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

ing fin and two horizontal lifting surfaces at the tail of
the rocket, plus two wings at the forward section.
Prognoz
A series of Soviet research satellites meant to study
processes of solar activity and their influence on the
interplanetary environment and Earth’s magnetosphere.
Each spacecraft consists of a hermetically sealed cylindrical
mainframe, 2 m in diameter, with a spherical base.
Located inside the 0.925-m-high mainframe is the platform
with instrumentation and equipment. Twelve Prognoz
satellites were launched between 1972 and 1996.
Prognoz 11 and 12 were also known as the Interball Tail
Probe and Auroral Probe, respectively.
prograde
See direct.
Progress
An unmanned Russian supply vessel used to ferry materials
to and from manned space stations. Progress was
derived from the Soyuz spacecraft. The Soyuz descent
progressive burning 329
module was replaced by a sealed unit that could carry
about 1 ton of propellants for Salyut’s propulsion system,
while the orbital module was transformed into a
cargo bay and made accessible to astronauts by a docking
system and a connecting hatch. In total, Progress had a
mass of about 7,000 kg, including 1,000 kg of propellant
for Salyut and 1,300 kg of cargo. It was first launched on
January 20, 1978, to rendezvous with Salyut 6. With the
arrival of Mir, a new version of the supply ship, known as
Progress-M, was brought into service. This had a recoverable
capsule that could be used to return material, such as
samples of crystals grown under weightless conditions, to
Earth. The latest version of Progress, called the Progress-
M1, has a larger cargo capacity and has been developed
for use with the International Space Station. Progress-
M1 can carry up to 2,230 kg of cargo, of which a maximum
of 1,950 kg can be propellant and a maximum of
1,800 kg can be equipment or supplies.
progressive burning
In solid-propellant rocket motors, the burning of the
fuel in such a way that the chamber pressure steadily rises
Progress A Progress supply ship (at bottom) docked with the Zvezda module of the International Space Station in October
2000. NASA