RE: starship-design: FTL and Special Relativity

["Walker, Chris" <Chris.Walker@BSKYB.COM>]

Hi Tom,

> -----Original Message-----
> From: STAR1SHIP@aol.com [mailto:STAR1SHIP@aol.com]
> Sent: 21 January 2000 01:59
> To: Chris.Walker@bskyb.com
> Subject: Re: starship-design: FTL and Special Relativity
>
> Yours was good response to issues with good questions.
> Have I answered them to your satisfaction?

Mostly...a few more questions though!

> Depending on the engines mission, I use any of a range of metals from cast
iron to > titanium or high temperature ceramic-metalic alloys. Their melting
point is not 
> important as the temperature of the plasma that is transferred by radiant,
> convection and conductive heat paths through as it is absorbed by the
selected
> propellant carried out the exhaust port and the casing is further
insulated by the
> steam (one of the best heat insulaters) generated when water as propellant
is used. 

The temperatures we are talking about are of the order of 100,000's degrees
C; titanium has a melting point in the low 1,000's. Water in a paper cup
doesn't need to transfer nearly so much heat from a candle flame as the
engine insulators will need to transfer from the plasma. Are the heat
transfer paths in your engine that efficient?

> Detecting the charge on the projectile from fields generated at light
speed to 
> charge the armor with the charged deflecting field requires microseconds
as does
> the change of exhaust (on already) direction to avoid neutral particle
collisions.

Surely if you're travelling at a high sublight speed, you won't have time to
change the ship's velocity (vector) sufficiently to avoid collision with a
neutral particle following its detection? 
 
> In Lab take shape memory alloy wire...the reaction is not instantaneous
but 
> very close.

My point was that if the particle impact rate was high (eg. thousands per
second), then you are activating the SMA shield thousands of time per
second. Given that it may need to function in this manner *continously* for
months or years, I think this gives rise to serious system reliablility and
material fatigue issues. Any proposals to deal with these problems?

> For a sand particle to be hit a near c by a hundred ton space craft recall
from SR
> momentum the mass relativistic to the sand is millions of tons. The
collision is
> readily absorbed without damage or change to velocity.

Maybe no appreciable change to ship velocity, but the SMA shield *will*
suffer some damage. Over a period of months/years, there will be noticeable
erosion of the shield.

> Mine is designed to be fired from lunar orbit for maximum safety. Ion
propulsion
> pollutes the atmosphere of earth. 

(1) What happens if someone gets imperial and metric units mixed up, and the
spacecraft is accidentally launched towards Earth? ;) <g>

(2) How do ions pollute the Earth's atmosphere in a more dangerous way (to
its inhabitants) than radioacticive debris?

Thanks,

Chris