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- Voyager 2 was one of a pair of spacecraft launched to explore the planets of the outer solar system and the interplanetary environment. Each Voyager had as its major objectives at each planet to: (1) investigate the circulation, dynamics, structure, and composition of the planet's atmosphere; (2) characterize the morphology, geology, and physical state of the satellites of the planet; (3) provide improved values for the mass, size, and shape of the planet, its satellites, and any rings; and, (4) determine the magnetic field structure and characterize the composition and distribution of energetic trapped particles and plasma therein. Originally planned as a Grand Tour of the outer planets, including dual launches to Jupiter, Saturn, and Pluto in 1976-77 and dual launches to Jupiter, Uranus, and Neptune in 1979, budgetary constraints caused a dramatic rescoping of the project to two spacecraft, each of which would go to only Jupiter and Saturn. The new mission was called Mariner Jupiter/Saturn, or MJS. It was subsequently renamed Voyager about six months prior to launch. The rescoped mission was estimated to cost $250 million (through the end of Saturn operations), only a third of what the Grand Tour design would have cost. Voyager 2 was the first of the two spacecraft to be launched, with liftoff occurring 20 Aug. 1977. What was at first an auspicious launch, however, proved to be the beginning of a number of problems. The primary cause of the initial problems were attributed to commanding by the AACS, including difficulty in determining the full deployment of the science boom. These problems resulted in a delay of four days in the launch of Voyager 1 to ensure they wouldn't occur for it. Although launched sixteen days after Voyager 2, Voyager 1's trajectory was the quicker one to Jupiter. On 15 Dec. 1977, while both spacecraft were in the asteroid belt, Voyager 1 surpassed Voyager 2's distance from the Sun. Several months after launch, in April 1978, Voyager 2's primary radio receiver failed, automatically kicking in the backup receiver which proved to be faulty. Attempts to recover the use of the primary receiver failed and the backup receiver was used for the remainder of the mission. Although use of the backup receiver made communication with the spacecraft more difficult, engineers were able to find workarounds. Voyager 2 proceeded with its primary mission and flew by Jupiter (closest approach on 09 July 1979) and Saturn (05 Aug. 1981). During these flybys, Voyager 2 obtained images roughly equal in number to Voyager 1 (18,000 at Jupiter, 16,000 at Saturn). Voyager 2's launch date had preserved one part of the original Grand Tour design, i.e. the possibility of an extended mission to Uranus and Neptune. Despite the difficulties encountered, scientists and engineers had been able to make Voyager enormously successful. As a result, approval was granted to extend the mission, first to Uranus, then to Neptune and later to continue observations well past Neptune. Voyager 2 made successful flybys of Uranus (24 Jan. 1986) and Neptune (25 Aug. 1989). Because of the additional distance of these two planets, adaptations had to made to accomodate the lower light levels and decreased communications. Voyager 2 was successfully able to obtain about 8,000 images of Uranus and its satellites. Additional improvements in the on-board software and use of image compression techniques allowed about 10,000 images of Neptune and its satellites to be taken. All of the experiments on Voyager 2 have produced useful data. Group: Platform_Details Entry_ID: VOYAGER 2 Group: Platform_Identification Platform_Category: Interplanetary Spacecraft Platform_Series_or_Entity: FLYBY Short_Name: VOYAGER 2 End_Group Group: Synonymous_Platform_Names Short_Name: Mariner Jupiter/Saturn B Short_Name: 10271 Short_Name: 1977-076A End_Group Creation_Date: 2007-03-06 Online_Resource: http://www.nasa.gov/mission_pages/voyager/index.html Online_Resource: http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1977-076A Sample_Image: http://nssdc.gsfc.nasa.gov/image/spacecraft/voyager.jpg Group: Platform_Logistics Launch_Date: 1977-08-20 Launch_Site: Cape Canaveral/Kennedy Space Center, USA Primary_Sponsor: NASA End_Group End_Group
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| Abstract from DBPedia | Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach gas giants Jupiter and Saturn but enabled further encounters with ice giants Uranus and Neptune. Voyager 2 remains the only spacecraft to have visited either of the ice giant planets. Voyager 2 was the fourth of five spacecraft to achieve Solar escape velocity, which allowed it to leave the Solar System. Voyager 2 successfully fulfilled its primary mission of visiting the Jovian system in 1979, the Saturnian system in 1981, Uranian system in 1986, and the Neptunian system in 1989. The spacecraft is now in its extended mission of studying interstellar space. It has been operating for 45 years, 3 months and 15 days as of December 6, 2022 UTC [refresh]; as of November 7, 2022, it has reached a distance of 132.05 AU (12.275 billion mi) from Earth. The probe entered interstellar space on November 5, 2018, at a distance of 122 AU (11.3 billion mi; 18.3 billion km) (about 16:58 light-hours) from the Sun and moving at a velocity of 15.341 km/s (34,320 mph) relative to the Sun. Voyager 2 has left the Sun's heliosphere and is traveling through the interstellar medium, a region of outer space beyond the influence of the Solar System, joining Voyager 1, which had reached the interstellar medium in 2012. Voyager 2 has begun to provide the first direct measurements of the density and temperature of the interstellar plasma. Voyager 2 remains in contact with Earth through the NASA Deep Space Network. In 2020, maintenance to the Deep Space Network cut outbound contact with the probe for eight months. Contact was reestablished on November 2, 2020, when a series of instructions was transmitted, subsequently executed, and relayed back with a successful communication message. On February 12, 2021, full communications with the probe were restored after a major antenna upgrade that took a year to complete. The DSS 43 communication antenna, which is solely responsible for communications with the probe, is located near Canberra, Australia.ボイジャー2号 (英語: Voyager 2)は、NASA (アメリカ航空宇宙局)により1977 年8月20日に打ち上げられた、木星よりも遠くの外惑星及び衛星の探査を目的として開発・運用されている無人宇宙探査機である。ボイジャー計画の一環として、姉妹機であるボイジャー1号の16日前に打ち上げられた。木星と土星に到達するのに時間はかかったが、さらにその先の天王星と海王星の接近に成功した。巨大氷惑星を訪れた唯一の探査機で、また木星・土星・天王星・海王星の「グランドツアー」を初めて実現した探査機となった。また、ボイジャー1 号 と同様に、はるか先に存在しているかもしれない地球外知的生命体の探査のためボイジャーのゴールデンレコードと呼ばれる、地球の生命や文化を伝えるためのレコードを搭載している。 その主な任務は、1979年に木星、1981年に土星、1986年に天王星を訪問した後の1989年10月2日の海王星探査に伴って終了した。ボイジャー2号は現在、 45年4か月と6日間稼働し続けており、ディープスペースネットワークを通じて通信を行っている。 ボイジャー2号は2022年8月時点で、太陽からの距離は130.5 au (195.2億 km)で、太陽に対して15.199 km/s (54,717 km/h)の速度で移動しており、太陽系を脱出する5つの探査機のうち、4番目に太陽系の脱出速度を達成した探査機である。2018年12月、ボイジャー2号が2018年11月5日に太陽圏（ヘリオスフィア）を離脱して恒星間空間に達したと公式に発表された。 (Source: http://dbpedia.org/resource/Voyager_2) |
