Shared orbit

During its normal observations, the telescope will fly independently in the same orbit as China's space station, but at a great distance apart. The in-orbit construction of the space station is expected to be completed this year.

Zhan said the telescope was initially designed to be mounted on the space station, but there would have been disadvantages such as vibration, potential contamination, stray light and line-of-sight obstruction caused by the space station's proximity.

As a result, a new design was adopted, putting the telescope in the orbit of the space station but keeping them far from each other during normal operations.

However, the CSST will dock with the space station for refueling and servicing－either as scheduled or whenever necessary－making its maintenance more affordable than Hubble.

From 1993 to 2009, NASA launched space shuttles on five servicing missions for Hubble to undertake repairs, replace parts and install new instruments.

The CSST, which is expected to start scientific operations in 2024, has a nominal mission life of 10 years, but in principle, that could be extended.

The telescope will take pictures of 40 percent of the sky and transmit massive amounts of data back to Earth, which scientists across the world will be able to study, Li said, adding that its main objective is to address the most basic questions about the universe.

It will observe well over 1 billion galaxies and measure their positions, shapes and brightness, which may help explain how those galaxies evolved.

"We know that our universe is expanding with an acceleration, and we can calculate its current expansion rate, but it's still unknown what causes the acceleration," Li said. "CSST observations may offer answers and unveil new physics."

The telescope will also be able to help determine the upper limit of neutrino mass and shed light on the mysterious phenomena of dark matter and dark energy. They are believed to account for the majority of the universe's mass-energy content.