OSO 3
| File:Oso3 small.gif The third Orbiting Solar Observatory, OSO 3, showing its "Sail" (upper), carrying solar experiments pointed at the Sun, and its rotating "Wheel" (lower), carrying two sky-scanning survey instruments: the UCSD hard X-ray experiment, and the MIT gamma-ray telescope | |
| Mission type | Solar physics |
|---|---|
| Operator | NASA |
| COSPAR ID | 1967-020A |
| Mission duration | 2 years, 8 months |
| Spacecraft properties | |
| Manufacturer | BBRC |
| Launch mass | 281 kilograms (619 lb) |
| Start of mission | |
| Launch date | March 8, 1967, 16:19:00 UTC |
| Rocket | Delta C |
| Launch site | Cape Canaveral LC-17A |
| End of mission | |
| Last contact | November 10, 1969 |
| Decay date | April 4, 1982 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.002164 |
| Perigee altitude | 534 kilometers (332 mi) |
| Apogee altitude | 564 kilometers (350 mi) |
| Inclination | 32.87 degrees |
| Period | 95.53 minutes |
| Mean motion | 15.07 |
| Epoch | May 8, 1967, 11:19:00 UTC[1] |
OSO 3 (Orbiting Solar Observatory 3), or Third Orbiting Solar Observatory[2][3] (known as OSO E2 before launch) was launched on March 8, 1967, into a nearly circular orbit of mean altitude 550 km, inclined at 33° to the equatorial plane. Its on-board tape recorder failed on June 28, 1968, allowing only the acquisition of sparse real-time data during station passes thereafter; the last data were received on November 10, 1969. OSO 3 reentered the Earth's atmosphere and burned up on April 4, 1982.
Like all of the early Orbiting Solar Observatory (OSO) series satellites, it had two major segments: one, the "Sail", was stabilized to face the Sun, and carried both solar panels and Sun-pointing experiments for solar physics. The other, "Wheel" section, rotated to provide overall gyroscopic stability and also carried sky-scanning instruments that swept the sky as the wheel turned, approximately every 2 seconds. OSO-8, the final spacecraft in this series, had 3-axis pointing.
Instrumentation
[edit | edit source]| Name | Target | Principal Investigator |
|---|---|---|
| High Energy Gamma Ray (> 50 MeV) | anti-solar | Kraushaar, W. L., Massachusetts Institute of Technology |
| Cosmic Ray Spectrum Detector and Gamma Ray Analyzer | Sun, all-sky | Kaplon, Morton F, University of Rochester |
| Directional Radiometer Experiment | Earth | Neel, Carr B Jr, NASA Ames Research Center |
| Earth Albedo (0.32- to 0.78-μm) | Earth | Neel, Carr B Jr, NASA Ames Research Center |
| Solar EUV Spectrometer 0.1 to 40.0 nm | Sun | Neupert, Werner M, NASA Goddard Space Flight Center |
| 0.8- to 1.2-nm Solar X-Ray Ion Chamber | Sun | Teske, Richard G, University of Michigan |
| Solar and Celestial Gamma-Ray Telescope (7.7 to 200 keV) | Sun, all-sky | Laurence E. Peterson University of California, San Diego |
| Thermal Radiation Emissivity | near-Earth space environment | Neel, Carr B Jr, NASA Ames Research Center |
| Extreme Ultraviolet Spectrometer | Sun | Hinteregger, Hans E, Phillips Laboratory |
The Sail carried a hard X-ray experiment from UCSD, with a single thin NaI(Tl) scintillation crystal plus phototube enclosed in a howitzer-shaped CsI(Tl) anti-coincidence shield. The energy resolution was 45% at 30 keV. The instrument operated from 7.7 to 210 keV with 6 channels. The Principal Investigator (PI) was Prof. Laurence E. Peterson of UCSD. Also in the wheel was a cosmic gamma-ray (>50 MeV) sky survey instrument contributed by MIT, with PI Prof. William L. Kraushaar.
Scientific results
[edit | edit source]OSO-3 obtained extensive hard X-ray observations of solar flares, the cosmic diffuse X-ray background, and multiple observations of Scorpius X-1, the first observation of an extrasolar X-ray source by an observatory satellite.[4][5][6][7]
The MIT gamma-ray instrument obtained the first identification of high-energy cosmic gamma rays emanating from both galactic and extra-galactic sources.[8]
See also
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References
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- ^ NASA GSFC X-ray Astronomy Satellites and Missions
- ^ [1] Archived August 13, 2009, at the Wayback Machine GSFC HEASARC "The Third Orbiting Solar Observatory (OSO-3)"
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- ^ Pelling, R. M. 1971, Ph.D. dissertation thesis, University of California at San Diego
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External links
[edit | edit source]The content of this article was adapted and expanded from NASA's HEASARC: Observatories OSO 3 [2] and NASA's National Space Science Data Center: OSO 3 [3] Archived March 2, 2021, at the Wayback Machine (Public Domain)
