Solrad 8
Mission typeSolar science
OperatorNASA
COSPAR ID1965-093A
SATCAT no.1738
Mission duration58 years, 1 month and 25 days (in orbit)
Spacecraft properties
ManufacturerNaval Research Lab
Launch mass56.7 kilograms (125 lb)
Start of mission
Launch dateNovember 19, 1965, 22:11:30 (1965-11-19UTC22:11:30Z) UTC [1][2]
RocketScout X-4
Launch siteWallops LA-3
End of mission
Last contactAugust 1967 (1967-09)
Orbital parameters
Reference systemGeocentric[3]
RegimeCircular orbit
Eccentricity0.01302
Perigee altitude704 kilometers (437 mi)
Apogee altitude891 kilometers (554 mi)
Inclination59.7 degrees
Period100.8 minutes
Epoch19 November 1965, 04:48:00 UTC
 

The SOLRAD 8,Explorer 30 or SE-A satellite was one of the NASA SOLRAD (Solar Radiation) program that began in 1960 to provide continuous coverage of solar radiation with a set of standard photometers. SOLRAD 8 was a spin-stabilized satellite oriented with its spin axis perpendicular to the sun-satellite line so that the 14 solar X-ray[4] and ultraviolet photometers[5] pointing radially outward from its equatorial belt viewed the sun on each revolution. Data were transmitted in real time by means of an FM / AM the satellite's telemetry system and were recorded by the stations on the Spacecraft Tracking and Data Acquisition Network (STADAN) tracking network.[6]

Eclipse 1966

The satellite observed the solar eclipse on 20 May 1966.[7] This observation may have been the first observation of a solar eclipse by an artificial satellite.[7]

Mission

The satellite performed normally, except for the spin system, which failed to maintain 60 rpm (at spin rates below 10 rpm data reduction became difficult). The spin rate gradually decreased to 4 rpm on 12 September 1966. At that time, ground command succeeded in reactivating spinup to 78 rpm, which exhausted the gas supply. From this point, the spin rate gradually decreased to 10 rpm in August 1967, when data collection was substantially decreased.[6]

The satellite performed normally, except for the spin system,[8] which failed to maintain 60 rpm (at spin rates below 10 rpm data reduction became difficult). The spin rate gradually decreased to 4 rpm on September 12, 1966.[9] At that time, ground command succeeded in reactivating spinup to 78 rpm, which exhausted the gas supply. From this point, the spin rate gradually decreased to 10 rpm in August 1967, when data collection was substantially decreased.[10]

Experiment

Solar X-Ray and Ultraviolet Monitor

This experiment was designed to monitor solar X-ray and ultraviolet emissions with a set of standardized detectors so that the data could be compared directly with that produced by other experiments in the SOLRAD series. Eight ion chambers and two Geiger counters covering the spectral regions from 0.5 A to 60 A and 1080 A to 1350 A were mounted perpendicular to the satellite spin axis. Analog outputs from the detectors were transmitted continuously on six IRIG telemetry channels. The experiment provided good data for all detectors from 27 November 1965 to 24 August 1967, with the following exceptions: (1) the Lyman-alpha detector and the UV detectors were saturated for normal aspect angles, (2) the core memory failed at launch so that the data were collected in real-time telemetry only, and (3) a gradual decrease in spin rate caused the aspect angle to drift away from normal in the second year of operation.[11]

See also

References

Public Domain This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

  1. ↑ "Solar-observing satellites". Rammb.cira.colostate.edu. Retrieved 2014-05-27.
  2. ↑ "Launch Log". Jonathan's Space Report. 21 July 2021. Retrieved 9 November 2021.
  3. ↑ "Trajectory: Explorer 30 (Solrad 8) 1965-093A". NASA. 28 October 2021. Retrieved 9 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  4. ↑ ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SATELLITE_ENVIRONMENT/XRAY_BGND/docs/solrad.txt
  5. ↑ "Solrad". Designation-systems.net. Retrieved 2014-05-27.
  6. 1 2 "Display: Explorer 30 (Solrad 8) 1965-093A". NASA. 28 October 2021. Retrieved 9 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  7. 1 2 Landini, M.; Russo, D.; Tagliaferri, G. L. (1966). "Solar Eclipse of 20 May 1966, observed by the Solrad 8 Satellite in X-ray and Ultraviolet Bands". Nature. 211 (5047): 393. Bibcode:1966Natur.211..393L. doi:10.1038/211393a0. S2CID 4174785.
  8. ↑ "SOLRAD 8". Space Archaeology. Archived from the original on 2017-12-08. Retrieved 2014-05-27.
  9. ↑ National Research Council (U.S.). Space Science Board, COSPAR (1967). United States Space Science Program: Report to COSPAR. National Academies. p. 47.
  10. ↑ "NASA:SP-4312 Dreams, Hopes, Realities-Chapter 1:Goddard's First Forty: The Quest to Learn". History.nasa.gov. 1957-10-04. Retrieved 2014-05-27.
  11. ↑ "Experiment: Solar X-Ray and Ultraviolet Monitor". NASA. 28 October 2021. Retrieved 9 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.

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