team now turns its attention to preparing for scientific observations of Venus during the June 2007 flyby. Over the coming months, the team will have at least three more opportunities to tweak MESSENGER’s route before the Venus encounter.