A few minutes later, the second stage began a dramatic spin as the rocket reached space. The roll was captured in views from an on-board camera.
"The roll on the second stage was also a non-fatal situation. We think the actuator may have overheated due to radiative heating from the nozzle," Musk said. "This is speculative, but we can trace the problem down to the roll actuator itself."
More insulation will be added around the actuator to prevent the same problem on the next launch.