Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space

[Bernard L Cohen <blc+@pitt.edu>]

On Tue, 30 Mar 1999, Wes Van Pelt wrote:

> Radsafers,
> 
> The below fascinating abstract is about inducing gamma decay as a deep space
> propulsion method.
> Can anyone explain:
>     How can isomeric transition be triggered?

	-Hitting the nucleus with a gamma ray can excite it to a higher
energy state which has a short half life

>     How can the resulting gamma rays be made to go in one direction so as to
> produce propulsion. I thought the direction of gammas must be isotropic.

	--Gamma rays going out the back of the space ship propel it
forward by recoil momentum. Gamma rays forward toward the space ship are
absorbed by the space ship so they give back to the space ship the
forward momentum they took from it by recoil in their emission-- they thus
do not affect the motion of the space ship. 


Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


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