Gyroscope
Close-up of a gyroscope toy

The world's roundest gyroscope is used on Gravity Probe B. Image Credit: NASA

      a spinning wheel set in a movable frame




Sentences:
Telescopes use gyroscopes to help the telescopes stay in their orbit.

NASA's Hubble Space Telescope will get new gyroscopes in 2009.



More Information:
http://www.nasa.gov/mission_pages/gpb/gpb_001.html
http://www.nasa.gov/mission_pages/gpb/gpb_003.html
http://www.nasa.gov/mission_pages/hubble/servicing/SM4/main/Gyro_FS_HTML.html