NSSDCA ID: 1969-068A-06
Mission Name: OSO 6This experiment simultaneously measured the solar EUV flux in several spectral lines--Fe XI at 180 A, He II at 256 A, He II at 304 A, He I at 537 A, O II, III at 835 A, N III at 991 A, C III at 1175 A, and H I at 1216 A--(1) to determine flux changes and density variations in active regions at various heights above the photosphere, (2) to determine the radiation input heating the earth's atmosphere, and (3) to measure the density of the earth's thermosphere by the absorption of the solar EUV at satellite dusk and dawn. The instrument consisted of a grazing incidence grating spectrometer utilizing channel photomultipliers as detectors. The instrumental field of view was plus or minus 2 deg in pitch and plus or minus 1/2 deg in spin. Inflight X-ray calibration of the detectors was accomplished using an iron 55 radioactive source. Inflight grating calibration was accomplished by simultaneous measurement of the solar Lyman-alpha flux at 1216 A. The background noise of each detector was less than 0.5 counts per second. Counts from each detector were stored in 8-bit scalers with prescalers that divided by four to extend the range to 636 counts. Each detector was read out successively during a rotation of the spacecraft. The three high-voltage supplies and the X-ray calibration source could be commanded on or off independently. During the first month of operation (August 1969), the spacecraft pitch angle of minus 2 deg compromised the flux accuracy, but after the first month the pitch angle was kept within plus or minus 1 deg. The experiment was operated only during satellite daytime (60 min of each 96 min orbit). The sensitivity of the experiment was degraded by a factor of three in 9 months, although the experiment was still operable at that time. High-voltage supply problems developed in May to August 1970. The experiment was turned off on January 21, 1972. For more information, see B. E. Woodgate et al., Proc. Roy. Soc. Lon., v. A 332, p. 291, 1973.
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Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Bruce E. Woodgate | Other Investigator | NASA Goddard Space Flight Center | |
Sir Robert L. F. Boyd | Principal Investigator | University College, London |