GALEX Basics

  • What is GALEX?

    The Galaxy Evolution Explorer (GALEX) is a NASA Small Explorer Class mission that is investigating the causes and evolution of star formation in galaxies over the history of the Universe.

  • When was GALEX launched?

    GALEX was launched from Cape Canaveral Air Force Station in Florida on April 28th, 2003.

  • How large is GALEX?

    GALEX weighs only 280 kilograms (a little over 617 pounds). It is 2 meters (6 feet 6 inches) tall and, with its solar panels unfurled, it is 2.8 meters (9 feet) wide. It was designed to fit into the nose cone of the Pegasus launch vehicle and so began its journey with its solar panels wrapped around the spacecraft. So until it reached orbit around the Earth it was only 1.1 meters (3 feet 8 inches) wide.

  • Can GALEX look at the Earth?

    No. The instruments on GALEX are designed to look at very faint objects in the sky. Because the detectors on GALEX are so sensitive, the telescope on GALEX must always be pointed away from the Earth and the Sun. In fact, the detectors are so sensitive that GALEX cannot look at any of the stars that we can see with the naked eye from the ground! This still leaves a lot of sky to survey and GALEX will need 29 months to complete its mission of surveying the Universe.

  • How long can GALEX stay in orbit?

    The batteries and solar panels that provide power to the spacecraft and telescope have a projected lifetime of 12 years and the orbit of GALEX is stable for at least 25 years after launch. Although originally planned as a 29-month mission, the NASA Senior Review Panel in 2006 recommended that the mission lifetime be extended.

  • Is GALEX data available to the public?

    All observations made by GALEX are publicly available through the Multimission Archive at the Space Telescope institute (MAST).