SpaceX had one more victory this evening in its historic reuse of a rocket: it also landed the nose cone on top of the rocket that surrounds the payload to keep it safe, called a fairing. This is a first for SpaceX.

You can think of the fairing like a hard protective bubble atop the rocket. So it’s big: five meters — or more than 16 feet — in diameter. Fairing recovery has been a target for SpaceX for at least a year; Elon Musk, the founder of SpaceX, mentioned fairing retrieval as a goal in April 2016.

Fairings can cost a couple million dollars each

That’s because those nose cones, which are made of carbon fiber and aluminum honeycomb, can cost a couple million dollars each, according to Musk. Being able to recover fairings is another step toward cheaper, multi-use rockets.

About three and a half minutes after liftoff, the fairing split in two and began to fall toward Earth — as it was designed to do. These parts have their own thruster systems, and when they’ve slowed enough, they deploy parachutes to land.

That doesn’t mean that SpaceX has necessarily recovered the fairing pieces, though. They must have landed in the ocean — no part of the rocket’s flight path goes over land. Still, it marks another success for SpaceX’s reusability project, along with its reflight and re-recovery.