Editing Voyager 2 (section)

=== Launch and trajectory ===
The ''Voyager 2'' probe was launched on August 20, 1977, by NASA from [[Cape Canaveral Air Force Station Space Launch Complex 41|Space Launch Complex 41]] at [[Cape Canaveral, Florida]], aboard a [[Titan IIIE]]/[[Centaur (rocket stage)|Centaur]] [[carrier rocket|launch vehicle]]. Two weeks later, the twin ''Voyager 1'' probe was launched on September 5, 1977. However, ''Voyager 1'' reached both Jupiter and Saturn sooner, as ''Voyager 2'' had been launched into a longer, more circular trajectory.<ref name="nasajpl">{{Cite web |url=https://voyager.jpl.nasa.gov/frequently-asked-questions/fact-sheet/ |access-date=June 9, 2024 |website=NASA/JPL |title=Voyager - Fact Sheet |archive-date=April 13, 2020 |archive-url=https://web.archive.org/web/20200413080739/https://voyager.jpl.nasa.gov/frequently-asked-questions/fact-sheet/ |url-status=live }}</ref><ref name="fastfacts">{{Cite web |url=https://voyager.jpl.nasa.gov/frequently-asked-questions/fast-facts/ |access-date=June 9, 2024 |website=NASA/JPL |title=Voyager - Fast Facts |archive-date=May 22, 2022 |archive-url=https://web.archive.org/web/20220522131332/https://voyager.jpl.nasa.gov/frequently-asked-questions/fast-facts/ |url-status=live }}</ref>

''Voyager 1''{{'}}s initial orbit had an [[aphelion]] of {{Convert|8.9|AU|e6mi e9km|abbr=unit}}<!-- gradually increasing to 9.1 AU because of perturbations -->, just a little short of Saturn's orbit of {{Convert|9.5|AU|e6mi e9km|abbr=unit}}. Whereas, ''Voyager 2''{{'}}s initial orbit had an aphelion of {{Convert|6.2|AU|e6mi e6km|abbr=unit}}<!-- gradually increasing to 6.7 AU because of perturbations -->, well short of Saturn's orbit.<ref>[https://ssd.jpl.nasa.gov/horizons.cgi HORIZONS] {{Webarchive|url=https://web.archive.org/web/20121007034731/https://ssd.jpl.nasa.gov/horizons.cgi |date=October 7, 2012 }}, JPL Solar System Dynamics (Ephemeris Type ELEMENTS; Target Body: Voyager ''n'' (spacecraft); Center: Sun (body center); Time Span: ''launch + 1 month'' to ''Jupiter encounter – 1 month'')</ref>

In April 1978, no commands were transmitted to ''Voyager 2'' for a period of time, causing the spacecraft to switch from its primary radio receiver to its backup receiver.<ref>{{cite web |title=40 Years Ago: Voyager 2 Explores Jupiter – NASA |url=https://www.nasa.gov/history/40-years-ago-voyager-2-explores-jupiter/ |access-date=April 4, 2024 |date=July 8, 2019 |archive-date=April 4, 2024 |archive-url=https://web.archive.org/web/20240404165002/https://www.nasa.gov/history/40-years-ago-voyager-2-explores-jupiter/ |url-status=live }}</ref> Sometime afterwards, the primary receiver failed altogether. The backup receiver was functional, but a failed capacitor in the receiver meant that it could only receive transmissions that were sent at a precise frequency, and this frequency would be affected by the Earth's rotation (due to the [[Doppler effect]]) and the onboard receiver's temperature, among other things.<ref>{{cite book |title=Planets Beyond: Discovering the Outer Solar System |last=Littmann |first=Mark |year=2004 |publisher=[[Courier Corporation]] |page=106 |url=https://books.google.com/books?id=RoJMadct4TQC&pg=PA106 |isbn=978-0-486-43602-9}}</ref><ref>{{cite magazine |last=Davies |first=John |date=January 23, 1986 |title=Voyage to the tilted planet |url= |magazine=New Scientist |page= |pages=39–42 |volume=109 |issue=1492 |id=[[Google Books]] [https://www.google.com/books/edition/New_Scientist/sIkoAAAAMAAJ?hl=en&gbpv=1&bsq=%22Voyage%20to%20the%20tilted%20planet%22%20%22Davies%22 sIkoAAAAMAAJ], [https://www.google.com/books/edition/New_Scientist/vdc-AQAAIAAJ?hl=en&gbpv=1&bsq=%22Voyage%20to%20the%20tilted%20planet%22%20%22Davies%22 vdc-AQAAIAAJ]. [[HathiTrust]] [https://babel.hathitrust.org/cgi/pt?id=mdp.39015038787464&q1=%22Voyage+to+the+tilted+planet%22&start=1 mdp.39015038787464], [https://babel.hathitrust.org/cgi/pt?id=uc1.31822015726458&q1=%22Voyage+to+the+tilted+planet%22&start=1 uc1.31822015726458].}}</ref>

<gallery class="center" widths="200" heights="200">
File:Titan 3E Centaur launches Voyager 2.jpg|''Voyager 2'' launch on August 20, 1977, with a [[Titan IIIE]]/[[Centaur (rocket stage)|Centaur]]
File:Animation of Voyager 2 trajectory.gif|Animation of ''Voyager 2''{{'s}} trajectory from August 20, 1977, to December 30, 2000<br />{{legend2|magenta| ''Voyager 2'' }}{{·}}{{legend2|Royalblue|Earth}}{{·}}{{legend2|Lime|[[Jupiter]]}} {{·}}{{legend2| Cyan |[[Saturn]]}}{{·}}{{legend2| Gold |[[Uranus]] }}{{·}}{{legend2| OrangeRed |[[Neptune]] }}{{·}}{{legend2| Yellow |[[Sun]] }}
File:Voyager 2 path.svg|Trajectory of ''Voyager 2'' primary mission
File:Voyager 2 velocity vs distance from sun.svg|Plot of ''Voyager 2''{{'s}} heliocentric velocity against its distance from the Sun, illustrating the use of gravity assists to accelerate the spacecraft by Jupiter, Saturn and Uranus.{{efn-ua|To observe [[Triton (moon)|Triton]], ''Voyager 2'' passed over Neptune's north pole, resulting in an acceleration out of the plane of the ecliptic, and, as a result, a reduced velocity relative to the Sun.<ref>{{cite web |url=https://solarsystem.nasa.gov/basics/bsf4-1.php |title=Basics of space flight: Interplanetary Trajectories |access-date=October 5, 2018 |archive-date=September 4, 2015 |archive-url=https://web.archive.org/web/20150904150022/https://solarsystem.nasa.gov/basics/bsf4-1.php |url-status=live }}</ref>}}
</gallery>