Considering their last rocket on the pad blew up in June, this is a stunning achievement and it has never been done before.
As you probably know, space rockets are built up from stages and the real problem with getting into space is weight. The more weight you put on the rocket, the more fuel you need to escape gravity. And obviously fuel has its own weight which then requires more fuel or perhaps larger fuel tanks which adds more weight and...
SpaceX Have Just Landed A Stage One Rocket
