August 24, 2004
MESSENGER completed its first planned maneuver today at 5:03:35 p.m., EDT, when the thrusters ignited to correct trajectory inaccuracies associated with launch. The spacecraft's four medium (5-pound) hydrazine-propellant thrusters did the brunt of the work with only minor tweaks needed from eight of the 12 small (1-pound) thrusters. It took only 26 seconds for a tracking station in Madrid, Spain, to pick up signals indicating the maneuver had begun.
"It was a beautiful maneuver with all maneuver commands executing as they were supposed to," says Mission Operations Manager Mark Holdridge. The 3.6-minute thruster burn cut the spacecraft's velocity by 40 mph (18 meters per second) relative to the sun and slowed the spacecraft to a mere 63,990 mph. MESSENGER is now 4.8 million miles from Earth.
On Aug.27, testing of instruments and subsystems will resume, with the back-up processor (DPU-B) being used to turn on the instruments as a test of its viability. Two more small maneuvers later this year (Sept. 24 and Nov. 19) are needed to precisely target the spacecraft for its August 2005 Earth swingby.