SpaceX's mission is to carry supplies to the ISS. It's NASA's new way of supplying the station following the retirement of the space shuttle.

The spacecraft needs its thrusters to reach the International Space Station. Without enough working thrusters, the ship cannot reach the space station and carry out the mission for which taxpayers are spending $133 million.

The issue comes four months after losing an engine on a previous launch.

A NASA spokeswoman said Saturday's scheduled rendezvous between Dragon and the ISS had been cancelled.

Late Friday, the thrusters began working after clearing a blockage in a propellant line.

NASA, however, is hesitant to have Dragon approach the ISS. SpaceX will have to convince NASA that its space craft is safe enough to dock with the space station, because any wrong move could kill the astronauts on board the ISS.

It may be a few days or a few weeks until Dragon is able to dock with the ISS.