The Mercury-bound MESSENGER spacecraft completed its fifth and final deep-space maneuver of the mission today, providing the expected velocity change needed to place the spacecraft on course to enter into orbit about Mercury in March 2011.

A 3.3-minute firing of its bi-propellant engine provided nearly all of the probe's 177 meter per second (396 mile per hour) increase in its speed relative to the Sun.

MESSENGER was 230.4 million kilometers (143.2 million miles) from Earth when today's maneuver began at 4:45 p.m. EST. Mission controllers at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., verified the start of the maneuver about 12 minutes, 49 seconds later, when the first signals indicating spacecraft thruster activity reached NASA's Deep Space Network tracking station outside Goldstone, Calif.

"The team was well-prepared for the maneuver," said MESSENGER Mission Systems Engineer Eric Finnegan, of APL.

"Initial data analysis indicates an extremely accurate maneuver execution. After sifting through all the post-burn data I expect we will find ourselves right on target."