When returning from space, the orbiter hurtles towards Earth at speeds of up to 27,360km/h (17,000mph). The confrontation with our atmosphere can heat the surface of the vehicle to temperatures of 1,600C (3,000F) – hot enough to melt steel. The wing of space shuttle Columbia was badly damaged by a suitcase-sized chunk of foam during lift-off. The foam slipped off the launch system’s external tank and breached the orbiter’s heatshield panels, letting hot gases into the shuttle when it tried to re-enter the atmosphere 16 days later. The STS-114 return-to-flight mission has been testing methods for repairing damage to these panels and other parts of the shuttle’s TPS. Inspections using the 15m-long Orbiter Boom Sensor System (OBSS) have identified six areas on the belly of Discovery with suspected minor damage. The main types of materials used in the TPS are reinforced carbon-carbon (RCC) panels, low and high temperature insulation tiles (or heatshield tiles), felt reusable insulation blankets and fibrous insulation blankets. RCC panels are made from a dense, charcoal-like material that has been used on tips of ballistic missiles. They are found on areas su...