The shuttle approached the station along the R-bar line and at a small distance from the ISS, usually around 600 feet (180 meters), the shuttle performed a slow 360° pitch, during which it exposed its underside, the heat shield, to the ISS. The crew inside the ISS visually inspected and photographed the heat shield to determine whether or not it had been damaged during liftoff and ascent. This maneuver required skilled piloting, as the Shuttle commander must fly very close to the ISS without the station always in full view. After the maneuver is complete the shuttle flew from the R-bar to the V-bar, a 90 degree angle change as seen from ISS and then continued along the V-bar line to close in on the space station and eventually complete the docking.