Pioneer 11

Pioneer 11 was a NASA space probe that flew past Jupiter in 1974 and Saturn in 1979, becoming the first spacecraft to encounter Saturn.

Gravity assist: A spacecraft maneuver that uses a planet’s motion and gravity to change the spacecraft’s speed or direction. Pioneer 11 used Jupiter’s gravity to redirect its path toward Saturn.
Jupiter: The largest planet in the Solar System, a gas giant with a system of moons and rings. Pioneer 11’s 1974 flyby used Jupiter as both a scientific target and a route to Saturn.
Pioneer program: A series of United States robotic space missions that explored the Moon, planets, and interplanetary space. Pioneer 11 belonged to the program’s first missions sent beyond the asteroid belt.
Voyager 1: A NASA spacecraft launched in 1977 that explored Jupiter and Saturn before continuing into interstellar space. Pioneer 11’s Saturn measurements helped inform Voyager’s later encounter planning.
Radioisotope thermoelectric generator: A power source that converts heat from radioactive decay into electricity. Radioisotope generators supplied electrical power far from the Sun.
Saturn: The sixth planet from the Sun, a gas giant distinguished by its extensive ring system. Pioneer 11 became the first spacecraft to pass Saturn, in September 1979.
Pioneer 10: A NASA spacecraft that made the first flyby of Jupiter in 1973 and continued outward through the Solar System. Its successful Jupiter encounter demonstrated the route and technology Pioneer 11 later used.
Voyager 2: A NASA spacecraft launched in 1977 that visited Jupiter, Saturn, Uranus, and Neptune. Pioneer 11 provided the first close reconnaissance of Saturn before Voyager 2 arrived.
Deep Space Network: NASA’s international system of antennas for communicating with spacecraft beyond Earth orbit. Its antennas tracked Pioneer 11 and received data across the outer Solar System.
Great Red Spot: A persistent, enormous anticyclonic storm in Jupiter’s atmosphere. Pioneer 11 observed Jupiter’s Great Red Spot during its close approach.

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HeliosphereRelated: Its distant solar-wind observations complemented those of Pioneer 10.