Once upon a time … the notion was that Space Station Freedom would be completed by say 1996 (after launch of the first elements in 1992), and would be used and occupied for roughly 20 years. After say 2015, it was thought, SSF would have been technologically obsolescent and worn out. It would need refurbishment, or perhaps total replacement. In the latter case, the ancient space station would have to be deorbited, since the US was signatory to a number of agreements aimed at reducing “space debris”. An unattended station was seen as a hazard which might reenter earth’s atmosphere at any time as its orbit decayed, and then smash down on some totally unpredicitable location on earth– so deorbiting the station purposefully and making sure its demise was under control was taken to be a NASA responsibility. Remember, we are talking about eliminating an old decrepit structure and replacing it with something new — in the 1980′s when space station planning began, all this made considerable sense.

Then… stuff happened. Space Shuttle Challenger exploded, and no heavy lift version of the shuttle was authorized, and most importantly, the NASA budget was essentially frozen, so the possibility of building a station by 1996 evaporated. For various reasons, the station switched from being an all-US project to one with “International Partners”, and the nominal date of completetion slolwy slipped from year to year until the Bush Administration came in and decided that 2006 or so would mark “Station Complete”. So things were quite a bit different, but the Reagan era assumptions about dumping the station into the ocean in 2015 or so never got reexamined.

So now the Russians are involved, and no, they don’t want to drop ISS into the drink in 2015. Presumably neither do the Europeans or the Japanese — the other International Partners. However the USA has some notion of returning to the moon by 2020 on a very limited budget, and deciding that after 2015 the US had no obligation to spend 2 Billion bucks per year on ISS maintenance and could use that money on the Constellation program appealed considerably to Mike Griffin and his cohorts.

Let’s agree — everyone agrees — that deorbiting ISS in 2015 is not a real option. The Russians will still want to use it, even if the USA doesn’t, and presumably the Japanese and Europeans will want to use it. The occasional space tourist might be welcome, if the Russians are still willing to carry space tourists (the situation is unclear; European and Japanese space agencies will probably pay the Russians 50 million bucks for each of their astronauts carried to orbit, which is much more lucrative than 20-30 million dollar tourists, and the Russians have announced a freeze on future tourism). Chinese and Indian astronauts, arriving in their own vehicles or on Soyuzes, might be welcome at the station — they aren’t currently, because they haven’t signed the sort of agreements the official International Partners signed, but if the USA bails out of financing and operating the station in 2015, presumably the Russians and Europeans and Japanese can make any sort of deals they want, and the US would find it hard to object.

Also, of course, private organizations like Bigelow or SpaceX might want to reach some sort of agreement with the IP’s, on bringing up supplies and tourists and astronauts. It’s reasonable to assume the remaining nations using the Station would be willing to make such deals; it’s reasonable to assume Bigelow et all would like to make such details. But just what attitude the US government might take in post-2015 period is very much undetermined. Quite possibly it would object — much depends on the inclinations of the President at that time, much depends on national politics.

Finally, there seems general agreement that by 2020 some elements of the ISS will be worn out, so the station will need to be refurbished or replaced at that point, whether or not the US remains as a partner. The Russians have indicated they will want to preserve some of their modules for use in a post-2020 space stations; the Japanese and Europeans — assuming they remain interestedd in space flight — will probably want to do the same with their modules. That will leave only the US-supplied portion of the ISS with no future use, and I suspect the US will be expected to manage the deorbiting of that material, whether or not it is willing to oblige.

So. We might handle this sanely. We might not. The deciding factor is likely to be US domestic politics. Are we all happy now?