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Projects: Pioneer Anomaly

Data Saved!

June 1, 2006

Several months ago, we went to you, our members, to help us save data from the Pioneer mission so that we can help study what is known as the Pioneer “anomaly.” Thanks to you, we have succeeded in saving and validating more data than we could have hoped for.

Until just recently, only about 11 years of the more than 30 years of Pioneer Doppler data (velocity data derived from the Doppler shift of the received frequency of the Pioneer signal) had been analyzed, and the mystery remained. NASA was not funding the rest of the data’s recovery, so The Planetary Society stepped in and funded the effort to recover and validate these precious data. We are happy to report that we have recovered large parts of the 30-year histories of the two spacecraft. The data are now being collected, arranged, validated, and written to modern media. They will then be provided to teams of scientists for analyses.

Pioneer Anomaly Data Tapes
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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

There was also another success beyond what we had hoped. Data about the spacecraft themselves, as well as science data, were contained in what are called Master Data Records (MDRs) at NASA Ames Research Center. Nominally, data like these would be kept for only 7 years, but fortunately, much of the history still existed. The recovered MDRs cover most of both missions. They, too, are now being collected, arranged, and written to modern media.

The MDR data include temperatures measured throughout the spacecraft during the course of the missions. This information will be critical for modeling the thermal radiation from the spacecraft, its variations over time, and whether it could help explain the anomaly.