China’s Hubble Gets a Shout-Out at the GA

The CSS and the CSS-OS from Zhan’s presentation. (CMSA)

Zhan and ESA’s Günther Hasinger discussion the future of space astronomy at the Focus Meeting 5. (Daniel Fischer)

The news hasn’t spread widely yet, but the path is clear: after two demonstration models, next year the People’s Republic of China is going to start building its first “real” space station in Low Earth orbit. Following its completion around 2022, a special module will be launched that only docks occasionally to the station but otherwise acts as a serviceable free-flyer equipped with an optical 2-meter telescope, a state-of-the-art wide-field camera and other instruments: in essence another Hubble Space Telescope or – since the field of view is much wider – a sibling to WFIRST.

As Hu Zhan of the National Astronomical Observatories of China (NAOC) confirmed in Focus Meeting 13 on Monday, the launch of the telescope, dubbed the China Space Station – Optical Survey (CSS-OS), is scheduled for 2024. The main mirror has already been cast, and a camera capable of covering over a square degree in a single shot is already under construction. The telescope’s prime task will be to survey 17 500 square degrees with at least 6 filters covering 255nm to 1000nm to a depth of 25.5 mag on average. It will also obtain slitless spectra of sources down to 20-21 mag. A region of 400 square degrees will be surveyed even deeper. Science objectives range from cosmology to solar system science, and synergies with other big surveys in space and on the ground are envisioned.

As Zhan explained at IAU, since China doesn’t have a long heritage in running massive optical telescopes, let alone space telescopes, international cooperation in certain aspects would be welcome. This includes an international invitation to supply an additional instrument (while several spectrographs and a coronagraph are under consideration on part of the Chinese). So while NASA’s Wide Field Infrared Survey Telescope (WFIRST) is currently in a rather uncertain “Schroedinger state”, as science administrator Thomas Zurbuchen put it in the same session, China is pushing ahead and is about to become a major player in yet another field of space science.

DANIEL FISCHER is a writer and also an astronomy tour guide from Germany, who has covered the Hubble Space Telescope since the 1990s and is now amazed by the pace of China’s space science program.