Washington ? A NASA research engineer warned two days before Columbia broke apart that the shuttle might be in “marginal” condition and that others in the space agency weren’t adequately considering the danger of a breach near its left wheels, according to internal e-mails NASA disclosed Friday.

“We can’t imagine why getting information is being treated like the plague,” the engineer wrote in one of a series of messages describing internal concerns about Columbia’s safety in the days before its breakup Feb. 1 over Texas.

The board investigating the accident, which only obtained the e-mails late Friday, believes the shuttle suffered a breach based on its analysis of rising temperatures inside the same wheel compartment that the engineer had cited for concern.

The engineer, Robert Daugherty of NASA’s Langley research facility in Hampton, Va., wrote two days before Columbia’s breakup that experts on the shuttle’s protective heat tiles were concerned that Columbia’s condition was “survivable but marginal” after it was struck by debris on liftoff.

Other documents NASA released showed engineers feared that Columbia was struck on liftoff by three pieces of loosened insulating foam, not just the one previously acknowledged. NASA spokesman Allard Beutel said Friday that officials now believed one large foam piece broke into three smaller chunks before at least one struck the spacecraft. The investigating board said it was looking into the matter.

Daugherty did not mention in his e-mails any concern that a breach might cause Columbia to break apart during its fiery descent, saying that the risks of deadly heat burning into the wheel compartment was “arguably very unlikely.”

But Daugherty explicitly warned in a Jan. 29 e-mail that “one of the bigger concerns” was that damage to thermal tiles near the wheel compartment seal could permit a hole there. He appeared worried most about pilots struggling to land Columbia with one or more tires inside damaged from extreme heat.

“It seems to me that if mission operations were to see both tire pressure indicators go to zero during entry, they would sure as hell want to know whether they should land with gear up, try to deploy the gear or go bailout,” Daugherty wrote.

The accident board has previously determined Columbia almost certainly suffered a devastating breach along its wing and possibly its wheel compartment that allowed searing air to seep inside during its descent at nearly 12,500 miles per hour.