Pioneer 11 was an American Pioneer Program deep space probe that was in service with NASA in the late 20th century. The probe surveyed the planets Jupiter and Saturn.
The probe was launched from Earth in 1973 one year after its immediate predecessor Pioneer 10 was launched. Six years later, in 1979, it became the first Human spacecraft to visit Saturn. During its survey of the giant planet, the probe discovered that Saturn had a magnetic field and a magnetosphere. These discoveries, with the knowledge gained from surveying the magnetic field and magnetosphere of Jupiter, presented Earth scientists with a better understanding of these giant planets.
Information on this probe was included in the Context Indices when Data was reviewing the file on the non-verbal language (gestural) M-9. (TNG: "Loud As A Whisper")