Space shuttle fleet to soar again

The space shuttle fleet is preparing to resume flight next month after temporarily being grounded because of tiny cracks found inside the hydrogen flowliners of the four orbiters.

Technicians at Kennedy Space Center, Fla., completed a welding process to smooth cracks inside the metal liners that are used to prevent the flow of hydrogen and oxygen into the engines during a vehicle's launch and climb to orbit. Additionally, the microscopic rough edges of the liner holes were polished to reduce the chance of more cracks developing in the future.

The welding repair was chosen after engineers determined that the most likely cause of these cracks, measuring less than three-tenths of an inch, was high-cycle fatigue—a phenomenon that occurs as a result of combined environmental elements such as vibration, thermal variations and acoustics.

Space Shuttle Atlantis is scheduled to lift off next month on mission STS-112, an assembly mission that will deliver the Boeing-built S1 (Starboard-One) truss to the International Space Station. The S1 Truss—44 feet by 15 feet and weighing over 27,000 pounds—was built by Boeing employees in Huntington Beach, Calif., and shipped to Kennedy Space Center in October 1999. STS-112 will be the 15th shuttle mission to visit the space station and Atlantis' 26th flight.

Boeing is the ISS' prime contractor and is a 50-percent partner in United Space Alliance, which is responsible for the pre- and post-flight processing and modification of the U.S. Space Shuttle fleet.