After lobbying in the 1960s and 70s for such a system to be built , Spitzer 's vision ultimately materialized into the world 's first space-based optical telescope , the Hubble Space Telescope , which was launched on April 20 , 1990 by the Space Shuttle Discovery ( STS-31 ) .
His efforts resulted in the world 's first space-based optical telescope , Hubble Space Telescope , which was launched on April 20 , 1990 by the Space Shuttle Discovery ( STS-31 ) .