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

[kuo@bit.csc.lsu.edu (Isaac Kuo)]

L. Parker wrote:
>On Thursday, December 04, 1997 1:30 PM, Isaac Kuo 
>[SMTP:kuo@bit.csc.lsu.edu] wrote:
>> >So was the Sat-V concept at the time.  But I agree the scale and its
>> >implied cost are critical problems.

>> No it wasn't.  It's only a couple orders of magnitude larger than its
>> predecessors.

>> The manned sail system is more like a dozen orders of magnitude beyond
>> what we've ever done in critical areas.

[...]

>I am assuming that you were starting with the V-2, that is the only way 
>your statement makes _any_ sense.

Yes, that was Von Braun's earlier work.

>This argument takes a fledgling 
>technology, unmanned V-2 rockets and moves to manned Saturn V's in one o  
>rder of magnitude. Using the SAME reasoning, we have already flown a first 
>generation unmanned solar sail, so it is only ONE ORDER OF MAGNITUDE to a 
>manned design. Maybe you want to use a different analogy?

Umm...it's only an order of magnitude from a manned design, yes.  That
means it's not inconceivable to have manned solar sail designs in the
next decades.  I'd perfectly expect it if we put our minds to it.

However, it's _not_ only an order of magnitude from an interstellar
laser sail design.  The unmanned solar sail can deal with microgee
forces from sunlight.  For interstellar travel, at _least_ 1 gee
should be designed for.  Also, the laser sail needs to be big.  Even
in the puniest of sail proposals, it's 1km big--far bigger than any
nonrigid moving vehicle we've ever built.

Second, the laser sail isn't even the toughest part.  The toughest
part is the lens.  Even in the puniest of interstellar proposals,
it's 1000km in diameter.

There are plenty of individual aspects which are many orders of
magnitude from what we can deal with with today's technology.
-- 
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
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