NASA is not alone in investing in large space telescopes like the James Webb. China is also developing its own galaxy hunter, which promises to have a field of view 300 times that of Hubble.
First announced in 2016, the Chinese telescope – dubbed the Xuntian – is expected to launch into space by the end of 2023, with scientific operations beginning in 2024.
Unlike James Webb – which was deployed at Lagrange Point L2, about 1.5 million km from Earth – Xuntian will be in low orbit around Earth, more precisely close to the Chinese Space Station Tiangong.
The reason for this proximity is so that the instrument can regularly dock at Tiangong for periodic maintenance, thus prolonging the telescope’s lifespan – currently expected to be 10 years.
Xuntian will study the sky on a different spectrum than James Webb
The Chinese space telescope is the length of a 3-story building and will weigh over 10 tons. In addition to the large field of view and a two-meter aperture, Xuntian will feature a 2.5 billion-pixel camera and five scientific instruments.
The idea is that it will take pictures of 40% of the sky, and be used to investigate matter and dark energy, the formation and evolution of galaxies, in addition to identifying exoplanets. For this, it will make observations in the visible spectrum range and also in the near ultraviolet. For comparison, James Webb photographs the sky in the infrared field.
The construction is done by the Chinese Academy of Sciences (CAS) Changchun Institute of Optics, Fine Mechanics and Physics, and according to state media CGTN, it should be completed by the end of this year. Currently, engineers are getting ready to start tests involving the set of all Xuntian subsystems, components and units.
Initially, the project envisaged that the telescope would work docked to the space station, but this was eventually discarded as it could experience vibrations, as well as limiting the Xuntian’s field of view. This will be China’s first large space telescope, and the largest operating in the ultraviolet for the next decade.