Explorer 27: Difference between revisions

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| mission_type =
| mission_type =
| operator = [[NASA]]
| operator = [[NASA]]
| website = [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-032A]
| website =
| Harvard_designation =
| Harvard_designation =
| SATCAT =
| SATCAT =
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Weighing {{convert|130|lb|kg|0|sp=us}}, the satellite was an octagonal spacecraft with a honeycomb [[nylon]] and [[Fiberglas]] hull, {{convert|18|in|cm|0|sp=us}} in diameter, {{convert|12|in|cm|0|sp=us}} high, with four solar panels {{convert|10|in|cm|0|sp=us}} wide and {{convert|66|in|cm|0|sp=us}} long.<ref name=envtest>{{cite web|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650005987.pdf|title=Environmental test program of the beacon explorer spacecraft|publisher = NASA Goddard Space Flight Center; Greenbelt, MD, United States |access-date=October 23, 2019}}</ref>
Weighing {{convert|130|lb|kg|0|sp=us}}, the satellite was an octagonal spacecraft with a honeycomb [[nylon]] and [[Fiberglas]] hull, {{convert|18|in|cm|0|sp=us}} in diameter, {{convert|12|in|cm|0|sp=us}} high, with four solar panels {{convert|10|in|cm|0|sp=us}} wide and {{convert|66|in|cm|0|sp=us}} long.<ref name=envtest>{{cite web|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650005987.pdf|title=Environmental test program of the beacon explorer spacecraft|publisher = NASA Goddard Space Flight Center; Greenbelt, MD, United States |access-date=October 23, 2019}}</ref>


A three-axis [[magnetometer]] and sun sensors provided information on the satellite attitude and spin rate.<ref name=Combrinck> Ludwig Combrinck, 2010. Sciences of Geodesy (Cap. 9). ''Springer-Verlag''. Retrieved June 9, 2018.</ref> There was no tape recorder aboard so that satellite could be received only when the satellite was within range of a ground [[telemetry]] station. Continuous [[Doppler effect|Doppler]] transmitters operated at 162 [[Hertz|MHz]] and 324 MHz to permit precise tracking by [[Transit_(satellite)|Transit]] tracking stations for navigation and geodetic studies.<ref name="nssdc">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1964-064A|title=BE-B|work=NSSDC Master Catalog|publisher=NASA Goddard Space Flight Center}} {{PD-notice}}</ref> Four other transmitters operated on 20, 40, 41, and 360 MHz to measure ionospheric density. S-66's last experiment was an Electron Density Experiment designed for measuring charged particles in the immediate vicinity of the satellite.<ref name=envtest/>
A three-axis [[magnetometer]] and sun sensors provided information on the satellite attitude and spin rate.<ref name=Combrinck> Ludwig Combrinck, 2010. Sciences of Geodesy (Cap. 9). ''Springer-Verlag''. Retrieved June 9, 2018.</ref> There was no tape recorder aboard so that satellite could be received only when the satellite was within range of a ground [[telemetry]] station. Continuous [[Doppler effect|Doppler]] transmitters operated at 162 [[Hertz|MHz]] and 324 MHz to permit precise tracking by [[Transit_(satellite)|Transit]] tracking stations for navigation and geodetic studies.<ref name="nssdc">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1964-064A|title=BE-C|website=NASA Space Science Data Coordinated Archive}} {{PD-notice}}</ref> Four other transmitters operated on 20, 40, 41, and 360 MHz to measure ionospheric density. S-66's last experiment was an Electron Density Experiment designed for measuring charged particles in the immediate vicinity of the satellite.<ref name=envtest/>


S-66 mounted 360 one-inch "cube corner" reflectors made of fused silica<ref name=envtest/> so that the satellite could be tracked via lasers beamed from mobile stations at Goddard's [[Wallops_Flight_Facility|Wallops Island facility]]<ref name=anda/>{{rp|346}}<ref name=philtrans>{{cite journal| date = 1977| title = Goddard laser systems and their accuracies| url = https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1977.0017| journal = Philosophical Transactions of the Royal Society|location = London| publisher = McGraw Hill Publishing Company|pages=443-444|access-date = October 21, 2019}}</ref> and other facilities.
S-66 mounted 360 one-inch "cube corner" reflectors made of fused silica<ref name=envtest/> so that the satellite could be tracked via lasers beamed from mobile stations at Goddard's [[Wallops_Flight_Facility|Wallops Island facility]]<ref name=anda/>{{rp|346}}<ref name=philtrans>{{cite journal| date = 1977| title = Goddard laser systems and their accuracies| url = https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1977.0017| journal = Philosophical Transactions of the Royal Society|location = London| publisher = McGraw Hill Publishing Company|pages=443-444|access-date = October 21, 2019}}</ref> and other facilities.
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==Results==
==Results==


Explorer 27 was turned off on 20 July 1973 because it was interfering with other satellites.<ref name=e27>{{cite web|title=NASA - NSSDCA - Spacecraft - Details|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-032A|website=nssdc.gsfc.nasa.gov}}</ref> The passive laser reflectors continue to be used due to the low inclination.<ref>{{Cite web|url=https://ilrs.cddis.eosdis.nasa.gov/missions/satellite_missions/current_missions/beac_general.html|title=International Laser Ranging Service: Beacon-C|website=ilrs.cddis.eosdis.nasa.gov|access-date=2018-04-19}}</ref>
Explorer 27 was turned off on 20 July 1973 because it was interfering with other satellites.<ref name=e27>{{cite web|title=BE-C|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-032A|website=NASA Space Science Data Coordinated Archive}}</ref> The passive laser reflectors continue to be used due to the low inclination.<ref>{{Cite web|url=https://ilrs.cddis.eosdis.nasa.gov/missions/satellite_missions/current_missions/beac_general.html|title=Beacon-C|website=International Laser Ranging Service|access-date=2018-04-19}}</ref>


==See also==
==See also==

Revision as of 17:01, 11 November 2019

Explorer 27
Depiction of Explorer 27 in orbit
OperatorNASA
COSPAR ID1965-032A Edit this at Wikidata
SATCAT no.01328Edit this on Wikidata
Mission duration~8 Years
Spacecraft properties
ManufacturerGSFC
PowerSolar Panels
Start of mission
Launch date29 April 1965 (1965-04-29)
RocketScout
Launch siteWallops Flight Facility
End of mission
Last contact20 July 1973 (1973-07-21)
Orbital parameters
Reference systemGeocentric
RegimeLEO
Eccentricity0.02618
Perigee altitude932.3 km (579.3 mi)
Apogee altitude1,311.3 km (814.8 mi)
Inclination41.1°
Period107.6 minutes
Instruments
Radio Beacon, Langmuir probe
 

Explorer 27 (or BE-C or Beacon Explorer-C or Beacon-C) was a satellite, launched in 1965, designed to conduct scientific research in the ionosphere.[1] It was powered by 4 solar panels. One goal or the mission was to study in detail the shape of the Earth by way of investigating variations in its gravitational field.[2] It was the third and last of the Beacons in the Explorers program. The satellite was shut off in 1973 because its transmission band was going to be used by higher-priority spacecraft.

Spacecraft design

S-66-35 mounted on vibration table
S-66-35 mounted on vibration table.[3]

Built at the Applied Physics Laboratory [4] under the direction of Goddard Space Flight Center (Project Manager F. T. Martin),[3] S-66 was the last of the five satellites in NASA's first stage of ionospheric exploration, and the first of five NASA geodetic satellites.[5]: 346  Its primary mission was "to conduct ionospheric measurements on a worldwide basis. The program will determine the total electron content of a vertical cross-section of the ionosphere located between the satellite and the earth. Accomplishing this objective will aid in establishing the behavior pattern of the ionosphere as a function of latitude, time of day, season, and solar cycle."[3]

Weighing 130 pounds (59 kg), the satellite was an octagonal spacecraft with a honeycomb nylon and Fiberglas hull, 18 inches (46 cm) in diameter, 12 inches (30 cm) high, with four solar panels 10 inches (25 cm) wide and 66 inches (168 cm) long.[3]

A three-axis magnetometer and sun sensors provided information on the satellite attitude and spin rate.[6] There was no tape recorder aboard so that satellite could be received only when the satellite was within range of a ground telemetry station. Continuous Doppler transmitters operated at 162 MHz and 324 MHz to permit precise tracking by Transit tracking stations for navigation and geodetic studies.[7] Four other transmitters operated on 20, 40, 41, and 360 MHz to measure ionospheric density. S-66's last experiment was an Electron Density Experiment designed for measuring charged particles in the immediate vicinity of the satellite.[3]

S-66 mounted 360 one-inch "cube corner" reflectors made of fused silica[3] so that the satellite could be tracked via lasers beamed from mobile stations at Goddard's Wallops Island facility[5]: 346 [8] and other facilities.

Mission

The first successful S-66 launch occurred on October 9, 1964, whereupon that satellite became known as Explorer 22. Its backup was scheduled for launch in March/April 1965 to extend the geodetic experiments of its predecessor.[9] This launch occurred on April 29, 1965 at 14:17 UT via Scout X-4 from Wallops Island[10]

Results

Explorer 27 was turned off on 20 July 1973 because it was interfering with other satellites.[1] The passive laser reflectors continue to be used due to the low inclination.[11]

See also

References

  1. ^ a b "BE-C". NASA Space Science Data Coordinated Archive.
  2. ^ "Explorer Series of Spacecraft". NASA. Retrieved April 12, 2018.
  3. ^ a b c d e f "Environmental test program of the beacon explorer spacecraft" (PDF). NASA Goddard Space Flight Center; Greenbelt, MD, United States. Retrieved October 23, 2019.
  4. ^ Brian Harvey (24 November 2017). Discovering the Cosmos with Small Spacecraft: The American Explorer Program. Springer. pp. 91–. ISBN 978-3-319-68140-5.
  5. ^ a b "Astronautics and Aeronautics, 1964" (PDF). NASA, Scientific and Technical Division. Retrieved October 23, 2019.
  6. ^ Ludwig Combrinck, 2010. Sciences of Geodesy (Cap. 9). Springer-Verlag. Retrieved June 9, 2018.
  7. ^ "BE-C". NASA Space Science Data Coordinated Archive. Public Domain This article incorporates text from this source, which is in the public domain.
  8. ^ "Goddard laser systems and their accuracies". Philosophical Transactions of the Royal Society. London: McGraw Hill Publishing Company: 443–444. 1977. Retrieved October 21, 2019.
  9. ^ "Beacon Explorer Surveys Ionosphere". Aviation Week and Space Technology. New York: McGraw Hill Publishing Company. October 19, 1964. p. 35. Retrieved October 21, 2019.
  10. ^ McDowell, Jonathan. "Launch Log". Jonathon's Space Report. Retrieved December 30, 2018.
  11. ^ "Beacon-C". International Laser Ranging Service. Retrieved 2018-04-19.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Explorer_27&oldid=925679210"