From the Horses Mouth (Score 2)

I got this from a High Level Engineer that works on the Project. (not me)

It seems to be be a third stage problem with the rocket. The third stage is by the Russians. The first and second stages are by the Ukraine. There have been problems with both systems before. A failure investigation is being done now

They have Delta rockets which work well. The Lauch platform could be modified to for the Deltas ... timeframe unknown. In his mind its a better launch system anyways.

But there is the possibility that this could shutdown SeaLaunch.