OV1-2

Summary

OV1-2
Ov1-1.jpg
OV1 series satellite
Mission typeEarth science
OperatorUSAF
Spacecraft properties
ManufacturerGeneral Dynamics
Launch mass86 kg (190 lb) with Altair
Start of mission
Launch date5 Oct 1965 09:07:08 (1965-10-05UTC09:07:08) UTC
RocketAtlas D
Launch siteVandenberg 576-B-3[1]
End of mission
Last contactAug 1967
Orbital parameters
RegimeMedium Earth Orbit
Eccentricity0.18393
Perigee altitude403.00 km (250.41 mi)
Apogee altitude3,462.00 km (2,151.19 mi)
Inclination144.300°
Period125.58 minutes [2]
Epoch1965-10-05 08:20:00
← OV1-3
OV1-4 →
 

Orbiting Vehicle 1-2 (also known as OV1-2), launched 5 October 1965, was the third, and first successful, satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. A radiation measuring satellite designed to conduct research for the planned Manned Orbital Laboratory project, OV1-2 was the first American spacecraft to be placed into orbit on a western (retrograde to Earth's rotation) trajectory. Plagued with technical issues starting from two months into the flight, the satellite stopped functioning in April 1967.

History

In the early 1960s, the US Air Force initiated an effort to reduce the expense of space research. Satellite production was standardized to improve reliability and cost-efficiency. The research satellites 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.[3]:417

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 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.[3]:417

The first OV1 satellite to be launched was OV1-1 on January 21, 1965. Though OV1-1's Atlas booster performed properly, the satellite's onboard Altair rocket did not fire, and the probe was lost. OV1-1 was the only satellite launched on an ABRES mission. Starting with OV1-3, launched and lost May 27, 1965, the remaining OV1 satellites all flew on Atlas D and F missiles that had been decommissioned from ICBM duty.[3]:418–419

Spacecraft design

OV1-2 was, like the rest of the OV1 satellite series, 1.387 m (4 ft 6.6 in) long and .69 m (2 ft 3 in) in diameter, consisting of a cylindrical experiment housing capped with flattened cones on both ends[4] 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.[3]:418

OV1-2 weighed, with its attached Altair booster, 86 kg (190 lb).[5]

Experiments

OV1-2 carried a six experiment package, sponsored by the Biophysics Group of the Air Force Weapons Laboratory to conduct radiation studies in orbit in support of the Manned Orbital Laboratory project. The data collected would be compared to theoretical radiation doses predicted by computer programs on the ground to verify the utility of their models. The experiment package included two tissue-equivalent ion counters and shielded proton-electron dosimeters, a magnetometer, an X-ray detector, and a proton-electron spectrometer.[3]:419

Mission

Launched from Vandenberg's 576-B-3 launch pad at 5 October 1965 09:07:08 UTC via Atlas D rocket,[1] OV1-2 was the first OV1 series satellite to mounted in the nose of the launcher rather than the side-mounted ARS, which instead carried a simulated payload for engineering purposes.[3]:419 Upon release into orbit, OV1-2 tumbled around the Earth, the period of the tumble slowly varying but in the tens of seconds. Though the spacecraft performed normally at first, OV1-2's onboard clock failed on December 1, 1965, this closely followed by the failure of the on-board tape recorder (which allowed data to be stored and transmitted later) on January 13, 1966. Real-time operations were carried out in a limited fashion until total spacecraft failure in April 1967.[2]

Despite its short lifespan, OV1-2 did contribute to the body of radiation data and helped verify various models of the interaction of the Sun and Earth's magnetic fields.[6][7] The data returned on the effectiveness of shielding against radiation doses was particularly significant.[8]

Legacy and status

As of 25 September 2020, OV1-2 is still in orbit, and its position can be tracked on-line.[9]

The OV1 program ultimately comprised 22 missions, the last flying on 19 September 1971.[3]:421

References

  1. ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Report. Retrieved September 25, 2020.
  2. ^ a b "OV1-2". NASA. Retrieved 26 Sep 2020.
  3. ^ a b c d e f g Powell, Joel W.; Richards, G.R. (1987). "The Orbiting Vehicle Series of Satellites". Journal of the British Interplanetary Society. Vol. 40. London: British Interplanetary Society.
  4. ^ Krebs, Gunter. "OV1". Retrieved 24 April 2020.
  5. ^ William R. Corliss (1967). Scientific Satellites. Washington D.C.: Science and Technical Information Division, Office of Technology Utilization, NASA. pp. 770–1. Retrieved 11 May 2020.
  6. ^ Friedman, Herbert (1968). "The Solar XUV Spectrum". The Astronomical Journal Supplement. Astronomical Journal. 73: 61. Bibcode:1968AJS....73R..61F. Retrieved 25 Sep 2020.
  7. ^ Farley, T. A.; Tomassian, A. D; Chapman, M. C. (1969). "Evaluation of the CRAND Source for 10- to 50-Mev trapped protons". Journal of Geophysical Research. 74 (19): 4721. Bibcode:1969JGR....74.4721F. doi:10.1029/JA074i019p04721. Retrieved 26 Sep 2020.
  8. ^ "Aerospace Research Support Program". TRW Space Log. Vol. 5 no. 2 No. 4. Winter 1965–66. p. 15.
  9. ^ "OV1-2". Retrieved 25 Sep 2020.