Orbiting Vehicle or OV, originally designated SATAR (SATellite - Atmospheric Research), comprised five different series of standardized American satellites operated by the US Air Force, launched between 1965 and 1971. Forty seven satellites were built, of which forty three were launched and thirty seven reached orbit. With the exception of the OV3 series and OV4-3, they were launched as secondary payloads, using excess space on other missions. This resulted in extremely low launch costs and short proposal-to-orbit times. Typically, OV satellites carried scientific and/or technological experiments, 184 being successfully orbited through the lifespan of the program. A common research focus was assessing the hazards of the near Earth environment to astronauts and equipment.

The first OV series, designated OV1, was built by General Dynamics and carried on suborbital Atlas missile tests; the satellites subsequently placed themselves into orbit by means of an Altair-2 kick motor. The three (of five planned) Northrop-built OV2 satellites were built using parts left over following the cancellation of the Advanced Research Environmental Test Satellite and flew on Titan IIIC test flights. Space General built the OV3 satellites, the only series to be launched on dedicated rockets; six were launched on Scout-B rockets between 1966 and 1967. OV4 satellites were launched as part of a test flight for the Manned Orbiting Laboratory (MOL), with two satellites conducting a communications experiment whilst a third, OV4-3, was the primary payload, a boilerplate mockup of the MOL space station. Two further OV4 satellites, duplicates of the first two, were built but not launched. OV5 satellites were launched as secondary payloads on Titan IIIC rockets as part of the Environmental Research Satellite program.

The OV program was phased out in the late 1960s, succeeded by the Space Test Program, which focused on tailored satellites with specific payloads rather than standardized ones. The last of the series (an OV1) flew in 1971 (under the auspices of the new program).

The Orbiting Vehicle satellite program arose from a US Air Force initiative, begun in the early 1960s, to reduce the expense of space research. Through this initiative, satellites would be standardized to improve reliability and cost-efficiency, and where possible, they would fly on test vehicles and/or piggybacked on other satellite launches. In 1961, the Air Force Office of Aerospace Research (OAR) created the Aerospace Research Support Program (ARSP) to request satellite research proposals and choose mission experiments. The USAF Space and Missiles Organization created their own analog of the ARSP called the Space Experiments Support Program (SESP), which sponsored a greater proportion of technological experiments than the ARSP.

In 1966, the OAR annual budget was only about US$10,000,000 (equivalent to $96,912,821 in 2024), which was notably low. This was partly possible due to the satellites being launched as secondary payloads on rocket test flights. Since these were necessarily of lower reliability than launches on seasons rockets, this meant the failure rate was higher: of the five OV missions launched in 1965, only one was successful. As each rocket launched to a unique orbit, failure to loft a satellite on a given launch meant the loss of data to be gained on that particular course. Experiments built for a certain flight, designed for their rocket's orbit, often had no back-up.

Experiments to be flown on the OV satellites (as well as the 100+ sounding rockets also flown under the auspices of OAR) were proposed by various laboratories in pursuit of their current research projects. These ranged in size from small black boxes to complete satellites. Each lab supported the building and testing of experiments as well as analysis of data returned from them. OAR prioritized the experiments on their scientific or engineering merit and also their feasibility; after picking the experiments, OAR then modified their choices based on funding available and managerial oversight. These final choices were passed by Air Force Headquarters and the Department of Defense—NASA was also consulted to ensure they were not launching flights to acquire the same data. OAR selected 22 experiments for satellite flights in 1966 and 30 for 1967.

Implementation of the OV program, as well as procurement of the launching rockets, was generally carried out by the Los Angeles OAR office, commanded by Lt. Col. John C. Hill, and sited at Air Force Space Systems Division (SSD) Headquarters in Los Angeles. Integration of the rocket and satellite was managed by SSD and the Air Force Ballistic Systems Division.

Five distinct OV series of standardized satellites were developed under the auspices of these agencies.