Undergrad Could a Smoke Detector Serve as a Sail for Spacecraft Propulsion?

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A smoke detector, with its metal plate and alpha source, could theoretically generate a minute net force due to the emission of alpha particles. However, this force is deemed too small to be practically useful as a propulsion method in space. Calculating the mass loss over time using E=mc² suggests that even after 100 years, the mass loss would be negligible. Comparatively, spacecraft like the Deep Space 1 probe utilize significant fuel for propulsion, highlighting the impracticality of using a smoke detector as a sail. Overall, while the concept is interesting, it lacks feasibility for effective space travel.
synch
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Looking at a humble smoke detector - a metal plate with some alpha source on one side. I guess the fission products / apha etc emitted in one direction are absorbed into the metal, and the opposite direction go into space. So there should be a minute net force ? Would that be useful as a "sail" in space ? It seems to me it would be simpler than a thermoelectric generator and ion engine (?)
 
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synch said:
Looking at a humble smoke detector - a metal plate with some alpha source on one side. I guess the fission products / apha etc emitted in one direction are absorbed into the metal, and the opposite direction go into space. So there should be a minute net force ? Would that be useful as a "sail" in space ? It seems to me it would be simpler than a thermoelectric generator and ion engine (?)
Why are you calling alpha decay "fission"?

https://en.wikipedia.org/wiki/Nuclear_fission

https://en.wikipedia.org/wiki/Alpha_decay
 
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synch said:
Looking at a humble smoke detector - a metal plate with some alpha source on one side. I guess the fission products / apha etc emitted in one direction are absorbed into the metal, and the opposite direction go into space. So there should be a minute net force ? Would that be useful as a "sail" in space ? It seems to me it would be simpler than a thermoelectric generator and ion engine (?)

Yeah a minute force would be expected, but far too small to be useful. To estimate how small it is, figure out how much mass loss the smoke detector experiences in a year, and then use ##E=mc^2## My guess is that after 100 years, the mass loss would still be far too small to measure by ordinary means.

By contrast, the Deep Space 1 probe carries 36kg of fuel for the ion thruster.
 
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