NASA to Pay Staggering $146 Million Per SLS Booster Engine

I've written a lot about the Space Launch System (SLS) over the years; it's that perpetually late, perpetually over budget system that NASA has been overseeing for about a decade.  The SLS was originally supposed to launch in 2017; right now it looks to be no earlier than 2021.  Interestingly, just the cost of schedule delays is in the vicinity of $8 Billion.  According to ARS Technica in 2018, for just the cost of the delays (for 3 years from 2017 until this year)

NASA could have bought by purchasing Falcon Heavy rockets from SpaceX in 2018, 2019, and 2020. That $7.8 billion equates to 86 launches of the reusable Falcon Heavy or 52 of the expendable version.  

The hits just keep on coming for SLS.  According to Ars Technica on Friday, NASA had recently announced a contract to Aerojet Rocketdyne for 18 additional space shuttle main engines for the SLS rocket. That was at a paltry $100 Million per engine; but as the infomercial guys say, “Wait!  There's more!” 

However, this is not the true price of these engines. NASA has previously given more than $1 billion to Aerojet to "restart" production of the space shuttle-era engines and a contract for six new ones. So, according to the space agency, NASA has spent $3.5 billion for a total of 24 rocket engines. That comes to $146 million per engine. 

Now the Space Shuttle Main Engines (SSME or RS-25s) are really awesome engines.  Always feared to be the weak spot in the shuttle program, they went on to have a flawless history.  

It is true that the shuttle main engine, or RS-25, is the Ferrari of rocket engines. NASA designed these brilliant engines in the 1970s for the space shuttle program, during which they each flew multiple launches. A total of 46 engines were built for the shuttle at an estimated cost of $40 million per engine. But now these formerly reusable engines will be flown a single time on the SLS rocket and then dropped into the ocean.

At the risk of beating the obvious dead horse, $146 million is 3.65 times the cost of the engines when they were being built to be reusable.  Aerojet Rocketdyne is asking that for a use-once-and-throw-away engine.  To borrow a line, "that just don't seem right." 

There are a lot of things one could buy in the aerospace industry for $146 million. One might, for example, buy at least six RD-180 engines from Russia. These engines have more than twice the thrust of a space shuttle main engine. Or, one might go to United Launch Alliance's Rocket Builder website and purchase two basic Atlas V rocket launches. You could buy three "flight-proven" Falcon 9 launches. One might even buy a Falcon Heavy launch, which has two-thirds the lift capacity of the Space Launch System at one-twentieth the price, and you'd still have enough money left over to buy several hundred actual Ferrari sports cars. [Bold added - SiG]

It's hard to come up with more pointed example than this final one from Eric Berger at Ars Technica

Speaking of engines, SpaceX is building the Raptor rocket engine to power its Super Heavy rocket and Starship upper stage. The Raptor has slightly more power at sea level than the RS-25 and is designed for dozens of uses. According to SpaceX founder Elon Musk, it costs less than $1 million to build a Raptor engine. The company has already built a couple dozen of them on its own dime. So there's that.

SpaceX has set a goal for the next version of the Raptor engine of $250 thousand.  The published thrust in a vacuum of the SSME is 512,000 lbs.  The stated thrust of the Raptor v2 is  250 tons, or 500,000 lbs.  I'll go out on a limb and say those ratings could well be the same. 

The SLS core currently at Stennis Space Center in Mississippi awaiting fueling and testing.  The testing was put on hold due to the COVID-19 shutdowns back in March.  The SSMEs, with red protective covers over them, are visible at the bottom.