Oleg Zabluda's blog
Wednesday, February 08, 2012
 
Gravity Probe B was designed to test general-relativistic Frame-dragging effect (more precisely Lense–Thirring...
Gravity Probe B was designed to test general-relativistic Frame-dragging effect (more precisely Lense–Thirring effect) with the precision of 1%. It was the longest-running major physics projects, spanning 40 years and $750M. During spaceflight, it turned out, unexpectedly, that gyroscopes had an electrostatic dipole moment, rendering data nearly useless. The funding for post-flight data analysis was cut by NASA, which listed the project as "failed". But $3M donation from the Saudi prince Dr. Turki bin Saud, who received his PHD in Aeronautics and Astronautics from Stanford University, allowed to finish the data analysis, which claimed to confirm frame dragging with precision of 19%. Many people remain skeptical of this claim, in no small part because the data is still not released.

Ciufolini, et al (2004) claim that frame-dragging has been measured using the laser ranging of LAGEOS satellites with 10 percent accuracy via presession of the nodes. Many people remain skeptical, because this result relies very heavily on currently imprecise Earth gravity models, which cause the same effect on the orbit.

Soon, LARES_(satellite) will be launched, which supposedly can measure frame-dragging with the precision of 1%, according to the same Ciufolini. Same people remain skeptical for the same reason. The advantage of LARES over LAGEOS is that its orbit has higher inclination, the disadvantage is that the orbit is lower.
http://en.wikipedia.org/wiki/Gravity_Probe_B

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