Gravity Measurement

NASA launched Gravity Probe B in 2004 using utra-precise sphere-shaped gyroscopes to measure Two Einstein Space-Time Theories.

http://www.nasa.gov/mission_pages/gpb/

The main difference in our ISS Falling Bodies Gravity Test is the spheres we will release are allowed to be acted upon by all natural forces as they accelerate in “free-fall” motion.

In NASA’s Gravity Probe B experiment the spheres were gyroscopes (spun mechanically) and enclosed in a spacecraft to measure gravity, shielded from the effects of all other forces.

http://www.nasa.gov/pdf/168810main_gpb_nutshell_ppt.pdf