- Exploration of Neptune
The exploration of Neptune has only begun with one explorer,
Voyager 2 , which visited onAugust 25 ,1989 . The possibility of aNeptune Orbiter is being discussed, yet other than that, no other missions have been given serious thought. AsNeptune is agas giant and has no solid surface, a surface mission such as a lander or rover is impossible.Voyager 2
In Voyager 2's last planetary encounter, Voyager 2 swooped only 3,000 miles above Neptune's north pole, the closest approach it made to any body since it left
Earth . Voyager 2 studiedNeptune's atmosphere ,Neptune's rings , itsmagnetosphere , andNeptune's moons . Several discoveries were made, including the discovery of theGreat Dark Spot and Triton's geysers.Voyager 2 revealed that Neptune's atmosphere was very dynamic, even though it receives only 3% of the sunlight
Jupiter receives. Voyager 2 discovered ananticyclone called theGreat Dark Spot , similar to Jupiter'sGreat Red Spot andLittle Red Spot . However, images taken by theHubble Space Telescope revealed that the Great Dark Spot had disappeared. Also seen in Neptune's atmosphere at that time was analmond -shaped spot designated D2, and a bright, quickly moving cloud high above the cloud decks dubbed "Scooter".Voyager 2 found four rings and evidence for
ring arcs , or incomplete rings above Neptune. Neptune's magnetosphere was also studied by Voyager 2. The planetary radio astronomy instrument found that Neptune's day lasts sixteen hours, seven minutes. Voyager 2 also discoveredauroras , like onEarth , but much more complex.Voyager 2 discovered six moons orbiting Neptune, but only three were photographed in detail: Proteus, Nereid, and Triton. Proteus turned out to be an
ellipsoid , as large as an ellipsoid could become without rounding in asphere . Proteus is very dark in color, almost likesoot . Nereid, though discovered in1949 , still has very little known about it. Triton was flown by at about 25,000 miles away, and became the last solid world Voyager 2 would ever explore. Triton was revealed to have remarkable activegeysers andpolar caps . A very thin atmosphere was found, as well as thin clouds.Future missions
Neptune Orbiter
A Neptune Orbiter is being considered to study Neptune in more detail, release atmospheric probes, and possibily release a Triton Lander. On the
NASA website, it lists the earliest possible launch date as2030 . This mission is still a proposal, and budget cuts may eliminate it.ee also
*
Neptune
*Triton
*Voyager 2
*Neptune Orbiter
*NASA References
Related websites
* [http://voyager.jpl.nasa.gov NASA Voyager website]
* [http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Neptune&MCode=NTO More information on the Neptune Orbiter]
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