Re: starship-design: Timothy's beamed power paper

[jimaclem@juno.com]

On Tue, 22 Jul 1997 14:35:54 +0200 (MET DST) Zenon Kulpa
<zkulpa@zmit1.ippt.gov.pl> writes:

>> Something just occurred to me (again) in light of recent discussions 
>
>> regarding the impact of interstellar hydrogen on the sail, it seems 
>to 
>> me that there is a "terminal velocity" where the pressure from the 
>> photons impactine the back of the sail will exactly balance the 
>pressure 
>> of the hydrogen impacting the front of the sail at relativistic 
>> velocities. This point is probably well short of the speed of light 
>> which would severely limit the usefuleness of sails. I can't recall 
>> having seen any calculations along these lines. Anyone care to 
>comment?
>> 
>That seems an important observation.
>My guess is that even more restrictive on the sail speed
>would be the physical damage inflicted on the sail by the 
>interstellar medium (even the hydrogen atoms, but also other debris,
>like dust). You cannot shield the entire sail...
>
>-- Zenon

Good points, reminds me that the Bussard Ramjet was  expected to have the
same drawback with drag interaction between the scoop field and the dust
and gas.
>