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

100 Deep Space Network (DSN)
Deep Space 1 An artist’s rendering
of Deep Space 1 with ion
engine thrusting. NASA/JPL
around the Earth for continuous tracking of deep-space
vehicles.
Deep Space Network (DSN)
An international network of antennas that supports interplanetary
missions, some selected Earth-orbiting missions,
and radio astronomy. Its three Deep Space
Communications Complexes combine to make the
largest and most sensitive telecommunications system in
the world. To give some idea of DSN’s sensitivity, the
antennas are still able to capture science information
from the Voyager probes even though the downlink signal
reaching a DSN antenna is 20 billion times weaker
than the power level at which a digital watch functions.
The DSN is a NASA facility managed and operated by
JPL (Jet Propulsion Laboratory).
Deep Space Station (DSS)
The antenna front-end equipment at each tracking site of
the Deep Space Communications Complex.
Defoe, Daniel (1660–1731)
A journalist and the chronicler of the adventures of
Robinson Crusoe, who, in The Consolidator: Or Memoirs of
Sundry Transactions from the World of the Moon (1705), 75
described the discovery of an eponymous spaceship
invented 2,000 years before the Flood by a Chinese scientist
named Mira-cho-cho-lasmo. The Consolidator is a
flying machine powered by an internal combustion
engine that also featured hibernation capsules to ease the
tedium of long spaceflights.
DeFrance, Smith J. (1896–1985)
An aeronautical engineer who played a major role in wind
tunnel design and experimentation before and during the
birth of the Space Age. DeFrance was a military aviator
with the Army’s 139th Aero Squadron during World War
I, then earned a B.S. in aeronautical engineering from the
University of Michigan in 1922 before beginning a career
withNACA(National Advisory Committee for Aeronautics).
He worked in the flight research section at Langley
Aeronautical Laboratory and designed its 9 × 18 m wind
tunnel, completed in 1931 and the largest in existence at
that time. He directed the research carried out in that tunnel
and designed others before becoming director of the
new Ames Aeronautical Laboratory in 1940, a position in
which he remained until his retirement in 1965. During
his time at Ames, the center built 19 major wind tunnels
and conducted extensive flight research, including the
blunt-body research necessary for returning spacecraft
134, 144
from orbit without burning up.
Delta
See article, pages 102–105.
Delta Clipper
Prototype for a single-stage-to-orbit launch vehicle,
designed by McDonnell Douglas. The Delta Clipper