PASADENA, CA—Proudly announcing the arrival of the newest additions to the NASA family, top officials at the U.S. space agency welcomed a litter of Mars rovers Thursday after successfully breeding Perseverance with Curiosity. “We’re happy to report that Perseverance gave birth to 12 healthy, bouncing baby rovers early this morning,” said Michael M. Watkins, director of NASA’s Jet Propulsion Laboratory, describing the emotional moment when a dozen viable research crafts—their tiny chassis covered in oil and titanium shavings—were expelled from the parent rover’s motorized womb into the red dust on the planet’s surface. “It will be months before these little guys can open up their image sensors and begin rolling around on their own, but once they do, their mother will teach them how to collect samples and analyze soil composition. Of course, our ultimate goal is to continue breeding them for generations so we can establish a permanent colony of rovers on Mars. For now, though, these tots will be cradled in their mother’s robotic arms, suckling on her power reserves until they reach maturity.” At press time, the Chinese National Space Administration had demanded joint custody of the infant rovers, claiming a routine paternity test would show its Tianwen-1 spacecraft, currently in orbit around Mars, was the true father.