The Voyager Mission
Only once every 175 years are the outer planets aligned in their orbits so that we can take advantage of gravity-assist trajectories to achieve encounters with Jupiter, Saturn, Uranus, and Neptune on one mission. The gravity-assist technique uses one planet’s gravity field and motion through space to alter the spacecraft’s flight path and propel it outward toward the next planet. Voyager 1’s trajectory, which was selected to best view Titan, has now propelled the spacecraft out of the ecliptic plane, while Voyager 2’s path will remain in this plane to provide future encounters with Uranus and possibly with Neptune.
MISSION OBJECTIVES
The Voyager Project was approved in June 1972 and had as its mission objectives:
★ Exploration of the Jupiter and Saturn planetary systems, including their atmospheres, rings, satellites, and magnetospheres ★ Comparative analyses of the two systems ★ Investigation of the interplanetary medium between Earth and Saturn
A fourth objective, added in 1976, was to preserve the possibility of extending the mission to include an investigation of the planet Uranus and the interstellar medium.
With the completion of Voyager 1’s Saturn flyby, it is now clear that these objectives will be achieved.
SPACECRAFT CHARACTERISTICS
Two identical spacecraft were developed for the 1977 launch opportunity. These marvelous machines were cleverly designed to survive the rigors of long voyages in outer space and to deliver high-quality scientific information required for detailed understanding of planetary systems. The spacecraft are both complex—automatically responding to their Earth-bound monitors that remotely control them via radio commands—and highly autonomous—capable of caring for themselves in many areas through a system of sensors, computers, and spare equipment. Each spacecraft functions on about 400 watts of electrical power which is provided by nuclear generators. Broadcasts of data across a billion miles to Earth are accomplished with a spacecraft transmitter power of only about 25 watts, the amount of energy required by a small household light bulb.
Voyager’s scientific payload was carefully chosen to observe Saturn over a wide range of wave-lengths and to measure magnetic fields, charged particles, and plasma waves.