[ExI] Written for another list

Adrian Tymes atymes at gmail.com
Mon Aug 6 22:47:14 UTC 2012


On Mon, Aug 6, 2012 at 9:00 AM, Keith Henson <hkeithhenson at gmail.com> wrote:
> (snip, concede, can't argue if you think power in space is worthless.)

You misunderstand to a degree that is somewhat insulting.

You're trying to put a price on it.  That can only be done if there
is a buyer for it.  If you are the only seller and the only buyer, then
no money is changing hands.

It may have worth, but that worth can not be measured in dollars.
It's like trying to measure distance in lumens, or mass in seconds.

> you
> can't change the impedance of free space one iota.  Sorry, it's built
> into the universe we live in.

No, but we can hack around it in localized regions - and some have.

hhttp://en.wikipedia.org/wiki/Metamaterial_antenna#Metamaterial_microwave_lens

>> Smaller beam waist = smaller footprint.
>
> The divergence of a beam of electromagnet energy is theta = 1.22
> lamda/diameter.  http://en.wikipedia.org/wiki/Airy_disk
>
> "the angle at which the first minimum occurs (which is sometimes
> described as the radius of the Airy disk) depends only on wavelength
> and aperture size"
>
> How does a maser affect this?

Perhaps it would have been more clear if I emphasized the smaller
beam waist, i.e. smaller aperture size or diameter.

> Read the document I sent and see if that answers your questions.  I
> would love to start this on my pocket change or even a few million.
> If you have a way to modify the concept to reduce the cost, please do.

1) Rather than go on about the possible use as weapons, note the
minimum effective diameter of destruction if these were used as
weapons.  Note that those are strategic sizes, and the military is
already better served by existing weapons for targets of that
scale.  (Sure, it *could* be used as a weapon, just like anyone
*could* hijack a plane and try to fly it into a skyscraper.  Having
seen the threat, we will now secure against it, and the US military
doesn't do that kind of weapon.)

2) Sell it as power first, propulsion second.  As noted above, you
can't really put a price on the value as propulsion, because you're
"buying" it from yourself - but you absolutely can put a price on the
value as electricity.  Besides, just operating a sat-solar power
plant is complex enough, and is a milestone that can be achieved
independently, without need of also doing space propulsion.

3) If the whole point is cheap electricity focused into a laser for
propulsion (and if you're convinced that energy worth $2 if sold on
the market is worth $200 for propulsion), consider the other way:
source energy from the ground and boost rockets that way,
possibly with a few reflectors in LEO.  (So that way you're spending
$2 to get $200 worth.  I say you aren't, because that $200 is based
on things that don't actually translate to dollars, but if you insist
that you are...)  No need for giant powersats beforehand, so this
more quickly gets profit (cheap launch).

The main thing is, you're doing solar power and laser launch tied
together.  That's a fine end goal, but accomplish one first, then the
other, and you'll probably find it more feasible.

(Consider: cars and roads.  Go great together, don't they?  Roads
existed long before cars, and the first internal combustion engines
weren't meant for use on roads.  Develop them separately, then
combine them once they exist.)



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