- The Washington Times - Sunday, February 2, 2003

WASHINGTON, Feb. 2 (UPI) — Throughout its 22-year lifetime, space shuttle Columbia had received numerous upgrades and improvements as part of a coordinated program to keep NASA's fleet of reusable orbiters flying.

In both 1994 and 1999, for example, the winged spacecraft received more than 100 improvements to its equipment and systems.

In its 1994 overhaul, Columbia received new thermal tiles to protect it during re-entry through the atmosphere, new brakes, and a parachute to slow it down after landing. The craft also received a state-of-the-art computer and new informational displays during its 1999 modifications.

Keeping the shuttles updated did not start in 1994, however. Since the shuttle flights began in 1981 — with Columbia — NASA has undertaken a continuous program of upgrades aimed at both improving the safety of the vehicles and increasing their ability to carry people and cargo into orbit.

The largest series of shuttle changes came following the 1986 Challenger explosion. Technicians installed a system in the shuttle's mid-deck to allow the crew to escape bailing out. Such a system, which never has been used, requires the craft's computers to put the shuttle into a controlled level flight. At that point, each crew member would leap from the spaceship and parachute to Earth.

The option could not be used, however, if the shuttle was either out of control or moving at high speed. In Saturday's accident, Columbia was flying at 18 times the speed of sound and 200,000 feet above the ground, too high and too fast to use the bailout system. So far, there has been no indication that astronauts had enough time to be aware of their situation to take any action.

NASA made additional modifications to the shuttle fleet in the 1990s to allow docking with the orbiting Russian MIR station. But Columbia was too heavy to be used in the shuttle-MIR program. As the first shuttle built for spaceflight, it weighed more than 178,000 pounds with its rear-facing engines installed, more than the newer shuttles Atlantis, Discovery, and Endeavour.

Thus the craft was used more in research and satellite deployment missions instead of visits to the International Space Station, where every pound of cargo brought up is at a premium.

In 1997, NASA budgeted $100 million for shuttle improvements, but in subsequent years some of the planned additions were delayed or cancelled. In 2002, the Aerospace Safety Advisory Panel, an independent watchdog group, wrote in its report of concerns shuttle safety might be compromised in future years as a result of insufficient budgets. All agreed, however, the shuttle fleet as currently operated was still safe.

NASA has asked other organizations to assess which shuttle systems should be prime candidates for upgrades or replacement. In 1999, the National Research Council published a study urging NASA to concentrate shuttle improvements on changes that could improve the vehicle's safety and operational life. Last year, NASA began an agency-wide review of the cost and other requirements of keeping the shuttles flying until 2020 or longer.

Original plans were to phase out the shuttles in 2015 with a new, fully reusable replacement. But technical issues and budget cuts have forced the agency to postpone development of the next generation shuttle, focusing instead on keeping the existing fleet flying for at least another 20 years.

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