The space shuttle, Discovery, is expected to be given the all-clear for its return to Earth.
Shuttle managers have said the heat-shield tiles and insulation blankets are in good shape for the re-entry to Earth's atmosphere.
A six-and-a-half-hour spacewalk to test repair techniques for heat shield tiles was completed by two of the astronauts yesterday.
It was the first such spacewalk for the US since the 2003 Columbia accident.
Future shuttle flights have been suspended because of the continuing problem of falling debris during launch which could damage the spacecraft's heat shielding.
American space agency NASA says Discovery will stay at the orbiting International Space Station for an extra day to allow its crew to do more work and transfer more supplies.
