SpaceX succeeds where Rotary Rockets failed: The first orbital flight by a privately funded rocket. On the other hand, they're doing two stages, rather than single stage to orbit, although their first stage is reusable. More to the point, they're founded and funded by Elon Musk, the founder of Paypal. They've got 550 employees -- Rotary never broke 100 even at its peak. As they say, you gotta have the bucks if you want the Buck Rogers.