The space shuttle Endeavour was grounded for the fifth time on Monday with stormy weather again causing NASA to cancel a scheduled launch.
A storm south of the Cape Canaveral, Florida launch site threatened not just the launch, but also a landing site should the flight need to be aborted after lift-off. The decision to scrub the launch came shortly before the planned 6.51 pm. (2251 GMT) launch.
NASA said it would try again Wednesday at 6.03 pm. (2203 GMT).
"When the time is right, we'll be here and we'll be ready," said Commander Mark Polansky, who had been strapped into the shuttle along with the rest of the crew when the effort was scrubbed.
The seven-member crew is to deliver an outside porch to be installed on the International Space Station's Japanese Kibo module to expose scientific experiments to the extremities of space.
The mission has suffered a slew of delays that kept the craft on the ground for weeks longer than planned. A planned Sunday launch was cancelled due to storms and a Saturday launch was also scrubbed due to lightening the night before that struck the launch pad, but sparred the shuttle itself.
NASA was forced to postponed the launch twice in just four days last month, after technicians detected hydrogen gas leaks during fuelling, just hours before scheduled liftoff.