Explorer_S-56_(satellite)
Explorer S-56 (satellite)
American air density research satellite launched in 1960
Explorer S-56 was a NASA satellite launched on 4 December 1960, at 21:14 GMT as part of the Explorer program.[1] The satellite was composed of a 3.66 m (12.0 ft) diameter inflatable sphere, and was intended to study the density of the upper atmosphere. The Scout X-1 rocket used to launch Explorer S-56 failed in flight, and the satellite never reached orbit.[2]