180 hours.

Centimeters (5 inches) in diameter and weighs 18 150 kilograms (40 000 pounds) can be replaced in 45 hours. REINFORCED CARBON-CARBON (RCC) HIGH-TEMPERATURE REUSABLE SURFACE INSULATION........... 4-27 PASSIVE THERMAL CONTROL .............. 4-30 A A a u AS А se FLIGHT PAYLOAD MISSION.