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

[synch]

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 (?)

 

[berkeman]

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

 

[anorlunda]

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.