The crews of space shuttle Discovery and of the International Space Station have exchanged warm hugs after their spacecrafts docked successfully. It is NASA’s first manned flight since the space agency grounded its fleet after the February 2003 Columbia disaster. The seven crew members were killed when the shuttle disintegrated on re-entry after one its wings was damaged by debris during take-off. This trip was meant to be a triumphant return to space for NASA, but a similar incident during Discovery’s launch on Tuesday has caused the space agency to ground its fleet once again. The decision was announced after images taken during take-off showed chunks of debris breaking off from the shuttle’s fuel tank. Discovery’s astronauts are not thought to be in danger, however, as the debris does not seem to have caused any damage.