Re: Fuel Chat

Tony Christney wrote:
> 
> At 02:55 PM 11/27/98 -0500, you wrote:
> [snip]
> >
> >What the heck is a 'photon' drive?  How does this produce thrust?
> 
> A photon drive basically uses a directed beam of light (or invisible
> electromagnetic radiation). The momentum of the photons (h*f/c where
> h=planck's constant, f=frequency of the light and c=speed of light)
> is transferred to the light source. 

	Photon drives represent a theoretical ultimate in rockets.
	After all, how can you beat a rocket where the exhaust
	velocity is the speed of light (short of some kind of
	tachyon exhaust).

	The thing to remember about such a drive is the Kzinti
	Lesson: "The more efficient a reaction drive is, the
	better a weapon it becomes".

	A highly efficient photon drive is basically
	a starship riding a titanic laser cannon.
	A cannon that could punch a hole in a small moon.

	There was a scene in THE MOTE IN GOD'S EYE where
	the starship was decelerating with it's photon
	drive in order to land at a Navy base on a moon.
	As the drive was pointed directly at the base,
	it was obliged to put up it's Langston field
	to avoid being fried by the drive exhaust.