A timer error prevented Boeing Co's new astronaut capsule on Friday from reaching the orbit it needed to get to the International Space Station, US space agency NASA said, cutting short a critical unmanned test mission.
The CST-100 Starliner astronaut capsule successfully launched earlier from Cape Canaveral in Florida, but then failed to reach the orbit that would have put it on track to meet up with the space station.
The debut journey to the space station was a milestone test for Boeing, which is vying with SpaceX to revive NASA's human spaceflight capabilities.

NASA astronauts Nicole Mann and Mike Fincke discuss the status of the Boeing CST-100 Starliner spacecraft orbital test flight at the Kennedy Space Center in Cape Canaveral, Florida

The thwarted mission took place as the aerospace giant sought an engineering and public relations win in a year punctuated by a corporate crisis over a ban on its 737 MAX jetliner following fatal crashes.
The plan was now for the capsule to head back to Earth, landing at White Sands, New Mexico on Sunday, Boeing's space chief executive Jim Chilton told a news conference.
This is the landing site that would have been used if the capsule had completed its planned week-long stay at the space station.
"That was the absolutely the right decision for this mission,” NASA Administrator Jim Bridenstine told the news conference.
He said the timer error meant the capsule burned fuel too soon, preventing it from reaching the desired orbit.
"We did obviously have some challenges today. When the spacecraft separated from the launch vehicle we did not get the orbital insertion burn that we were hoping for,” Bridenstine said.
Had astronauts been on board, they would have been safe, he said.
"The challenge here has to do with automation,” he said of the unmanned craft, adding that if astronauts had been on board they would have been able to override the automated system that caused the error.
"I would say that that’s safe to take off the table at this point,” Bridenstine said of Starliner’s prospects of docking to the space station as originally planned. "It’s not worth it given the amount of fuel that we’ve burned.”
The spacecraft, a cone-shaped pod with seven astronaut seats, blasted off from Cape Canaveral at 6:36 a.m. (1136 GMT) atop an Atlas V rocket from Boeing-Lockheed Martin Corp's United Launch Alliance.
Minutes after liftoff, Starliner detached from the main rocket booster, aiming for a rendezvous some 409 km into space on Saturday morning with the space station.
Both Boeing and NASA said that while the capsule had not reached the intended orbit it was in a stable position.
Nicole Mann, one of three astronauts slated to fly on Boeing’s first crewed flight test, told the news conference, "We are looking forward to flying on Starliner. We don't have any safety concerns”. ? NASA astronaut Mike Fincke added, "Had we been on board, we could have given the flight control team more options on what to do in this situation”.
The test is one of the most daunting milestones required by NASA's Commercial Crew Program to certify the capsule for eventual human spaceflight - a long-delayed goal set back years by development hurdles from both Boeing and SpaceX.
In November, a blistering government watchdog report found Boeing received an "unnecessary" contract boost from NASA.
Boeing was awarded $4.2 billion and Elon Musk's SpaceX $2.5 billion by the US space agency in 2014 to develop separate capsule systems capable of ferrying astronauts to the space station from American soil for the first time since the US Space Shuttle was retired from service in 2011.
The program, primarily meant to end America's reliance on Russia's space program for rides to the space station, had initially expected its first crewed flights on Starliner and SpaceX's Crew Dragon capsule in late 2017.
A slew of design and safety concerns for both vehicles have led to schedule delays.
The current target date for the first crewed flight is planned for mid-2020 for Boeing and SpaceX.
Occupying one of Starliner's astronaut seats on Friday was a mannequin named Rosie, outfitted with sensors to measure the pressure a real astronaut would endure on ascent to the space station and during hypersonic re-entry back through Earth's atmosphere.
If the mission had gone to plan, the Starliner would have stayed at the space station for a week before undocking and beginning its return to Earth early on Dec. 28, deploying three parachutes to slow its descent to the desert surface of White Sands, New Mexico.
SpaceX's Crew Dragon capsule carried out its unmanned test flight to the space station in March.