OV1-13/OV1-14

Orbiting Vehicle 1–13 (also known as OV1-13) was a satellite launched on 6 April 1968 to measure the level of radiation in orbit at altitudes as high as 8,000 km (5,000 mi). Part of the OV1 series of USAF satellites, using standardized designs and sent to orbit on decommissioned Atlas ICBMs to reduce development and launching costs, OV1-13 was launched side-by-side with OV1-14. The launch marked the first usage of the Atlas F in the OV program. Operating for more than a year and a half, OV1-13 mapped the grosser characteristics of the Van Allen radiation belts and contributed to the understanding of how particles flow and cause increased intensities during solar storms. As of 12 May 2023, OV1-13 is still in orbit.

Orbiting Vehicle 1–14 (also known as OV1-14) was a satellite launched on 6 April 1968 to measure electromagnetic interference and measure proton and electron flux at altitudes up to 8,000 km (5,000 mi). OV1-14 was also supposed to study the Sun in the Lyman-alpha line. Part of the OV1 series of USAF satellites, using standardized designs and sent to orbit on decommissioned Atlas ICBMs to reduce development and launching costs, OV1-14 was launched side-by-side with OV1-13. The launch marked the first usage of the Atlas F in the OV program. Unfortunately, the satellite failed after four to seven days, returning about 24 hours of usable data.