Aug 25 1981
From The Space Library
August 25-31: Press coverage of the Voyager 2 encounter with Saturn came from JPL, Pasadena, Calif. New NASA Administrator James M. Beggs told reporters that the mission was "one of the really great scientific achievements of our age." Under questioning, Beggs said that he could not promise any new planetary missions in the near future. The New York Times said that the encounter meant "farewell to American planetary exploration for at least five years," alluding to the expected encounter with Uranus in January 1986.
The 1,800-pound Voyager 2, having arrived within Saturn's magnetic field early August 25 after a four-year 1.2 billion-mile journey, was sending back data and pictures "as perplexing as they are dazzling," the New York Times said. The craft photographed four of Saturn's moons in greater detail than before, sent data on the thousands of strands in Saturn's rings, and dived behind the planet for a close approach and a gravity-assisted push toward arrival at Uranus in 4'/2 years. So far, it had found no new moons of Saturn, which had been one of its aims.
When Voyager 2 reappeared, JPL engineers reported that its camera platform was stuck, affecting three scientific sensors as well as the two television cameras. Chief project scientist Dr. Edward C. Stone said Voyager 2 "basically completed" all of its observations before the malfunction: "We were fortunate that the troubles didn't happen a few hours earlier," he told a news conference.
Signals needed 1 hour and 27 minutes to travel to Earth. Controllers picked up the signals again at 3 a.m. EDT after Voyager had been out of touch with Earth for 2 hours and 20 minutes; the cameras were showing black space, indicating that the platform was pointing away from Saturn. The platform could be rotated in two dimensions, and controllers countermanded the original program so that the swivel could operate in high torque and expel or destroy whatever foreign object was making the platform stick. A similar problem with Voyager 1 in 1978 was solved by manipulation of the swivel, after records showed a tiny piece of plastic had been left in a gearbox during construction.
Further reports Thursday, August 27, said that the platform (which had been jammed for 17 hours) was working again but not perfectly. Project Director Esker K. Davis said that it was moving sluggishly in low gear; the plan was to keep moving it, but it took three hours just to send a command and get back a signal that the spacecraft responded. Stone said that his main objective was to recover use of the platform for the voyage to Uranus. Project scientists had turned the cameras off when the platform stuck and would not turn them on again until the problem was solved.
Loss of about 600 pictures of Saturn's rings and darkside, as well as infrared and ultraviolet measurements of clouds and atmosphere, did not mean that the mission had failed, Stone said, calling it "a 200 percent success." Thousands of photos stored on Voyager's tape recorders were still pouring back to Earth, showing sights never seen before. Dr. Arthur L. Lane's telescope aimed at a distant star to catch it blinking on and off as Voyager 2 passed through Saturn's rings was so successful that he said it would take years to map the rings, 45,000 miles of which were shown by his telescope.
Early on Friday, August 28, flight directors restarted one of the five blacked-out cameras to photograph "a rapidly receding Saturn" from Voyager 2's location already 2 million miles beyond the planet. The platform had responsed by rotating 40° on command in exactly the proper time. NASA would photograph Saturn's outermost moon Phoebe next week when Voyager crossed its orbit: Phoebe, rotating in a direction opposite to that of the other 16 moons, might be a burned-out comet nucleus captured by Saturn.(NASA MOR S-802-77-01/02, July 16/81. WSJ, Aug 24/81, 15; NY Times, Aug 14/81, A-13; Aug 26/81, A-1; Aug 27/81, A-1; Aug 28/81, B-5; Aug 29/81, A-9; Aug 30/81, F-1; Aug 31/81, B-6; W Post, Aug 25/81, A-2; Aug 26/81, A-3; Aug 27/81, A-1; Aug 28/81, A-1, Aug 29/81, A-3; Aug 30/81, A-5; Aug 31/81, A-5; Science, Sept 11/81, 1236; Dscvr, Sept 81; 79)
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