30 Years of Pioneer Spacecraft Data Rescued: The Planetary Society Enables Study of the Mysterious Pioneer Anomaly

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FOR IMMEDIATE RELEASE
June 5, 2006
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30 Years of Pioneer Spacecraft Data Rescued:
The Planetary Society Enables Study of the Mysterious Pioneer Anomaly

Pasadena, CA, - There's a mystery at the edge of our solar system. Two
spacecraft, Pioneers 10 and 11, which were launched to Jupiter and
Saturn more than 30 years ago, are hurtling towards the edge of our
solar system -- but at a slower than expected rate. Called the
"Pioneer
Anomaly," http://planetary.org/programs/projects/pioneer_anomaly/ the
effect of this slowing is small, but measurable, and so far
unexplained.

[Pioneer Anomaly Data Tapes]

Before The Planetary Society stepped in to help, only about 11 years of
Pioneer Doppler data had been analyzed, and the Pioneer anomaly
remained
a mystery. A lot of the remaining data (more than 19 years of it) were
stored on old 7- and 9-track magnetic tapes needed to be saved and
converted to modern media. By June 2006, scientists and engineers led
by
Slava Turyshev at the Jet Propulsion Laboratory were able to recover
much of the more than 30-year navigational histories of both
spacecraft.
Color: True color. Credit: JPL

This riddle has sparked an array of possible explanations, ranging from
dark matter to spacecraft equipment to - most provocative of all - a
new
physics.

"More data" is what scientists need to solve the mystery, and more data
is what they now possess, thanks to Planetary Society members.

Only a fraction of the Pioneer spacecraft navigational data have ever
been analyzed to study this anomaly. But much of the more than 30
years
of mission data was in disarray, on ancient media, and in danger of
being destroyed. That's where The Planetary Society's members stepped
in.

Only about 11 years of the Pioneer Doppler data, which measured the
spacecrafts' velocity through the Doppler shift of the received
frequency of the Pioneer signal, had been analyzed, and no solution to
the slowdown had been determined. Much of the remaining data was
stored
on old 7- and 9-track magnetic tapes and needed to be identified,
recovered and saved. No NASA funding was available for that task.

The Planetary Society issued an appeal to its
worldwide membership and raised the funding needed to recover and
validate this trove of information.

"We were happy to come to the rescue when no one else would," said
Bruce
Betts, Project Manager of The Planetary Society. "Whether the new data
show the anomaly to be caused by some mundane effect from the
spacecraft
itself or lead to a new understanding of physics, the Pioneer Anomaly
has been a mystery calling out to be solved."

After The Planetary Society initiated the project, the Jet Propulsion
Laboratory (JPL) also contributed in-house funds to further support the
Pioneer Anomaly team. Scientists and engineers led by Slava G.
Turyshev
at JPL were able to recover much of the more-than-30-year navigational
histories of both spacecraft, including data from their Jupiter and
Saturn encounters in the 1970s. The data are now being collected,
arranged, validated, and written to modern media and will be provided
to
teams of scientists to analyze.

Success extended beyond the recovery of the velocity data. Information
about the spacecraft themselves, as well as science data, were
contained
in what are called Master Data Records (MDRs), discovered in storage at
NASA Ames Research Center (which operated the Pioneer spacecraft).
Original plans called for that data to be kept for 7 years, but
fortunately, many records were turned up in the search for more data.
Thanks to Viktor Toth, a software designer from Canada, these telemetry
data files are also being collected and arranged, all useful data is
being extracted, and they are being written to modern media.

What can these additional data tell scientists? For one thing, MDR
data
include temperatures measured throughout the spacecraft during the
course of the missions. These will be critical for modeling the
thermal
radiation from the spacecraft, its variations over time, and whether it
could help explain the anomaly. Planetary Society college intern Merek
Chertkow is beginning to analyze this information, as are various
professional scientists.

The Pioneer Anomaly was discovered when John D. Anderson and colleagues
at JPL realized that the trajectories of the two spacecraft were
deviating from the known laws of motion. After about 30 years of
travel,
the Pioneer Anomaly has resulted in the spacecraft being about 240,000
miles (the Earth Moon distance) closer to the Sun than we would expect.

That may sound like a trivial amount when one considers the Pioneer
spacecraft are traveling at 30,000 miles per hour, but scientists were
intrigued because no known factor explained the slowdown.

What could be affecting their speed? Many hypotheses have been
suggested:

* the interplanetary plasma and solar wind
* thermal recoil force due to heat from the spacecraft's nuclear power
sources
* mysterious Dark Matter in the galaxy
* a manifestation of new physics

No hypothesis could be adequately explained by known data, but with the
data saved with the help of The Planetary Society, scientists will now
have far more information available to help them solve the Pioneer
Anomaly.

For more information, visit the Press Room
http://planetary.org/programs/projects/pioneer_anomaly/press.html
pages of the Pioneer Anomaly section of the Society's website.


About the Planetary Society

The Planetary Society has inspired millions of people to explore other
worlds and seek other life. Today, its international membership makes
the non-governmental Planetary Society the largest space interest group
in the world. Carl Sagan, Bruce Murray and Louis Friedman founded The
Planetary Society in 1980.

The Planetary Society
65 N. Catalina Avenue
Pasadena, CA 91106-2301 USA
Web: www.planetary.org
Voice: (626) 793-5100
Fax: (626) 793-5528
Email:

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