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Diane Farrar, Jan. 28, 1997
NASA Ames Research Center, Mountain View, CA
Phone: 415/604-3934

NASA News Release: 97-05


Twenty five year old Pioneer 10, the first spacecraft to leave the solar system and Earth's farthest probe in deep space, successfully executed a targeting maneuver more than 6 billion miles from the Earth.

The maneuver was necessary to point the Pioneer 10 antenna back to Earth after its natural drift away leading to a decrease in signal strength. The signal after the maneuver was increased to its normal strength after the maneuver was completed.

To attain enough power to perform the procedure, the spacecraft transmitter had to be turned off, and the hearty spacecraft executed the procedure in the blind for 90 minutes, said Dr. Larry Lasher, Pioneer Project Manager at NASA Ames Research Center.

"This is almost miraculous---the first time in the Pioneer 10's history that a maneuver had been performed with the transmitter off. We were concerned that turning the transmitter's traveling wave tube off in the deep cold of space for 90 minutes and then back on again would cause a thermal shock that might shatter the helix in the tube," Lasher said.

The spacecraft, 6.6 billion miles from the Earth, has a round-trip light time of 18 hours 20 minutes. The command-off signal to the spacecraft transmitter was sent at 3:00 am PST, Jan. 26; the command-on signal at 4:30 am PST. Confirmation of the transmitter's turn-off was received at 9:20 pm Jan. 26 Notice of the transmitter's restoration and the maneuver's success was received in the jubilant Pioneer Control Room at 10:50 pm that evening, Lasher said.

Pioneer 10, launched in 1972, made the first successful passage through the asteroid belt and captured Earth's first close up images of the giant planet Jupiter. Pioneer 10 is managed by the Space Projects Division at NASA Ames Research Center in Mountain View, CA.