Even as Elon Musk got everyone's attention with the Hyperloop, his wild idea to remake mass transit, his engineers at SpaceX did something far cooler: They proved their reusable rocket can go sideways.

Almost immediately after Tuesday's lift off, the 10-story-tall Grasshopper rocket made a "hard lateral deviation," as Musk put it, of 100 meters during its ascent to 250 meters. It then returned to the center of the launch pad at touchdown.

That is rocket science. Literally. The really cool kind of rocket science.

Grasshopper already has made a few short hops and a few higher-altitude flights, and the flight, announced Wednesday, greatly expands the maneuvering envelope of the vertical take-off/vertical landing vehicle. It's a major milestone in Musk's plan to reboot the space sector. And it was but one milestone we've hit this week in the private space race. Sierra Nevada completed important – if pedestrian – testing of its new lifting body spacecraft, and Virgin Galactic signed up still more customers for flights it plans next year.

For all the debate among pseudo rocket scientists arguing whether carrying the fuel needed to return to Earth is a worthwhile proposition, those signing the checks still need to develop the technology to make it work. Musk is doing just that. He's made it clear that reusing the first stage of a rocket will greatly improve the economics of delivering payloads to space, and his engineers continue making some impressive flights even as his critics continue piling on doubt.

The Grasshopper test is a big deal because there aren't, at the moment, any rockets in use capable of the kind of lateral maneuvers SpaceX showed off Tuesday. Some smaller rockets have done it, but none of them even approaches Grasshopper's size. The ability to make significant corrections to the trajectory is a key part of developing a reusable rocket, as the first stage will return to Earth at hypersonic speed. The only way to decrease its lateral speed, and guide it to a landing site, is through such moves.

"The test demonstrated the vehicle's ability to perform more aggressive steering maneuvers than have been attempted in previous flights," the company said in announcing the news. "Grasshopper is taller than a 10-story building, which makes the control problem particularly challenging."

The braking and steering tests performed by Sierra Nevada Corporation are far less dramatic, though they are crucial to preparing its lifting body spacecraft for the company's first glide flights in the coming months. After all, before you can fly to space, first you have to be sure you can come to a complete stop before unbuckling your seat belt.

The Dream Chaser is Sierra Nevada's entry into the NASA competition for delivering astronauts to the International Space Station (and elsewhere in low Earth orbit). Unlike the entries from SpaceX and Boeing, the Dream Chaser is not a classic capsule. Instead, it's a flying vehicle that would land like the space shuttle orbiters, rather than falling back to Earth under parachute.

The recent tests took place at Edwards Air Force Base in southern California, where the space shuttle orbiters were initially tested and landed several times after returning from space. The first four tests on the runway effectively looked at the final moments of the rollout after landing. Performed at just 10, 20, 40 and 60 miles per hour, the vehicles' braking and steering were verified and several other on-board systems were tested while in motion.

This fall Sierra Nevada will be carrying the Dream Chaser to altitude and performing unmanned approach and landing tests at Edwards as it expands the flight envelope of the vehicle.

Virgin Galactic completed another glide flight of SpaceShipTwo this month as the company announced it now has 625 people who have signed up for its suborbital spaceflights. The price has gone up $50,000 since the company first starting selling rides, with a ticket now costing $250,000 for a view of the black sky and a few minutes of weightlessness.

If the current flight testing continues going well, Virgin Galactic hopes to perform its first flights with SpaceShipTwo later this year, and begin commercial flights some time in 2014.