(Web Desk) - Two Nasa astronauts are still orbiting Earth on the International Space Station, going on two weeks since they were supposed to be back on land.
Barry "Butch" Wilmore and Suni Williams remain on the ISS as Boeing and Nasa engineers work to fix a series of helium leaks on the Boeing Starliner spacecraft that ferried them into space on its first crewed voyage.
Starliner, which had been delayed several times before its June 5 liftoff, experienced some thruster issues en route to the ISS in addition to the helium leaks, though Nasa says the spacecraft has been "performing well in orbit while docked to the space station."
The space agency also said Wilmore and Williams are not "stranded" as they could undock and fly home at any time if deemed necessary.
They are being kept in orbit passed their planned return to "allow mission teams time to review propulsion system data."
The Starliner can spend up to 45 days docked to the space station.
"We are taking our time and following our standard mission management team process," Steve Stich, Nasa's Commercial Crew Program manager, said in a statement.
"We are letting the data drive our decision making relative to managing the small helium system leaks and thruster performance."
Wilmore and Williams were originally scheduled to return to Earth via the Starliner on June 22.
That was pushed back to June 26, and then pushed back again on Friday to an undetermined date.
It took three attempts for the Starliner's first crewed mission to launch. The project, intended to provide a second option for astronauts and cargo to reach orbit in addition to SpaceX's Crew Dragon program, had been sidelined by delays and engineering issues for years.
Despite the delays, Mark Nappi, the vice president and program manager of the Commercial Crew Program for Boeing, said in a statement that Wilmore and Williams remain "overwhelmingly positive."