Orbiting Vehicle

In the early 1960s, the US Air Force initiated an effort to reduce the expense of space research by standardizing series of satellites for reliability and cost-efficiency. Space would be utilized on test vehicles and piggyback with other satellites, room permitting. 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.[1]^:417

A typical OV1 satellite

The OV1 series was originally designed as adaptations of the 2.7 m "Scientific Passenger Pods" (SPP), which, starting on 2 October 1961, rode piggyback on suborbital Atlas missile tests and conducted scientific experiments during their short time in space. General Dynamics received a $2 million contract on 13 September 1963 to build a new version of the SPP (called the Atlas Retained Structure (ARS)) that would carry a self-orbiting satellite. Once the Atlas missile and ARS reached apogee, the satellite inside would be deployed and thrust itself into orbit. In addition to the orbital SPP, General Dynamics would create six of these satellites, each to be 3.66 m (12.0 ft) long with a diameter of .762 m (2 ft 6.0 in), able to carry a 136 kg (300 lb) payload into a circular 805 km (500 mi) orbit.

Dubbed "Satellite for Aerospace Research" (SATAR), the series of satellites were originally to be launched from the Eastern Test Range on Atlas missions testing experimental Advanced Ballistic Re-Entry System (ABRES) nosecones. However, in 1964, the Air Force transferred ABRES launches to the Western Test Rangecausing a year's delay for the program. Moreover, because WTR launches would be into polar orbit as opposed to the low-inclination orbits typical of ETR launches, less mass could be lofted into orbit using the same thrust, and the mass of the SATAR satellites had to be reduced.[1]^:417

The standard OV1 satellite, 1.387 m (4 ft 6.6 in) long and .69 m (2 ft 3 in) in diameter, consisted of a cylindrical experiment housing capped with flattened cones on both ends[2] containing 5000 solar cells producing 22 watts of power. Two .46 m (1 ft 6 in) antennae for transmitting telemetry and receiving commands extended from the sides of the spacecraft. 12 helium-pressurized hydrogen peroxide thrusters provided attitude control.

Ultimately, only the first of the SATARs, (OV1-1, called Atmospheric Research Vehicle (ARV) at the time)[3]^:24 ever flew piggyback on an ABRES mission. The rest were flown on ex-ICBM Atlas D and F boosters specifically purchased by the OAR for the OV1 series. Typically, the satellites were mounted in the nose cone of the launching rocket; OV1-1, OV1-3 and OV1-86 were side mounted. A jettisonable propulsion module with an Altair 2 solid-propellant motor provided the thrust for final orbital insertion.

The OV1/Atlas combination was economical for the time, costing just $1.25 million per launch ($4545 per 1 kg (2.2 lb) of payload). The standardized format also afforded a quick experiment proposal-to-launch period of just fifteen months.[1]^:418

OV1 Missions

[7][8]

OV2-2

The OV2 series of satellites was originally designed as part of the ARENTS (Advanced Research Environmental Test Satellite) program, intended to obtain supporting data for the Vela satellites, which monitored the Earth for violations of the 1963 Partial Test Ban Treaty. Upon the cancellation of ARENTS due to delays in the Centaur rocket stage, the program's hardware (developed by General Dynamics) was repurposed to fly on the Titan III [1]^:417:422 (initially the A,[9] ultimately the C) booster test launches.[1] The USAF contracted Northrop to produce these satellites, with William C. Armstrong of Northrop Space Laboratories serving as the program manager.[9]

The OV2 satellites were all designed on the same plan, roughly cubical structures of aluminum honeycomb, .61 m (2.0 ft) in height, and .58 m (1.9 ft) wide, with four 2.3 m (7.5 ft) paddle-like solar panels mounted at the four upper corners, each with 20,160 solar cells. The power system, which included NiCd batteries for night-time operations, provided 63 W of power. Experiments were generally mounted outside the cube while satellite systems, including tape recorder, command receiver, and PAM/FM/FM telemetry system, were installed inside. Four small solid rocket motors spun, one on each paddle, were designed to spin the OV2 satellites upon reaching orbit, providing gyroscopic stability. Cold-gas jets maintained this stability, receiving information on the satellite's alignment with respect to the Sun via an onboard solar aspect sensor, and with respect to the local magnetic field via two onboard fluxgate magnetometers. A damper kept the satellite from precessing (wobbling around its spin axis). Passive thermal control kept the satellite from overheating.[1]^:422

Three OV2 satellites with different mission objectives were originally planned when the OV2 program began.[9] The OV2 series was ultimately expanded to five satellites, all with different goals. Only OV2-5, a radiation and astronomical satellite, achieved a degree of success.[10]

OV2 Missions

[7][8]

The Space General-built OV3 series were of octagonal shape measuring 74 cm in diameter and launched by Scout launch vehicles.

OV3 Missions

[7]

The OV4 series was designed to test components of the Manned Orbital Laboratory (MOL) system (later cancelled). The OV4-1 pair of satellites, dubbed "Whispering Gallery", tested the feasibility of using the ionosphere's F layer as a wave guidance for HF and VHF transmissions between satellites out of line of sight of each other.

OV4 Missions

[7]

The first six of this series were tetrahedonal spacecraft, also designated Environmental Research Satellites (ERS).

OV5 Missions

[7]