Rocket boosters launch rockets in stages, propelling them into orbit. Right now, when a booster separates from a rocket, it’s wasted.   

But last night, SpaceX was able to steer its first-stage booster back to Earth safely and land it. It’ll have to be refurbished before it can be used again. 

“So initially, they’ll still be taking a lot of time to analyze the data, look at the structure,” said David Alexander, director of Rice University’s  Space Institute. “Maybe do a test flight of it.”

But, Alexander said, once all that becomes routine, SpaceX could save a lot of money — maybe half the cost of a first-stage booster, which he said is around $16 million.

But SpaceX will also make money because it’ll be able to schedule more launches.

“If you can get the turnaround time down from, say, one launch a month to one launch  a week, then you can launch more,” Alexander said.

SpaceX CEO Elon Musk has said he hopes to start routinely reusing rockets in a few years.