Shuttle Safety Checks Missed, NASA Reports

NASA has been flying shuttles since last spring without properly inspecting them because of a paperwork problem, the space agency announced Wednesday as it delayed the next scheduled flight until March.

Confusion over shuttle engine parts was not brought to the attention of top managers until last week, said Larry Salter, a main engine expert at the National Aeronautics and Space Administration. The problem prompted a delay in the shuttle Columbia’s research mission.

Columbia had been scheduled for a German-chartered science research mission starting about Feb. 25. Launch now is not expected until about the second week of March.

Salter said officials are uncertain if the retainers for seals in Columbia’s high-pressure oxidizer pumps are a new and tighter kind or an old variety. There is one such pump for each of the three main engines.

The metal retainers, or clips, hold down seals around the turbine blades of the pumps. The seals minimize the flow of gas around the tips of the blades. If a retainer broke, a piece of it could damage the turbine blades and the engine could shut down, Salter said.

Workers are required to inspect the retainers before each flight when the old ones are used, a process that was not done on Columbia, Salter said. There is no such requirement for the new retainers, which have been used since March, 1992.

Salter said the two types of retainers were mixed up and technicians for Rockwell International’s Rocketdyne division mistakenly installed some old retainers in the oxidizer pumps. Officials are investigating how and why that happened.

“They just didn’t follow that paperwork” calling for only new retainers to be installed, Salter said.