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Pioneer 5

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Pioneer 5
Pioneer 5mounted to itsThor Ablelauncher.
Mission typeInterplanetary space research
OperatorNASA
Harvard designation1960 Alpha 1
COSPAR ID1960-001AEdit this at Wikidata
SATCATno.27
Mission durationLaunch to last contact 107 days; launch to last data received 50 days
Spacecraft properties
ManufacturerTRW
Launch mass43.2 kilograms (95 lb)[1]
Start of mission
Launch date11 March 1960, 13:00:07 UTC(1960-03-11UTC13:00:07)
RocketThor DM 18-Able IV
Launch siteCape Canaveral,LC-17A
ContractorDouglas
End of mission
Last contactLast contact 26 June 1960(1960-06-27);[1]last data received 30 April 1960[2]
Orbital parameters
Reference systemHeliocentric
Eccentricity0.1689
Perihelion altitude0.7061 astronomical units (105,630,000 km; 65,640,000 mi)
Aphelion altitude0.9931 astronomical units (148,570,000 km; 92,310,000 mi)
Inclination3.35°
Period311.6 days

Pioneer 5(also known asPioneer P-2,andAble 4,and nicknamed the "Paddle-Wheel Satellite"[3]) was aspin-stabilizedspace probe in the NASAPioneer programused to investigate interplanetary space between the orbits ofEarthandVenus.It was launched on 11 March 1960 fromCape Canaveral Air Force StationLaunch Complex 17Aat 13:00:00 UTC[4]with an on-orbit dry mass of 43 kilograms (95 lb). It was a 0.66 metres (2 ft 2 in) diameterspherewith 1.4 metres (4 ft 7 in) span across its foursolar panelsand achieved a solar orbit of 0.806 × 0.995 AU (121,000,000 by 149,000,000 km).

Data was received until 30 April 1960. Among other accomplishments, the probe confirmed the existence ofinterplanetary magnetic fields.[5]Pioneer 5was the most successful probe in the Pioneer/Able series.

The original mission plan was for a launch in November 1959 wherePioneer 5would conduct a flyby of Venus, but technical issues prevented the launch from occurring until early 1960 by which time the Venus window for the year had closed. Since it was not possible to send the probe to Venus, it would instead merely investigate interplanetary space and an actual mission to the planet would have to wait another three years.[6]

Design and instruments[edit]

The spacecraft was a 0.66 metres (2 ft 2 in) diameter sphere with four solar panels that spanned over 1.4 metres (4 ft 7 in) and it was equipped with four scientific instruments:

  1. Atriple coincidence omnidirectional proportional counter telescopeto detectsolar particlesand observe terrestrial trapped radiation. It could detectphotonswith E > 75MeVandelectronswith E > 13 MeV.[7]
  2. Arotating search coilmagnetometerto measure themagnetic fieldin the distant field of the Earth, near the geomagnetic boundary, and in interplanetary space.[8][9]It was capable of measuring fields from 1microgaussto 12 milligauss. It consisted of a single search coil that was mounted on the spacecraft in such a way that it measured the magnetic field perpendicular to the spin axis of the spacecraft. It could output its measurements in both an analog and a digital format.[10]
  3. ANeher-type integratingionization chamberand anAnton 302Geiger-Müller tube(which functioned as acosmic raydetector) to measure cosmic radiation. It was mounted normal to the spin axis of the spacecraft.[11]
  4. Amicrometeoritemomentumspectrometer(or micrometeorite detector) that consisted of twodiaphragmandmicrophonecombinations. It was used to measure the amount of meteoritic dust particles and the momentum of these particles.[12]

Mission[edit]

Booster performance during launch was overall excellent considering the numerous earlier difficulties with the Thor-Able vehicle. There were some minor anomalies with the second stage flight control system that resulted in unplanned pitch and roll motions, however, they were not enough to endanger the mission.

The spacecraft returned data collected by the magnetometer on the magnetic field and it measured that the median undisturbed interplanetary field was approximately 5 γ ± 0.5 γ in magnitude.[13] The spacecraft also measuredsolar flareparticles, and cosmic radiation in the interplanetary region. The micrometeorite counter failed to operate as the data system saturated and failed to operate properly.[12]

Pioneer 5 with test equipment.

The recorded digital data were transmitted at 1, 8, and 64 bit/s, depending on the distance of the spacecraft from Earth and the size of the receiving antenna. Weight limitations on thesolar cellsprevented continuous operation of the telemetry transmitters. About four operations of 25 min duration were scheduled per day with occasional increases during times of special interest. A total of 138.9 h of operation was completed, and over three megabits of data were received. The major portion of the data was received by theLovell radio telescopeatJodrell Bank Observatoryand theHawaii Tracking Stationbecause their antennas provided grid reception. Data was received until 30 April 1960, after which telemetry noise and weak signal strength made data reception impossible. The spacecraft's signal was detected by Jodrell Bank from a record distance of 36.2 million km (22.5 million miles) on 26 June 1960, although it was much too weak by then to acquire data.[2]

Communications[edit]

In common withExplorer 6,Pioneer 5 used the earliest known digital telemetry system used on spacecraft, codenamed "Telebit",[14]which was a tenfold (or 10 dB)[14]improvement in channel efficiency on previous generation "Microlock" analog systems in use sinceExplorer 1and the biggest single improvement in signal encoding on western spacecraft. The spacecraft received the uplink carrier at 401.8 MHz and converted it to a 378.2 MHz signal using a 16/17 coherent oscillator circuit.[15]The telemetry system phase modulated a 512 Hz subcarrier, which was in turn amplitude modulated at 64, 8, or 1bit/s. The spacecraft was unable to aim its antennas, and so had no high-gain dish antenna common on later spacecraft. Instead, the system could introduce a 150W amplifier into its normally 5W transmitter circuit. It was powered by a battery of 28 F-size NiCd cells recharged by the solar paddles, allowing up to eight minutes of high power communications before risking damage to the batteries.[16]Each hour of 5W communications or five minutes of 150W communications required ten hours of recharging the batteries. Unlike later interplanetary spacecraft (Mariner 2and beyond), this spacecraft did not use theDeep Space Network,which was not yet available, but a somewhat ad hoc Space Network called SPAN consisting of the 76mLovell Telescope(then called Manchester Mark I), a 26-meter radio telescope in Hawaii, and a small helical array in Singapore.

See also[edit]

References[edit]

  1. ^ab"Pioneer 5 - NASA Science".science.nasa.gov.NASA.Retrieved1 December2022.
  2. ^ab"Pioneer 5".nssdc.gsfc.nasa.gov.NASA.Retrieved31 January2008.
  3. ^Patrick Moore (1962).The Observer's Book of Astronomy.Frederick Warne & Co.ISBN978-0-723-21575-2.
  4. ^Mark Wade."1960 Chronology".Encyclopedia Astronautica.Retrieved31 January2008.
  5. ^"The Pioneer Spacecraft".NASAFacts.NF-31/Vol 4, No. 3. U.S. Government Printing Office, 1967.
  6. ^Andrew LePage (17 April 2015)."Vintage Micro: The First Interplanetary Probe".drewexmachina.
  7. ^"Pioneer 5: Proportional Counter Telescope".nssdc.gsfc.nasa.gov.NASA.Retrieved31 January2008.
  8. ^P. J. Coleman; L. Davis; C. P. Sonett (15 July 1960). "Steady Component of the Interplanetary Magnetic Field: Pioneer V".Physical Review Letters.5(2): 43–46.Bibcode:1960PhRvL...5...43C.doi:10.1103/PhysRevLett.5.43.
  9. ^J. W. Dungey (15 January 1961)."Interplanetary Magnetic Field and the Auroral Zones".Physical Review Letters.6(2): 47–48.Bibcode:1961PhRvL...6...47D.doi:10.1103/PhysRevLett.6.47.Archived fromthe originalon 24 September 2017.
  10. ^"Pioneer 5: Search-Coil Magnetometer".nssdc.gsfc.nasa.gov.NASA.Retrieved31 January2008.
  11. ^"Pioneer 5: Ion Chamber and GM Tube".nssdc.gsfc.nasa.gov.NASA.Retrieved31 January2008.
  12. ^ab"Pioneer 5: Micrometeorite Spectrometer".nssdc.gsfc.nasa.gov.NASA.Retrieved31 January2008.
  13. ^E. W. Greenstadt (July 1966). "Final Estimate of the Interplanetary Magnetic Field at 1 A.U. from Measurements made by Pioneer V in March and April 1960".Astrophysical Journal.145(1): 270–295.Bibcode:1966ApJ...145..270G.doi:10.1086/148761.
  14. ^abG. E. Miller; J. E. Taber (1959).An Interplanetary Communication System abstract(PDF).STL/TR.Retrieved6 August2015.
  15. ^A. Good (1 June 1960).Payload Command Receiver/Doppler Transponder(PDF).STL/TR.Retrieved6 August2015.
  16. ^Project Thor-Able 4 Final Mission Report(PDF).STL/TR. 25 May 1960. pp. 4–25.Retrieved6 August2015.

External links[edit]

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