Stormy weather is threatening to delay SpaceX's first astronaut launch.

A SpaceX rocket is scheduled to blast off Wednesday from Florida, carrying a Dragon capsule with NASA astronauts Doug Hurley and Bob Behnken to the International Space Station. It will be the first time astronauts launch from the U.S. in nine years and a first for a private company.

Forecasters put the odds of acceptable weather at 40%. But that doesn't include the need for favorable conditions all the way up the U.S. and Canadian coasts and across the sea to Ireland.

The Dragon's emergency escape system can kick in, if necessary, all the way to orbit.