NASA's MErcury Surface, Space ENvironment, Geochemistry, and Ranging (MESSENGER) spacecraft successfully achieved orbit around Mercury at approximately 9:00 p.m. EDT March 17. This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system's innermost planet.
"This mission will continue to revolutionize our understanding of Mercury during the coming year," said Charles Bolden from NASA, who was at MESSENGER mission control at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, as engineers received telemetry data confirming orbit insertion. "NASA science is rewriting textbooks. MESSENGER is a great example of how our scientists are innovating to push the envelope of human knowledge."
At 9:10 p.m. EDT, engineers from Operations Center received the anticipated radiometric signals confirming nominal burn shutdown and successful insertion of the MESSENGER probe into orbit around the planet Mercury. NASA's MESSENGER rotated back to Earth by 9:45 p.m. EDT and started transmitting data. Upon review of the data, the engineering and operations teams confirmed the burn executed nominally with all subsystems reporting a clean burn and no logged errors.
MESSENGER's main thruster fired for approximately 15 minutes at 8:45 p.m., slowing the spacecraft by 1,929 mph (3,104 km/h) and easing it into the planned orbit about Mercury. The rendezvous took place about 96 million miles (154 million km) from Earth.
"Achieving Mercury orbit was by far the biggest milestone since MESSENGER was launched more than 6 and a half years ago," said Peter Bedini from the Applied Physics Laboratory (APL). "This accomplishment is the fruit of a tremendous amount of labor on the part of the navigation, guidance-and-control, and mission operations teams, who shepherded the spacecraft through its 4.9-billion-mile (7.9 billion km) journey."
For the next several weeks, APL engineers will be focused on ensuring the spacecraft's systems are all working well in Mercury's harsh thermal environment. Starting March 23, the instruments will be turned on and checked out, and on April 4 the mission's primary science phase will begin.
"Despite its proximity to Earth, Mercury has for decades been comparatively unexplored," said Sean Solomon from the Carnegie Institution of Washington. "For the first time in history, a scientific observatory is in orbit about our solar system's innermost planet. Mercury's secrets, and the implications they hold for the formation and evolution of earthlike planets, are about to be revealed."
View the MESSENGER video