Today marks the third time in just over four months that Blue Origin has successfully launched and landed its New Shepard spacecraft and propulsion module. The launch and landing took place in a remote area of West Texas and is a significant step for a company that wants to dramatically cut the cost of access to space.

Before last November, when New Shepard made its historic first flight, it was unclear how difficult it would be to land a rocket vertically on the ground after sending it into space. But then Blue Origin did it. A month later SpaceX performed the same feat with its Falcon 9, a much larger and more powerful booster that had just delivered a payload into orbit.

That led to the next hurdle: could rockets be refurbished quickly and relatively inexpensively for subsequent flights? This was a stumbling block for the space shuttle, which required hundreds of millions of dollars in engine tests and retrofitting after every flight. Blue Origin has begun jumping this hurdle too. First, it flew the New Shepard module again in January, a turn-around time of about two months.

During a test flight, when New Shepard nears the 100km line that marks the internationally accepted boundary of space, a capsule capable of carrying six people separates from the rocket. This capsule flies into space for a few minutes before parachuting back to Earth. Meanwhile, the propulsion module's air brakes deploy and, as it returns to the ground, the module's BE-3 engine fires to slow its descent and make a vertical landing.

After the January flight, Blue Origin's founder Jeff Bezos told Ars that refurbishing the propulsion module after that first flight cost “in the small tens of thousands of dollars.” His technicians never even removed the engine from the vehicle. “We inspected it and said, 'Let's go.' It was designed to be reusable from the start.”

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin

Blue Origin raised the stakes Saturday by testing its engine in a non-nominal flight. The company's engineers restarted the BE-3 engine just 3,600 feet above the ground at high thrust. Had the test failed the rocket would have crashed, but everything went smoothly. Bezos apparently expected it to because for the first time he announced a launch test in advance. He tweeted out details as the rocket lifted off and returned to the West Texas site.

Blue Origin even included two research payloads on Saturday's flight: the "Box of Rocks" experiment from the Southwest Research Institute will test how rocky debris settles in microgravity, while the University of Central Florida's "Collisions into Dust" experiment aims to better understand how large bodies interacted with dust in the early Solar System. This marks the beginning of Blue Origin's plan to use New Shepard as a reliable testbed for suborbital science experiments.

Saturday's flight is significant not only because it continues to demonstrate the potential of reusable rockets to lower the cost of access to space. Regular flights have an added, critical benefit for any launch system. The more New Shepard flies, the more confidence Blue Origin will have in its reliability and safety, which is vital for a company that hopes to begin human test flights in 2017, and perhaps take paying passengers to space as early as 2018.

"One of the things I feel very, very strongly about is if you want to get good at spaceflight you have to practice," Bezos explained in March to Ars. "If you’ve ever had surgery, there are very good statistics that suggest you should find a surgeon who does it five times a week, preferably 10 or 20 times a week, because that’s the kind of rate we humans get really good at things. We need to get to the point where we are flying more than 100 times a year. We want a vehicle we can fly over and over again with only the lightest of refurbishment."

With Saturday's test Blue Origin continued to practice, and all apparently went well. It is aiming for a design goal of 100 missions for each New Shepard system it builds and ultimately puts into commercial service. After three flights with an experimental vehicle, that doesn't seem like such a crazy idea.