Boeing's Starliner crew capsule, which is making its way to the International Space Station on its first mission carrying astronauts, has developed two helium leaks since entering orbit but remains stable and on course for docking, NASA said.
The spaceship finally blasted off from Florida on Wednesday following years of delays and safety scares -- as well as two recently aborted launch attempts, before it finally got off the ground.
NASA and Boeing teams were already aware of one small helium leak affecting one of Starliner's thrusters, which they discovered following the first aborted launch attempt in May.
After testing it, they said the leak rate was well within safety limits and decided not to repair it, which would have been a complex procedure and involved taking Starliner apart at its factory.
But Starliner developed two more helium leaks during the mission, NASA said in a late update Wednesday on X.
"Two of the affected helium valves have been closed and the spacecraft remains stable," the space agency said, adding in a later update that mission managers have "polled go" for docking at the space station at 12:15 ET (1615 GMT).
Astronauts Butch Wilmore and Suni Williams are the first crew to fly Starliner, which Boeing and NASA are hoping to certify for regular rides to the orbital outpost -- a role SpaceX has been fulfilling for the past four years, at significantly lower cost to the US taxpayer.
Starliner is just the sixth type of US-built spaceship to fly NASA astronauts, following the Mercury, Gemini and Apollo programs in the 1960s and 1970s, the Space Shuttle from 1981 to 2011, and SpaceX's Crew Dragon from 2020.
Boeing's program faced setbacks ranging from a software bug that put the spaceship on a bad trajectory on its first uncrewed test, to the discovery that the cabin was filled with flammable electrical tape after the second.