The Space Launch System that will one day take us to Mars is a serious beast made up of four leftover space shuttle engines. Of course, before the engines are strapped together and aimed into the sky, they have to be tested. And that involves some fireworks.
The first RS-25 engine that will actually take flight had a successful test in Mississippi this week, burning for 500 seconds without incident. It was last used five years ago to power Endeavour into orbit, one of the last shuttle missions before the program was shut down.
Engineers won't know if everything is working perfectly until they review the engine and the data from the test fire, but the first indication -- that giant cloud of smoke -- is very good indeed.