The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. It is identical to its sister Voyager program craft, Voyager 1 (a.k.a. Mariner 11). Voyager 2 followed a somewhat different trajectory during its Saturn encounter, however, bypassing a close encounter with Titan in favour of taking advantage of a gravitational slingshot to travel on to Uranus and Neptune. It became the first and so far only probe to visit those two planets and the first spacecraft to make the Grand Tour of Jupiter, Saturn, Uranus and Neptune due to a rare geometric arrangement of those four planets that only occurs once every 175 years[2].
For details on the Voyager instrument packages, see the separate article on the Voyager program.
Mission planning and launch
Voyager 2 was launched on August 20, 1977, from Cape Canaveral, Florida aboard a Titan IIIE Centaur rocket.
When ground crews became engrossed in a launch problem with Voyager 1, they forgot to send an important activation code to Voyager 2. This caused the probe to shut down its main high-gain antenna. Ground crews were able to establish contact through its low-gain antenna and reactivate it.
Jupiter
The closest approach to Jupiter occurred on July 9, 1979.
Saturn
Saturn taken by Voyager 2
The closest approach to
Saturn occurred on
August 25,
1981.
While behind Saturn (as viewed from Earth), Voyager 2 probed Saturn's upper atomosphere with its radar, to measure temperature and density profiles. Voyager 2 found that at the highest levels (70 Millibars) Saturn's temperature was 70 Kelvins, while at the deepest levels measured (1200 Millibars) the temperature increased to 143 Kelvins. The North pole was found to be 10 Kelvin cooler, although this may be seasonal (see also Saturn Oppositions).
Uranus
Uranus viewed from 18 million kilometers
The closest approach to
Uranus occurred on
January 24,
1986.
Voyager 2 discovered 10 previously unknown moons, studied its unique atmosphere (Uranus has an Axial tilt of 97.77°), and its ring system.
Neptune
Voyager 2 image of Neptune
The closest approach to
Neptune occurred on
August 25,
1989. Since this was the last major planet Voyager 2 could visit, it was decided to make a close flyby of
Triton, regardless of the consequences to the trajectory, similar to
Voyager 1 and its encounter with
Saturn and its moon
Titan.
The probe also discovered Great Dark Spot, which has since disappeared according to Hubble Space Telescope observations.
Escaping Solar System
As of January 11 2005, Voyager 2 was at a distance of 75.4 AU and is escaping the solar system at a speed of about 3.3 AU per year (ca. 15.6 km/s). It will be approximately 40,000 years before Voyager 2 approaches another star.
Voyager 2 is expected to keep on transmitting into the 2030s.
Fiction about Voyager
The motion picture Starman portrayed Voyager 2 as having been located by an alien intelligence who subsequently sent one of their own race to investigate intelligent life on Earth.
Although only two Voyagers were launched in real life (at least as of 2004), Star Trek: The Motion Picture makes reference to a "Voyager 6" which disappears into a black hole and emerges on the far side of the galaxy. The title vessel of the TV series Star Trek: Voyager is named for the space probes, for the title vessel disappearance into other side of the galaxy, making both the ship and the probe made voyage into deep space that is farther than most man made objects go; the T.V. series also has one of the characters (Dr. Lewis Zimmerman) accidentally wrongfully mentioned Voyager as Pioneer due to his senility, as inside joke since currently in real life, both the Pioneer 10 space probe and Pioneer 11 space probe shared the same fate as the Voyager 1 space probe and the Voyager 2 space probe, the Pathfinder project in the same episode probably is named after the real life Mars exploration Pathfinder project.
See also
External links
References
"Uranus Science Results." Voyager Science Results at Uranus. Accessed on February 8, 2005.
