00:00They are former Space Shuttle main engines. Extremely powerful, extremely efficient,
00:05but also extremely expensive. A single newly manufactured RS-25 engine costs around 145
00:14million dollars today. Back in the Space Shuttle era they were still reusable, but of course you
00:21wouldn't even consider that today. The engines were converted for several billion US dollars
00:27from reusable to expendable mode. You couldn't make this stuff up. For Artemis II, refurbished
00:35shuttle engines are still being used. Later SLS flights will then get newly built variants.
00:40Here are the performance specs of an RS-25. They deliver about 235 metric tons of thrust each in a
00:48vacuum. So almost 940 metric tons of thrust in total. The specific impulse is around 452 seconds.
00:57Which is extremely efficient. The burn time of the core stage is about 8 minutes. This stage
01:04is basically an engineering marvel. Thank you very much.
