The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

parallel operation of engines
The operation of two or more engines in a system to provide
more thrust than from a single engine without having
thrust misalignment or interference of one engine
with another.
parallel staging
A practice similar to clustering, in which two or more
stages mounted parallel to the main engine ignite simultaneously.
The stages usually contain shorter-burning,
higher-thrust motors than the main airframe, or sustainer,
and drop off when their motors burn out.
PARASOL (Polarization and Anisotropy of
Reflectances for Atmospheric Science coupled
with Observations from a Lidar)
One of a constellation of satellites, which also includes
Aqua, CALIPSO, and Aura, that will fly in similar orbits
around the Earth studying various processes on the land
and ocean, and in the atmosphere. PARASOL, a CNES
(the French space agency) mission, is specifically
designed to measure the direction and polarization of
Paris Gun 315
parabolic flight NASA’s 1995
class of astronaut candidates
weightless aboard a KC-135
“zero-gravity” aircraft. NASA
light reflected from areas of land observed by the lidar
carried by CALIPSO. It is scheduled for launch in 2004.
Paris Gun
The supercannon with which the German army bombarded
Paris from the woods of Crepy from March 1918
to the end of World War I. Also known as the Wilhelm
Geschuetz (after Kaiser Wilhelm II) and Lange Max
(Long Max), it is frequently confused with the Big
Berthas, giant howitzers used by the Germans to smash
the Belgian frontier fortresses, notably that at Liege in
1914. Although the famous Krupp-family artillery makers
produced both guns, the resemblance ended there.
The Paris Gun was a weapon like no other, capable of
hurling a 94-kg shell to a range of 130 km and a maximum
altitude of 40 km—the greatest height reached by a
human-made object until the first successful flight of the
V-2 (see “V” weapons) in October 1942. At the start of its
170-second trajectory, each shell from the Paris Gun
reached a speed of 1,600 m/s (almost five times the speed
of sound). The gun itself, which weighed 256 tons and
was mounted on rails, had a 28-m-long, 210-mm-caliber