Boeing is examining whether to redesign the propulsion valves on its Starliner crew capsule, a crucial system that has kept the company from flying astronauts for NASA — and competing with Elon Musk's SpaceX.

Depending on the outcome of OFT-2, Boeing would then prepare for a crewed flight test that would see the first astronauts fly on Starliner.

A valve redesign may further delay that crewed launch, however, given the need for Boeing to test the fix and for NASA to certify the solution.

Reuters first reported, citing sources, that Boeing will redesign the Aerojet Rocketdyne-made propulsion valves, although neither the plane-maker nor NASA had previously revealed the plans.