Washington  - The space shuttle Endeavour was grounded for the fourth time on Sunday with stormy weather causing NASA to cancel a scheduled launch.

Storms within 20 miles 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.

NASA said it would attempt to launch Endeavour again at 6:51 pm (2250 GMT) Monday.

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 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. (dpa)