Getting out of Earth's gravity well is hard. Conventional rockets are expensive, wasteful, and as we're frequently reminded, very dangerous. Thankfully, there are alternative ways of getting ourselves and all our stuff off this rock. Here's how we'll get from Earth to space in the future.
We've known about DARPA's plan to build a reusable, unmanned space plane for quite some time, but the agency just announced the companies that will help. Unsurprisingly, two feature famous billionaires who love space.