With today's second scrub of the Space Shuttle Endeavor's flight STS-127, the schedule gets a bit tighter to fit in the remaining International Space Station Assembly flights before the Space Shuttle fleet retires in September 2010. A recurring hydrogen leak caused the scrub of the flight today.

A hydrogen leak was first encountered in March with the Space Shuttle Discovery, but a temporary fix allowed the Shuttle to lift off successfully and complete its mission. But the temporary fixes for Endeavor did not work, causing the delay.

The next launch attempt for Endeavor will be on July 11th. NASA would like to have determined the root cause of this problem before the next attempt, to prevent further delay of this and future missions.For more information on the Space Shuttle Endeavor, STS-127, and the hydrogen leak problems, you can check out www.nasa.gov .