Ice risk won’t freeze countdown

CAPE CANAVERAL, Fla. — NASA officials believe the risk of pieces of ice flying off the external fuel tank and striking the space shuttle is low enough to proceed with plans for a mid-July launch of Discovery.

The conclusion came after a Friday meeting of NASA managers and engineers who have spent the past six weeks running millions of computer simulations and testing various ways ice might strike the orbiter. The launch window opens July 13.

“There are still some areas we’re going to continue to watch very closely and will probably continue to look for ways to mitigate those areas in the future,” Bill Parsons, space shuttle program manager, said at a news conference.

Discovery was transported to the pad in April but removed May 26 after NASA determined that ice could form over an expansion joint on the external fuel tank after the super-chilled fuel was loaded. Managers decided to install a heater at the joint, located along the liquid oxygen feed line.

Falling chunks of ice could be even more menacing than pieces of the fuel tank’s insulating foam, which was responsible for Columbia’s destruction during re-entry and the deaths of seven astronauts in 2003.

NASA officials have tested the effects of ice strikes in wind tunnels.

Two more meetings will determine whether Discovery lifts off on schedule. A task force overseeing return-to-flight efforts has one more public meeting on Monday, and a NASA readiness review meeting is next Wednesday.