Takeoff was slated for Wednesday evening from Kennedy Space Center in Florida, but the company waived off the launch attempt because of an issue with the launchpad’s ground system. The problem stemmed from a hydraulics system used to control one of two clamps that hold on to the upper portion of the rocket as it sits vertically on the ground pad before launch.

A launch pad problem has forced a flight delay to replace NASA's two stuck astronauts. The new crew needs to get to the International Space Station before Butch Wilmore and Suni Williams can head home after nine months in orbit.