Somewhere around 700,000 years ago, an asteroid or comet slammed into Mars and sent debris flying everywhere. And perhaps 1,000 years ago, one small piece of rock finally ended up on Earth. Now that same bit of basalt is going back to Mars, reports the BBC. As the Guardian explains, NASA is ferrying the tiny meteorite back to the red planet as part of a new mission that blasts off Thursday. The flight home is not about nostalgia: The rock will be used to help calibrate instruments on the Perseverance rover before it is sent out to explore. “When you turn on instruments and begin to tune them up before using them for research, you calibrate them on materials that are going to be like the unknown substances you are about to study," says Caroline Smith of London's Natural History Museum, where the meteorite has been stored. "So what better for studying rocks on Mars than a lump that originated there?"
It will take about seven months for the rover to reach Mars, at which point it will touch down in the planet's Jezero Crater, per Space.com. The crater, 28 miles wide, is believed to have once been home to a lake, and Perseverance will hunt for signs of ancient life. NASA has a number of different technologies it plans to test, but the rover is the focus of the $2.7 billion mission. Don't hold your breath waiting for new Mars rocks as a result of this trip. The rover will seal up the most promising specimens it finds and leave them on the planet's surface for future robotic missions to collect. The museum's Smith, for example, hopes she'll be able to get her hands on new samples—in 10 to 15 years. As for the traveling meteorite and its unusual journey: "This little rock's got quite a life story," she says. (Read more Mars stories.)