Voyager program
NASA’s planetary exploration program sent Voyager 1 and Voyager 2 to study the outer planets and, later, the space beyond the heliosphere.
Voyager 1: NASA spacecraft launched in 1977 that studied Jupiter and Saturn before entering interstellar space. Its Saturn encounter redirected it onto a trajectory out of the planetary region.
Gravity assist: A maneuver that changes a spacecraft’s speed and direction by passing near a moving celestial body. Planetary flybys supplied the momentum needed to reach distant targets.
Planetary Grand Tour: A proposed late-20th-century mission concept to visit the outer planets during a favorable alignment. Its ambitious plan supplied the scientific vision behind Voyager’s planetary itinerary.
Jupiter: The largest planet in the Solar System, a gas giant with a complex atmosphere and extensive moon system. Voyager revealed volcanic activity on Io and detailed Jupiter’s rings and atmosphere.
Voyager 2: NASA spacecraft launched in 1977 that visited all four giant planets and later entered interstellar space. Its trajectory enabled the only close-up visits to Uranus and Neptune.
Grand Tour: A proposed sequence of spacecraft encounters with the outer planets using favorable planetary alignments. Voyager 2 carried out the rare multi-planet tour that this geometry made possible.
Mariner program: NASA’s early planetary exploration program, which sent robotic spacecraft to Mars, Venus, and Mercury. Voyager inherited spacecraft engineering and institutional experience from earlier Mariner missions.
Saturn: The sixth planet from the Sun, a gas giant distinguished by its extensive ring system. Voyager’s flybys mapped its rings, atmosphere, and moons in unprecedented detail.
Voyager Golden Record: A phonograph record carried by both Voyager spacecraft, containing sounds, music, images, and greetings from Earth. The missions carried a cultural message alongside their scientific instruments.
Radioisotope thermoelectric generator: A power source that converts heat from radioactive decay into electricity. Its steady output powered the spacecraft far beyond the reach of sunlight.