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  • Category: Tech

China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST), known as the "China Sky Eye," is planning a major Phase II upgrade that will transform it from a single-dish telescope into a powerful array, dramatically enhancing its observational capabilities.

The Upgrade Plan

The Phase II project, known as the FAST Core Array, will construct dozens of 40-meter-aperture medium-sized radio telescopes in a ring around the existing FAST dish. This will create the world's only "giant telescope-centered, medium telescope-surrounded" composite aperture array, leveraging the excellent electromagnetic environment within a 5-kilometer radius of the FAST site. According to Jiang Peng, Deputy Director of the National Astronomical Observatories and Chief Engineer of FAST, the team plans to build 64 such 40-meter antennas to form this mega array.

Performance Improvements

Upon completion, the array is expected to deliver transformative gains:

  • Resolution: Increased by 200 times, enabling high-resolution imaging of celestial objects
  • Sensitivity: Improved by approximately 1 to 2 times (about twofold)

This upgrade will effectively compensate for the inherent limitation of single-dish telescopes in spatial resolution, allowing FAST to not only "see far" but also "see clearly".

Scientific Objectives

The enhanced capabilities will significantly expand research frontiers, particularly in:

  • Gravitational wave events
  • Fast radio bursts (FRBs)
  • Gamma-ray bursts
  • Supernovae
  • Black hole tidal disruption events

Beyond astrophysics, the array will also play a strategic role in near-Earth object warning systems and deep-space satellite communications, providing important support for China's aerospace sector.

Current Progress

Construction of the upgrade is already underway. A test array of six small antennas has been built, and key technologies such as the receivers have been successfully developed. The fifth 40-meter telescope of the test array recently reached a critical construction milestone. The newly developed room-temperature receiver installed atop these test antennas has achieved world-leading performance after several years of development.

Significance

This upgrade will consolidate China's international leadership in radio astronomy and help Chinese astronomers produce major scientific findings more efficiently. Over its first decade of operation, FAST has already discovered more than 1,300 pulsars and 156,000 galaxies, with its pulsar discoveries exceeding the total found by all other telescopes worldwide during the same period.