CAPE CANAVERAL, Fla.—Boeing’s astronaut capsule is grounded for months and possibly even until next year because of a vexing valve problem. Boeing and NASA officials said Friday that the Starliner capsule will be removed from the top of its rocket and returned to its Kennedy Space Center hangar for more extensive repairs. Starliner was poised to blast off on a repeat test flight to the International Space Station last week—carrying a mannequin but no astronauts—when the trouble arose. A similar capsule was plagued by software issues in 2019 that prevented it from reaching the space station. “We’re obviously disappointed,” said John Vollmer, vice president and program manager of Boeing’s commercial crew program. “We will fly this test when we’re ready to fly it and it’s safe to do so.” Kathy Lueders, head of NASA’s human exploration office, said it’s “another example of why these demo missions are so very important …