Key Dates and Status: 08/20/77 Launch
- 07/09/79 Jupiter Flyby
- 08/26/81 Saturn Flyby
- 01/24/86 Uranus Flyby
- 08/24/89 - 08/25/89 Neptune Flyby
- Status: Headed to Interstellar Space
Fast Facts:
Both Voyager spacecraft carry a greeting to any form of life. The message is on a 12-inch gold-plated copper disk (right) containing sounds and images that portray the diversity of life and culture on Earth.
One of the musical selections on the Voyager gold record is Chuck Berry's 1950s hit
Voyager 2 is escaping the solar system at a speed of about 3.3 A.U. (495,000,000 km) per year.
Overview:
Voyager 2 achieved the Grand Tour of our outer solar system, taking advantage of a rare planetary alignment to visit the four giant outer planets Jupiter, Saturn, Uranus, and Neptune, a feat not likely to be repeated in our lifetimes.
The primary mission of Voyager 2 was to be a backup for Voyager 1 in case anything should prevent it from completing its mission, or in case Voyager 1 made some fantastic discovery.
It flew by Jupiter at a distance of 722,000 kilometers (448,600 miles), taking rich images of the planet, its rings, and satellites. Some discoveries made by Voyeger 2 included a total of nine active sulfur-spewing volcanoes identified on Io, the possibilty of a liquid ocean beneath the frozen crust of Europa, and possible plate tectonics on the surface of Ganymede.
Saturn was Voyager 2's second stop. While its path was based on the desire to continue to Uranus, the timing of its flight was chosen to provide close looks at several Saturnian satellites, including Enceladus, Tethys, Hyperion, Iapetus, Phoebe, and several others. Voyager 2 flew by Saturn's cloudtops at a distance of 100,800 kilometers (62,600 miles), and returned more sensitive images of jet streams and storms in the atmosphere.
Ultraviolet emissions in the upper atmosphere at high latitudes may be connected to auroral activity. Voyager 2 also took a closer look at some of the ring features found by Voyager 1. Unfortunately, a serious problem developed with the steerable platform on which its optical instruments are mounted, which resulted in the loss of some of the highest resolution data about Tethys and the rings of Saturn.
Fortunately, by the time the spacecraft reached Uranus 4-1/2 years later, lubricant had migrated back into the gear trains, permitting normal usage of the scan platform at somewhat conservative speeds, so that all of the science objectives at Uranus could be met.
Voyager 2 flew by Uranus at a distance of 107,000 kilometers (66,500 miles) from the planet's center, threading through a broad ring system of dust- to boulder-sized particles. Ten new moons were imaged, in addition to the five moons already known. The geological jumble of Miranda may indicate partial internal melting and episodic upwelling of icy material, possibly triggered by multiple meteor or asteroid impacts with Miranda. At the time of Voyager 2's visit, Uranus's atmosphere showed few features, possibly due to the planet's pole-on orientation to the Sun at that time. Also unusual is the planet's magnetic field, which is tilted by 60 degrees with respect to the rotational axis, and offset from the center of the planet by a third of its radius.
The final visit within our solar system was Neptune. Voyager 2 skimmed the north pole of Neptune by a mere 4800 kilometers (3000 miles), and determined basic characteristics of Neptune and its largest moon Triton: color, cloud-top features, size, mass, composition, temperature, and rotation rate. Voyager 2 found six new Neptunian moons and three new rings plus a broad sheet of ring material. Unexpectedly, geysers of gaseous nitrogen were found on the largest moon, Triton. Neptune's magnetic field also confounded: tilted 47 degrees with respect to the rotational axis, and offset from the center of the planet by half the planet's radius.
As of September 2003, Voyager 2 was about 10,657,000,000 km (6,622,000,000 miles) from our Sun.
Even at speeds of more than 56,000 kph (35,000 mph), it will take nearly 20,000 years for the Voyagers to reach the middle of the comet swarm and possibly twice this long for them to pass the outer boundaries of cometary space. By this time, they will have traveled a distance of two light-years, equivalent to half of the distance to Proxima Centauri, the nearest star.
