Spacecraft Velocity Anomalies

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Spacecraft Velocity Anomalies refers to unexplained variances in the velocity of multiple spacecraft, where the spacecraft are traveling faster than expected or can so far be accounted for, relative to Earth orbit. Although the effect exists with spacecraft in orbits roughly parallel to Earth's equator, the effect is most pronounced with spacecraft in non-equatorial orbits. The scale of such measurements is in millimeters per second (mm/sec), performed by bouncing electromagnetic radio waves off the spacecraft and determining the Doppler shift in the returning signal, and the precision of the measurement is believed to be .1 mm/sec.

The first observation was a measurement of the Pioneer 10 spacecraft in 1998 by a team at NASA's Jet Propulsion Laboratory in California,^[1] and a new report to be published in 2008 by the same team reveals a similar anomaly with the NEAR spacecraft.^[2]

Contents 1 Spacecraft with observed, significant velocity anomalies 2 Spacecraft being assessed for significant velocity anomalies 3 See also 4 References

[edit] Spacecraft with observed, significant velocity anomalies

• Galileo
• NEAR Shoemaker
• Pioneer 10
• Pioneer 11
• Ulysses

[edit] Spacecraft being assessed for significant velocity anomalies

• Rosetta (spacecraft)

[edit] See also

• Pioneer Effect This older article explains more details, but is specific to Pioneer 10 and Pioneer 11.

[edit] References

1. ^ American Institute of Physics John D. Anderson et al., Physical Review Letters
2. ^ American Institute of Physics Number 857 #2, February 28, 2008 by Phil Schewe