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Re: starship-design: Re: Perihelion Maneuver

In a message dated 11/18/97 2:33:10 AM, kuo@bit.csc.lsu.edu wrote:

>L. Parker wrote:
>>On Monday, November 17, 1997 11:15 AM, Isaac Kuo [SMTP:kuo@bit.csc.lsu.edu]

>>> He never bothered with the engineering difficulties of making
>>> and stabalizing such a huge fresnel lens, though.
>>Not to switch sides or anything, but I don't believe the fresnel lens will 
>>even work for several different reasons. His use of the fresnel lens was 
>>for a larger, manned proposal. The Starwisp received ALL of its 
>>acceleration while still within range of the original...uhh, maser.
>No, it still needs a fresnel lens.  Without it, diffraction limits
>are too severe.  The beam needs to fall on a spot 1km wide at a
>range of 30,000,000,000km.  With a wavelength of 1mm, that requires
>an aperture around 30,000km wide.  Don't tell me you're going to
>make a microwave laser that big.

As I mentioned a phased array maser cluseer of 2 AU recently (for fuel sail),
and we have done extensive conversations of it a year ago, I'ld think we'ld
already covered that to death?  Hell they're even talking optical telescope
clusters on that scale.