China's Tiangong space station reached full operational capability in May 2026 with the successful docking of its third and final core module, Xuntian — an optical telescope module that gives the station a space telescope comparable in capability to the Hubble Space Telescope, but with the ability to dock with Tiangong for servicing and upgrades.

The completed station, now comprising the Tianhe core module, the Wentian experiment module, the Mengtian science module, and the new Xuntian telescope module, has a total pressurised volume of 340 cubic metres — roughly two-thirds the size of the International Space Station. It is now permanently crewed by a rotating team of six taikonauts.

The Xuntian Telescope

Xuntian is the centrepiece of the expanded station and represents a significant leap in China's space science capabilities. The telescope has a 2-metre primary mirror — the same diameter as Hubble — but a field of view 300 times larger, allowing it to survey vast swaths of sky in a single observation. Its primary mission is a 10-year survey of the universe's large-scale structure, dark matter distribution, and dark energy.

The telescope's ability to dock with Tiangong for servicing is a key advantage over Hubble, which required five separate Space Shuttle servicing missions and is now beyond reach of any current crewed spacecraft. Xuntian can be upgraded with new instruments as detector technology improves, potentially extending its scientific life indefinitely.

International Partnerships — and Complications

China has invited international partners to conduct research on Tiangong, and 17 countries have signed memoranda of understanding with the China Manned Space Agency. However, the geopolitical reality is more complicated. The Wolf Amendment, a US law passed in 2011, prohibits NASA from engaging in bilateral cooperation with China's space programme without explicit Congressional approval. American scientists are effectively barred from Tiangong.

European space agencies are in a more ambiguous position. ESA has conducted joint training exercises with Chinese taikonauts and has expressed interest in flying European astronauts to Tiangong, but political pressure from the United States has slowed progress. Several European member states have bilateral agreements with China that are proceeding independently of ESA.

The Two-Station Reality

The completion of Tiangong means that for the first time since the Soviet Mir station, there are two permanently crewed space stations in orbit simultaneously. The ISS, now in its 26th year of continuous habitation, is scheduled for deorbit in 2030. NASA is funding three commercial space station programmes — from Axiom Space, Blue Origin, and Northrop Grumman — to replace it, but none are expected to be operational before 2028 at the earliest.

There is a real possibility of a gap in US crewed space station access between the ISS deorbit and the availability of commercial successors. During that gap, Tiangong would be the only crewed space station in orbit — a situation that has significant implications for US space leadership and the geopolitics of the new space race.

What China's Space Programme Signals

The completion of Tiangong is the latest milestone in a Chinese space programme that has been executing its roadmap with remarkable consistency. China landed on the far side of the Moon in 2019, returned lunar samples in 2020, landed a rover on Mars in 2021, and has now completed a permanent space station. The next milestones on Beijing's published roadmap are a crewed lunar landing by 2030 and a permanent lunar base by 2035.

Whether these timelines are achievable is debated, but the programme's track record suggests they should be taken seriously. The space race of the 21st century is well underway.

Scientific Output

Beyond the geopolitical dimensions, Tiangong is producing genuine science. The Mengtian science module hosts experiments in fluid physics, materials science, and life sciences that take advantage of the microgravity environment. Chinese researchers have published over 200 peer-reviewed papers based on Tiangong data since the station became operational, covering topics from crystal growth in microgravity to the long-term effects of space radiation on biological systems.

The Xuntian telescope's first light images, released in April 2026, demonstrated image quality comparable to Hubble and confirmed the telescope's ability to conduct the wide-field surveys it was designed for. The first major science results — from a survey of galaxy clusters in the nearby universe — are expected in late 2026.

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