Voyager - Mission Timeline
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Summer 1965
Calculations reveal it is possible for a spacecraft launched in the late 1970's to visit all four giant outer planets, using the gravity of each planet to swing the spacecraft on to the next. This alignment occurs once every 176 years.
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July 1, 1972
"Mariner Jupiter/Saturn 1977", the name of the mission before it became Voyager, is approved by NASA, with day-to-day management by the Jet Propulsion Laboratory in Pasadena, California. The original planss commit only to flybys of Jupiter and Saturn and build upon the heritage of earlier Mariner spacecraft that flew by Venus, Mars and Mercury.
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December 13-15, 1972
The Mariner Jupiter/Saturn 1977 project (the mission's name before Voyager) holds its first science steering group meeting at the Jet Propulsion Laboratory.
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March 1977
The Mariner Jupiter/Saturn 1977 project is renamed Voyager.
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August 20, 1977
Voyager 2 launches from NASA's Kennedy Space Center. It is named Voyager 2 because, even though it launches first, Voyager 2 is planned to reach Jupiter and Saturn after Voyager 1.
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September 5, 1977
Voyager 1 launches from NASA's Kennedy Space Center. It is named Voyager 1 even though it launches second because Voyager 1 will reach Jupiter and Saturn first.
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September 6, 1977
Voyager 1 returns first spacecraft photo of Earth and the Moon.
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March 5, 1979
Voyager 1 makes its closest approach to Jupiter. Highlights of the encounter include the discoveries of the first active volcanoes spotted beyond Earth at the moon Io (discovered on March 9 in optical navigation images), the Jovian ring system and two moons (Thebe and Metis). Scientists also find that the Great Red Spot is a huge cyclone-like storm, Ganymede has grooved terrain (suggesting an early history of tectonic activity), and Jupiter has lightning (the first time lightning is detected at a world beyond Earth). The spacecraft encounter reveals other strange phenomena connected to Io: Ions stripped from its surface create a torus (or doughnut) around Jupiter and inflate the planet's magnetic field; and Io acts like an electric generator in Jupiter's magnetic field, sending 5 million amperes of current along the magnetic field to Jupiter.
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July 9, 1979
Voyager 2 makes its closest approach to Jupiter. Highlights of the encounter include the first images of Jupiter's ring system; discovery of a third moon (Adrastea); and a close approach to the moon Europa, which reveals intersecting linear features that suggest cracks in ice over a liquid water ocean. Voyager 2 observes that six of the Io volcanoes erupting during Voyager 1's encounter are still erupting -- meaning their active periods last at least several months, and that Io's volcanoes can turn on and off.
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November 9, 1980
Voyager 1 makes its closest approach to Saturn’s largest moon Titan and Saturn itself. Highlights from the Saturn encounter include the discovery of three moons (Atlas, Prometheus and Pandora). The discovery of Prometheus and Pandora around Saturn’s F ring confirms scientists’ theory that shepherding moons have to exist around narrow rings to keep ring material in line. The kinked, multi-stranded nature of Saturn’s F ring is also seen for the first time. Other highlights include the discovery of ghostly features in Saturn’s rings that resemble broad spokes in a wheel and views of the surprisingly bright surface of Enceladus. Data gathered from the Titan encounter show a thick, Earth-like atmosphere -- the first nitrogen-rich atmosphere found beyond our home planet -- and suggest the possibility of seas of liquid methane and ethane on Titan’s surface. After the Saturn encounter, Voyager 1 begins its trip out of the solar system, heading upwards out of the plane of the planets.
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August 25, 1981
Voyager 2 makes its closest approach to Saturn. Highlights include close encounters with several of Saturn’s icy moons (including Tethys, Iapetus and some of the moons discovered on Voyager 1’s encounter) and images of the half-young, half-old terrain of Enceladus, which suggests it might be geologically active. Images of the north pole of Saturn from this encounter are later stitched together to reveal a hexagonal-shaped weather feature circulating around the pole.
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January 24, 1986 -
Voyager 2 makes its closest approach to Uranus, the first time the seventh planet from the Sun has been seen up-close. Upon approach, Voyager 2 images reveal 11 new moons (Puck, Juliet, Portia, Cressida, Desdemona, Rosalind, Belinda, Perdita, Cordelia, Ophelia and Bianca). Bewildering images of the moon Miranda show that it likely experienced periods of heating from the tug of other Uranian moons. Scientists also learn that Uranus’s magnetic field is tilted, so that the poles of its magnetic field are closer to the equator, unlike the Earth where magnetic pole and the rotational poles are nearly aligned. Voyager 2 is the first to image Uranus’s very dark rings and to detect temperatures as low as minus 353 degrees (59 Kelvin), which makes Uranus the coldest planet in our solar system. This encounter also marks the first time NASA’s Deep Space Network, which enables Earth to communicate with spacecraft beyond the moon, arrays antennas together to improve our ability to capture the weak radio signals from very distant spacecraft.
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August 1987
NASA’s Deep Space Network completes the expansion of its big dishes at all three communications complexes (Goldstone, California; Madrid, Spain; and Canberra, Australia) from 64 meters to 70 meters wide, improving our ability to capture the weak radio signals Voyager is later expected to send back from Neptune.
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August 25, 1989
Voyager 2 makes its closest approach to Neptune, making it the first spacecraft to observe Neptune up close and the first to visit four planets beyond Earth. Highlights from the encounter include the discovery of six new moons in its images (Despina, Galatea, Larissa, Proteus, Naiad and Thalassa), the first images of Neptune’s rings, and the discovery of a huge, counter-clockwise rotating storm in Neptune’s southern hemisphere, dubbed “The Great Dark Spot.” Five hours after the closest approach to Neptune, Voyager 2 gave us our first close-up views of Triton, a bitterly cold, fractured moon with terrain the texture of a cantaloupe rind and geysers erupting from pinkish- hued nitrogen ice that forms the moon’s south polar cap. After the Neptune encounter, Voyager 2 begins its trip out of the solar system, below the plane of the planets.
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October 10 & December 5, 1989
Engineers turn off Voyager 2’s wide-angle and narrow-angle cameras because they want to use the power, computer memory and data rate for other instruments that collect key data on the solar wind and interstellar space. The spacecraft will never fly close enough to any astronomical object to take images again.
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February 14, 1990
At a distance of about 4 billion miles (6 billion kilometers) from the sun, Voyager 1 takes the last images of the mission: the “Solar System Family Portrait.” It is the only series of images that captures Venus, Earth, Jupiter, Saturn, Uranus and Neptune arrayed about the sun. Earth is captured as a tiny speck in a beam of scattered sunlight , inspiring Carl Sagan to think about the fragility and uniqueness of our home planet, “a pale blue dot.” After the images are transmitted from the spacecraft in real- time on this day, engineers turn off Voyager 1’s cameras because they want to use the power, computer memory and data rate for other instruments that collect key data on the solar wind and interstellar space. The spacecraft will never fly close enough to any astronomical object to take images again.
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February 17, 1998
Voyager 1 passes the distance of Pioneer 10 to become the farthest human- made object from Earth in space.
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December 16, 2004
Voyager 1 crosses the termination shock, where the solar wind abruptly slows down and heats up as it encounters the interstellar wind. The termination shock marks the inner boundary of heliosheath, which is the turbulent outer layer of the bubble the Sun blows itself and all of the planets. Unfortunately, on the day Voyager 1 crosses the shock, ground antennas are not scheduled to listen for the data the spacecraft is transmitting.
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August 30, 2007
Voyager 2 crosses the termination shock into the heliosheath, the outer layer of the bubble the Sun blows around itself and all of the planets. This time, antennas at Earth are listening for Voyager 2’s data transmissions and scientists are able to analyze the first measurements of the passage through the termination shock.
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August 12, 2012
Voyager 2 becomes NASA's longest-operating mission, breaking the previous record for continuous operation by Pioneer 6 (12,758 days of operation starting on Dec. 16, 1965).
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August 25, 2012
Voyager 1 enters interstellar space, passing beyond the heliopause, which is the boundary between our solar bubble and the matter ejected by explosions of other stars. It is the first time a human-made object crosses the threshold of interstellar space. Since the spacecraft is continually collecting data, Voyager detects the full intensity of cosmic rays in interstellar space for the first time on this day and also makes the first measurement of the interstellar magnetic field wrapped around the outside of the heliosheath. The crossing itself, however, is not confirmed until April 9, 2013.
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April 9, 2013
Voyager 1 makes the first measurement of the density of the interstellar medium, when a wave caused by a coronal mass ejection from the Sun reaches Voyager 1 and causes the plasma in interstellar space to ring. The high pitch of the ringing indicates the density of the plasma surrounding Voyager 1 is more than 40 times higher than previously measured, confirming the spacecraft is in the interstellar space and has been since Aug. 25, 2012.
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November 5, 2018
For the second time in history, a human-made object reaches the space between the stars. NASA's Voyager 2 probe exits the heliosphere – the protective bubble of particles and magnetic fields created by the Sun.
