Orbiting Vehicle 1-4 (also known as OV1-4), launched 30 Mar 1966, was the fourth, and second successful, satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-4 was a long-term bioscience and materials science satellite, designed to return data relevant to long-term human presence in space. Its launch marked the first time two satellites (the other being OV1-5) were placed into orbit side-by-side with each other.