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Line 95: − + − [[Voyager 1]]+ − − == External links == − [http://voyager.jpl.nasa.gov/index.html NASA's Voyager website] − + − + +
Expansion and gallery
'''Voyager 2''' is a [[NASA]] satellite launched on August 20 1977 from [[Cape Canaveral]], [[Florida]]
{{Rocketbox
|image=Voyager.jpg
|caption=Artist's conception of a Voyager vessel
|projet=Project Voyager
|launchauth=National Aeronautics and Space Administration
|launchauthabbr=NASA
|contraut=Jet Propulsion Laboratory
|contrautabr=JPL
|misstype=flyby
|target=Jupiter
|target2=Saturn
|target3=Uranus
|target4=Neptune
|launch=August 20, 1977
|nssdcid=1977-076A
|webpage=http://voyager.jpl.nasa.gov/
|webtitle=Voyager project site
|mass=721.9 kg
|power=420 W
}}'''Voyager 2''' or '''Mariner 12''' is a [[NASA]] rocket probe, launched in 1977 originally to visit the [[gas giant]] [[planet]]s [[Jupiter]] and [[Saturn]]. A highly favorable trajectory that resulted from its flyby of Saturn convinced mission controllers to extend the mission to visit [[Uranus]] and [[Neptune]] as well. The surprising discoveries that this vessel made, and especially its rendezvous with four gas giants, make it the most productive rocket probe ever launched.
== Technical specifications ==
Voyager 2 is actually a [[Project Mariner]] probe of mass 721.9 kg. It derives its power from three Radioisotope Thermal Generators (RTGs), which provide 420 W of power to Voyager's systems.<ref name=Bell>Bell, Edwin V. "[http://nssdc.gsfc.nasa.gov/planetary/voyager.html NASA Voyager Project Information]." National Space Science Data Center, [[NASA]], March 11, 2008. Accessed July 2, 2008.</ref>
== Mission history ==
In the early 1970s, NASA [[astronomy|astronomers]] realized that the outer planets would align in a manner that would allow a rocket probe to visit all four gas giants in a short time and using a small amount of fuel. This kind of favorable alignment occurs once in 175 years.<ref name=Angrum>Angrum, Andrea. "[http://voyager.jpl.nasa.gov/science/planetary.html Voyager - Science - Planetary Voyage]." [[Jet Propulsion Laboratory|JPL]], [[NASA]], March 23, 2004. Accessed July 2, 2008.</ref> NASA at first planned to conduct a "Grand Tour" of the gas giants using a total of four probes. But such a project was deemed too expensive, and so NASA cancelled "Project Grand Tour" and conceived of a more limited project, [[Project Voyager]], to use two probes to study [[Jupiter]], [[Saturn]], and their respective moon and ring systems only.<ref name=Angrum/> They then changed the names of the last two probes in the Mariner series to [[Voyager 1]] and Voyager 2 and prepared each for the new, limited mission.
Voyager 2 launched first, but on a slower trajectory so that it was the second of the two probes to arrive at Jupiter and Saturn. Mission planners also planned Voyager 2's flight path to allow it to visit Uranus and Neptune.
Voyager 2 reached Jupiter on July 9, 1979, and Saturn on August 25, 1981. Both encounters were judged successful, though Voyager 2 suffered a failure of its primary transmitter. Mission controllers carefully kept Voyager 2 on a path that would send it on to Uranus. After the Saturn flyby, the controllers realized that all of Voyager 2's instruments were still operating. NASA extended the mission twice, to allow one encounter each with Uranus and Neptune.<ref name=Angrum/> The extended mission required extensive and innovative remote reprogramming.<ref name=Leech>Leech, Jon. "[http://www.landfield.com/faqs/space/probe/ Space FAQ 08/13 - Planetary Probe History]." March 5, 2003. Accessed July 2, 2008.</ref>
Voyager 2 reached Uranus on January 24, 1986, and Neptune on August 25, 1989. With the Neptune flyby, the probe turned south and achieved [[escape speed]]. Voyager 2 is now flying out of the [[solar system]], headed 48 degrees "south" at a speed of 470 million kilometers per year.<ref name=Angrum/>
The mission of Voyager 2 continues to this day (July 2, 2008) and is expected to continue for at least another decade.<ref name=Angrum/><ref name=Leech/> Voyager 2 crossed the heliosheath, or termination shock, on August 30, 2007 and thus joined Voyager 1 as one of two vessels returning data from interstellar space.<ref name=release1>"[http://www.nasa.gov/mission_pages/voyager/termination_shock.html Voyager 2 Proves the Solar System is Squashed]." [[NASA]] Press Release 07-78, December 10, 2007. Accessed July 2, 2008.</ref><ref name=Angrum2>Angrum, Andrea. "[http://voyager.jpl.nasa.gov/mission/fastfacts.html Voyager - Mission - Fast Facts]." [[Jet Propulsion Laboratory|JPL]], [[NASA]], February 21, 2008. Accessed July 2, 2008.</ref> The mission will continue as long as its RTGs can provide sufficient power to operate its key sensors. Reliable estimates state that by 2020 Voyager 2 will no longer have enough power to run its systems.<ref name=Arnett>Arnett, Bill. "[http://www.nineplanets.org/spacecraft.html Spacecraft]." ''The <s>Nine</s>8 Planets'', January 18, 2005. Accessed July 2, 2008.</ref>
== Scientific accomplishments ==
The discoveries made by Voyagers 1 and 2 are extensive and spectacular. A short list of these includes:<ref name=Bell/>
* Twenty-two previously undiscovered satellites of the four gas giants
* Auroras at Jupiter, Saturn, and Neptune
* Rings of Jupiter
* Volcanism on [[Io]]
* Spoke-like formations in Saturn's B ring, and a braided structure in Saturn's F ring.
* Two previously unsuspected rings of Uranus
* Neptune's rings found to be complete and not interrupted
* Geyser-like eruptions on [[Triton]]
The scientific findings most important to the debate between [[creationism]] and [[uniformitarianism]] were the discoveries of the magnetic fields of [[Uranus]] and [[Neptune]]. Uniformitarians had not predicted that those fields would exist. [[Russell Humphreys]] had predicted both their existence and their strength,<ref name=Humphreys>Humphreys, D. R. "[http://www.creationresearch.org/crsq/articles/21/21_3/21_3.html The Creation of Planetary Magnetic Fields]." ''[[Creation Research Society Quarterly]]'' 21(3), December 1984. Accessed April 29, 2008.</ref> and Voyager 2 vindicated his model completely.<ref name=Humphreys2>Humphreys, D. R. "[http://www.icr.org/index.php?module=articles&action=view&page=329 Beyond Neptune: Voyager II Supports Creation]." [[Institute for Creation Research]]. Accessed April 30, 2008</ref> The tremendous skew between the magnetic and rotational axes of the two gas giants surprised creationist and uniformitarian alike.<ref name=Humphreys2/>
== Gallery ==
<gallery>
Image:JupiterVoyager2.jpg|Jupiter and the Great Red Spot
Image:IoRotation.gif|Io in rotation
Image:SaturnRingVoyager2.jpg|Saturn and its rings
Image:Enceladus Voyager.jpg|Enceladus
Image:Tethys Voyager 2.jpg|Tethys
Image:Miranda.jpg|Miranda, showing its multiple terrains
Image:MirandaVoyagerColor.jpg|Miranda in color
Image:MirandaFault.jpg|Miranda fault in high resolution
Image:Ariel color.jpg|Ariel
Image:Umbriel.jpg|Umbriel
Image:Titania color.jpg|Titania in color
Image:Titania High-res.jpg|Titania in high resolution
Image:Oberon.jpg|Oberon
Image:Neptune Full-browse.jpg|Neptune and Great Dark Spot
Image:NeptuneFraternity.jpg|Neptune ring arc
Image:Triton2 Voyager2.jpg|Triton in full face
Image:Triton1 Voyager2.jpg|Triton at close range
Image:Nereid.jpg|Nereid
Image:Voyager interstellar.gif|Voyagers 1 and 2 leave the solar system
Image:Voyager family portraits.jpg|Distant images of six planets from interstellar space
</gallery>
== Timeline ==
== Timeline ==
*Jan. 5: Voyagers Surpass 10,000 Days Of Operation.
*Jan. 5: Voyagers Surpass 10,000 Days Of Operation.
==See Also==
== References ==
{{reflist|2}}
[[Category:Science]]
== See also ==
[[Category:Space Exploration]]
* [[Project Voyager]]
* [[Voyager 1]]