SpaceX accomplished an incredible feat by launching the Falcon Heavy earlier this month. The rocket was an untested platform, and things went much smoother than Elon Musk ever could have anticipated.
The booster landings, on the other hand, didn't go as smoothly. Only two of the Falcon Heavy's three boosters landed successfully, and the third missed the drone ship in the Atlantic Ocean by more than 300 feet.
SpaceX went days without explaining what went wrong, but according to Musk, it was a fueling problem that prevented two of the booster's engines from igniting for the landing. As it would seem, SpaceX should be able to fix this by loading the center stage up with a bit more fuel, and the commercial space company plans to address this problem head-on during future launches.
In other news, SpaceX seems to be building a second drone ship so that it can land multiple boosters in the ocean instead of just one. Ocean-based landings are significantly safer than land-based landings because of the lack of surrounding population, so it's probably for the best.