  We give an overview of the Galaxy Evolution Explorer (GALEX), a NASA Explorer
Mission launched on April 28, 2003. GALEX is performing the first space UV
sky-survey, including imaging and grism surveys in two bands (1350-1750
Angstroms and 1750-2750 Angstroms). The surveys include an all-sky imaging
survey (m[AB] ~ 20.5), a medium imaging survey of 1000 square degrees (m[AB] ~
23), a deep imaging survey of 100 square degrees (m[AB] ~ 25), and a nearby
galaxy survey. Spectroscopic grism surveys (R=100-200) are underway with
various depths and sky coverage. Many targets overlap existing or planned
surveys. We will use the measured UV properties of local galaxies, along with
corollary observations, to calibrate the UV-global star formation rate
relationship in local galaxies. We will apply this calibration to distant
galaxies discovered in the deep imaging and spectroscopic surveys to map the
history of star formation in the universe over the redshift range 0 < z < 1.5,
and probe the physical drivers of star formation in galaxies. The GALEX mission
includes a Guest Investigator program supporting the wide variety of programs
made possible by the first UV sky survey.
