Re: RE: RE: starship-design: Re: Perihelion Maneuver

[KellySt@aol.com]

In a message dated 11/29/97 8:53:20 AM, you wrote:

>On Sunday, November 23, 1997 4:55 PM, KellySt@aol.com 
>[SMTP:KellySt@aol.com] wrote:
>>
>> Why?  I thought everyone was prewtty comfortable with a phased array
>> emmiter
>> cluster?  (See details in recent Fuel/Sail is dumb responce)
>>
>Its not that I don't think it will work as advertised as far as beaming 
>power to a sail, what I am not comfortable with is station keeping, ALL of 
>the components of the system will experience thrust as a direct result of 
>the power being transmitted. The laws of physics can't be thwarted, it will 
>still require as much or more reaction mass as any other concept (probably 
>more) the only difference is that it isn't necessary for the fuel to be 
>aboard the vehicle.

True, but since they can stay at home where normal ships can get at them and
refuel them thats not as big a concern.  Also the power sats don't have to be
light and easy to move.


>Although not impossible, the design and logistics of such a system are 
>enormously complex, and we don't have a very good track record with complex 
>systems. Perhaps the simplest idea would be to "waste" half of the energy 
>by reflecting in the direction opposite the emitter to balance the thrust. 
>I don't know, but it sounds awfully complicated.

The emiters don't really bother me.  They are basically just big O'Neil style
power sats, and their thrust might be easy to ofset by the solar sail effect
from their solar collectors.  Keeping the beam cleanly focused into a beam
that the sail can get into and get balenced thrust from over widly varing
distences without refocusing is a bigger challege, and we'll probably need to
waste the vast bulk of the power outside of the central sweet spot the sail
needs to stay in (and that sweet spot will need to be far larger then the
sail) so its efficency will be terrible.  But unless we come up with some
much better physics trics it seem about as good as we'll be able to manage.  

At least the fuel/sail system itself seems prety solid and relyable.  No cryo
tanks or unstable fuels.  Pretty simple brute force tech.

But yeah a nice trick with inertia or zero-point energy would be really nice,
but we can't even guess at any of that.

Kelly


>Lee