Space Shuttle Atlantis launches on mission STS-30 to deploy the Venus-bound Magellan space probe.

Space Shuttle Atlantis is a retired Space Shuttle orbiter vehicle which belongs to NASA, the spaceflight and space exploration agency of the United States. Atlantis was manufactured by the Rockwell International company in Southern California and was delivered to the Kennedy Space Center in Eastern Florida in April 1985. Atlantis is the fourth operational and the second-to-last Space Shuttle built. Its maiden flight was STS-51-J made from October 3 to 7, 1985.

STS-30 was the 29th NASA Space Shuttle mission and the fourth mission for Space Shuttle Atlantis. It was the fourth shuttle launch since the Challenger disaster and the first shuttle mission since the disaster to have a female astronaut on board. The mission launched from Kennedy Space Center, Florida, on May 4, 1989, and landed four days later on May 8, 1989. During the mission, Atlantis deployed the Venus-bound Magellan probe into orbit.

Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" among the planets of the Solar System for its orbit being the closest to Earth's, both being rocky planets and having the most similar and nearly equal size and mass. Venus, though, differs significantly by having no liquid water, and its atmosphere is far thicker and denser than that of any other rocky body in the Solar System. It is composed of mostly carbon dioxide and has a cloud layer of sulfuric acid that spans the whole planet. At the mean surface level, the atmosphere reaches a temperature of 737 K and a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a supercritical fluid. From Earth Venus is visible as a star-like point of light, appearing brighter than any other natural point of light in Earth's sky, and as an inferior planet always relatively close to the Sun, either as the brightest "morning star" or "evening star".