SpaceX's CRS-6 mission launched successfully
SpaceX succeeded in launching a Falcon 9 rocket to carry supplies up to the International Space Station. But the company's second attempt to land a rocket stage on a floating barge was, once again, a failure: Ascent successful. Dragon enroute to Space Station. Rocket landed on droneship, but too hard for survival.
To be fair, landing a rocket this way would have been a totally unprecedented feat. The company tried this once before, in January, and it didn't go exactly as planned. Because of a shortage of hydraulic fluid, the uncrewed rocket became destabilized and exploded as it hit the barge. The fact that the rocket was roughly on target, though, was a sign of progress and could lead to something big.
Normally, rockets are simply allowed to break up into pieces or sink into the ocean after each use. But controlled landings could allow SpaceX to reuse rocket stages on future flights, and reusing these multimillion-dollar pieces of equipment, rather than throwing them out after every launch, could dramatically drive down the cost of space travel.