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Fwd: starship-design: Rex Finke's "Starflight Mechanics Notes"




In a message dated 3/13/01 9:50:52 AM, kgstarks@collins.rockwell.com writes:

>
>Rex,
>Just read your LIT starflight paper.  Thanks for collecting it together.
>
>I noticed you sometimes forgot to include units.  For example in the MeV
>to
>speed table you didn't list the units for the resulting speed, nor in all
>the definitions of the letters in the equations.  (I caught Tim doing that
>a couple years ago and he got embarased since his instructors had just
>chewed him out for that.  ;)  )  This significantly limited the number
>of
>readers who can make use of - or understand - the information.
>
>I'm not sure why you didn't include reaction rate numbers for all the
>fusion reactions on page 14?
>
>You might want to include full names in quotes?
>
>Quotes came with " >" at the start of each line; but since you didn't add
>hard returns when you added them to the paper, they now sometimes float
>in
>the sentences.
>
>I'ld argue with some of your implications that there's a physics limit
>to
>the project.  A nasty engineering to cost limit, yes; but that would
>require a very differnt set of solutions.  For example my fuel sail concept
>(which you didn't mention) with a assumption of greatly reduced automated
>systems costs.  Or refueling at the target system to eliminate the need
>to
>carry round trip fuel.  Or using a lithium base fusion fuel to eliminate
>the need for a tank.  Or suplying power/fuel in flight from earth to
>eliminate having to carry it.
>
>
>I have a serious problem figuring out the beam power to thrust
>relationships for something like a microwave sail system.  Even more
>problems understanding how the beamed energy can be consentrated into a
>conversion system for retro thrust, and get more retrothrust - then forward
>thrust from the sail?  A critical point since it seems counter-intuative.
>(Oh, did anyone consider converting the microwaves to electricity in the
>sail [rectena sail?] rather then reflecting and concentrating it?  Does
>this help?)
>
>
>You might want to look up conversino numbers for free-electron and LED
>lasers.  I beleave their conversion efficencies are higher.  Not sure
>though.
>
>
>
>In general though a great summary.  If I still had access to the web site
>I'ld convert it to HTML and link it it.
>
>Kelly



Rex,
Just read your LIT starflight paper.  Thanks for collecting it together.

I noticed you sometimes forgot to include units.  For example in the MeV to
speed table you didn't list the units for the resulting speed, nor in all
the definitions of the letters in the equations.  (I caught Tim doing that
a couple years ago and he got embarased since his instructors had just
chewed him out for that.  ;)  )  This significantly limited the number of
readers who can make use of - or understand - the information.

I'm not sure why you didn't include reaction rate numbers for all the
fusion reactions on page 14?

You might want to include full names in quotes?

Quotes came with " >" at the start of each line; but since you didn't add
hard returns when you added them to the paper, they now sometimes float in
the sentences.

I'ld argue with some of your implications that there's a physics limit to
the project.  A nasty engineering to cost limit, yes; but that would
require a very differnt set of solutions.  For example my fuel sail concept
(which you didn't mention) with a assumption of greatly reduced automated
systems costs.  Or refueling at the target system to eliminate the need to
carry round trip fuel.  Or using a lithium base fusion fuel to eliminate
the need for a tank.  Or suplying power/fuel in flight from earth to
eliminate having to carry it.


I have a serious problem figuring out the beam power to thrust
relationships for something like a microwave sail system.  Even more
problems understanding how the beamed energy can be consentrated into a
conversion system for retro thrust, and get more retrothrust - then forward
thrust from the sail?  A critical point since it seems counter-intuative.
(Oh, did anyone consider converting the microwaves to electricity in the
sail [rectena sail?] rather then reflecting and concentrating it?  Does
this help?)


You might want to look up conversino numbers for free-electron and LED
lasers.  I beleave their conversion efficencies are higher.  Not sure
though.



In general though a great summary.  If I still had access to the web site
I'ld convert it to HTML and link it it.

Kelly






KellySt@aol.com on 03/12/2001 10:32:25 PM

To:   kgstarks@crnotes.collins.rockwell.com
cc:

Subject:  Fwd: starship-design: Rex Finke's "Starflight Mechanics Notes"



In a message dated 3/12/01 3:18:53 PM, stevev@darkwing.uoregon.edu writes:

>List member Rex Finke has written a paper "Starflight Mechanics Notes"
>which collects and summarizes many of the major physics and engineering
>topics discussed earlier in starship-design.  As the paper is a bit too
>large to post to the list directly, I'm offering it as part of the
>starship-design archive pages.  He has provided both Microsoft Word and
>Postscript versions of the document.
>
>You can get the paper from:
>
>http://darkwing.uoregon.edu/~stevev/sd-archive/starflight.doc (Microsoft
>Word)
>http://darkwing.uoregon.edu/~stevev/sd-archive/starflight.ps (Postscript)
>
>I've also included links to the paper from the main starship-design
>archive web page,
>
>http://darkwing.uoregon.edu/~stevev/sd-archive/

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Subject: starship-design: Rex Finke's "Starflight Mechanics Notes"
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List member Rex Finke has written a paper "Starflight Mechanics Notes"
which collects and summarizes many of the major physics and engineering
topics discussed earlier in starship-design.  As the paper is a bit too
large to post to the list directly, I'm offering it as part of the
starship-design archive pages.  He has provided both Microsoft Word and
Postscript versions of the document.

You can get the paper from:

http://darkwing.uoregon.edu/~stevev/sd-archive/starflight.doc (Microsoft
Word)
http://darkwing.uoregon.edu/~stevev/sd-archive/starflight.ps (Postscript)

I've also included links to the paper from the main starship-design
archive web page,

http://darkwing.uoregon.edu/~stevev/sd-archive/