Zipping through space 2.67 billion miles from Earth, the Voyager 2 spacecraft changed course in a maneuver that targeted it for its Aug. 24 picture-taking encounter with Neptune.
Thursday's trajectory change took place 183 million miles from Neptune as the hardy space probe cruised at a speed of 42,279 mph, said Mary Beth Murrill, spokeswoman for NASA's Jet Propulsion Laboratory.Radio commands sent by mission controllers traveled at the speed of light - nearly 670 million mph - but still took four hours to reach the distant Voyager 2, which started its journey in 1977 and explored Jupiter in 1979, Saturn in 1981 and Uranus in 1986.
The commands made Voyager 2 fire some of its thrusters and adjust onboard gyroscopes to execute the course correction, Murrill said. She added that it is one of the last maneuvers needed to propel the probe toward the solar system's eighth planet.
"This puts the spacecraft on target for Neptune," she said at the laboratory, which operates America's unmanned space exploration program for the National Aeronautics and Space Administration.
Voyager 2 is scheduled to take numerous television pictures as it swoops within 3,013 miles of Neptune's cloud tops Aug. 24.
The spacecraft is controlled with radio commands sent through NASA's Deep Space Network, which includes large antennas in Goldstone, Calif., Spain and Australia.