Boeing's new Starliner capsule had problems on its first test flight shortly after takeoff.
The unmanned launch is a test for next year's planned flight that will have astronauts on board.
The takeoff went smoothly, with the Atlas V rocket rising from Florida shortly before sunrise and heading to the International Space Station, where it is due to arrive tomorrow.
But only half an hour on its journey, Boeing reported that the insertion of the capsule into orbit was not normal.
Flight controllers are understood to consider their options and insist that the capsule is in a stable orbit.
Inside is a test doll named Rosie, who is sitting in the commander's seat.
Rosie is dressed in a red polka dot bandana and a royal blue space suit. It is named after the biceps flexing riveter on World War II posters.
"She's pretty tough. She's going to hit us," said Mike Fincke of NASA, one of three astronauts to fly at the next Starliner.
Also aboard are a bunch of candy and Christmas gifts for the space station's six astronauts, plus hundreds of seeds.
Boeing's launch is seen as an attempt to compete with SpaceX, which made a successful launch in March.
SpaceX plans to launch two astronauts into orbit in the spring.
The last time an astronaut was launched into space from US ground was in July 2011, when Atlantis made the final shuttle flight.
Since then, people travel to and from the space station through Kazakhstan, costing NASA $ 86 million (£ 65 million) at a time.