Getting people and equipment into space is an expensive business, and it’s far from easy. Take away all of the calculations, planning, and hundreds of people that all have to work together, and there’s still one basic problem – breaking the gravity’s hold. To get anything into orbit around the earth, it has to reach speeds of about 4.9 miles per second or 17,600 mph. To do this, we’ve traditionally used multiple-stage rockets, in which the first stage does most of the legwork while the second stage completes the job. First stage rockets, until now, have generally been one-use items, but Elon Musk and SpaceX just made the first major step in making spaceflight significantly cheaper.