* Astronomy

OSCAR is an acronym for Orbiting Satellite Carrying Amateur Radio. OSCAR series satellites use amateur radio frequencies to facilitate communication between amateur radio stations.
The first amateur satellite simply named OSCAR-1, was launched on December 12, 1961, barely four years after the launch of world's first satellite, Sputnik I.
Source

Barely four months after the successful launch of Sputnik I, the United States launches the unmanned Explorer I on January 31, 1958. At about that same time, a group of hams on the West Coast -- Lance Ginner, K6GSJ; Chuck Smallhouse, W6MGZ; Ed Beck, K6ZX; Al Diem; Chuck Townes, K6LFH (SK), and Nick Marshall, W6OLO (SK) -- begin toying with the idea of launching an Amateur Radio satellite into orbit and organized themselves into Project OSCAR. After a series of high level exchanges among Project OSCAR members, the ARRL and the US Air Force, a launch opportunity on a Thor DM-21 Agena-B rocket from Vandenberg Air Force Base in California was secured for the very first Amateur Radio satellite: OSCAR I. It was successfully launched into a low Earth orbit on the morning of December 12, 1961 -- four years after the launch of Sputnik I. The satellite was also the worlds first non-government bird.
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