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Old May 18th 17, 01:53 AM posted to rec.arts.sf.science,sci.space.policy,sci.optics,sci.physics,sci.military.naval
Robert Clark[_5_]
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Posts: 245
Default Reusable Laser Launcher

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"Robert Clark" wrote in message news
The Navy has already tested ship-borne lasers at 30 kW power to shoot down
drones:

US Navy Laser Blasts Drone Out Of The Sky.
Published on Dec 11, 2014
"A laser weapon tested for four months by the US Navy can blast drones out
of the sky in seconds."
https://youtu.be/2InzyGE9K6U?t=77

The more powerful 150 kW laser is expected to be able to shoot down larger
aircraft:

US Navy will fire 150 kilowatt laser on a test ship in 2018 and then from
carriers and destroyers in 2019.
brian wang | January 26, 2017 |
http://www.nextbigfuture.com/2017/01...-laser-on.html

BTW, about the cost, one of the producers of the 10 kW commercial lasers,
not part of weapons system, gave a price of $472,000. So a thousand would
be $472 million for a total power of 10 MW. Actually for such a large order
the price would likely be significantly discounted from this. Also, it may
be buying a fewer number of say, 30 kW, or 100 kW lasers may result in a
lower total cost.

According to the standard estimate this could launch 10 kg to orbit. Mook in
his posts to this thread estimates it could be three times more, ca. 30 kg.
This could still be useful for getting propellant to orbit when launched at
high frequency.


Bob Clark

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We now have the capability to do laser launch. The problem is the initial
cost outlay for the lasers is still prohibitive to launch a sizable payload.

But is it possible to do it without using lasers, just high intensity
noncoherent light focused by mirrors or lenses?

I wondered about this because of two reports I saw doing a web search
actually on optical communication:

InfiniLED MicroLEDs achieve 300 W/cm2 output density from tiny source.
The MicroLEDs semiconductor manufacturing process includes construction of a
parabolic reflector to enable optimal light control and high efficiency from
micro-meter-sized LEDs.
Published on:Jan 29, 2013
By Maury Wright
http://www.ledsmagazine.com/articles...ny-source.html

and:

Optical communications using coherent and non-coherent light.
http://modulatedlight.org/optical_co...cal_about.html

The first report discusses micro-scale LED's whose light output scales up to
300 W per square centimeter, 3 megawatts per meter. From the appearance of
these micro-scale LED's, they should permit simple automated production to
produce many copies to cover a macro-scale area to generate light even at
gigawatt power levels.

The second report discusses experimentation that suggests atmospheric
dispersion is actually worse for lasers than for noncoherent light generated
by LED's. See for instance the video in Fig. 2 on this page.

The advantage of the lasers however is that generating a parallel beam, you
can use a parabolic mirror to focus the light at the focal point (more
precisely at the Airy disk). Still, nevertheless a parabolic mirror will
still focus a large portion of the light at the focal point even for
noncoherent light.

So the question is if the beam is noncoherent, how much of the light can
still be focused at the focal point (Airy disk)?


Bob Clark


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