https://www.vice.com/en_us/article/m7v974/a-piece-of-spacex-rocket-junk-is-going-to-slam-into-the-moon

Part of a rocket launched by Elon Musk’s company, SpaceX, in 2015, is expected to slam into the Moon in a matter of weeks.

The object is a second stage, which is a section that has been separated from the bottom of the rocket, known as the first stage, equipped with its own engines and propellant. Rockets are made up of stages that detach from one another at different locations in the Earth’s atmosphere and in space, and the remains become debris.