Space probe enters orbit around Mercury

LAUREL, Md., March 18 (UPI) -- U.S. scientists said NASA's Messenger probe to Mercury has successfully entered orbit around the innermost planet in our solar system.

Scientists at the mission operations center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., said radio signals confirmed the end of a 15-minute thruster burn and insertion of the probe into orbit at 9:10 p.m. EDT Thursday, a NASA release said.

By 9:45 p.m. the spacecraft had rotated to face Earth and was sending back data, scientists said.

"Achieving Mercury orbit was by far the biggest milestone since Messenger was launched more than six and a half years ago," Project Manager Peter Bedini of APL said.

For the next several weeks, APL engineers will focus on making sure the probe's systems are all working well in Mercury's harsh high-temperature environment.

Beginning March 23, the instruments will be turned on and checked out. The primary science phase of the mission will begin April 4.

"For the first time in history, a scientific observatory is in orbit about our solar system's innermost planet," principal investigator Sean Solomon of the Carnegie Institution of Washington said. "Mercury's secrets, and the implications they hold for the formation and evolution of Earth-like planets, are about to be revealed."