Updated 9:00 a.m. Eastern with comments from Bridenstine.

KENNEDY SPACE CENTER, Fla. — Boeing’s CST-100 Starliner commercial crew vehicle launched early Dec. 20 on a critical uncrewed test flight, but appeared to suffer thruster problems after reaching space.

The Atlas 5 N22 rocket carrying the uncrewed Starliner spacecraft lifted off from Space Launch Complex 41 at Cape Canaveral, Florida, at 6:36 a.m. Eastern. The rocket’s dual-engine Centaur upper stage separated from the first stage about four and a half minutes after liftoff, its two RL10 engines firing for more than seven minutes.

The Starliner spacecraft separated from the Centaur nearly 15 minutes after liftoff, having been placed into a suborbital trajectory designed to permit safe aborts for the Starliner during ascent. Four orbital maneuvering and attitude control thrusters on the Starliner were scheduled to fire 31 minutes after liftoff to put the spacecraft into an initial orbit.

However, that burn did not take place as planned. NASA and Boeing commentators said the spacecraft suffered an “off-nominal” orbital insertion and was in a “stable” orbit with electrical power, but didn’t specify the orbital parameters. Spacecraft controllers “are assessing options,” they said.

“Boeing’s CST-100 Starliner is not in its planned orbit. The spacecraft currently is in a stable configuration while flight controllers are troubleshooting,” NASA said in a brief statement. NASA Administrator Jim Bridenstine tweeted that a thruster burn did not take place but that the spacecraft was in a stable orbit.

Starliner in stable orbit. The burn needed for a rendezvous with the ISS did not happen. Working the issue. — Jim Bridenstine (@JimBridenstine) December 20, 2019

“The Boeing Starliner space vehicle experienced an off-nominal insertion. The spacecraft currently is in a safe and stable configuration. Flight controllers have completed a successful initial burn and are assessing next steps,” Boeing spokesperson Kelly Kaplan said. “Boeing and NASA are working together to review options for the test and mission opportunities available while the Starliner remains in orbit.”

Bridenstine later tweeted that the problem was a “Mission Elapsed Time (MET) anomaly” with Starliner, “causing the spacecraft to believe that it was in an orbital insertion burn, when it was not.” The spacecraft, he said, consumed more fuel than expected, precluding a docking with the International Space Station.

This mission, formally unknown as Orbital Flight Test (OFT), is a key test of the spacecraft before carrying people, and is similar to the Demo-1 mission that SpaceX’s Crew Dragon spacecraft flew in March. A successful OFT would allow a crewed flight to take place some time in 2020, although both NASA and Boeing officials have been hesitant to estimate a more precise date until after the OFT mission ends.

“This test flight tomorrow by the Boeing Starliner is the next step in this mighty vision,” NASA Administrator Jim Bridenstine said during a Dec. 19 press conference here to preview the mission. “By early next year, we’re going to be launching American astronauts on American rockets from American soil again.”

Bridenstine also noted that vision of returning human orbital spaceflight capabilities “started a long time ago.” Boeing received its first commercial crew award from NASA in 2010 as part of the original Commercial Crew Development program. In 2014, Boeing and SpaceX received Commercial Crew Transportation Capability contracts to complete development of their spacecraft, which at the time called for the vehicles to be certified to carry astronauts by the end of 2017.

Development delays and testing setbacks, though, have pushed out certification to some time in 2020. Boeing has also faced specific criticism for receiving more money than SpaceX — $4.2 billion versus $2.6 billion in their 2014 contracts — and also for having a higher per-seat price according to a recent report by NASA’s Office of Inspector General. That report last month concluded that a Starliner seat will cost NASA $90 million, more than the $55 million on a SpaceX Crew Dragon spacecraft or even what NASA pays Roscosmos for Soyuz seats.

Boeing has disputed those prices, and Bridenstine rose to the company’s defense at the preflight press conference. “I’ve seen a lot of reporting on what the cost per seat will be. I will also tell you, NASA has not negotiated what the cost per seat will be, so I don’t know where a lot of these numbers are coming from,” he said.

Bridenstine said Boeing had a more challenging development approach from SpaceX, which could leverage the work it did on the initial cargo version of Dragon for its Crew Dragon spacecraft. “Boeing has had a very different task from what SpaceX had,” he said. “The cost to modify from commercial [cargo] resupply to commercial crew was not as much as what Boeing did, basically starting scratch and trying to meet the same timeline for commercial human spaceflight.”

Among those attending the launch were NASA astronauts Mike Fincke and Nicole Mann and Boeing astronaut Chris Ferguson, who will fly on the Crew Flight Test mission, as well as NASA astronauts Suni Williams and Josh Cassada, who will be part of the crew for the first operational Starliner mission after the Crew Flight Test.

“As flight testers — all of us are flight testers here — this is a dream come true,” Fincke said of himself and his fellow astronauts at the pre-launch press conference. “This is an exciting time. This is what we live for.”