Voyager 2 Neptune Encounter 1989 NASA Briefing by Project Scientist Ed Stone

• published: 06 Nov 2014
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more at http://scitech.quickfound.net/astro/planet_news.html NASA Jet Propulsion Laboratory press briefing by Voyager Project Scientist Edward Stone prior to the Voyager 2 Neptune Encounter (flyby). Includes comparative planetary data on moons, magnetic fields, ring systems, etc. Stone would become director of JPL in 1991. Public domain film from the US National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original). http://creativecommons.org/licenses/by-sa/3.0/ http://en.wikipedia.org/wiki/Voyager_2 Voyager 2 is a 722 kg (1,592 lb) space probe launched by NASA on August 20, 1977 to study the outer Solar System and eventually interstellar space... Voyager 2 has been operating for 37 years, 2 months and 16 days as of 5 November 2014, and the Deep Space Network is still receiving its data transmissions. At a distance of 106.6 AU (1.595×1010 km) as of November 2, 2014 from Earth, it is one of the most distant human made objects (along with Voyager 1, Pioneer 10 and Pioneer 11). Voyager 2 is part of the Voyager program with its identical sister craft Voyager 1, and is in extended mission, tasked with locating and studying the boundaries of the Solar System, including the Kuiper belt, the heliosphere and interstellar space. The primary mission ended December 31, 1989 after encountering the Jovian system in 1979, Saturnian system in 1981, Uranian system in 1986, and the Neptunian system in 1989. It is still the only spacecraft to have visited the two outer giant planets Uranus and Neptune. The probe is now moving at a velocity of 15.428 km/s relative to the Sun... Spacecraft design Constructed by the Jet Propulsion Laboratory (JPL), Voyager 2 included 16 hydrazine thrusters, three-axis stabilization, gyroscopes and celestial referencing instruments (Sun sensor/Canopus Star Tracker) to maintain pointing of the high-gain antenna toward Earth.... Communications Built with the intent for eventual interstellar travel, Voyager 2 included a large, 3.7 m (12 ft) parabolic, high-gain antenna (see diagram) to transceive data via the Deep Space Network on the Earth. Communications are conducted over the S-band (about 13 cm wavelength) and X-band (about 3.6 cm wavelength) providing data rates as high as 115.2 kilobits per second at the distance of Jupiter, and then ever-decreasing as the distance increased... Power The spacecraft was built with 3 Multihundred-Watt radioisotope thermoelectric generators (MHW RTG). Each RTG includes 24 pressed plutonium oxide spheres and provides enough heat to generate approximately 157 watts of power at launch. Collectively, the RTGs supply the spacecraft with 470 watts at launch and will allow operations to continue until at least 2020... Encounter with Neptune Voyager 2's closest approach to Neptune occurred on August 25, 1989.... flight controllers decided to also perform a close fly-by of Triton, the larger of Neptune's two originally known moons... ...Since the plane of the orbit of Triton is tilted significantly with respect to the plane of the ecliptic, through mid-course corrections, Voyager 2 was directed into a path several thousand miles over the north pole of Neptune. At that time, Triton was behind and below (south of) Neptune (at an angle of about 25 degrees below the ecliptic), close to the apoapsis of its elliptical orbit. The gravitational pull of Neptune bent the trajectory of Voyager 2 down in the direction of Triton. In less than 24 hours, Voyager 2 traversed the distance between Neptune and Triton, and then observed Triton's northern hemisphere as it passed over its north pole. The net and final effect on the trajectory of Voyager 2 was to bend its trajectory south below the plane of the ecliptic by about 30 degrees. Voyager 2 is on this path permanently, and hence, it is exploring space south of the plane of the ecliptic, measuring magnetic fields, charged particles, etc., there, and sending the measurements back to the Earth via telemetry. While in the neighborhood of Neptune, Voyager 2 discovered the "Great Dark Spot"... the "Great Dark Spot" was later hypothesized to be a hole in the visible cloud deck of Neptune. Neptune's atmosphere consists of hydrogen, helium, and methane... With the decision of the International Astronomical Union to reclassify Pluto as a "plutoid" in 2008, the flyby of Neptune by Voyager 2 in 1989 became the point when every known planet in the Solar System had been visited at least once by a space probe... http://en.wikipedia.org/wiki/Edward_C._Stone Edward Carroll Stone (born January 23, 1936) is an American space scientist, professor of physics at the California Institute of Technology, and former director of the NASA Jet Propulsion Laboratory (JPL)...