In the Orbiter Processing Facility Columbia's engine no. 2 is seen at left after its removal.

In the Orbiter Processing Facility, Columbia's engine no. 2 is seen at left after its removal from the orbiter. After small cracks were discovered on the LH2 Main Propulsion System (MPS) flow liners in two other orbiters, program managers decided to move forward with inspections on Columbia before clearing it for flight on STS-107. The heat shields were removed, and after removing the three main engines, inspections of the flow liners will follow. The July 19 launch of Columbia on STS-107 has been delayed a few weeks