May 7 (Reuters) - The target date for the next attempt

to launch Boeing Co's ( BA ) Starliner space capsule on its

first crewed test flight has been pushed back to no earlier than

May 17, to replace a pressure valve on its booster rocket, NASA

said on Tuesday.

The CST-100 Starliner's debut voyage carrying astronauts

to the International Space Station (ISS) has been highly

anticipated and much-delayed as Boeing ( BA ) scrambles to compete with

Elon Musk's SpaceX for a greater share of lucrative NASA

business.

The test flight was called off on Monday night with less

than two hours left in the countdown after a pressure regulation

valve malfunctioned on the upper-stage liquid oxygen tank of the

Atlas V rocket that was to launch the new capsule into orbit.

The rocket, a separate component from the Starliner

capsule, was furnished for the mission by United Launch Alliance

(ULA), a Boeing-Lockheed Martin joint venture.

After Monday night's aborted launch attempt, NASA,

Boeing ( BA ) and ULA announced that they would seek to try again as

early as Friday, May 10.

But in an update posted Tuesday evening, NASA said more

time was needed after ULA "decided to remove and replace" the

faulty pressure valve. That will require the rocket to be rolled

back to its hangar on Wednesday for repairs, leak checks and

other reviews ahead of a second launch attempt, NASA said.

Those operations pushed the potential launch date back

another week, NASA said.