Orbiting Vehicle or OV, originally designated SATAR (SATellite - Atmospheric Research), comprised five disparate 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.
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 Northrop-built OV2 satellites were built using parts left over following the cancellation of the Advanced Research Environmental Test Satellite; three OV2 spacecraft 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 ERS project.
Typically, OV satellites carried scientific and/or technological experiments.
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 or be piggybacked with other satellites. 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.:417 Five distinct OV series of standardized satellites were developed under the auspices of these agencies.:425
|Series||Contractor||First launch||Last launch||Built||Launched||Failed to orbit||Remarks|
|OV4||US Air Force
The OV1 series was an evolution 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 was 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 Range causing 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.: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 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):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.:418
|OV1-1||45 kg (99 lb),:24 86 kg (190 lb) with Altair booster||21 Jan 1965||Geophysics; first westward launch of a satellite; orbited, but on-board Altair failed to fire.:24|
|OV1-2||86 kg (190 lb) with Altair booster||1965 078A||5 Oct 1965||Radiation studies|
|OV1-3||92 kg (203 lb)||27 May 1965||Biomedical radiation studies; Atlas failed two minutes into flight.:419|
|OV1-4||87.6 kg (193 lb)||1966 025A||30 Mar 1966||Thermal control experiments|
|OV1-5||114.3 kg (252 lb)||1966 025B||30 Mar 1966||Optical radiation test|
|OV1-6||202 kg||1966 099C||3 Nov 1966||31 Dec 1966||Inflatable decoy|
|OV1-7||117 kg||14 Jul 1966||Failed to orbit|
|OV1-8||3.2 kg||1966 063A||14 Jul 1966||4 Jan 1978||Communications experiment|
|OV1-9||104 kg||1966 111A||11 Dec 1966||Radiation studies|
|OV1-10||130 kg||1966 111B||11 Dec 1966||30 Nov 2002||Radiation studies|
|OV1-11||153 kg||27 July 1967||Failed to orbit|
|OV1-86||105 kg||1966 072D||27 July 1967||22 Feb 1972||Cosmic ray telescope|
|OV1-12||140 kg||1966 072D||27 July 1967||22 Jul 1980||Radiation studies; also known as Flare Activated Radio-biological Observatory (Faro)|
|OV1-13||107 kg||1968 026A||6 Apr 1968||Radiation studies|
|OV1-14||100 kg||1968 026B||6 Apr 1968||Radiation studies|
|OV1-15||213 kg||1968 059A||11 July 1968||6 Nov 1968||Air density, solar studies; also known as Solar Perturbation of Atmospheric Density Experiments Satellite (Spades)|
|OV1-16||272 kg||1968 059B||11 July 1968||19 Aug 1968||Ionospheric drag experiment; also known as Cannonball-1|
|OV1-17||142 kg||1969 025A||18 Mar 1969||5 Mar 1970||Solar studies|
|OV1-17A||221 kg||1969 025D||18 Mar 1969||24 Mar 1969||Ionospheric studies; also known as Orbis Cal-2|
|OV1-18||1969 025B||18 Mar 1969||27 Aug 1972||Ionospheric studies|
|OV1-19||1969 025C||18 Mar 1969||Radiation studies|
|OV1-20||1971 061A||7 Aug 1971||28 Aug 1971||Radar calibration, radiation studies|
|OV1-21||1971 061B||7 Aug 1971||Radar calibration, air density studies|
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 :417:422 (initially the A, ultimately the C) booster test launches. The USAF contracted Northrop to produce these satellites, with William C. Armstrong of Northrop Space Laboratories serving as the program manager.
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.:422
Three OV2 satellites with different mission objectives were originally planned when the OV2 program began. 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.
|OV2-1||170 kg (59 kg experimental payload)||1965 082A||15 Oct 1965||27 Jul 1972||Monitoring biological hazards of near Earth charged particles; failed to separate from LCS-2|
|OV2-2||Cancelled when the Titan-3C test program was changed; was to have conducted optical measurements from orbit.|
|OV2-3||193 kg||1965 108A||21 Dec 1965||Radiation studies; the payload failed to separate from the Transtage and contact was lost after launch.|
|OV2-4||Cancelled when the Titan-3C test program was changed; designed to observe radiation from trans-lunar orbit|
|OV2-5||204 kg||1968 081A||26 Sep 1968||Radiation studies: cosmic rays, trapped particle fluxes and changes in fluxes arising from solar and geomagnetic disturbances|
Unlike the OV1 and OV2 series satellites, which were designed to use empty payload space on rocket test launches, the OV3 series was more akin to its civilian science program counterparts (e.g. Explorer). The six OV3 satellites all had dedicated Scout boosters and an integrated set of experiments. OV3 differed from NASA programs in its heavy use of off-the-shelf equipment, which resulted in lower unit cost.
The basic OV3 was an octagonal prism, .74 m (2 ft 5 in) in length and width, with experiments mounted on booms. 2560 solar cells provided 30 Watts of power. Designed for a six month mission, their attitude in orbit was maintained by a precession damper.
The first four satellites in the series were made the Aerojet subsidiary Space General Corporation under a $1.35m contract awarded 2 December 1964, the first satellite due October 1965. The last two satellites were built by Air Force Cambridge Research Laboratory (AFCRL), which also managed the entire series and provided four of the OV3 payloads.:422–423
Charles H. Reynolds, who worked at AFCRL from 1955, was the technical manager for the OV3 program.
|OV3-1||68 kg||1966 034A||22 Apr 1966||Radiation studies; OPS-1527|
|OV3-2||80 kg||1966 097A||28 Oct 1966||29 Sep 1971||Radiation studies|
|OV3-3||75 kg||1966 070A||4 Aug 1966||Radiation studies|
|OV3-4||79 kg||1966 052A||10 Jun 1966||Radiation studies; also known as Personnel Hazards Associated with Space Radiation (Phasr) or Ops-1427|
|OV3-5||94 kg||31 Jan 1967||Ionospheric studies; also known as Atmospheric Composition Satellite (Atcos)-1; failed to orbit|
|OV3-6||202 kg||1967 120A||4 Dec 1967||9 Mar 1969||Ionospheric studies; also known as Atcos-2|
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.
|OV4-1R||68 kg||1966 099B||3 Nov 1966||5 Jan 1967||"Whispering Gallery" receiver|
|OV4-1T||109 kg||1966 099D||3-Nov-1966||11-Jan-1967||"Whispering Gallery" transmitter|
|OV4-2R||"Whispering Gallery" receiver (cancelled)|
|OV4-2T||"Whispering Gallery" transmitter (cancelled)|
|OV4-3||9661 kg||1966 099A||3-Nov-1966||9-Jan-1967||Boiler plate model of the Manned Orbiting Laboratory (MOL) to which the reconditioned Gemini-2 (which had been used on a sub-orbital flight on 19 January 1965) was attached; included several experiments; also known as Ops-0855|
The first six of this series were tetrahedonal spacecraft, also designated Environmental Research Satellites (ERS).
|OV5-1||6 kg||1967 040E||28 Apr 1967||Materials sciences research; also known as ERS-27|
|OV5-2||10 kg||1968 081B||26 Sep 1968||15 Feb 1971||Radiation studies; also known as ERS-28|
|OV5-3||8.6 kg||1967 040D||28 Apr 1967||Radiation studies; also known as ERS-20|
|OV5-4||12 kg||1968 081C||26 Sep 1968||Heat transfer studies; also known as ERS-21|
|OV5-5||11 kg||1969 046A||23-May-1969||Radiation studies; also known as ERS-29|
|OV5-6||11 kg||1969 046B||23-May-1969||Solar flare studies; also known as ERS-26|
|OV5-7||Solar studies; cancelled|
|OV5-8||9 kg||16 Aug 1968||Materials sciences research – materials friction experiment; failed to orbit|
|OV5-9||13 kg||1969 046C||23 May 1969||Radiation studies – carried low-energy proton detectors, a dE/dx telescope, a Cerenkov counter, a VLF radiation detector, a solar X-ray monitor and a solar flare electron detector to provide further basic research data on solar radiation and its effects on the magnetosphere|