NASA’s IRAS became the first space observatory dedicated to infrared astronomy.
The Infrared Astronomical Satellite launched in January 1983 as a joint project involving NASA, the Netherlands, and the United Kingdom. Operating above Earth’s atmosphere was essential because atmospheric water vapor blocks much infrared radiation from reaching ground-based telescopes.
IRAS surveyed more than 96 percent of the sky during its roughly ten-month mission. It discovered hundreds of thousands of infrared sources, including previously hidden star-forming regions, galaxies, and dusty stellar systems. The survey also identified a disk of dust around the nearby star Vega, helping popularize the study of debris disks around other stars.
IRAS used liquid helium to cool its instruments. Once that coolant ran out, its main survey ended. Later infrared missions such as Spitzer and WISE built on its pioneering all-sky observations.