Facebook Builds UAS That Beams Down Wi-Fi

Larry Dighera wrote in
:

Questions:

1. Will the laser beams directed toward the Earth's surface be a
hazard to human sight?

2. Will the airborne lasers be able to penetrate cloud layers below
them?

3. Will it be necessary for each sovereign government over which
the UAS operate to grant FaceBook permission to shine laser beams
toward them?

One of my many hobbies is with lasers (see sig below). I have dozens
of them, and they ain't little pointers. Ironically, I don't even own
any laser pointers. But I have a little knowledge of lasers and laser
safety.

Anyway, after reading, the lasers are used to communicate between the
aircraft, not with the ground. Comms between the ground and the drone
are done via wi-fi signals. So the lasers are pointed at other drones
and not at the ground. It appears they are developing a tracking
system to accurately point the lasers at the other drones.

No specifics are given on the laser comms, but free space laser
communications is nothing new. "Free space" means the lasers are
beaming around freely as opposed to being confined in a tube or a
fiber optic.

Based on my knowledge and without bogging down the post with all the
technical details, I seriously doubt there is any danger. It doesn't
take much power to do free space comms (eye safe), and at those
altitudes it will be even easier due to the lack of interferring
dust and moisture in the rarified air.

Further, free space comms is done typically with invisible infrared
but it can be done with visible lasers as well. Choosing an appropriate
IR wavelength would have the benefit of increasing transmission through
the air, thus reducing power requirements, and overall increasing eye
safety.

Although there is a real danger in lasers being targetted at aircraft,
there is also much hyperbole, misinformation, and dramatacism regarding
lasers in the media.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
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