There’s a saying amongst the space enthusiast community that the shuttle only continued on for so long in order to build the International Space Station and the ISS only existed so that the shuttle had some place to go. Indeed for the last 13 years of the shuttle program it pretty much exclusively visited the ISS taking only a few missions elsewhere, usually to service the Hubble Space Telescope. With the shuttle now retired many are looking now looking towards the future of the ISS and the various manned space programs that have contributed to its creation. It’s now looking very likely that the ISS will face the same fate as Mir did before it, but there are a multitude of possibilities of what could be done instead.
Originally the ISS was slated for decommission in 2016 and with it still not being fully constructed (it is expected to be finished by next year) that would give it a full useful life of only 4 years. The deadline was extended back in 2009 to 2020 in order to more closely match the designed functional lifetime of 7 years and hopefully recoup some of the massive investment that has gone into it. It was a good move and many of the ISS components are designed to last well beyond that deadline (especially the Russian ones which can be refurbished on orbit) and there’s still plenty of science that can be done using it as a platform.
The ISS, like Mir before it, has only one option for retirement: a fiery plunge through the atmosphere into a watery grave. Whilst there’s been lots of talk of boosting it up to a higher orbit, sending it to the moon or even using it as an interplanetary craft all these ideas are simply infeasible. The ISS was designed and built to be stuck in low earth orbit its entire life with many assumptions made that preclude it from going any further. It lacks the proper shielding to go any higher than say the Hubble Space Telescope and the structure is too weak to withstand the required amount of thrust that would get it to a transit orbit (at least in any reasonable time frame). The modifications required to make such ideas feasible would be akin to rebuilding the entire station again and thus to avoid cluttering up the already cluttered area of low earth orbit it must be sent back down to earth.
Russia however has expressed interest in keeping at least some of the parts of the ISS in orbit past the 2020 deadline. It appears they want to use them as a base for their next generation space station OPSEK. This space station would differ significantly from all the previous space stations in that it would be focused on deep space exploration activities rather than direct science like its predecessors were. It would seem that those plans have hit some roadblocks as the Russian Federal Space Agency has recently stated that the ISS will need to be de-orbited at the end of its life. Of course there’s still a good 8 years to go before this will happen and the space game could change completely between now and then, thanks in part to China and the private space industry.
China has tried to be part of the ISS project in the past but has usually faced strong opposition from the USA. So strong was the opposition that they have now started their own independent manned space program with an eye to set up their own permanent space station called Tiangong. China has already succeeded in putting several people into space and even successfully conducted an extravehicular activity (EVA), showing that they have much of the needed technology to build and maintain a presence in space. Coincidentally much of their technology was imported from Russia meaning that their craft are technically capable of docking with the Russian segments of the ISS. That’s also good news for Russia as well as their Soyuz craft could provide transport services to Tiangong in the future.
Private space companies are also changing the space ecosystem significantly, both in regards to transport costs and providing services in space. SpaceX has just been approved to roll up two of its demonstration missions to the ISS which means that the next Dragon capsule will actually end up docking with the ISS. Should this prove successful SpaceX would then begin flying routine cargo missions to the ISS and man rating of their capsule would begin in earnest. Couple this with Bigelow Aerospace gearing up to launch their next inflatable space habitat in 2014~2015 the possibility of the ISS being re-purposed by private industry becomes a possible (if slightly far fetched) idea.
The next decade is definitely going to be one of the most fascinating ones for space technologies. The power international power dynamic is shifting considerably with super powers giving way to private industry and new players wowing the world stage with the capabilities. We may not have a definitive future for the ISS but its creation and continued use has provided much of the ground work necessary to flag in the next era of space.