Washington, Oct 10 (IANS): NASA has officially postponed the launch of its Orbital Flight-Test 2 until next year due to an unresolved valve issue.

NASA said that the team behind OFT-2 "is working toward launch opportunities in the first half of 2022."

"Safety of the Starliner spacecraft, our employees, and our crew members is this team's number one priority," said John Vollmer, vice president and program manager, Boeing's Starliner program.

"We are taking the appropriate amount of time to work through the process now to set this system up for success on OFT-2 and all future Starliner missions."

Boeing and NASA had originally aimed to launch Starliner's Orbital Test Flight 2 (OFT-2), a crucial uncrewed trial mission to the International Space Station (ISS), from Florida's Cape Canaveral Space Force Station on July 30. But preflight checks revealed 13 stuck valves in Starliner's service module, nixing that liftoff plan.

Boeing had signed a contract with NASA's Commercial Crew Programme to fly operational missions to and from the space station with Starliner in 2014. However, a series of setbacks have thus far prevented the Starliner from reaching the ISS.

Its debut uncrewed orbital flight mission in 2019 did not go exactly as planned, requiring it to make another try before putting astronauts on board for the crewed flight test.

The second launch has been held up since late last year due to ongoing software checks.

First scheduled for launch early in August, it was postponed after the thrusters on the ISS' new Russian module Nauka Multipurpose Laboratory Module unexpectedly fired hours after docking, causing the station to move out of orientation. The space station was shoved 45 degrees off track. However, it was repositioned back to normal.