NASA sent a spaceship rocketing by an asteroid — and discovered the space rock has a little baby one dancing around it

NASA's Lucy spacecraft discovered that the asteroid Dinkinesh is actually a binary asteroid system.

• NASA sent a spacecraft flying by the Dinkinesh asteroid.
• The agency discovered that Dinkinesh is actually a binary asteroid system.
• The Lucy spacecraft discovered that the larger asteroid has a baby asteroid dancing around it. 

NASA sent a spacecraft flying by what it initially thought was one asteroid.

But the Lucy spacecraft returned images showing that the asteroid Dinkinesh is actually a binary asteroid system, meaning there are two asteroids orbiting a common center. In this case, the system features asteroids of different sizes — one much smaller than the other.

"Dinkinesh really did live up to its name; this is marvelous," Hal Levison, the principal investigator for Lucy who works at the Southwest Research Institute, said in a press release from NASA. "When Lucy was originally selected for flight, we planned to fly by seven asteroids. With the addition of Dinkinesh, two Trojan moons, and now this satellite, we've turned it up to 11."

Lucy flew by the asteroid system at a speed of 10,000 miles per hour, NASA said. The researchers working on the spacecraft had suspected that Dinkinesh might be a binary pair because of the way its brightness changed with time. The images the spacecraft returned confirmed their theory, according to the news release.

Lucy's flight was intended to be a test of the spacecraft — and it passed with flying colors.

"This is an awesome series of images," Tom Kennedy, a guidance and navigation engineer at Lockheed Martin in Colorado, said in the news release. "They indicate that the terminal tracking system worked as intended, even when the universe presented us with a more difficult target than we expected."