# The 8th Anniversary of China's FAST: Launching the Second-Phase Project, How to Make Greater Strides in Cosmic Exploration? On September 25, 2024, China's FAST (Five-hundred-meter Aperture Spherical radio Telescope) marked the important 8th anniversary of its completion and commissioning. Eight years ago, this telescope, located in Dawodang, Pingtang County, Guizhou Province, was officially completed and put into operation, embarking on its "journey of astronomical observation". As the world's largest single-aperture radio telescope independently developed by China, it shines like a brilliant pearl embedded in the path of humanity's exploration of the vast universe. Over the past eight years, China's FAST has delivered a series of remarkable achievements. On April 17 this year, the FAST Operation and Development Center of the National Astronomical Observatories (NAO), Chinese Academy of Sciences (CAS), announced that the number of new pulsars discovered by FAST had exceeded 900—more than three times the total number of pulsars found by other international telescopes in the same period. Behind this stunning figure lies FAST's outstanding observation capabilities and the unremitting efforts of its research team. Pulsars, these mysterious celestial bodies in the universe, are like cosmic clocks, providing crucial clues for humanity to explore the mysteries of time and space. This achievement of FAST has undoubtedly injected new vitality into the global astronomical community. Beyond this, FAST has continued to make heavyweight discoveries. It observed "pulses" from black holes in the radio band for the first time—like mysterious heartbeats emanating from the depths of the universe—deepening humanity's understanding of black hole mysteries. It discovered the shortest orbital-period pulsar binary system to date, offering precious samples for studying celestial evolution and gravitational interactions. It detected and constructed the world's largest sample of neutral hydrogen galaxies, providing critical data support for exploring the origin and evolution of the universe. More than 10 papers based on FAST's observation results have been published in top international academic journals such as *Nature* and *Science*. This not only represents high recognition of FAST's scientific achievements but also demonstrates China's international influence in the field of astronomy. Currently, FAST maintains a stable annual observation time of approximately 5,300 hours, operating nearly non-stop throughout the year. Like an indefatigable cosmic watcher, it keeps its gaze fixed on the vast starry sky, aiding humanity's exploration of cosmic mysteries. FAST not only provides us with a powerful tool to probe the depths of the universe but also exerts a profound impact on basic scientific research. It helps us explore the origin, evolution, and structure of the universe, offering essential observational data support for understanding cutting-edge scientific issues in cosmology. Meanwhile, FAST serves as a key platform for the international scientific community, promoting exchanges and cooperation between scientists at home and abroad. On the occasion of FAST's 8th anniversary, a project of great significance—the construction of the FAST core array test prototype—was officially launched. Jiang Peng, Deputy Director of NAO, CAS, stated that the plan is to leverage the excellent electromagnetic environment within 5 kilometers of FAST to build 24 radio telescopes with 40-meter apertures, which will form a core array together with FAST. This marks the first second-phase project of FAST since its completion eight years ago. The construction of the core array will bring new vitality and opportunities to FAST, further enhancing its observation capabilities and scientific research level. ## 01 Technological Innovations and Challenges of China's FAST The construction and operation of China's FAST stand as outstanding representatives of China's technological innovation. Every step, from design to construction, has been filled with challenges and innovations. The unique design of the 500-meter aperture spherical radio telescope endows it with extremely high sensitivity and resolution, enabling it to capture weak signals from the universe. The 30-ton feed cabin, controlled by 6 steel cables, can achieve real-time positioning within a range of 140 meters in height and 206 meters in scale—an unprecedented technological innovation worldwide. Ultra-high fatigue-resistant steel cables can withstand a stress amplitude of 500 MPa under 2 million cycles of loading, providing a solid guarantee for FAST's stable operation. However, the path of technological innovation is always fraught with challenges. The construction of the FAST core array faces two key technological difficulties. First is the development of high-performance room-temperature receivers. This is an entirely new challenge, as the research team has no prior experience in developing such receivers. The performance of room-temperature receivers directly affects the quality and accuracy of observational data; therefore, developing high-performance room-temperature receivers has become one of the key tasks in the construction of the FAST core array. The research team needs to continuously explore new technologies and materials to improve the performance of these receivers and meet the observation requirements of the core array. Second is the technology for synthetic aperture data processing—especially the data processing technology for combining telescopes of different apertures—which currently lacks mature experience in China. This requires the research team to conduct in-depth research and achieve technological breakthroughs to ensure the efficient and accurate operation of the FAST core array. Data processing is a crucial link in astronomical research. How to effectively process massive amounts of observational data and extract valuable information is a major challenge for the team. They need to develop new algorithms and software to improve the speed and accuracy of data processing, providing strong support for scientific research. ## 02 The Great Significance and Future Prospects of the FAST Core Array The construction of the FAST core array will bring multiple significant benefits. Zhu Weiwei, Researcher at NAO, CAS, and Chief Scientist of the FAST Operation and Development Center, explained that adding auxiliary telescopes around FAST to form a core array is equivalent to transforming FAST into a telescope with an extremely large aperture. This will greatly enhance its resolution and enable it to achieve better imaging capabilities. The FAST core array will effectively improve observation resolution and imaging capabilities, which holds great value for astrophysics research. It will play a crucial role in the study of gravitational wave events, fast radio bursts (FRBs), gamma-ray bursts, supernovae, black hole tidal disruption events, and more. For example, in the observation of gravitational wave events, high-resolution observations will help scientists more accurately locate gravitational wave sources and conduct in-depth research on the mechanisms of gravitational wave generation and propagation. In the study of FRBs, clear imaging capabilities will allow scientists to better understand the origin and evolution of these bursts. Beyond astrophysics research, the FAST core array can also play an important role in deep-space exploration fields such as near-Earth object (NEO) early warning and deep-space satellite communications. In terms of NEO early warning, high-resolution observations can detect potentially hazardous NEOs in advance, safeguarding human security. In the field of deep-space satellite communications, the FAST core array can serve as a powerful communication relay station, improving the quality and stability of deep-space satellite communications and providing important strategic support for China's aerospace sector. In the days to come, we look forward to the smooth construction and commissioning of the FAST core array, which will bring us more surprises and discoveries. China's FAST will continue to expand the limits of humanity's astronomical observation, contributing Chinese wisdom to global astronomy and Chinese technology to the world's engineering community. Let us jointly witness the new glory of China's FAST on its journey of cosmic exploration and contribute more wisdom and strength to the realization of the Chinese Dream of national rejuvenation. ## 03 The International Influence of China's FAST and Win-Win Cooperation China's FAST, officially named the Five-hundred-meter Aperture Spherical radio Telescope (with the acronym FAST), is the world's largest single-aperture radio telescope independently designed and built by China. Its completion and operation not only demonstrate China's strength and determination in technological innovation but also exert a significant international impact. As early as the construction phase, FAST contributed China's experience and innovative practices in mega-science projects to the global engineering community. Its advanced technology and unique design attracted widespread attention from the international astronomical community. On March 31, 2021, FAST was officially opened to the global scientific community. To date, it has supported research teams from 15 countries (including the United States, the Netherlands, and Australia) in conducting over 900 hours of observations, covering fields such as drift-scan surveys for scientific targets, neutral hydrogen galaxy surveys, Galactic polarization surveys, pulsar timing, and FRB observations. This initiative fully demonstrates China's open attitude and sense of responsibility as a major country in international scientific cooperation. At 00:00 on April 6 this year, FAST once again opened the application channel for free observation projects in the 2024 August–2025 July observation season, offering 1,600 hours of telescope time for free application projects. British astronomer Ralph Eatough stated that FAST's continuous opening to the global scientific community means that scientists around the world can apply to use this groundbreaking instrument according to their research plans, allowing astronomers to conduct experiments that were previously impossible due to insufficient telescope sensitivity. Laura Spitler, an astronomer at the Max Planck Institute for Radio Astronomy in Germany, predicted that by the 2030s, FAST will accumulate massive amounts of data for humanity's research on cutting-edge astronomical topics such as supermassive black hole mergers. FAST is helping humanity explore the origin, evolution, and structure of the universe, providing essential observational data support for understanding cutting-edge scientific issues in cosmology, and building a key platform for exchanges and cooperation in the international scientific community. The low-noise amplifier—a core component of FAST independently developed by the team led by Chai Xiaoming, a senior engineer at NAO, CAS—will be officially exported to Brazil in the near future. This will mark the first time that China's independently developed core components of radio telescopes are exported overseas, signifying the continuous enhancement of China's international influence in the field of radio telescope technology. International cooperation on FAST not only promotes the development of global astronomy but also brings new opportunities and challenges to China's astronomical community. Through exchanges and cooperation with international counterparts, Chinese scientists can learn advanced technologies and experience to improve their own research capabilities. At the same time, they can also promote China's astronomical research achievements to the world, making greater contributions to humanity's scientific endeavors. ## Final Remarks As the world's largest single-aperture radio telescope, China's FAST shoulders a major mission and responsibility. It is not only a landmark achievement of China's technological innovation but also an important tool for humanity to explore the mysteries of the universe. In the days ahead, FAST will continue to leverage its powerful observation capabilities to provide more observational data support for humanity's exploration of the origin, evolution, and structure of the universe. Meanwhile, it will remain an important platform for the international scientific community, promoting exchanges and cooperation between scientists at home and abroad. We believe that under the leadership of FAST, China's astronomical research will continue to achieve new breakthroughs and make greater contributions to humanity's scientific cause. Let us jointly look forward to FAST creating more glory on its journey of cosmic exploration and adding more splendor to the realization of the Chinese Dream of national rejuvenation.