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Post Info TOPIC: Pioneer 10 and 11


L

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Pioneer Anomaly
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Study Finds Heat is Source of 'Pioneer Anomaly'

The unexpected slowing of NASA's Pioneer 10 and 11 spacecraft - the so-called "Pioneer Anomaly" - turns out to be due to the slight, but detectable effect of heat pushing back on the spacecraft, according to a recent paper. The heat emanates from electrical current flowing through instruments and the thermoelectric power supply. The results were published on June 12 in the journal Physical Review Letters.
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L

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RE: Pioneer 10 spacecraft
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On July 15, 1972, Pioneer 10 was the first spacecraft to enter the asteroid belt.



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L

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RE: Pioneer 10 and 11
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Pioneer 10 become the first man-made object to depart the inner solar system on the 13th June 1983.

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Jim


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Is the solution discovered a "closed form" solution. Did the asymetric force come from a model that had been tested or was the force arrived at by fitting the data. I assume there some fitting of data but how well did the model fit and where are the equations specifying the force for a given heat radiation.

Ed ~ the two post dated 'Dec 16 14:24 2010' and 'Mar 31 17:10 2011' describe the modelling used. Basically, once the thermal radiation pressure forces were accounted for, they could explain the small spacecraft drag.



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L

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Pioneer 10
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The last successful reception of telemetry was received from Pioneer 10 on April 27, 2002; subsequent signals were barely strong enough to detect, and provided no usable data. The final, very weak signal from Pioneer 10 was received on January 23, 2003 when it was 12 billion-kilometres (80 AU) from Earth. Further attempts to contact the spacecraft were unsuccessful. 
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L

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RE: Pioneer 10 and 11
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Anniversary of the Pioneer 10 launch in 1972

Launched on March 2, 1972, Pioneer 10 was the first spacecraft to travel through the asteroid belt, and the first spacecraft to make direct observations and obtain close-up images of Jupiter. Pioneer 10 is now coasting silently through deep space toward the red star Aldebarran, a journey of over 2 million years.



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L

Posts: 131433
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Pioneer 10 spaceprobe
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Pioneer 10 (also known as Pioneer F) is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System.
Communication has been lost since January 23, 2003 because of power constraints, with the probe at a distance of 12 billion-kilometres (80 AU) from Earth.

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L

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RE: Pioneer 10 and 11
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On July 15, 1972, Pioneer 10 was the first spacecraft to enter the asteroid belt, located between the orbits of Mars and Jupiter. Surprisingly, the on-board experiments demonstrated a deficiency of particles below a micrometre (m) in the belt, as compared to the vicinity of the Earth. The density of dust particles between 10100 m did not vary significantly during the trip from the Earth to the outer edge of the belt. Only for particles with a diameter of 100 m to 1.0 mm did the density show an increase, by a factor of three-fold in the region of the belt. No fragments larger than a millimetre were observed in the belt, indicating these are likely rare; certainly much less common than anticipated. As the spacecraft did not collide with any particles of substantial size, it passed safely through the belt, emerging on the other side about February 15, 1973.
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L

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Pioneer 10
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On the 13th June, 1983, Pioneer 10 passed the orbit of Neptune, the outermost planet, and became the first man-made object to leave the solar system.
(Although Pluto was considered to be a planet at the time, it was closer to the Sun than Neptune at that stage due to its highly eccentric orbit passing within that of Neptune.)

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L

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RE: Pioneer 10 and 11
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Mundane explanation for bizarre Pioneer anomaly

Bad news for those anticipating an exotic explanation for the bizarre "Pioneer anomaly". The latest analysis suggests the mysterious deviation in the paths of NASA's twin Pioneer probes may be due to uneven radiation of their heat into space.
Launched in the 1970s, the Pioneer 10 and 11 spacecraft are coasting out of the solar system in different directions. As expected, they are slowing down due to the pull of the sun's gravity. However, the deceleration is 8.7 × 10^-10 metres per second squared stronger than predicted. This may seem slight but it has prompted all manner of explanations, from dark energy to changes in the constants of nature or the law of gravity.
Now Frederico Francisco of the Instituto Superior Técnico in Lisbon, Portugal, and colleagues reckon that a more mundane explanation will do.

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