Re: (Re:)^4 starship-design: The Size of the Problem

[T.L.G.vanderLinden@student.utwente.nl (Timothy van der Linden)]

Hi Steve,

A while ago (August 19th) you sent this letter to SD.

>While I haven't had time to do a more complete write-up, I thought I
>would also mention an interesting corollary to Rex's analysis of the
>energy requirements of beaming power to accelerate a relativistic
>spacecraft.  Not only is a large amount of power required, but the
>beaming equipment must be capable of (typically) output at a rate that
>can be over two orders of magnitude larger than is needed to accelerate
>the spacecraft at the start of the trip.
>
>I'm going to present some of the math without proof or demonstration at
>this time, but I'm sure it will be interesting fodder for discussion
>(either because Timothy or Rex will find any mistakes I might have made
>or because it shows another facet of difficulty to the problem of
>beaming power).
>
>I've recently been working on the physics of light signals between a
>"stationary" object and an object undergoing relativistic acceleration
>relative to it.  Consider an object undergoing uniform accleration
>relative to itself; its frame position at its proper time t1 is:
>
>[ t x ] = [ 1/a * sinh(a * t1)
>            1/a * cosh(a * t1) ]

Do you still have a copy of that letter? For some reason I only have the
first part of it, the rest seems to have been deleted by unknown forces.
I'd like to have a complete letter once more, if you still have it, would
you be so kind to sent it to me?

(Note that I did get the complete letter originally.)

Timothy