NASA’s Implementation Plan for Space Shuttle Return to Flight and Beyond

June 20, 2006
Volume 1, Twelfth Edition
Full Report (8MB PDF)

Return to Flight Update from the Associate Administrator for Space Operations

When the first edition of NASA’s Implementation Plan for Space Shuttle Return to Flight and Beyond was released nearly three years ago, its purpose was to provide a clear path for returning the Space Shuttle to flight and to ensure full transparency and accountability during that process. But through diligence, hard work, and a reinvigorated programmatic and safety review process, the Space Shuttle team made enormous progress towards the ultimate goal of improving the Space Shuttle system.

The results of that effort were seen on STS-114. The systems and procedures developed during Return to Flight worked. Mission managers knew, to an unprecedented degree, exactly what the condition of Discovery was before the return home. The Space Shuttle and the International Space Station teams worked together flawlessly and were able to complete not only the Space Shuttle test objectives but all tasks planned for the International Space Station.

Nevertheless, STS-114 was a test flight, and as such the teams learned that there were some areas that needed more attention. Two areas in particular, the protuberance air load (PAL) ramps and gap fillers, required additional engineering work. The data collected during preparations for and the flight of STS-114 were vital in pinpointing previously unimagined foam loss mechanisms. Given these data, engineers made the necessary hardware modifications, including the removal of the PAL ramps. With these changes, the Space Shuttle is once again ready to be tested in flight. While we expect to see some foam loss again on STS-121, the data from this second test flight will add to our knowledge of loss mechanisms and will allow additional modifications to be made to the foam on subsequent flights. This will be a process of continual learning and constant improvement.

At the same time, the Space Shuttle Program decided not to remove foam from the External Tank’s ice/frost ramps prior to STS-121. This was a difficult decision, but the options for ice/frost foam removal left as much uncertainty as flying with the existing design. Wind tunnels and analysis cannot fully predict performance of these ramps. The decision was made to fly the existing design and monitor performance with our new camera systems, giving us additional data and confidence in the changes we will make to future External Tanks.

This 12th Edition of the Implementation Plan details NASA’s work in these and other areas over the past year. Despite enormous challenges, especially the devastation wrought by Hurricane Katrina on the External Tank team, everyone involved has shown tremendous dedication and resolve in keeping this critical program on track. Their efforts are an inspiration to us all and show the boundless tenacity and drive of this team. The challenges of space flight truly bring out the best in us all.

We are ready for the challenge of resuming recurring Space Shuttle flights, and for setting course aboard new ships for new destinations.

[signed]

William H. Gerstenmaier
Associate Administrator for Space Operations