The National Aeronautics and Space Administration yesterday rejected the recommendations of its scientists and decided to fly the Pioneer 11 spacecraft outside the rings of Saturns instead of between the two large rings.
The decision means that Pioneer 11 will pass Saturn in 1979 at a distance of about 18,000 miles frofm the edge of its outermost ring, then swing in under the rings to a distance of 15,000 miles from the planet. Scientists had recommended that Pioneer 11 be targeted to a gap about 6,000 miles wide between the outer and inner rings.
The decision to fly outside the rigns was made by Dr. Noel W. Hinners. NASA's associate administrator for space science, and A. Thomas Young, Young, director of planetary programs.
Young said the decision to fly away from the rings is based on a desire to use Pioneer as a "pathfinder" for two Voyager spacecraft headed for encounters with Saturn in 1980 and 1981. Young said NASA wants to find out if Pioneer can safely navigate past the planet so that the agency could target Voyager 2 to Uranus after it flies by Saturn in 1981.
"A successful Pioneer will greatly increase our willingness to commit Voyager 2 to Uranus." Young said."The survival or nonsurvival of Pioneer on the outside trajectory cand have an important influence on achieving the maximum science return from all three spacecraft."
When asked their wishes on the voyage past Saturn, the 11 scientists whose instruments are aboard Pioneer 11 voted twice in favor of flying the spacecraft inside the rings.
"The team felt that going inside the rings is important because it's a region that will not be explored by the two Voyager spacecraft," said one scientist, who asked not to be identified. "If you fly inside and do not survive the flight through the rings, you at least get some data about the rings. If you fly outside and hit something you don't know is there, you have a chance of getting no data at all."
The target zone for ioneer 11 out side Saturn's rings is identical to the flight path that will be taken by Voyage 2 when it flies by Saturn in 1981, voyager 2 will continue to the planet Uranus, which will not be visited in the foreseeable future by any other spacecraft.