Re: Detection by IR

On 20-Apr-00 at 10:36, sportyspam@harm.dhs.org (sportyspam@harm.dhs.org)
wrote:
> 
> 
> On Thu, 20 Apr 2000, Brian Quirt wrote:
> 
> >	 As for 'future drives' I'm guessing that they would radiate AT
LEAST
> >	 as 
> > much as the space shuttle (they have to move a larger mass at
greater
> > acceleration, at least assuming 1 thrust = 1g). Also, the best way
to
> > increase the efficiency of a drive is to make the reaction mass
hotter
> > (and thus easier to detect), while the best way to increase the
thrust
> > is to increase the mass of propellant used per unit time, thus also
> > making it easier to detect. Yes, ejecta would be directional, but it
> > would still be detectable pretty far out.
> 
>   I would assume that another way to make a drive more efficient is to
> make the ejecta more uniformly directed.  Sorta like a laser that is
> invisible until you blow smoke through them to reflect some of the
light.

You know, that does bring up the question of a laser drive.  Point the
laser to thrust.  If the laser happens to be pointing the right
directions you could pick it up, otherwise you would see nothing,
rec.sf notwithstanding.  As a matter of fact if I throw little steel
pellets out (accelerating them with an linac type device) you would
never pick them out from earth with passive systems.  (heck, I could
cool them to 1K before I accelerate them)

Roger