July 12, 1961

1961: Midas 3 (Missile Defense Alarm System), a 3,527-pound infrared missile-scanning satellite went into a near-circular polar orbit from Point Arguello, Calif. With a “kick-in-the-apogee” technique, scientists maneuvered it from an elliptical orbit into a high circular orbit. It was the heaviest object orbited by the US to date.