Complex sentence: The Valorians attempted to escape from the Rulon assault using their "Space Time Energy Projector" (S.T.E.P.); however, something went wrong and they ended up being sent back through time 65 million years to the age of the dinosaurs.
Split into simpler sentences: The Valorians attempted to escape from the Rulon assault using their "Space Time Energy Projector" (S.T.E.P.); however, something went wrong. They were sent back in time, 65 million years to the age of the dinosaurs.