NASA - National Aeronautics and Space Administration

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

      a spinning wheel set in a movable frame

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

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

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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