Astronomy Today

Ultraviolet Space Telescopes

What is the GALEX mission?

The Galaxy Evolution Explorer (GALEX) mission is an orbiting, ultraviolet space telescope that was launched on April 28, 2003. A Pegasus rocket placed GALEX into a nearly circular orbit at an altitude of 432 miles (697 kilometers). Its primary mission has been to take ultraviolet images and photometric measurements of more than 100,000 galaxies, stars, and other astronomical objects. GALEX was designed to be particularly sensitive to very hot stars—usually either very young and luminous main sequence stars, or hot white dwarfs—and thus has made very important discoveries about the star formation histories and processes in both nearby and distant galaxies.


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