Corona (satellite) retrieved two days later by a C-119 Flying Boxcar transport plane. This was the first successful return of photographic film from orbit. In comparison, Sputnik 5 was launched into orbit on August 19, 1960, one day after the launch of Discoverer 14. Sputnik 5 was a biosatellite that took into orbit the two Soviet space dogs, Belka and Strelka, and then safely returned them to the Earth . At least two launches of "Discoverers" were used to test satellites for the Missile Defense Alarm System (MIDAS), an early missile-launch-detection program that used infrared cameras to detect the heat signature of
Korabl-Sputnik 2 orbit by a Swedish radio station. The spacecraft carried two dogs, Belka and Strelka, 40 mice, two rats and a variety of plants, as well as a television camera, which took images of the dogs. One of its objectives was to intercept the US Echo 1A satellite, which was a passive, nitrogen-filled balloon covered in reflective foil and thus highly visible as it passed overhead. Korabl-Sputnik 2 passed near Echo on the second orbit, and the radio system returned audio of the dogs barking as they saw it out the window. The spacecraft returned to Earth at 06:00:00 UTC on