Now that both Blue Origin and Space X have landed rockets upright after launch, it looks like the one-off era of rockets is coming to a close. Before the two landings, rockets were regarded essentially as trash after take-off, if they weren't totally destroyed on their missions. By landing its first phase of the Falcon 9 rocket, SpaceX has preserved at least part of the main engines to use another day.

If the private space industry will be viable in the long term — whether for satellite launches or taking people to low-earth-orbit — it's going to need to figure out cost savings. The first stage of the Falcon 9 rocket, which is the size of a 14-story building, is the most expensive to manufacture; it has the engines and the fuel. That's the bit SpaceX landed. The next question is if the components are in any state to be reused — and, if so, how much that will cost. (Elon Musk has said today's rocket boosters won't be sent back to space. "It's kind of unique," he said. "It's the first one we've brought back.") Musk's reusability ideas don't end with the first stage, either — he hopes, eventually, to recover and reuse the entire rocket.

Meanwhile, the United Launch Alliance — the joint venture of Boeing and Lockheed Martin — is also getting into the reusability game with a new rocket, the Vulcan. The Vulcan is designed so that the most expensive part of the first stage, the main engines, can be captured mid-air by helicopters. Blue Origin is making the engines.

This year was the first time we saw rockets land. Perhaps one day soon — not next year, but probably not too long from now either — rocket landings will be as regular as rocket launches.