76K views · 1.5K reactions | It IS  science! Today at 4:45 p.m. EST, we’re firing up one of the four RS-25 engines that will power NASA's Space Launch System rocket to destinations like the Moon and Mars! What is an RS-25 engine? Watch this video and tune in live to see the fire, smoke and steam during today’s test: https://www.nasa.gov/live | NASA - National Aeronautics and Space Administration | Facebook

54K views · 2K reactions | Tomorrow, we're bringing the  by testing one of the four RS-25 engines that will power our NASA's Space Launch System rocket! But first, what is an RS-25? Discover how it will launch NASA Astronauts on missions of deep space exploration: https://go.nasa.gov/2FN8Z2p | NASA - National Aeronautics and Space Administration | Facebook