Two astronauts await homecoming as Boeing races to understand the problems facing spacecraft. This is what is at stake

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Boeing's Starliner spacecraft is set to mark its crowning achievement this month: carrying two NASA astronauts on a round trip to the International Space Station, proving the long-delayed and overpriced capsule is up to the task.

Starliner is halfway to that goal.

But the two veteran astronauts piloting this test flight are now in a tentative position: Extending their stay aboard the space station for a second time, while engineers on the ground rush to learn more about the problems ...