scholarly journals Testing Einstein in Space: The Gravity Probe B Relativity Mission

2007 ◽  
pp. 101-109
Author(s):  
John Mester ◽  
2000 ◽  
Vol 25 (6) ◽  
pp. 1181-1184 ◽  
Author(s):  
Saps Buchman ◽  
C.W.F. Everitt ◽  
Brad Parkinson ◽  
J.P. Turneaure ◽  
R. Brumley ◽  
...  

1996 ◽  
Vol 441 ◽  
Author(s):  
Ping Zhou ◽  
Saps Buchman ◽  
Chris Gray ◽  
John Turneaure ◽  
James E. Turlo

AbstractWe have characterized the stress and its effects on surface morphology for multi-layer thin films of about 3μm total thickness, consisting of three or seven layers of Ti and Cu. These films constitute the electrostatic suspension electrodes for the gyroscope housings of the Relativity Mission Gravity Probe B. Full understanding of surface morphology is critical for meeting the complex requirements of this application.The residual stresses have been measured using a laser curvature technique, while the surface morphology was studied by scanning electron microscopy (SEM). We find that the surface morphology depends strongly on the stress, which evolves with the Ti-Cu multi-layer period. Average stress and the resulting surface roughness decrease for thinner Cu layers (increased total number of layers). Seven layer Ti-Cu films with low stress and very smooth surface have been successfully used for the electrodes of the gyroscope housings.


1998 ◽  
Vol 164 ◽  
pp. 385-386
Author(s):  
M. I. Ratner ◽  
D. E. Lebach ◽  
I. I. Shapiro ◽  
N. Bartel ◽  
M. F. Bietenholz ◽  
...  

AbstractThe NASA/Stanford Relativity Mission (Gravity Probe B) is to test the unverified “frame-dragging” prediction of general relativity through measurements of the precessions of orbiting gyroscopes. For mission accuracy goals to be met, the proper motion of a “guide star,” whose position will be used as an inertial reference, must be determined in an extragalactic reference frame with a standard error less than 0.5 mas/yr. We discuss our VLBI observations of the current guide-star candidates (radio stars HR 1099, HR 5110, and HR 8703) and our techniques for obtaining differential astrometric positions with the needed accuracy.


1996 ◽  
Vol 13 (11A) ◽  
pp. A185-A191 ◽  
Author(s):  
Saps Buchman ◽  
Francis Everitt ◽  
Brad Parkinson ◽  
John Turneaure ◽  
Mac Keiser ◽  
...  

1995 ◽  
Vol 76-77 ◽  
pp. 516-520 ◽  
Author(s):  
P. Zhou ◽  
Saps Buchman ◽  
K. Davis ◽  
C. Gray ◽  
J.P. Turneaure

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