Boeing has sent two astronauts into space. Now it has to bring them back home.

Problems with leaks and thrusters surfaced after the launch of Boeing's Starliner spacecraft this month, carrying astronauts Barry Wilmore and Sunita Williams. Officials with the aerospace company and the National Aeronautics and Space Administration said Tuesday that the astronauts will return to Earth on June 26.

With the latest postponement, astronauts will spend about 20 days in space, more than double the approximately eight days originally planned.

Starliner is facing two main problems: a series of helium leaks in the propulsion system and problems with several thrusters used to power the vehicle. Teams from NASA and Boeing are studying both issues before allowing Starliner to leave the station with Wilmore and Williams, re-enter Earth's atmosphere and land under parachutes.

“We're taking a little extra time to work through what we've seen and make sure we have all the plans in place to get the crew back,” NASA program manager Steve Stich said Tuesday.

NASA officials have said the space station has at least four months of food and other consumables for astronauts. They said Starliner could stay docked to the station for up to 45 days in total, though it ultimately aims to stay there for a six-month mission.

Long-duration stays on the ISS have happened before. In September, NASA astronaut Frank Rubio returned to Earth after spending more than a year at the facility, a record-breaking flight for an American. His return was delayed because a micrometeorite punched a hole in his Russian-built return vehicle and Russia sent another one.

Stich said Starliner is capable of returning crew members to Earth in an emergency. He said teams want to analyze Starliner and its technical challenges as much as possible while on the station.

The delay is a new setback for Boeing, which had hoped to conduct its first astronaut flight several years ago. Boeing is under contract with NASA under which it will conduct six more crewed flights to the space station if it receives agency certification for the vehicle.

SpaceX has sent cargo to the space station for years and completed its first astronaut mission for NASA in 2020.

Mike Leinbach, a former space shuttle launch director at NASA's Kennedy Space Center, said mission managers would not allow the Starliner to return to Earth with astronauts on board if the spacecraft could pose a threat to them.

“There are a few more issues with it than I expected,” said Leinbach, who is not involved with the Starliner mission. “We were hoping the flight would be safe, but it wasn't and we're dealing with that. They'll figure it out.”

Mark Nappi, Boeing vice president who oversees the Starliner program, said during the briefing that the Starliner crewed flight has so far completed 77 of 87 test objectives.

NASA and Boeing are investigating five helium leaks identified in the vehicle's service module – a propulsion system that includes the thrusters. One of the leaks was detected before the flight began.

Starliner needs about seven hours of helium to complete the flight, and has about 70 hours remaining.

Five of Starliner's thrusters temporarily failed as the vehicle made its final rendezvous with the ISS, but four came back online. One thruster will be turned off for the remainder of the mission, Stich said.

Write to Micah Maidenberg at [email protected]