CAPE CANAVERAL, Fla. - NASA will conduct a fuelling test next week on space shuttle Endeavour to see if a hydrogen gas leak has been plugged.

The leak led to back-to-back launch delays earlier this month while the spacecraft was being fuelled.

Engineers suspect the leak was caused by a misaligned plate on the shuttle's external fuel tank, where it hooks up to a vent line.

A pair of Teflon seals will be replaced, this time with more supple ones, and the misalignment will be corrected.

A fuelling test is planned for next Wednesday to make sure that the repairs are successful.

If all goes well, NASA hopes to launch Endeavour to the International Space Station on July 11.

The shuttle and a crew of seven -- including Canadian astronaut Julie Payette, will deliver the final segment of a Japanese lab.