To the extent that the numbers can be untangled, how was the cost of the ISS distributed in categories such as launch, hardware, and R&D?

Since the retirement of the ISS is in the offing, I'm wondering how much it would be to replace it, and whether or not starting now, it might be an order of magnitude less to build a replacement than it cost to do it the first time, due in part to experience that could only have been gained in putting together the ISS in the first place.

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    $\begingroup$ Do not ask your question about 'today'. Today always changes and any answers will become out of date. Ask what the cost equivalent is in 2018 instead. $\endgroup$ Commented Feb 27, 2018 at 17:49
  • $\begingroup$ That's seems like a good idea. $\endgroup$ Commented Feb 27, 2018 at 17:50
  • $\begingroup$ What are the requirements for this "replacement"? International partner co-operation? 120 kw power generation? Same internal cubage as the ISS? Crew complement? In aerospace, requirements drive the design, and the cost. $\endgroup$ Commented Feb 27, 2018 at 19:43

1 Answer 1


Without the Space Shuttle in 2018, the ISS could not be built as it currently exists.

The Russians would likely just build their segment the same way. Launching major modules on Proton (Zarya, Zvezda). The minor modules launched on a Soyuz booster using a modified Progress module for controlling the flight.

You can tell this is the case, since the Russian plan for their next station is to use the next two ISS Modules (Nuaka and OM) in 2024 (or whenever) to form the core of their next station, with additional modules launched as needed.

US side a Falcon Heavy could launch a lot of mass, and SpaceX could probably derive the Dragon propulsion system onto a satellite bus style approach, to deliver the modules.

But there will be no construction base with a manipulator arm, that was there with the Shuttle and CanadaArm.

Thus the design would be quite different in all likelyhood, and in fact almost with certainty.

Launch costs by Falcon Heavy would be hugely cheaper than by Space Shuttle, which could help a lot of the costs.

Bigelow would likely be able to provide more modules, and when building several, reduce costs further. But more so, they would charge for a module, and deliver it.

If you waited a couple of years from now, when the BFR/BFS is in flight launch costs would be even cheaper.

But how much did flight costs dominate ISS costs?

Absolutely it has a large affect, but I suspect that if you could ditch the ISS management overhead and run it simpler (I.e. Get rid of NASA entirely in running it) it would be much cheaper and a much larger component than the launch costs.

Conversely if you look at cost of the Shuttle, not very much of it (of the whole) was actually materials costs. Rather it was the 24,000 someodd employees of NASA working on the programs salaries that were fixed cost each year.

I.e. The key is that the cost of the ISS is less about materials and almost entirely about salaries. Ditch the thousands (tens of thousands?) employees of NASA and replace it with a leaner company to run it, and overall cost will be much cheaper.

Thus short answer - no way to compare. Longer answer, if done smart and not the NASA big government way, much cheaper.

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    $\begingroup$ The current ISS design requires a large staff of flight controllers constantly sending commands to it and monitoring it 24/7. Even if you changed the management, that requirement wouldn't go away. This doesn't invalidate your main point, but it's important to note that a lot of those personnel are not management overhead, but a "feature" of the current design. $\endgroup$ Commented Feb 27, 2018 at 19:36
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    $\begingroup$ How many thousands does mission control employ? Not THAT many. More than needed, in the modern world. $\endgroup$
    – geoffc
    Commented Feb 27, 2018 at 19:59
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    $\begingroup$ Flight controllers have to be trained and certified. In the NASA world, that means a training organization. They require a simulator to train on. That means a simulator development and maintenance organization. The MCC has to be developed and maintained. That requires an MCC developement organization. Tip of the spear, y'know. Duplicate that x times for Russian MCC, European MCC, Japan MCC, Canadian remote MPSR.... $\endgroup$ Commented Feb 27, 2018 at 20:47
  • $\begingroup$ Flight controllers also don't have detailed knowledge of every piece of hardware on the vehicle. For every flight controller, there are dozens of engineers whose job it is to know every single bolt on every piece of hardware. There's far more to operating the space station than just the folks in the MCC building. $\endgroup$
    – Tristan
    Commented Feb 28, 2018 at 18:26
  • $\begingroup$ To add to my previous comment: the drawing database I have access to has more than 85,000 drawings in it. That absolutely does not cover everything that is up there. You need an army of people who can provide answers when the flight controllers don't know the answer. $\endgroup$
    – Tristan
    Commented Feb 28, 2018 at 18:33

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