By MARCIA DUNN
AP Aerospace Writer

CAPE CANAVERAL, Fla. (AP) - NASA has replaced an astronaut assigned to Boeing's first launch with a crew.

Astronaut Eric Boe was pulled Tuesday from the upcoming test flight for unspecified medical reasons, after more than three years of training. Taking his seat will be Mike Fincke, a former space station commander.

Boeing plans to launch its first Starliner capsule without a crew this spring, followed by a launch with astronauts this summer to the International Space Station.

SpaceX - NASA's other commercial crew partner - could launch its Dragon capsule, minus a crew, next month. The capsule and Falcon rocket were on the launch pad Wednesday for a test engine firing.

Boe and three other NASA astronauts were chosen in 2015 as the first commercial crew members.

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