Pioneers 10 and 11
Classification: Flyby spacecraft.
Mission: Jupiter, Saturn, and interstellar space.
Features: Pioneer 10 and 11 launched in 1972 and 1973, and penetrated the asteroid belt. Pioneer 10 was the first spacecraft to study Jupiter and its environment, and obtain spin-scan images of the planet. Pioneer 11 also encountered Jupiter, and went on to become the first to encounter Saturn, its rings and moons. Pioneers 10 and 11 are still operative in the far reaches of the outer solar system, and are still being tracked in November 1995. Pioneer 11's science operations and daily telemetry ceased on September 30, 1995 when the RTG power level was insufficient to operate any experiments. It is likely that Pioneer 10 will follow suit around the time of this publication in November 2000, as recent attempts to track it have been largely unsuccessful.
Stabilization: Spin stabilized.