The flaws include struts connecting the shuttle to the launch pad that are supposed to separate on ignition, but sometimes do not; dangerous fuel that powers the shuttle's steering system; and metal balls that are used to protect the shuttle's internal piping during take-off, according to The Washington Post.
The board led by Admiral Harold W. Gehman does not believe these problems contributed to the Feb.1 accident that killed all seven astronauts aboard Columbia. While the panel is not expected to release a final report until next month, it believes a fragment of the foam that insulates the external fuel tank broke off and struck the body of the shuttle, exposing a wing to excessive heat when Columbia reentered the earth's atmosphere.
But the newly discovered flaws could pose risks to future flights by the shuttles Atlantis, Discovery or Endeavour.
Two weeks ago, the panel noted another problem that could harm the remaining shuttles: weakness in the "bolt catchers" meant to secure 40-pound fragments of explosive bolts that fall away when the shuttle's booster rockets separate from the craft.
The bolt catcher used on Columbia was made by a new manufacturer and records showed it had not been tested dynamically. When board investigators conducted a test on the device, it failed.
According to The Post, Gehman's team is looking for possible new problems as part of a broad review that goes beyond the Columbia disaster to look at the shuttle program as a whole, especially its management culture.
The problem with the struts that connect the shuttle to the launch pad is potentially the most serious. The two large rocket boosters that lift the shuttle into orbit cannot be shut down once fired, so if the craft ever failed to lift off, a catastrophic explosion would occur on the launch pad.
The rockets are connected to the launch pad by struts that are supposed to blow off of time for liftoff. But sometimes they fail — in October, the primary signal to one of the bolts failed. A backup signal averted disaster. In a 1992 launch of Columbia, The Post found, one of the bolts never blew and part of the booster was ripped off as it rocketed off the launcher.
The fuel used to power systems of hydraulic controls is flammable and caustic, the panel found, which could lead to accidents.
The steel balls that separate tubes inside the shuttle, and protects them from snapping against each other during rough flight, sometimes crack. That could lead to dangerous leaks, the panel has found.