The relatively new Chinese space program is expected to become dominant by the 2030s. The most obvious aspect of this is space stations. There are only two in orbit. The ISS (International Space Station) is the largest (419 tons) occupied (usually by a crew of six), the longest in orbit (over 23 years) and the longest occupied (21 years). The ISS was initially expected to have a useful (occupied) life of fifteen years. The ISS was not completed until 2011. The longer it was up there the more space station tech was developed. That led to extensions to the useful life. Until recently the ISS was to be used until 2028 but it is proposed to extend that to 2030. Without any new government proposals for a new space station, the only one up there after 2030 would be the Chinese Tiangong 3, which has been occupied since 2021 and will be completed in 2022 as a 66-ton unit with a useful life of 15 years. Tiangong 3 was designed to easily be doubled in size and extend useful life to 30 years.
China's new space station could be built so quickly because space tech has advanced over the years. For that reason, there are several proposals by Western firms to finance, build and operate commercial space stations. This development is no surprise to veteran space program engineers and administrators. Most of these new developments go unnoticed by the public because it is kind of boring tech stuff. One exception was commercial firm SpaceX with its revolutionary SLV (Satellite Launch Vehicle) tech which greatly reduced the cost of putting anything into orbit. The Chinese didn’t use SpaceX tech to build their new space station.
The ISS cost about $150 billion to build and operate so far. The Tiangong 3 is expected to cost much less (as in over 50 percent less) because it's now cheaper to build and launch satellite components and China plans to include lots of space for profitable science experiments. The large number of such experiments carried out in the ISS demonstrated that there is a market for this and that’s the motivation behind commercial space stations, especially those using SpaceX SLV tech and similar new tech developed by SpaceX and a number of other firms. Space stations no longer have to be government funded science experiments. Few noticed how much the costs were coming down at the same time income sources increased. Current plans are to have the first commercial space station operational before ISS retires in 2030. More commercial stations will follow.
China seemed to sense this trend when, without much fanfare, they put their first space station into orbit in 2011, This was the eight-ton Tiangong 1. It lasted two years and provided practical experience for the construction and launch of the 8.6-ton Tiangong 2 in late 2016. This one was built to last longer and in early 2017 a Chinese cargo vehicle made an automated docking with the Tiangong 2. This was a major step for the Chinese, who could now maintain two or three people in the Tiangong 2 for up to 30 days with the supplies from one cargo vehicle. China put the first 22 t0n module of the Tiangong 3 in orbit during April 2021 and it has been occupied since September, 2021. Two laboratory modules, each weighing the same as the first, are planned for 2022. The first of these was launched in July with the second one scheduled for October. This will make the initial Tiangong 3 complete. Three more modules can be added to double the crew size to six.
China wanted to join the consortium (United States, Russia, European Union, Japan and Canada) that built and managed the ISS. There was opposition within the U.S. government about Chinese espionage efforts that had obtained data from the United States for peaceful use of space but had used that information for military purposes. The U.S. passed the Wolf Act in early 2011 prohibiting the American space agency NASA from cooperating with China on the ISS. That ended Chinese efforts to participate in the ISS. Later in 2011 China launched, on schedule, Tiangong 1, its first space station.
Russia is withdrawing from space station efforts because their space program (Roscosmos) is broke, and sanctions because the invasion of Ukraine only added to the many problems the Russian space program has had in the last decade. The Mir space station was the last of eight Russian built space stations and the one that remained occupied the longest (4,594 days). The 130-ton Mir was brought down in 2001 after Russia joined the ISS consortium. The 420-ton ISS has been in orbit since 1998, when the first of 17 modules was operational. Other nations have built similar, and rather temporary space stations. That effort began in the 1970s with the Russian Salyut 1 but since the 1990s most nations with space programs have put their resources into supporting the ISS. Now the development of commercial space stations will dominate simply because it’s cheaper and more efficient than government run operations. This has already happened, again without much media fanfare, to the design, launch and operation of space satellites.