sentences:  The unpowered Upper Stage Simulator (USS), which was not meant to be retrieved, impacted further out into the Atlantic Ocean.The USS began to tumble, in a flat, counterclockwise spin almost immediately after staging.After initial concerns that the motion might have been caused by a collision between the USS and the first stage, further analysis showed that no actual recontact happened and that the tumble had been one of the possible behaviours predicted by pre-flight simulations.