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A gallery of unusual reflector photos

Below: the frog and the lion convey a somewhat confused safety message, as photographed in a bike rack at the Massachusetts Institute of Technology. Duh, duh alma mater!


booster.jpg (18832 bytes)


Reflectors on the Moon! Several U.S. Apollo missions and one Soviet Lunakhod lunar probe deployed cube-corner reflector arrays on the surface of the Moon. When these are illuminated by beams of pulsed laser light sent from large telescopes on Earth, measurements of the two-way travel time allow extremely accurate calculation of the Earth-Moon distance. The measurements are used to determine the Moon's orbit with great accuracy, to record disturbances in the Moon's motion caused by meteorite impacts, and to measure the length of the Earth day.

Laser ranging is commonly used by surveyors on Earth, too.


A cube-corner array
of the type deployed by
the Apollo astronauts.

LRRR array.jpg (14246 bytes)
apollo_laser_reflector1.jpg (27970 bytes) One of the cube-corner
arrays in place on the Moon
(note astronaut footprints).
Earth-based telescope
(McDonald Observatory,
Texas) "shooting the Moon"
with a laser beam.
telescope.jpg (7721 bytes)

NASA photos


Below: "Early Warning Tie Tack," from Items from Our Catalog, a parody of the L. L. Bean catalog (Avon Books, 1972). Early Warning reflectorized fabric was heavily advertised around 1971, but the fictional product here is actually based on a three-panel cube-corner reflector.


ewtietack.gif (8743 bytes)


Below: electron micrograph of a high-tech cube-corner reflector element (at the center of the image), an electromechanical device on the face of a computer chip. The square panel which is lying flat against the chip surface can be misaligned in response to an electrical signal, to modulate the strength of the reflected light beam.


lzhou.jpg (18765 bytes)


Almost every gasoline-powered vehicle has a generator-powered lighting system, but the Zapbikes foldable scooter below is the exception: it has only a very small headlight powered by disposable batteries. Being neither a bicycle nor a moped, a scooter falls neatly into the cracks in laws and standards.

The rear reflector, like those on a trailer on an earlier page, is angled upward and works quite well for moths flying around overhead streetlights -- not for anyone else.

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zapbike.jpg (34302 bytes)


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Contents 2001, John S. Allen
Last revised April 27, 2002