Internal video shows the booster hitting the water about 100 feet away from the drone ship/platform. The booster was coming in "hot". The design is for the booster to arc back on a "ballistic" path, essentially like a missile would fly, with the target about 100 feet or so off of the barge so that if something goes wrong it comes up short and doesn't hit and damage the drone ship. The re-entry boosters then fire and slow and reorient the booster so that it gets upright and shifts over the target landing area on the drone ship to allow a soft and stable landing. Unfortunately a data error led to several of the booster rockets not firing so it didn't redirect and it hit the water (and not the drone ship) at a high rate of speed, as planned when there is a failure in some part of the process.
[Post edited by 133743Hokie at 02/08/2018 10:16AM]