Voyager 2 is a spacecraft launched by NASA in 1977, part of the Voyager program to study the outer Solar System. Operating for 42 years as of 2019, the spacecraft is currently about 18.6 billion kilometers (11.6 billion miles, or 100 AU) from Earth, and is moving further away at about 3.3 AU per year. The spacecraft has two main instrument payloads: an imaging system and a spectrometer. The imaging system returned images of Jupiter, Saturn, Uranus, and Neptune; while the spectrometer Probe performed measurements of the atmospheres and surfaces of these planets. Voyager 2 is only the second spacecraft (after Pioneer 10) to visit the outer four giant planets, and also the second to visit Uranus and Neptune (after Voyager 1).
- Voyager 2’s primary mission was completed on November 20, 1980, when it made its closest approach to Saturn at a distance of 21,000 km (13,000 mi). It studied Saturn’s atmosphere and its moons Titan and Enceladus. Following this close encounter, the spacecraft’s trajectory took it out of the plane of the Solar System ecliptic, making it the first human-made object to do so. As Voyager 2 passed Jupiter in 1979 and then Saturn in 1980, the spacecraft’s cameras returned dramatic images of active volcanoes on Jupiter’s moon Io and Saturn’s rings.
- On August 25, 1981, Voyager 2 became the first (and so far only) spacecraft to fly by Uranus. It discovered ten new moons, two new rings, and evidence that the planet’s temperature was much colder than had been expected. The encounter with Uranus also provided information that allowed scientists to determine the length of a day on the planet: 17 hours 14 minutes 24 seconds.
- On April 9, 1986, Voyager 2 made its closest approach to Neptune at a distance of about 50,000 km (30,000 mi). It discovered six new moons and two narrow rings around Neptune. In1989, Voyager 2 became the only spacecraft to visit Neptune.
- During its journey, Voyager 2 also made important discoveries about the asteroid belt, the Kuiper belt, and interstellar space. In 1990, it detected three new moons of Saturn, two of Uranus, and one of Neptune.
- On February 14, 1998, Voyager 2 crossed the heliopause to become the first human-made object in interstellar space. As of 2019, it is about 18.6 billion kilometers (11.6 billion miles) from Earth and is moving away at about 3.3 AU per year.
- Voyager 2 was designed to last for five years and carry enough fuel for 12 years of operation. The spacecraft is equipped with three radioisotope thermoelectric generators (RTGs) that provide power for the spacecraft’s systems and scientific instruments. The RTGs use the heat from the decay of plutonium-238 to generate electricity.
- The spacecraft has two main instrument payloads: an imaging system and a spectrometer. The imaging system includes a narrow-angle camera (NAC), a wide-angle camera (WAC), and an infrared spectrometer/radiometer (IRIS). The NAC and WAC are identical to the cameras on Voyager 1. The IRIS was added to study the atmospheres of Jupiter and Saturn.
- The spectrometer Probe consists of four instruments: an ultraviolet spectrometer (UVS), a mass spectrometer (MS), a charged-particle spectrometer (CPS), and an energetic particle spectrometer (EPS). UVS is used to study the composition of planetary atmospheres and surfaces. The MS is used to measure the masses of atoms and molecules in the atmospheres of Jupiter and Saturn. The CPS is used to study the charged particles in the solar wind and planetary magnetospheres. The EPS is used to study the energetic particles in the solar wind and planetary magnetospheres.
- Voyager 2 is operated by the Jet Propulsion Laboratory (JPL) in Pasadena, California. JPL is a division of the California Institute of Technology (Caltech). Voyager 2 was launched on August 20, 1977, from Cape Canaveral Air Force Station in Florida. The spacecraft’s trajectory took it past Jupiter in 1979, Saturn in 1980, and Uranus in 1981.
- In 1989, Voyager 2 became the first (and so far only) spacecraft to visit Neptune. During its journey, Voyager 2 also made important discoveries about the asteroid belt, the Kuiper belt, and interstellar space. On February 14, 1998, Voyager 2 crossed the heliopause to become the first human-made object in interstellar space. As of 2019, it is about 18.6 billion kilometers (11.6 billion miles) from Earth and is moving away at about 3.3 AU per year.
- Data return from Voyager 2 has continued until the present day. As of June 2019, Voyager 2 is still returning useful scientific data and is expected to do so for several more years.