Orbiting Vehicle 1–13 was a satellite launched on 6 April 1968 to measure the level of radiation in orbit at altitudes as high as 8,000 km. Part of the OV1 series of USAF satellites, using standardize

Orbiting Vehicle 1–14 was a satellite launched 6 April 1968 to measure electromagnetic interference and measure proton and electron flux at altitudes up to 8,000 km. OV1-14 was also supposed to study