On this day in 1977, the Voyager 2 space probe was launched by NASA. It was developed as part of the Voyager program, which saw two identical probes sent to study the outer Solar System and eventually interstellar space.
The unmanned crafts – each weighing 721.9 kg at launch, with a power of 420 watts, and communicating by means of a 3.7-metre parabolic high-gain antenna – were launched from Cape Canaveral, Florida. After Voyager 2’s ascent on 20 August, Voyager 1 was launched a couple of weeks later, on 5 September.
The probes were initially sent on what was conceived as a ‘Planetary Grand Tour’, to cover the giant outer planets of Jupiter, Saturn, Uranus, and Neptune. These planets were due to align at the end of the 1970s, an event which would not recur for another 175 years.
Though Voyager 2 was launched first, Voyager 1 was sent at a different trajectory and sooner reached Jupiter and Saturn. Voyager 1 passed through the Jovian system in 1979, and the Saturnian system in 1980 – thus completing its primary mission, after which it embarked for Titan, Saturn’s largest moon.
Voyager 2’s primary mission came to a conclusion at the close of 1989, after it had encountered the Jovian system in 1979, the Saturnian system in 1981, the Uranian system in 1986, and the Neptunian system in 1989. Voyager 2 remains the only space craft to have visited the outer planets of Uranus and Neptune.
After opting, on the basis of scientific value and calculated risk, to send Voyager 1 by Titan rather than towards Pluto, beyond 1989 Voyager 2’s trajectory could not be altered to make it pass what was still then considered the ninth planet from the sun. Pluto therefore remained unexplored until the New Horizons spacecraft passed by it and its five moons, on 14 July 2015.
Voyager 2 has now been in operation for precisely 38 years. The Deep Space Network continues to receive its data transmissions. Along with Voyager 1, it is expected to keep sending weak radio messages until at least 2025.
At a distance of 108 AU (1.62×1010 km) from the Sun, and moving at a velocity of 15.4 km/s, Voyager 2 is one of the most distant man-made objects from Earth: accompanied by Voyager 1, and by Pioneer 10 and Pioneer 11, which embarked in 1972 and 1973 on earlier missions to the asteroid belt, Jupiter, and Saturn. Voyager 1 is currently the farthest man-made object from Earth, becoming on 25 August 2012 the first to enter interstellar space.
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Both Voyager space probes carry aboard the Voyager Golden Record. The contents of this phonograph record were selected for NASA by a committee chaired by the prominent astronomer and astrophysicist Carl Sagan.
Together Sagan and committee members selected 115 images (although they were forbidden, after controversy over the Pioneer plaques, to send any nudity); an array of natural sounds, from volcanoes to wild dogs to the brainwaves of Sagan’s partner Ann Druyan; a medley of varied musical compositions; greetings in 55 languages both modern and ancient; and printed messages from then-US President Jimmy Carter and UN Secretary-General Kurt Waldheim. Carter’s message states:
‘This is a present from a small, distant world, a token of our sounds, our science, our images, our music, our thoughts and our feelings. We are attempting to survive our time so we may live into yours. We hope someday, having solved the problems we face, to join a community of galactic civilizations. This record represents our hope and our determination, and our good will in a vast and awesome universe.’
Each Golden Record is encased in a protective aluminum jacket, together with a cartridge and needle. Symbolic instructions indicate how the enclosed record should be played. But if the size of the probes and the chances of reaching a suitable audience are small, still the Golden Record is as much a celebration of the diversity of life on Earth.
The selection of music on the Golden Record plays for ninety minutes. The pieces included are as follows:
|•||Bach, Brandenburg Concerto No. 2 in F. First Movement, Munich Bach Orchestra, Karl Richter, conductor. 4:40|
|•||Java, court gamelan, “Kinds of Flowers,” recorded by Robert Brown. 4:43|
|•||Senegal, percussion, recorded by Charles Duvelle. 2:08|
|•||Zaire, Pygmy girls’ initiation song, recorded by Colin Turnbull. 0:56|
|•||Australia, Aborigine songs, “Morning Star” and “Devil Bird,” recorded by Sandra LeBrun Holmes. 1:26|
|•||Mexico, “El Cascabel,” performed by Lorenzo Barcelata and the Mariachi México. 3:14|
|•||“Johnny B. Goode,” written and performed by Chuck Berry. 2:38|
|•||New Guinea, men’s house song, recorded by Robert MacLennan. 1:20|
|•||Japan, shakuhachi, “Tsuru No Sugomori” (“Crane’s Nest,”) performed by Goro Yamaguchi. 4:51|
|•||Bach, “Gavotte en rondeaux” from the Partita No. 3 in E major for Violin, performed by Arthur Grumiaux. 2:55|
|•||Mozart, The Magic Flute, Queen of the Night aria, no. 14. Edda Moser, soprano. Bavarian State Opera, Munich, Wolfgang Sawallisch, conductor. 2:55|
|•||Georgian S.S.R., chorus, “Tchakrulo,” collected by Radio Moscow. 2:18|
|•||Peru, panpipes and drum, collected by Casa de la Cultura, Lima. 0:52|
|•||“Melancholy Blues,” performed by Louis Armstrong and his Hot Seven. 3:05|
|•||Azerbaijan S.S.R., bagpipes, recorded by Radio Moscow. 2:30|
|•||Stravinsky, Rite of Spring, Sacrificial Dance, Columbia Symphony Orchestra, Igor Stravinsky, conductor. 4:35|
|•||Bach, The Well-Tempered Clavier, Book 2, Prelude and Fugue in C, No.1. Glenn Gould, piano. 4:48|
|•||Beethoven, Fifth Symphony, First Movement, the Philharmonia Orchestra, Otto Klemperer, conductor. 7:20|
|•||Bulgaria, “Izlel je Delyo Hagdutin,” sung by Valya Balkanska. 4:59|
|•||Navajo Indians, Night Chant, recorded by Willard Rhodes. 0:57|
|•||Holborne, Paueans, Galliards, Almains and Other Short Aeirs, “The Fairie Round,” performed by David Munrow and the Early Music Consort of London. 1:17|
|•||Solomon Islands, panpipes, collected by the Solomon Islands Broadcasting Service. 1:12|
|•||Peru, wedding song, recorded by John Cohen. 0:38|
|•||China, ch’in, “Flowing Streams,” performed by Kuan P’ing-hu. 7:37|
|•||India, raga, “Jaat Kahan Ho,” sung by Surshri Kesar Bai Kerkar. 3:30|
|•||“Dark Was the Night,” written and performed by Blind Willie Johnson. 3:15|
|•||Beethoven, String Quartet No. 13 in B flat, Opus 130, Cavatina, performed by Budapest String Quartet. 6:37|
Carl Sagan had originally requested permission to include ‘Here Comes the Sun’, from the Beatles’ 1969 album Abbey Road. However EMI had concerns over copyright, and denied the request.
The great field recorder and musicologist Alan Lomax was one of Sagan’s main consultants when it came to choosing the music on the Golden Record. Aside from the blues, jazz, and rock music of Blind Willie Johnson, Louis Armstrong, and Chuck Berry, Lomax was responsible for much of the record’s scope: forwarding among other things Peruvian panpipes; a polyphonic Pygmy girls’ initiation song from Zaire; an Azerbaijani mugham performed by Kamil Jalilov; and a Bulgarian folk song, with traditional bagpipes, sung by Valya Balkanska. Sagan wrote that Lomax:
‘was a persistent and vigorous advocate for including ethnic music even at the expense of Western classical music. He brought pieces so compelling and beautiful that we gave in to his suggestions more often than I would have thought possible. There was, for example, no room for Debussy among our selections, because Azerbaijanis play bagpipe-sounding instruments and Peruvians play panpipes and such exquisite pieces had been recorded by ethnomusicologists known to Lomax.’