Planning for the Flip
Preparations and testing continue for the scheduled March 8 spacecraft "flip," which will point MESSENGER's sunshade toward the Sun. The spacecraft and mission operations teams held a final review at the Johns Hopkins Applied Physics Laboratory on Feb. 25 to go over plans for the operation, which included both nominal and contingency scenarios. Shortly after the flip, MESSENGER will deploy the boom for the Magnetometer instrument.
Using the large 70-meter antenna at NASA's Deep Space Network station near Madrid, Spain, the team checked out MESSENGER's front fanbeam and phased array antennas on Feb. 28. This, the first in-flight test of the medium- and high-gain antennas on MESSENGER's sunshade side, confirmed the systems were working normally. MESSENGER is currently using the antennas on its back side to communicate with operators on Earth.
On Feb. 15, after six months and 12 days in space, MESSENGER reached the 300-million-mile mark (about 483 million kilometers) in its travels around the Sun. Only 4.6 billion miles - roughly 7.4 billion kilometers - to go before reaching orbit around Mercury!
MESSENGER is about 89.3 million miles (143.7 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 69,266 miles (111,473 kilometers) per hour. MESSENGER's onboard computers have executed 27,151 commands from mission operators since launch.