The RS-25 is a rocket engine originally developed for the Space Shuttle program by NASA. It is known for its high efficiency and reliability, utilizing liquid hydrogen and liquid oxygen as propellants. The engine produces a thrust of about 512,000 pounds, making it one of the most powerful rocket engines ever built. Currently, the RS-25 is being repurposed for the Space Launch System (SLS), which is designed to carry astronauts and cargo beyond low Earth orbit. The engine's advanced technology and proven performance are crucial for future missions to the Moon and Mars.