The Voyagers: The Longest Travelling Spacecrafts Ever

Voyagers 1 and 2 are identical spacecraft, equipped with television cameras, infrared and ultraviolet sensors, magnetometers, plasma detectors, cosmic-ray, charged-particle sensors, and a spacecraft radio, launched as a part of NASA’s twin series in 1977.

Instead of solar panels, the Voyagers were powered using radioisotope thermoelectric generators (RTGs). These devices, used on deep space missions, convert the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft instruments, computers, radio and other systems.

The initial missions of the Voyagers were to conduct closeup studies of Jupiter and Saturn, Saturn's rings, and the larger moons of the two planets. And hence, they were built to last for 5 years, but one of the twins Voyager 2 is still active today.

The Voyager mission was designed in the late 1970s-80s to take advantage of a rare geometric arrangement of the outer planets which created conditions for a four-planet tour with a minimum of propellant fuel and trip time. This layout of Jupiter, Saturn, Uranus and Neptune, which occurs about every 175 years, allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems, making use of the gravity assist technique.

NASA, however, assessed that it would be too expensive to build spacecraft that could go the distance, carry the instruments needed and last long enough to accomplish this impossibly long mission. Thus, the Voyagers were funded to conduct intensive flyby studies of Jupiter and Saturn only. More than 10,000 trajectories were studied before choosing the two that would allow close flybys of Jupiter its large moon Io, and Saturn along with its large moon Titan; the chosen flight path for Voyager 2 also preserved the option to continue to Uranus and Neptune.?

12 years through the mission the spacecraft had already collected exceptional data about the four planets, revealing unexpected facts.

1. Jupiter- the presence of active volcanoes on Jupiter and Io, Io’s impact on Jupiter’s magnetosphere, a revelation of the mystery of the red spot, a persistent high-pressure region in the atmosphere of Jupiter, producing the largest anticyclonic storm in the solar system.
2. Saturn - The discovery of five new moons, and the presence of a new ring called the G-ring.
3. Uranus-At Uranus, Voyager 2 discovered 10 new moons and two new rings.
4. Neptune-At Neptune, Voyager 2 discovered five moons, four rings, and a "Great Dark Spot” a hole in the methane cloud deck of Neptune.

On Feb. 14, 1990, Voyager 1’s cameras were pointed backwards and captured about 60 images of the Sun and planets –known to be the first "family portrait" of our solar system as seen from the outside. The images were taken when the spacecraft was about 40 AU from the Sun (3.7 billion miles or 6 billion kilometres).

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