Vela 1A and 1B launched in 1963 to detect nuclear explosions in space

An Atlas-Agena booster launched the first Vela satellite pair on Oct. 17, 1963, days after a treaty banned nuclear tests in space, the atmosphere and underwater. Their X-ray, gamma-ray and neutron sensors were built to detect clandestine detonations. Later Vela missions also opened an unexpected window on the cosmos by helping scientists discover gamma-ray bursts.