[Laser] Aerospace Laser/strobelight Use Coordination

[James Whitfield]

Pat

Interesting set of questions.

If you had in mind to suggest an experiment with ISS, you would probably
need to contact the NASA ISS program office.

On the chance that it might be what you are looking for, I would like to
point out that NASA/JPL has an Optical Communications Group.  You can Google
their web page.

I am not sure if the FAA would be open to any experimentation directed at an
aircraft.  For other purposes that might have an undesirable effect on
aircraft you would be required, as a minimum, to file a Notice to Airmen
with the FAA field office for publication.  They would be able to tell you
how far in advance you would need to file the notice, just like testing high
powered rockets or a baloon launch above a minimum size.

The FAA field office should also be able to direct you to the regulations
about lighting requirements, such as strobe lights, for radio towers.

 I suggest that you start by looking in your local telephone book the the
FAA under US Government agencies.

You might also see if there is an advertising agency that provides
searchlights for commercial events ( store openings ) and ask them if they
have to contact the FAA.  At the least I would expect they are prohibited on
airport approach paths.



I think that you have the second question turned around backward.  How well
an astronaut can see does not depend on how dark it is on the ground.
Consider the reverse situation: If you were in the dark area of the country,
with normal eyesight and given enough time for your eyes to be fully adapted
to the darkness, you should be able to just see a sixth magnitude star.
Perhaps your question should be how bright of a lamp on ISS would look like
a sixth magnitude star.  When it is in sunshine it is rated about second
magnitude, varying perhaps as much as a full magnitude.

On the other hand, IMAX claims that its projection bulb can be seen from the
Moon.  They obviously had some basis for making that claim.  Perhaps you can
find the power rating , then figure the distance ratio, and then translate
that into a lamp power ratio.   If it helps any, there was a rule of thumb
used to size heliograph mirrors that stated the sun's reflection could be
seen ( in broad daylight no less ) for ten times as many miles as the number
of inches of mirror diameter.

If you are just "speculating" about the possible, then consider this:

We expect robotic explorers to be sent to the Moon in a few years.  Suppose
that one of them had a visible laser rangefinder mounted on a TV camera.  At
some time when the rangefinder and camera were not occupied by primary
duties, the camera is pointed toward the Earth such that the visible light
from the rangefinder is pointed toward the Earth as well.  Calculate the
minimum size amateur telescope would be needed to detect the beam.  Invite
amateur astronomers, particularly clubs with school affiliations to report
their success, or lack thereof, seeing the beam.  After the enthusiasm of
just detecting the beam wears off, send down telemetry data in Morse code
and digital data formats.  Maybe a stored picture of an interesting rock,
the Earth, or the robots trail.

Now that would be an interesting project.

Best Wishes,

James
 n5gui

----- Original Message -----
From: "Pat Barthelow" <aa6eg at hotmail.com>
To: "Free Space LASER Communications" <laser at mailman.qth.net>
Sent: Thursday, June 05, 2008 3:11 PM
Subject: [Laser] Aerospace Laser/strobelight Use Coordination



Does anyone know the Points of contact within the FAA and other regulating
bodies, that manage optical aerospace experiments between ground locations
and, for example the ISS?

Another question; in a very dark area of the country, 50 miles from Major
City lights, etc, How much incandescent lamp power does one need for
astronauts in the ISS to see a flashing signal lamp?  In a dark area, or
rural neighborhood, would a properly aimed flashing, 500 watt flood lamp be
easily seen by an astronaut at 200 miles?

73,    All the best,
Pat Barthelow   AA6EG
Jamesburg Moonbounce Team
aa6eg at hotmail.com

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