OSO

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OSO
Credit - NASA

Class: Solar. Destination: Medium Earth Orbit. Nation: USA. Agency: NASA. Manufacturer: Ball.

The Orbiting Solar Observatories, developed for NASA's Goddard Space Flight Center, were designed primarily as stabilized platforms for solar-oriented scientific instruments. The OSOs permitted the first extended study of the sun (from above the earth's filtering atmosphere) with accurate positioning. Experiments on the satellites studied the sun, flares and other solar activities, X-ray, gamma and ultraviolet radiation and radiation from extra-solar sources.

The two section space observatory was stabilized because the lower section, the "wheel," spinned as a gyroscope at a near constant 30 revolutions per minute. The upper fan-shaped section, the "sail," was joined to the wheel by a connecting shaft and remained pointed toward the sun during the OSO daytime. Experiments in the wheel scanned the sun every 2 seconds and those in the sail pointed continuously at the sun. The OSO was placed in orbit 565 km above earth by a Delta booster and circled the earth every 96 minutes. Each spacecraft weighed from 200 to 280 kg (including experiments) and carried up to 9 experiments Each of the 3 successful OSO's exceeded their five month design specification. OSO 1, launched March 7, 1962, was. in operation nearly 18 months; OSO 2, launched February 3, 1965, nearly 9 months; OSO 3, launched March 8, 1967, and OSO 4, launched October 18, 1967, continued to send back scientific data through year-end 1968. Prime Contractor was Ball Brothers Research Corporation.

Typical orbit: 501 km circular orbit, 32.9 deg inclination.

OSO Chronology

1962 March 7 - OSO 1 - Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Mass: 208 kg (458 lb). Perigee: 522 km (324 mi). Apogee: 553 km (343 mi). Inclination: 32.80 deg. Period: 95.30 min.
Orbiting Solar Observatory; solar flare observations. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1965 February 3 - OSO 2 - Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. Mass: 247 kg (544 lb). Perigee: 294 km (182 mi). Apogee: 306 km (190 mi). Inclination: 32.80 deg. Period: 90.50 min.
Orbiting Solar Observatory; returned solar X-ray, UV, gamma ray data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1965 August 25 - OSO C - Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. FAILURE: Premature third stage ignition. Mass: 280 kg (610 lb).

1967 March 8 - OSO 3 - Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Mass: 281 kg (619 lb). Perigee: 546 km (339 mi). Apogee: 570 km (350 mi). Inclination: 32.80 deg. Period: 95.80 min.
Orbiting Solar Observatory. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1967 October 18 - OSO 4 - Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. Mass: 272 kg (599 lb). Perigee: 552 km (342 mi). Apogee: 555 km (344 mi). Inclination: 32.90 deg. Period: 95.70 min.
Extreme UV solar observations. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1969 January 22 - OSO 5 - Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. Mass: 291 kg (641 lb). Perigee: 538 km (334 mi). Apogee: 559 km (347 mi). Inclination: 33.00 deg. Period: 95.60 min.
Orbiting Solar Observatory; solar radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1969 August 9 - OSO 6 - Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Mass: 290 kg (630 lb). Perigee: 489 km (303 mi). Apogee: 554 km (344 mi). Inclination: 32.90 deg. Period: 95.10 min.
Orbiting Solar Observatory; solar physics experiments. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1971 September 29 - OSO 7 - Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Mass: 635 kg (1,399 lb). Perigee: 326 km (202 mi). Apogee: 572 km (355 mi). Inclination: 33.10 deg. Period: 93.50 min.
Orbiting Solar Observatory. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

1975 June 21 - OSO 8 - Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. Mass: 1,066 kg (2,350 lb). Perigee: 539 km (334 mi). Apogee: 553 km (343 mi). Inclination: 32.90 deg. Period: 95.60 min.
Orbiting Solar Observatory. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Bibliography:

McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: http://www.planet4589.org/jsr.html.
JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: http://msl.jpl.nasa.gov/home.html.
Bramscher, Robert G, Spaceflight, "A Survey of Launch Vehicle Failures", 1980, Volume 22, page 351.
Aerospace Yearbook, 1966,
NASA Report,
NASA Report, The Observatory Generation of Satellites, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19630005290_1963005290.pdf.
NASA Report, Preliminary Solar Flare Observations with Soft X-ray Spectrometer on Orbiting Solar Observatory Satellite , Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19630006832_1963006832.pdf.
NASA Report, Orbiting Solar Observatory Satellite OSO 1- The Project Summary, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660020192_1966020192.pdf.
NASA Report, Scientific Results of the First Orbiting Solar Observatory, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19640001345_1964001345.pdf.
NASA Report, The OSO 1 Solar Neutron Experiment, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19670010533_1967010533.pdf.
NASA Report, OSO spacecraft manual, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19670002066_1967002066.pdf.
NASA Report, History of orbiting solar observatory OSO-2, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19670002039_1967002039.pdf.
NASA Report, Observations of solar active regions and solar flares by OSO-7, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780009034_1978009034.pdf.
NASA Report, Orbiting Solar Observatory - B Final Report, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680065429_1968065429.pdf.
NASA Report, OSO-1 Final Program Report; Performance Evaluation of the OSO-1, Web Address when accessed: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770008119_1977008119.pdf.

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