Dutch-born US astronomer who made extensive studies of the Solar System. His discoveries included the atmosphere of the planet Mars and that of Titan, the largest moon of the planet Saturn.
Kuiper was adviser to many NASA exploratory missions, and pioneered the use of telescopes on high-flying aircraft. The Kuiper Airborne Observatory, one such telescope, is named after him.

Kuiper was born in Harenkarspel and educated at Leiden, emigrating to the USA 1933. He joined the staff of the Yerkes Observatory (affiliated to the University of Chicago) and was its director 1947-49 and 1957-60. From 1960 he held a similar position at the Lunar and Planetary Laboratory at the University of Arizona.
In 1948, Kuiper correctly predicted that carbon dioxide was one of the chief constituents of the Martian atmosphere. He discovered the fifth moon of Uranus, which he called Miranda, also in 1948; and in 1949 he discovered the second moon of Neptune, Nereid. Kuiper's spectroscopic studies of Uranus and Neptune led to the discovery of features subsequently named Kuiper bands, which indicate the presence of methane.