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RE: starship-design: Re: regarding fuel expenditures

On Wednesday, November 12, 1997 11:02 PM, KellySt@aol.com 
[SMTP:KellySt@aol.com] wrote:
> In a message dated 11/10/97 1:10:00 PM, you wrote:
> >Hello Kelly Stark,
> >  One question for you.  Suppose you use a modified Ramjet fuel scoop
> >concept where instead of relying solely upon it, rely on it to refuel
> >the onboard tanks.  In other words, instead of a steady accelleration,
> >why not figure on spurts of accelleration and deceleration?
> >
> >       Hal
> Sorry for the delay, been busy.
> The problem with the ram scoops is that you are slowed down more by the
> drag,
> then any interstellar fuel scooped up could possibly make up for.  You
> would
> save fuel buy not needing to accelerate the whole fuel load at once, but
> the
> drag and weight gain from the scoop would blow the advantage.
> Kelly

It seems to me that the scoop which is travelling at some arbitrary 
velocity relative to the matter it is scooping will have to slow the matter 
down in order to store it in a tank, which would impart velocity to the 
ship in the form of deceleration. The only reason a ram scoop is feasible 
at all is that it doesn't slow the material down relative to the ship, it 
actually accelerates it to an even higher velocity as it exits the drive 
out the back of the ship. The only "drag" is caused by any velocity 
component imparted by the inevitable steering into the center of the scoop. 
This isn't true if you want to capture and store the material.