Volkswacht Bodensee - Boeing's Starliner docks with ISS on first crewed mission

Crewmates Butch Wilmore and Suni Williams monitored as the spaceship maneuvered autonomously in the final moments, making contact with the orbital outpost at 1:34 pm ET (1734 GMT) over the southern Indian Ocean.

Rendezvous was initially planned for just over an hour earlier, but was delayed as teams worked to troubleshoot issues with some of the reaction control system (RCS) thrusters that provide fine maneuvering capabilities.

The astronauts, both ex-Navy test pilots who each have two spaceflights under their belts, carried out "hot fire tests" in an effort to restart the malfunctioning thrusters during a stage when they were flying the craft manually.

Earlier, NASA said the spaceship had sprung two new helium leaks since entering orbit, in addition to one leak that teams knew about before liftoff but chose not to repair, because the leak rate was within manageable limits.

Helium is a non-toxic and non-combustible gas used to provide pressure to Starliner's propulsion system. It was not yet clear if the leaks and the thruster issues were linked.

The spaceship blasted off from Florida on Wednesday following years of delays and safety scares -- as well as two recently aborted launch attempts that came as astronauts were already strapped in and ready to go.

Wilmore and Williams are the first crew to fly Starliner, which Boeing and NASA are hoping to certify for regular rides to the ISS -- a role SpaceX has been fulfilling for the past four years, at significantly lower cost to the US taxpayer.

- Select club of spaceships -

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.

A successful mission would help dispel the bitter taste left by the years of safety scares and delays, and provide Boeing a much-needed reprieve from the intense safety concerns surrounding its passenger jets.

During their roughly weeklong stay on the orbital outpost, Wilmore and Williams will continue to evaluate the spacecraft systems, including simulating whether the ship can be used as a safe haven in the event of problems.

After undocking from the ISS, Starliner will re-enter the atmosphere, with the crew experiencing 3.5G as they slow down from 17,500 miles (28,000 kilometers) per hour to a gentle parachute- and airbag-assisted touchdown in the western United States.

M.Schneider--VB