The Galaxy Evolution Explorer (GALEX) is an orbiting space telescope that is investigating the causes and evolution of star formation in galaxies over the history of the universe. The telescope will help scientists understand how do galaxies grow and change over 10 billion years of cosmic history. It surveys millions of galaxies at ultraviolet wavelengths, enabling researchers to determine where and how rapidly stars are forming within the galaxies. An aircraft-launched Pegasus rocket took GALEX into orbit in April 2003. GALEX was decommissioned June 28, 2013.