“Even given everything we’ve learned, the odds of succeeding on our third attempt to land on a drone ship (a new one named “Of Course I Still Love You”) are uncertain, but tune in here this Sunday as we try to get one step closer toward a fully and rapidly reusable rocket.”
Good explanation, with pix and video, from SpaceX. Good luck, y’all.
UPDATE: The SpaceX rocket Sunday never had a chance to attempt a landing. It blew up shortly after launch. The first loss in 19 tries. Thank goodness it wasn’t manned.
THE TEXAS SCRIBBLER 
Pity. I hope they will persist.
I doubt they could stop. Too much invested and the Rooskie resupply of the ISS is having problems of its own.