The Voyager Mission

Updated: Oct 19

One of NASA's most successful missions, Voyager 1 and 2, was launched less than a month apart. Voyager 1 was launched on 5 Sept 1977, and Voyager 2 was launched on 20 Aug 1977.


Although Voyager 2 was launched earlier than its twin, Voyager 1 crossed Voyager 2 on Dec. 15, 1977, due to its faster route.

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As it approached Jupiter in April 1978, the spacecraft began imaging the planet from 165 million miles away. Images sent back by January 1979 indicated that the atmosphere of Jupiter was more turbulent than during the Pioneer flybys in 1973-1974. Voyager 1 took a picture every 96 seconds for 100 hours beginning Jan. 30, 1979, to create a color time-lapse movie of Jupiter's 10 rotations.


Early in March 1979, the spacecraft discovered a thin ring circling Jupiter (less than 19 miles or 30 kilometers thick) after crossing into the Jovian moon system. The closest approach of Voyager 1 to Jupiter occurred at 12:05 UT on March 5, 1979, at a distance of about 174,000 miles. Following this, it encountered several of Jupiter's moons, including Amalthea (260,100 miles away), Europa (45,830 miles away), Ganymede (71,280 miles away), and Callisto (78,540 miles away), in that order, returning spectacular images of their terrain and opening up whole new worlds for planetary scientists to explore.


Images of Io showed a bizarre yellow, orange, and brown world with at least eight active volcanoes spewing material into space, making it one of the most geologically active planetary bodies in the solar system. Volcanic plumes from Io may be responsible for the sulfur and oxygen in Jovian space due to their sulfur dioxide content.

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As part of its preparation for its meeting with Saturn, Voyager 1 completed an initial course correction following its encounter with Jupiter on April 9, 1979.

A second correction on October 10, 1979, made sure that the spacecraft wouldn't hit Saturn's moon Titan. Its flyby of Saturn in November 1979 was as exciting as its previous encounter. During Voyager 1, scientists discovered five new moons, thousands of bands within a ring system, transient clouds of tiny particles known as "spokes" in the B-ring, a new ring (the G-ring), and satellites that shepherd the F-rings.


The spacecraft photographed Titan, Mimas, Enceladus, Tethys, Dione, and Rhea during its flyby of Saturn. According to incoming data, all the moons appeared to be composed mostly of water ice. The most interesting target was Titan, which Voyager 1 passed at 05:41 UT on Nov. 12, 1979.


The surface was hidden by a thick atmosphere in the images. The spacecraft found that 90% of the moon's atmosphere is nitrogen. At Titan's surface, the pressure was 1.6 atmospheres, and the temperature was minus 292 degrees Fahrenheit (minus 180 degrees Celsius). Atmospheric data indicate that liquid might exist on Titan's surface for the first time. Titan might also be able to support prebiotic chemical reactions due to the presence of nitrogen, methane, and more complex hydrocarbons.


In 1980, Voyager 1 came closest to Saturn at 23:46 UT, at a range of 78,290 miles (126,000 kilometers). After its encounter with Saturn, Voyager 1 left the solar system at about 3.5 AU (325 million miles or 523 million kilometers) per year, 35 degrees to the north of the ecliptic plane and in the direction of the Sun as it moves with nearby stars. Uranus and Neptune were not targeted because of Titan's specific requirements.


Voyager 1 captured about 60 images of the Sun and planets on Feb 14, 1990, the first "portrait" of our solar system seen from space. As the Voyager spacecraft approached 40 AU from the Sun (3.7 billion miles or 6 billion kilometers), a mosaic of those images developed into the famous "Pale Blue Dot" image made famous by Cornell University professor and Voyager team member Carl Sagan (1934-1996).


The image has also been referred to as the "Solar System Family Portrait", even though Mercury and Mars are not visible in the picture. Mercury was too close to the Sun to be seen, and Mars was on the same side of the Sun as Voyager 1, so only its dark side was visible to the cameras. Voyager 1 and 2 were declared part of the Voyager Interstellar Mission (VIM), which began on January 1, 1990, after all the planetary encounters were over in 1989.


NASA's new mission aims to expand its solar system exploration past the outer planets, to the outer limits of the Sun's sphere of influence, and possibly beyond. In this study, the transition between the heliosphere and the interstellar medium will be investigated, a region dominated by solar and magnetic fields.


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The Voyager 1 spacecraft overtook Pioneer 10 on Feb. 17, 1998, becoming the most distant human-made object in the universe at 69.4 AU from the Sun. The Voyager team announced on Dec. 16, 2004, that the spacecraft had reported high magnetic field intensity values at 94 AU, indicating that it had reached the termination shock and entered the heliosheath. It exited the heliosphere on Aug. 25, 2012.


The 40th anniversary of Voyager 1's launch was marked on Sept. 5, 2017. The spacecraft continues to communicate with NASA's Deep Space Network and send data back from four still-functioning instruments, including a cosmic ray telescope, a magnetometer, and a plasma wave experiment.


In each Voyager, a team led by Carl Sagan prepared a message in the form of a gold-plated copper disc with a diameter of 12 inches (30 centimeters) for extraterrestrials who might find the spacecraft. Like Pioneers 10 and 11, the record has symbols to show Earth's relative position to several pulsars. As with vinyl records, it includes instructions for playing them with cartridges and needles.

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The disc contains greetings in 55 languages, 35 sounds from life on Earth (like whale songs, laughter, etc.), and 90 minutes of generally Western music from Mozart and Bach to Chuck Berry and Blind Willie Johnson. Also included are 115 images of life on Earth and greetings from then-US President Jimmy Carter (1924-2007) and then-UN Secretary-General Kurt Waldheim (1918-2007).


The two Voyagers are now over 11 billion miles (18 billion kilometers) away from the Sun. Mission engineers began implementing a new plan to manage the vintage robots in 2019 to ensure they continue to return the best scientific data. Making difficult decisions about the spacecraft's instruments and thrusters is part of the plan.