Pioneer Anomaly

For years now, since the Pioneer spacecrafts have been whizzing through deep space on their way out of the Solar System, scientists have been aware of a divergence between their actual flight paths and their projected flight paths. No one can yet explain why.

Now, studies have found that various space probes that have swung around Earth as a speed assist to slingshot them to their final targets farther out from the Sun-- Galileo and Cassini among them-- have also veered from the mathematically true course. No one can yet explain why. Clearly, though, whatever's happening is not solely a deep space phenomenon. Discrepancies in the Pioneer flight paths were not recognized until the probes were well beyond their target planets, but none of the others studied have reached those distances.

The Planetary Society is pursuing a project to study the Pioneer Anomaly. Part of that study involves retrieving and saving the data stored in 1970s-vintage computers. With these new flights, that project might have more data than anyone imagined.