[1] http://www.space.com/24208-international-space-station-exten...
Here is a recent article that mentions a few possibilities: http://spacenews.com/companies-pitch-plans-for-commercial-sp...
Notably, the company Axiom plans on making their potential module be able to function independently after detaching from the ISS. Bigelow also has plans for using their inflatable technology, although they've been working on this for quite a while and I've heard rumors of that the management is dysfunctional so for them to be ready in time for 2024 seems unlikely to me, a layperson.
My guess: 2024 will come and there will be perhaps some commercial space stations or modules attached but they will lengthen the date until ISS decommission at least one time.
We can also reapproproate tax dollars from failed programs to science.
Who is we? And by what standard is "plenty" measured?
Less tax revenue will result in less accomplished by government; it's inevitable. Already, important programs are cut in the US and UK. For example, as people were dying the US Congress wouldn't fund Zika virus research, and CDC (or NIH) shifted resources from Ebola research and/or treatment. The US military has clearly stated they cannot defend the country and accomplish their mission with current funding.
People can always claim they can 'trim the fat', etc.; it's just words; a promise of something for nothing, government services without having to pay for them. It's been used by politicians for as long as taxes have existed.
I'd be interested in serious research showing where such inefficiencies exist and what can be done, but the claim by itself isn't substantive.
If you use ion thrusters, the delta-V becomes larger (7km/sec), but with an Isp of 3000 sec you can do it with only about 4.5 falcons. So this plan could be reasonable.
The real problem seems to be that crewed missions to the ISS probably can't use ion engines, and so take a huge payload hit getting there and back, right?
Also, won't radiation be an issue that far from earth?
When the US stopped sending people to the moon it stopped to be capable of sending people past LEO. A space station at least ensures that we can still send people to space.
For manned spaceflight, NASA's top priority should be basic research into breakthrough propulsion technologies. It's pretty clear that we'll never be able to safely send a large number of people anywhere worthwhile using chemical rockets.
I never understood this mentality that when the US is between launchers everyone suddenly has a renewed appreciation for last-gen achievements. We did the LEO psce bucket with the ISS. It leads to nowhere and had questionable space science utility. Its not a stepping stone to anywhere[1]. We're building the SLS and investing in SpaceX, Blue Origin, ATK, Sierra, and ULA to get out of LEO and to have a variety of spacecraft on tap. Nations still stuck in LEO with 60+ old launch systems are going to be left behind and they shouldn't be applauded for it.
A few years of downtime will be forgotten the same way we've forgotten the time between Apollo and the STS. Meanwhile, anti-US biased people will dance during this peroid and project questionable attitudes like the US not being interested in space (No one comes close NASA's achievements, missions, and budget) or how the US is declining because a pig like Soyuz can still fly to LEO.
[1] by the time the ISS was built we had enough know-how to do things like permanent moon bases and other achievements that were within our technical grasp but not within our political one. Its very easy to vote for splitting the bill on a space station with a bunch of other countries. Its a whole other thing to propose risky things like moonbases and to have them funded by Congress. Thankfully with the SLS and SpaceX we're back to doing risky things.
Russia is developing Angara-5, a new rocket that made its debut in 2014. Russia upgraded in 2016 its soyuz capsule and is working on a new design crewed vehicle.
Europe started developing its Ariane 6 next gen-launcher, following the success of its current Ariane 5.
Europe also landed on a comet earlier this year.
I am less versed in Japan launch schedules, but they also have a strong program.
During this time, US is developing reusable launchers that land on their launchpad.
Space is a global effort and every country is participating in this exploration. Each has strengths and weakness. For instance, USA can land rockets but cannot send crew in space.
There is no more a 'me versus them' situation in space development. Everyone works somewhat together. Russia sends US astronauts in orbit. US refuels the ISS with Cigna cargo. Antares engines are Russian RD-181. The service of the orion capsule is made in France and Germany. The Chinese spacecraft is derived from Russian Soyuz.
1. http://www.cnn.com/2016/05/23/asia/india-space-shuttle-succe...
There absolutely is and frankly its the only thing that's ever worked - competition. Before it was between nation states and now it will be between corporations, which is going to be much more efficient. We are entering a new age of space travel here where nation states take a backseat to big centrally planned government programs, at least in the US.
Losing the ISS will be a step backwards for space exploration.
For a decade or so that might be worth it, but on a more long-term timeline it would be more efficient to just launch what you need when you actually need it.
EDIT: what I didn't think about is that one maybe could push it further out and reduce atmospheric drag and thus fuel needs that way, but I suspect the safety aspect still wins.
Now the shuttle's gone, there's no realistic proposal for delivering heavy components to the station, so it could be reboosted into a higher orbit. You'd end up spending less fuel on stationkeeping, but more fuel on routine deliveries and crew transfers.
I really have no idea whether this would be worthwhile. Anyone?