[nordsieck]

> I'm not sure that's true.

From the OIG report[1]:

> We project the cost to fly a single SLS/Orion system through at least Artemis IV to be $4.1 billion per launch at a cadence of approximately one mission per year.47 Building and launching one Orion capsule costs approximately $1 billion, with an additional $300 million for the Service Module supplied by the ESA through a barter agreement in exchange for ESA’s responsibility for ISS common system operating costs, transportation costs to the ISS, and other ISS supporting services. In addition, we estimate the single-use SLS will cost $2.2 billion to produce, including two rocket stages, two solid rocket boosters, four RS-25 engines, and two stage adapters. Ground systems located at Kennedy where the launches will take place—the Vehicle Assembly Building, Crawler-Transporter, Mobile Launcher 1, Launch Pad, and Launch Control Center—are estimated to cost $568 million per year due to the large support structure that must be maintained. The $4.1 billion total cost represents production of the rocket and the operations needed to launch the SLS/Orion system including materials, labor, facilities, and overhead, but does not include any money spent either on prior development of the system or for next-generation technologies such as the SLS’s Exploration Upper Stage, Orion’s docking system, or Mobile Launcher 2.

> And we don't really yet know the cost of the EUS.

We have an idea of an initial cost estimate from this[2].

NASA agreed to buy 2 core stages and 2 EUSes for $3.2B. Since RS-25s are around $100M each and the SRBs are around $200M each, this pushes the cost of the rocket up to $2.4B, maybe a bit more.

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1. https://oig.nasa.gov/wp-content/uploads/2024/02/IG-22-003.pd...

2. https://www.nasa.gov/humans-in-space/nasa-commits-to-future-...

[panick21_]

> We project the cost to fly a single SLS/Orion system through at least Artemis IV to be $4.1 billion per launch at a cadence of approximately one mission per year.

Yeah but you see, they will miss that 'one mission per year' thing by quite a large margin. And it will be more expensive because of that alone.

There are other traps in these numbers. OIG numbers are far better then NASA but I bet in 20-30 years when somebody does the total cost it will be higher.

> prior development of the system or for next-generation technologies such as the SLS’s Exploration Upper Stage, Orion’s docking system, or Mobile Launcher 2.

And I don't think just excluding all 'prior development' as if it was irrelevant makes much sense. Development cost should be considered as part of a program.

[nordsieck]

> Yeah but you see, they will miss that 'one mission per year' thing by quite a large margin.

So, that's fair. But it's also complicated. Part of that number (for EGS) is for the upkeep of buildings like the VAB. Which is fair - SLS is the only real user, so they get charged for it.

But it's also kind of not fair, since NASA's going to keep it around, even if SLS wasn't a thing. As evidenced by NASA doing just that in the interim period between Constellation and SLS.

> And I don't think just excluding all 'prior development' as if it was irrelevant makes much sense. Development cost should be considered as part of a program.

I completely agree with you in general.

But I think that it's easier to tally the development costs separately.

And it's important to know how much it costs to just build and launch the rocket. A number which NASA (outside of OIG) has been extremely reluctant to release to the public. As far as I know, NASA leadership has never made specific claims about how much SLS costs, just that the OIG numbers are wrong and/or misleading.

Once the program ends, we'll have a better idea of how to amortize the develop costs over the total number of launches.