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
Soviet space dogs the preferred animal for the experiments because scientists felt dogs were well suited to endure long periods of inactivity. As part of their training, they were confined in small boxes for 15–20 days at a time. Stray dogs, rather than animals accustomed to living in a house, were chosen because the scientists felt they would be able to tolerate the rigorous and extreme stresses of space flight better than other dogs. Female dogs were used because of their temperament and because the suit the dogs wore in order to collect urine and feces was equipped with a special device, designed