SpaceX has landed its boosters on drone ships many times before, but this one was a particular challenge.
The rocket, which was refurbished after its first launch in January of this year, had to send BulgariaSat-1 into a particularly high orbit today. That means the booster had to endure extra heat—and thus extra jostling—while crashing back into Earth’s atmosphere. The land wasn't super smooth, but the rocket survived, and that's pretty impressive.
This is SpaceX's second time flying a used rocket—an important component to proving that its reusable rockets might actually make spaceflight cheaper. Whereas the first reused rocket waited a year between its two launches, today's launch shows that SpaceX is able to refurbish the Falcon 9 first stage boosters in six months or less. Quick refurbishment is key to cutting the costs of spaceflight. Ultimately, SpaceX CEO Elon Musk hopes to fly the boosters out again the next day—so there's still plenty of room for improvement.