Looking Ahead: MESSENGER is in good health and operating normally. Last week mission operators at the Johns Hopkins University Applied Physics Laboratory transmitted commands to MESSENGER's computers that will trigger all sequenced operations for the next two weeks, including additional calibration and checkout of the Mercury Dual Imaging System (MDIS) instrument.
Beyond that, the spacecraft and science teams are looking toward several key events in 2005:
- Long Distance: MESSENGER will be 30.74 million miles (49.47 million kilometers) from Earth on February 5 - its farthest point from home before heading back toward Earth for the August gravity-assist flyby.
- Busy Spring: On March 30, mission operators will "flip" the spacecraft, pointing its sunshade toward the Sun for the first time. Within an hour of the flip, they'll deploy the boom for MESSENGER's Magnetometer instrument. In May MESSENGER will make a small adjustment in its flight path with a trajectory correction maneuver, its fourth since launch and the first of three on the 2005 calendar.
- Earth Swingby: MESSENGER makes its first major shift on the path to Mercury on August 2 - using the tug of Earth's gravity to redirect itself toward the inner solar system. Closest approach will bring it 1,339 miles (2,155 kilometers) over northern Asia.
- Deep Space Maneuvering: MESSENGER conducts its first deep space maneuver (DSM-1) on December 13, firing its large bipropellant thruster for the first time. DSM-1 is the first of five such maneuvers planned for MESSENGER's cruise, designed (with the planetary flybys) to help the spacecraft reach Mercury orbit. DSM-1 will reduce MESSENGER's speed relative to the Sun and set the arrival time for the first Venus flyby in October 2006.
Stat Corner: MESSENGER is about 95.2 million miles (153.3 million kilometers) from the Sun and 29.8 million miles (47.9 million kilometers) from Earth. At that distance, a signal from Earth reaches the spacecraft in 2 minutes, 40 seconds. The spacecraft is moving around the Sun at 64,971 miles (104, 561 kilometers) per hour. MESSENGER's onboard computers have executed 22,820 commands from mission operators since launch.