The Space Launch System is NASA's next-generation rocket, an absolute behemoth that is supposed to get us to Mars.
The SLS's booster system was tested for the first time today—basically, the booster was anchored and stabilized in a desert in Utah, where it fired for two consecutive minutes in what's known as a "static test."
When the full launch system is eventually ready to go, two boosters will fire, carrying NASA's next-generation Orion space capsule to destinations such as an asteroid or even Mars.
Scientists with the mission said all went well: "It looked really clean, we're really excited. It all looked great. Really nice result," an SLS project scientist said on NASA TV.