The test flight was originally intended to last about nine days.
The decision to bring Starliner back from the ISS empty marks a dramatic about-face for NASA and Boeing, as the organizations were previously adamant that the capsule was the primary choice for returning the crew.
But Starliner's crew flight test, which had been seen as the final major milestone in the spacecraft's development, faced problems — most notably with its propulsion system.
"Boeing has worked very hard with NASA to get the necessary data to make this decision," NASA Administrator Bill Nelson said during a press conference with top NASA officials at Johnson Space Center in Houston on Saturday.
NASA will now conduct another phase of its Flight Readiness Review to determine when to bring the empty Starliner home.
Persons:
Butch Wilmore, Suni Williams, Wilmore, Williams, Bill Nelson
Organizations:
NASA, International, Station, Boeing, ISS, SpaceX's, Johnson Space Center
Locations:
Starliner, Houston