As a spacecraft approaches a target, such as a space station or an artificial satellite, radar helps the crew members control the craft's course and speed. Such a meeting in space is called a rendezvous . A space shuttle can also use its robot arm to make contact with targets. Maintaining and repairing equipment. The thousands of pieces of equipment on a modern space vehicle are extremely reliable, but some of them still break down.
Accidents damage some equipment.
Other units must be replaced when they get old. Astronauts must find out what has gone wrong, locate the failed unit, and repair or replace it. Assembling space stations. Astronauts may serve as construction workers in space, assembling a space station from components carried up in the shuttle. On existing space stations, crews often must add new sections or set up new antennas and solar panels.