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That Voyager and several other spacecraft have had anomalous changes in speed is known. According to the news reports, the differences are unsettling. But just how large are these anomalies really? Are they 'way down there' at the levels of computational precession? Or, if I understood how to calculate them, could I do so with my home computer in a reasonable period of time? (Say a few days calculation.)

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    $\begingroup$ possible duplicate of The Pioneer anomaly finally explained? $\endgroup$ – user4552 Oct 18 '13 at 21:39
  • $\begingroup$ @BenCrowell - no, there are other vehicles besides those involved in the so-called "Pioneer Anomaly" which you link to in your comment immediately above. The ones mentioned in this news article, for example, are near-earth. (And no, I don't take NBC as a definitive source for astrophysics :)), but it is a good jump point: nbcnews.com/id/23410705/#.UlyDetJmg6Y $\endgroup$ – Howard Pautz Oct 18 '13 at 22:13
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    $\begingroup$ OK, so are you specifically asking about the flyby anomalies? How about editing your question to make it specifically about that? IMO that would change it from a not-so-useful question to a useful one. $\endgroup$ – user4552 Oct 19 '13 at 1:51
  • $\begingroup$ I am a little skeptical of the comments in that article. I have never heard of JPL knowing a spacecraft's velocity to better than 0.1 mm/s. It is possible that I am wrong, but a ~13 mm/s difference between predictions and measurements is not anomalous as the article seems to suggest. Often during flybys, the spacecraft will use thrusters or other attitude controls to maneuver or accelerate the spacecraft. Most thrusters are not capable of producing an accuracy in a velocity change as small as reported herein. I would be wary of this article's comments. $\endgroup$ – honeste_vivere Jan 19 '15 at 17:48

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