Tuesday, December 1, 2009

The Pioneer Anomaly in the Light of New Data

Carl Walter asked me for an update on the Pioneer Anomaly and I had to check and see if anything new was being published.
I thought I would check and see if Dr. Slava Turyshev and Viktor Toth might have something and sure enough, google found this.
[Note: Viktor hosts my web site so maybe a bit biased. - LRK -]
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The Pioneer Anomaly in the Light of New Data
Abstract
The radio-metric tracking data received from the Pioneer 10 and 11 spacecraft from the distances between 20–70 astronomical units from the Sun has consistently indicated the presence of a small, anomalous, blue-shifted Doppler frequency drift that limited the accuracy of the orbit reconstruction for these vehicles. This drift was interpreted as a sunward acceleration of aP = (8.74±1.33)×10−10 m/s2 for each particular spacecraft. This signal has become known as the Pioneer anomaly; the nature of this anomaly is still being investigated.

Recently new Pioneer 10 and 11 radio-metric Doppler and flight telemetry data became available. The newly available Doppler data set is much larger when compared to the data used in previous investigations and is the primary source for new investigation of the anomaly. In addition, the flight telemetry files, original project documentation, and newly developed software tools are now used to reconstruct the engineering history of spacecraft. With the help of this information, a thermal model of the Pioneers was developed to study possible contribution of thermal recoil force acting on the spacecraft. The goal of the ongoing efforts is to evaluate the effect of on-board systems on the spacecrafts’ trajectories and possibly identify the nature of this anomaly.

Techniques developed for the investigation of the Pioneer anomaly are applicable to the New Horizons mission. Analysis shows that anisotropic thermal radiation from on-board sources will accelerate this spacecraft by ∼41×10−10 m/s2.We discuss the lessons learned from the study of the Pioneer anomaly for the New Horizons spacecraft. Keywords Pioneer anomaly · gravitational experiments · deep-space navigation · thermal modeling.

Slava G. Turyshev
Jet Propulsion Laboratory, California Institute of Technology,
4800 Oak Grove Drive, Pasadena, CA 91109 USA
E-mail: turyshev@jpl.nasa.gov
Viktor T. Toth
Ottawa, ON K1N 9H5, Canada
E-mail: vttoth@vttoth.com
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We haven't always had spacecraft you know.
I just finished reading a chapter from "The YOUNG FOLKS TREASURY", Vol. VIII, "WONDERS OF SCIENCE AND INVENTION", entitled "The Motor Vehicle," by Herbert T. Wade, where he talks about cars that used steam, or electricity, or even a gas-engine. Oh, I failed to mention, the books were copyright 1909, a year before my mom started her life of living through all these technological advances. :-)
[Note to myself - I can still read a hundred year old book - Wonder if my Amiga computer still works.]
I can't wait to read the next chapter, "The Flying Machine," and then "The Gyroscope and Its Applications."
Could they have even thought about Cell Phones that show pictures that rotate to match which way you hold it?
Are we having fun yet? And what will we think of when we start developing the resources of the Moon?

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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK

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