Construction

gravity probe B team- Stanford

• The 'heart' of GP-B is a block of quartz almost two feet long containing "four gyroscopes and a proof mass, all bonded to a quartz telescope.  The package is inserted into a 1,500L liquid Helium Dewer.  The gyroscopes are consructed of ultrasmooth quartz balls coated with niobium (a superconductor at liquid helium temperatures), allowing the gyroscopes to be suspended electrically."samadhi.jpl.nasa.gov

 
• The ping-pong ball sized gyros spin at 10,000 r.p.m.

 
• Any variation in the gyro's spin axis will be detected and recorded by the satelites onboard magnetometers.

 
• Helium is drawn out of the experiment and allowed to 'boil' into space for attitude control.