[Illustration: 90. _Skylab 4_ Command Module is hoisted aboard the
U.S.S. _New Orleans_ after completing 1214 orbits.]
The _Skylab 4_ command module ferried the crew of the last Skylab
mission—astronauts Gerald P. Carr, Edward G. Gibson, and William R.
Pogue. The _Skylab 4_ crew lived in the Skylab for 84 days, from
November 16, 1973, to February 8, 1974.
In flight, the Apollo command module operated with a service module—an
equipment section, 7.4 meters (24 feet) long and 4 meters (13 feet) in
diameter—attached to the command module. The service module provided
electrical power, oxygen, and water for the command module for most of a
typical flight.
In addition, the service module contained the 9300-kilogram
(20,500-pound) thrust Service Propulsion System, an engine capable of
being throttled and restarted. During Apollo lunar flights, the engine
provided thrust for mid-course trajectory changes and boosted the
command/service module combination out of lunar orbit and back to Earth.
The service module was jettisoned just before reentry into the earth’s
atmosphere.
During reentry, the command module’s exterior was subjected to
temperatures of around 2800°C (5000°F). The command module is covered
with an ablative heat shield composed of a phenolic epoxy resin in a
fiberglass honeycomb structure. As friction with the earth’s atmosphere
caused the heat shield to char and vaporize, the heat was carried away
from the spacecraft. The heat shield varies in thickness from 7
centimeters (2.75 inches) at the base to .6 centimeter (.25 inch) at the
forward section. Total weight of the heat shield is about 1400 kilograms
(3000 pounds).
The prime contractor for the Apollo Command Module was North American
Rockwell Corporation.
The command module is from the National Aeronautics and Space
Administration.
Diameter 3.9 m. (12 ft., 10 in.) max.
Length 3.2 m. (10 ft., 7 in.)