In
space shuttle terminology, capcom also stands for
capsule communications (even though the transport device is not called a capsule anymore). They are responsible for most of the
talking to the
shuttle during the
missions. They relay all the messages to and from the shuttle. It's a very important, very
stressful position in the space flight
system.
If you watch the movies
Apollo 13 or
Armageddon carefully, you will see the capcom position in the ground control. "
Houston, we have a problem", was first heard by CAPCOM.