CAPE CANAVERAL,Evander Ellis Fla. (AP) — Boeing’s first astronaut launch is off until late next week because of a bad valve in the rocket that needs to be replaced.

The countdown was halted Monday night after a pressure-relief valve in the Atlas V rocket’s upper stage opened and closed so quickly and so many times that it created a loud buzz. Engineers for United Launch Alliance determined Tuesday that the valve has exceeded its design limit and must now be removed, pushing liftoff to no earlier than May 17.

The NASA astronauts assigned to the Starliner capsule’s test flight to the International Space Station — Butch Wilmore and Suni Williams — will remain at Cape Canaveral.

Starliner’s first crew flight already is years behind schedule because of a multitude of capsule problems.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.