Space probes have provided astronomers with data on the composition of Saturn’s rings.
As of 2011, four separate unmanned spacecrafts have been sent to Saturn. Saturn is a ringed, gaseous planet that lies approximately 930 million miles from the sun. When at its closest, Saturn is 743 million miles from the Earth, although the distance varies widely with the orbits of each planet. Saturn is known for its rings, which are composed of dust and rocky debris. In addition to investigating Saturn, the four space missions have also provided considerable information on many of Saturn’s 62 moons.
Pioneer 11 was launched by NASA in 1973 from Cape Canaveral, Florida. It was the first spacecraft to travel to Saturn, also visiting Jupiter and the outer reaches of the solar system. The small probe, which weighs 569 pounds, was particularly focused on reporting data regarding magnetic fields, atmospheres, and the moons surrounding Saturn and Jupiter. Pioneer 11 reached Saturn in September of 1979. Among its findings was a report that Saturn is composed mostly of liquid hydrogen, at an average temperature of -180 degrees Celsius. The last communication from the probe arrived in 1995, as its power source ran out.
Voyager 1 was launched by NASA in September, 1977. The 1,592-pound space probe has a mission of studying the outer solar system and interstellar space, also visiting Jupiter and Saturn. Still in operation, Voyager 1 is currently the furthest manmade object from the Earth. The probe flew past Saturn in November, 1980, providing photographic images and data regarding the planet’s atmosphere. Voyager 1 found five new moons around Saturn, made a close flyby of the moon Titan, and provided photos and data regarding the rings of Saturn.
Voyager 2, sister probe to Voyager 1, was launched by NASA in August, 1977. NASA decided to send two separate probes due to the unique alignment of planets in the outer solar system during the late 1970s and early 1980s. The two spacecrafts, which are very similar physically, were sent on different trajectories, with Voyager 2 visiting Neptune and Uranus, in addition to Jupiter and Saturn. Voyager 2 reached Saturn in August, 1981, providing data on the planet’s upper atmosphere, along with photos. The probe continues to operate, studying the outer reaches of the solar system and beyond.
The Cassini orbiter and Huygens space probe were launched by NASA and the European Space Agency in October, 1997, and have been orbiting Saturn since 2004. In December, 2004, the Huygens probe separated from Cassini to make a landing on Titan. The ongoing space mission has provided considerable information about Saturn, its moons and its rings, including data regarding atmosphere, geology, climate and temperatures, and magnetic fields. Cassini-Huygens has also provided an immense quantity of photographs of Saturn and its satellites.