US astronomer, scientist, and inventor of the bolometer, an instrument
that measures radiation. His steam-driven aeroplane flew for 90 seconds
in 1896 - the first flight by an engine-equipped aircraft.
He was professor of physics and astronomy at the Western University
of Pennsylvania 1866-87, and studied the infrared portions of the solar
From 1887 he was secretary of the Smithsonian Institution in Washington
DC. He founded the Smithsonian Astrophysical Observatory in 1890 and
turned to pioneering work in aerodynamics, contributing greatly to the
design of early aircraft. He built and tested the first successful (but
uncrewed) heavier-than-air craft (aeroplane), which he launched by catapult
and which flew over the Potomac River in 1896. The subsequent catapult-launched
flights of the Wright brothers at Kitty Hawk owed much to Langley's
principles as well as to the more powerful engines available by the
early 1900s. The Langley design was tested in later years by using a
model with a modern engine; it flew successfully with a pilot aboard.