THE EXPENSE ISN’T COMICAL: How NASA’s Comically Big Moon Rocket Is Coming Along.
Via Bob Zubrin:
Comparison of SSME [Space Shuttle Main Engine] and [SLS’s] RS-25:
SSME
Thrust: 512,000 lbf
Isp: 453 s
Reusable? Yes
Maker: Rocketdyne
Cost: $50 million
RS-25
Thrust: 512,000 lbf
Isp: 453 s
Reusable? No
Maker: Rocketdyne
Cost: $146 million