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Answers Your Questions

From: Brad, of
To: Bill Reeves, flight director for the planning team

Question: For space propulsion, would putting a cathode ray tube on a space ship as means for propulsion work? Why? or Why not?

Answer: Brad, you offer an interesting theory. NASA recently launched a satellite that is propelled by an ion engine. However, that satellite uses much heavier charged particles than electrons for propulsion. Electrons are just too small to provide an accelerating force (protons are about 1700 times heavier) for conventional spacecraft. Although ion engines are powered by emitting very small charged particles, those ions are thousands of times more massive than electrons, and assuming a very similar emission velocity of the particles, ions would provide thousands of times more thrust than a CRT.

A CRT could behave very similarly to an ion engine. Unless the spacecraft was very, small (size of a grape), a CRT would not be practical as a propulsion source.

Thanks for your question.

John McKinnie
Orbit 2 Instrumentation Officer

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Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 04/07/2002
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