Pioneer 5

Infobox Spacecraft
Name = Pioneer 5


Caption = Pioneer 5 mounted to its Thor Able launcher.
Organization = NASA
Mission_Type = Interplanetary space
Satellite_Of = Sun
Launch = March 11 1960 13:00:00 UTC
Launch_Vehicle = Thor Able
NSSDC_ID = 1960-001A
Mass = 43 kg
Eccentricity = 0.1689
Inclination = 3.35°
Orbital_Period = 311.6 days
Apoapsis = 0.9931 AU
Periapsis = 0.7061 AU

Pioneer 5 (also known as 1960 Alpha 1, Pioneer V, Pioneer P-2, and Thor Able 4) was a spin-stabilized space probe in the NASA Pioneer program used to investigate interplanetary space between the orbits of Earth and Venus. It was launched on March 11 1960 from Cape Canaveral Air Force Station Launch Complex 17a at 13:00:00 UTCcite web
url = http://www.astronautix.com/chrono/19601.htm
title = Chronology - Quarter 1 1960
accessdate = 2008-01-31
publisher = Encyclopedia Astronautica] with an on-orbit dry mass of 43 kg. It is a 0.66 m diameter sphere with 1.4 m span across its four solar panels and achieved a solar orbit of 0.806 × 0.995 AU (121,000,000 by 149,000,000 km). Among other accomplishments, the probe confirmed the existence of interplanetary magnetic fields. ["The Pioneer Spacecraft". "NASAFacts". NF-31/Vol 4, No. 3. U.S. Government Printing Office, 1967.] Pioneer 5 was the only successful probe in the Pioneer/Able missions.

Design and instruments

The spacecraft was a 0.66 m diameter sphere with four solar panels that spanned over 1.4 m. It was equipped with four scientific instruments:
# A triple coincidence omnidirectional proportional counter telescope to detect solar particles and observe terrestrial trapped radiation. It could detect photons with E > 75 MeV and electrons with E > 13 MeV.cite web
url = http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1960-001A-01
title = NSSDC Master Catalog: Proportional Counter Telescope
accessdate = 2008-01-31
publisher = NASA]
# A rotating search coil magnetometer to measure the magnetic field in the distant field of the Earth, near the geomagnetic boundary, and in interplanetary space.cite journal
author = Coleman, Jr., P.J., Davis, Jr., Sonett, C.P.
date = July 15, 1960
title = Steady Component of the Interplanetary Magnetic Field: Pioneer V
journal = Physical Review Letters
volume = 5
issue = 2
pages = 43–46
doi = 10.1103/PhysRevLett.5.43
format = fee required
accessdate = 2008-01-29 ] cite journal
author = Dungey, J.W.
date = January 15, 1961
title = Interplanetary Magnetic Field and the Auroral Zones
journal = Physical Review Letters
volume = 6
issue = 2
pages = 47–48
doi = 10.1103/PhysRevLett.6.47
format = fee required
accessdate = 2008-01-29 ] It was capable of measuring fields from 1 microgauss to 12 milligauss. It consisted of a single search coil that was mounted on the spacecraft in such a way that is 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.cite web
url = http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1960-001A-02
title = NSSDC Master Catalog: Search-Coil Magnetometer
accessdate = 2008-01-31
publisher = NASA]
# A Neher-type integrating ionization chamber and an Anton 302 Geiger-Müller tube (which functioned as a cosmic ray detector) to measure cosmic radiation. It was mounted normal to the spin axis of the spacecraft.cite web
url = http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1960-001A-03
title = NSSDC Master Catalog: Ion Chamber and GM Tube
accessdate = 2008-01-31
publisher = NASA]
# A micrometeorite momentum spectrometer (or micrometeorite detector) that consisted of two diaphragm and microphone combinations. It was used to measure the amount of meteoritic dust particles and the momentum of these particles.cite web
url = http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1960-001A-04
title = NSSDC Master Catalog: Micrometeorite Spectrometer
accessdate = 2008-01-31
publisher = NASA]

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.cite journal
author = Greenstadt, E.W.
month = July | year = 1966
title = Final Estimate of the Interplanetary Magnetic Field at 1 A.U. from Measurements made by Pioneer V in March and April 1960
journal = Astrophysical Journal
volume = 145
issue = 1
pages = 270–295
url = http://adsabs.harvard.edu/abs/1966ApJ...145..270G
format = fee required
accessdate = 2008-01-29
doi = 10.1086/148761] The spacecraft also measured solar flare particles, and cosmic radiation in the interplanetary region. The micrometeorite counter failed to operate as the data system saturated and failed to operate properly.

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 the solar cells prevented 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 3 megabits of data were received. The major portion of the data was received by the Lovell radio telescope at Jodrell Bank Observatory and the Hawaii Tracking Station because their antennas provided grid reception. Data was received until April 30, 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 June 26, 1960, although it was much too weak by then to acquire data.cite web
url = http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1960-001A
title = NSSDC Master Catalog: Pioneer 5
accessdate = 2008-01-31
publisher = NASA]

See also

References

External links

* [http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Pioneer_05 Pioneer 5 Profile] by [http://solarsystem.nasa.gov NASA's Solar System Exploration]