This afternoon, SpaceX landed the most powerful version yet of its Falcon 9 rocket, after launching the vehicle from Cape Canaveral, Florida. The so-named Block 5 upgrade took off from the company’s launchpad at Kennedy Space Center, sending a communications satellite into orbit for Bangladesh and then touched down on one of the company’s drone ships in the Atlantic. It was the 25th successful rocket landing for SpaceX, and the 14th on one of the company’s drone ships.

It also marks the first launch of the Block 5, the vehicle that will carry humans to space for NASA. The Block 5 is meant to be SpaceX’s most reusable rocket yet, with many upgrades put in place that negate the need for extensive refurbishment between flights. In fact, the first Block 5 rockets will eventually be able to fly up to 10 times without the need for any maintenance after landings, SpaceX CEO Elon Musk said during a pre-launch press conference. Ideally, once one of these rocket lands, SpaceX will turn it horizontal, attach a new upper stage and nose cone on top, turn it vertical on the launchpad, fill it with propellant, and then launch it again. Musk noted that the vehicles would need some kind of moderate maintenance after the 10-flight mark, but it’s possible that each rocket could fly up to 100 times in total.

“Ironically, we need to take it apart to confirm that it does not need to be taken apart.”

It’ll be a while before SpaceX is that efficient, though. Since this is the first launch and landing of the Block 5, the company will still deconstruct the vehicle and do inspections to see if it can indeed fly again without refurbishment. “Ironically, we need to take it apart to confirm that it does not need to be taken apart,” Musk said. He noted that this particular rocket probably won’t fly again for a couple months.

But the goal is to ultimately close the gap on the Falcon 9’s turnaround time between flights. Musk says that to show the true power of the Block 5, SpaceX plans to launch the same rocket twice within a 24-hour period sometime next year. So far, the smallest gap between SpaceX launches has been two days — though the missions were on opposite coasts of the US and the company used different rockets for each flight. It’s usually taken a few months for the same Falcon 9 rocket to fly again.

Not only is the Block 5 more equipped for reuse, but it’s also got much more power than its predecessors. The main Merlin engines at the bottom of the rocket have 8 percent more thrust than before, and Musk thinks there’s more room for improvement. “The thrust we’re getting is truly incredible at this point,” he said. Meanwhile, the Merlin engine in the upper stage of the rocket — the one that operates in the vacuum of space — has 5 percent more thrust than before.

The Block 5 is also the rocket that SpaceX will use to send astronauts to the International Space Station, as part of NASA’s Commercial Crew Program. In order to make the vehicle certified for carrying humans, SpaceX had to make a huge number of improvements to the rocket’s design. “There are thousands and thousands and thousands of requirements,” Musk said. For one, the rocket has to be able to handle more loads during launch and it has to have a much higher tolerance for small failures. In other words, if a few things go wrong during flight, the rocket will be okay. Musk noted that a few engines could go out on this vehicle and the Falcon 9 would still be able to make it to orbit. But just to be safe, NASA is requiring that SpaceX fly the Block 5 at least seven times, without making any major changes to the rocket, before people can ride on it.

“The reason that it’s so hard to make an orbital rocket work is that your passing grade is 100 percent.”

Before the launch, Musk indicated that testing out all of these new changes made him particularly nervous. “The reason that it’s so hard to make an orbital rocket work is that your passing grade is 100 percent,” he said. “And you can’t fully and properly test an orbital rocket until it launches, because you cannot recreate those conditions on Earth… Man, anyway, I’m stressed.”

SpaceX doesn’t intend to make any major revisions to the Block 5, though, save for small changes to improve flight reliability and reusability. The company will likely have between 30 to 50 Block 5 rockets in rotation at some point, according to Musk. The number depends on which customers insist on flying satellites on a new vehicle, though he’s hoping the mentality on used rockets will change in the coming years. “The general sentiment will change from... feeling like, ‘A flown rocket is scary,’ to ‘An unflown rocket is scary,’” Musk said.

Customers that do want to fly on a used rocket will get a bit of a discount. The starting cost of a flown Falcon 9 is about $50 million, while new vehicles start around $60 million. And if the Block 5 really doesn’t need any refurbishment between flights, SpaceX could see even more cost savings and choose to lower its prices even further. It all depends on how the next few flights of the Block 5 play out.

But if all goes well, Musk predicted that the Falcon 9 will do 300 more flights before it’s retired. Then, the bulk of SpaceX’s missions will be done on the company’s next big rocket, the BFR.