This answer shows that the mass of the ISS has changed by about 27,000 kg in the last three years.

09-Mar-2011    417,289   kg      (per @DavidMorris' comment)
10-Jun-2015    390,377.5 kg
22-Jun-2018    417,501.6 kg

I suppose it will fluctuate a lot depending on the number of capsules docked, plus the current level of supply water, food, experiments, and new modules.

Is there a plot of the approximate total mass over time, say a decade or longer? Perhaps a fancy one that shows steps indicating docking and undocking of the other spacecraft? Something like this https://i.sstatic.net/t0Pda.png except for mass rather than altitude, but also the overall growth as well?

update: with the addition of the 2011 value and it being so close to the June 2018 value, it looks more like fluctuation rather than a steady trend upwards.

  • 2
    $\begingroup$ I reached out to openNASA and NASAdata on Twitter to see if historical data might be available. Another line for your sheet (so far): 09-March-2011 417,289 kg $\endgroup$ Commented Jun 23, 2018 at 3:03
  • $\begingroup$ @DavidMorris thank you. I appreciate the interest/help! $\endgroup$
    – uhoh
    Commented Jun 23, 2018 at 11:19

1 Answer 1


I don't know if there's a graph, but the historical data can be found in the On-Orbit Assembly, Modeling, and Mass Properties Data Book:

I haven't found a more recent edition than 2008.

  • $\begingroup$ That's great! Let me see if I'm reading this correctly. In Table 5.2-1 Mass Summary of Free Flying Configurations on the last line (Step No. 108) on page 5-9 of volume 1, I see 391,880 kg. I don't know the difference between configuration number and step number, or dates, but would it be fair to say that "circa end-of-2008" the mass was "about 391,880 kg"? $\endgroup$
    – uhoh
    Commented Jun 23, 2018 at 11:08
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    $\begingroup$ Don't know about that, but the Step numbers are tied to missions and configurations in the Step descriptions from page 92 onward. $\endgroup$
    – Hobbes
    Commented Jun 23, 2018 at 11:42

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