NASA's two stuck astronauts may end up back on Earth a little sooner than planned.

Officials say two NASA astronauts will remain at the International Space Station until engineers finish working on problems plaguing their Boeing capsule.

Two astronauts are spending extra time at the International Space Station as NASA and Boeing troubleshoot capsule problems that popped up on the way there.

Boeing is now aiming for its first astronaut launch at the beginning of June.

Boeing has called off its first astronaut launch because of a fluttering rocket valve.

CAPE CANAVERAL, Fla. NASA has added more safety fixes for Boeings space capsule before it can fly astronauts following a pair of close calls during last years test flight. Its a bit of a wake-up call for NASA and its contractors across the board, said Steve Stich, manager of NASA's commercial crew program. During its space debut last December with no one on board, the Starliner ended up in the wrong orbit and could not reach the International Space Station. SpaceX, meanwhile, successfully launched two NASA astronauts to the space station in May. In hindsight, NASA did not focus enough on the software portion of the Boeing flight, Stich said.