Falcon 9 is a reusable rocket designed and built by SpaceX, a company founded by Elon Musk. It is used to transport satellites and supplies to the International Space Station (ISS). The rocket has two stages, with the first stage capable of landing back on Earth after launch, which helps reduce costs and makes space travel more sustainable. The Falcon 9 is known for its reliability and has completed numerous successful missions since its first flight in 2010. Its ability to carry heavy payloads and return safely has revolutionized the space industry, paving the way for future exploration and commercial space travel.