Since the tragic accident involving the space shuttle Columbia, the remainder of NASA's space shuttle fleet has been grounded indefinitely. This paper is "a periodically updated document demonstrating our progress toward safe return to flight and implementation of the Columbia Accident Investigation Board recommendations." Nearly 250 pages in length, the paper looks at specific systems of the space shuttle and identifies those that need to be upgraded, replaced, or redesigned to ensure a greater level of safety for future missions. It also addresses scenarios for dealing with shuttle damage during a mission and repairing it. This document is Revision 1.1 of Volume 1, and many more revisions can be expected over the long process of returning to flight.