So, I have set up a test scenario for the these mods: TAC 0.10, IFLS, Ioncross andSnacks! We assume we want to take a 5 year trip with 2 Kerbals using Kerbin timeframe, the different mods give us the following numbers: IFLS: 1 Kerbal consumes 1 u/K-d, we would need 4260u of LS (426*2*5) -plus EC, but thats not considered now-, the included larger container holds 1000u, the smaller one 125u, meaning you would need 4 large and 2 small ones, weighing in at 23.425 tons. With added safety margin it would be 27.5t. Snacks! with added Containers by Whyren: Due to the randomized nature of consumption, it's rather difficult to assess the needed quantity. I tend to play it safe and will assume a wider safety margin. Kerbals consume ~1/2 snack /K-day, so one would need ~3000 snacks, equaling 3 of the largest container by Whyren, these amount to 12.375 tons Ioncross (Starwaster's branch): Ioncross focuses on O2/CO2-conversion. If you want to make the trip without reclaiming, you would need just 1 of the largest containers, at a striking 0.8tons. O.o TAC, default containers: One could tweak consumption etc., but for the purpose of this, I am staying with the default numbers (plus TAC tells you how many days you have in the build window). You need different resources plus space for waste managment or recyclers. For ~2800 days worth of LS plus Waste you'll get 4.71t. Now to the real experiments TAC, using the approximate 5 tons described above, gave me 6 years, 286 days of survival for 2 Kerbals, astounding weight/worth-ratio...and, of course very hard to beat... Snacks!, at ~12tons was at 9 years, 70 days in this instance, I think we could be in the same ballpark for other trials with IFLS it was nearest to the prediction, 5 years, 14 days at a rather heavy ~ 28 tons for Ioncross I took that 1 can up, in 5 years and 14 days i used only about 7% of it (with an acitvated CO2-scrubber), so this mod seems a bit on the funny side In summary: There does not seem to be a concise weight for LS, so everything goes. Personally I would go with TAC at ~5 tons, this seems to be a realistic choice... Cheers PS: I would be very glad if someone could verify these numbers