But NASA TV’s host noted the engineers were celebrating with what they call a “TAG five,” a move named after Osiris-Rex’s robotic arm that will collect a sample from Bennu. Cerna’s high-five hand was the flat surface of Bennu, while fists represented the “Touch-and-Go Sample Acquisition Mechanism,” or TAGSAM, that will pound Bennu’s surface to loosen up and then collect rock.

It’s the second custom NASA handshake in a week. After the InSight rover successfully touched down on the surface of Mars, two engineers celebrating with a complex and clearly rehearsed handshake of hand slaps, punches, arm bumps, and fist pumps, that culminate with a high five. The video went viral.

In an interview with the engineers, who introduced themselves as Brooke and Gene, they said it was an homage to a different touchdown handshake, one shared by 49ers receivers Marquise Goodwin and Kendrick Bourne. Brooke, a Chiefs fan, and Gene, a Patriots fan, bonded over football and decided it’d be an appropriate celebration for the historic moment. They practiced for five or six weeks before, watching tapes of the original touchdown handshake. (Quartz has reached out to NASA to see if there have been other special NASA celebration handshakes, and will update this post with their response.)

Epic handshakes and celebrations are huge in sports. Let’s hope they’ll become a part of NASA culture, too. These mission milestones are undeniably epic—the culmination of years of painstaking work, and billions of dollars—and, arguably, have implications for all of humanity.

Osiris-Rex’s arrival at Bennu kicks off the most exciting part of its five-year mission, and scientists hope that close-up observation of the asteroid—thought to have formed about 4.6 billion years ago—will reveal clues about the early building blocks of our solar system’s planets and the origins of life. Now that InSight has landed on Mars, it will spend the next two years studying the planet’sinterior structure for clues about its formation, which might help us understand other Earth-like planets.

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