The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) Project (1105.3794v2)

Abstract: Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. Its innovative engineering concept and design pave a new road to realize a huge single dish in the most effective way. FAST also represents Chinese contribution in the international efforts to build the square kilometer array (SKA). Being the most sensitive single dish radio telescope, FAST will enable astronomers to jump-start many science goals, for example, surveying the neutral hydrogen in the Milky Way and other galaxies, detecting faint pulsars, looking for the first shining stars, hearing the possible signals from other civilizations, etc. The idea of sitting a large spherical dish in a karst depression is rooted in Arecibo telescope. FAST is an Arecibo-type antenna with three outstanding aspects: the karst depression used as the site, which is large to host the 500-meter telescope and deep to allow a zenith angle of 40 degrees; the active main reflector correcting for spherical aberration on the ground to achieve a full polarization and a wide band without involving complex feed systems; and the light-weight feed cabin driven by cables and servomechanism plus a parallel robot as a secondary adjustable system to move with high precision. The feasibility studies for FAST have been carried out for 14 years, supported by Chinese and world astronomical communities. The project time is 5.5 years from the commencement of work in March of 2011 and the first light is expected to be in 2016. This review intends to introduce FAST project with emphasis on the recent progress since 2006. In this paper, the subsystems of FAST are described in modest details followed by discussions of the fundamental science goals and examples of early science projects.

• The paper presents FAST’s groundbreaking design, featuring an adaptive cable-net and active reflector system that corrects spherical aberrations.
• The paper details advanced subsystems and methodologies that enhance survey speed and sensitivity for pulsar and HI galaxy detection.
• The paper highlights FAST’s transformative impact on radio astronomy, paving the way for deeper insights into cosmic evolution and SETI research.

The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) Project

The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) represents a significant advancement in radio astronomy, proposed by the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC). This paper provides an extensive overview of the technological innovations and scientific aspirations related to the FAST project. FAST is not only the largest single-dish radio telescope but also embodies the integration of novel engineering techniques with ambitious scientific objectives, aiming to contribute substantially to the global astronomical community.

Technical Innovations and Design

FAST's design is a notable evolution of the Arecibo-type spherical telescopes, incorporating distinctive features such as the utilization of a karst depression in Guizhou province as its foundational site. This geographical choice allows for the placement of a 500-meter aperture spherical dish. A central innovation is the active main reflector mechanism, which effectively corrects spherical aberrations, enabling full polarization capabilities without the need for complex feed systems. Additionally, a lightweight feed cabin suspended by cables and operated through a servomechanism ensures precise adjustments required for diverse observations.

The subdivision of FAST into critical subsystems—site surveying, the main active reflector, feed cabin suspension, measurement and control, and receivers—is methodically described, underlining the substantial collaborative efforts of over twenty institutions. Noteworthy is the adaptive cable-net structure that transforms the spherical dish into a paraboloid for focused celestial observations, underlining FAST's engineering prowess.

Scientific Goals and Observational Ambitions

The scientific motivations of FAST are directed towards broadening our understanding of cosmic phenomena, leveraging its unparalleled sensitivity and survey speed. FAST will enable the survey of Galactic interstellar medium (ISM) with a focus on the HI 21cm line, predictive of discovering approximately 4,000 new Galactic pulsars. Furthermore, FAST aims to unveil tens of thousands of HI galaxies and provide insight into high-redshift galaxies, crucial for studying galaxy formation and evolution.

Strategically positioned to probe fundamental questions regarding cosmic origins, FAST's capability to detect atomic hydrogen (HI) offers a promising avenue for contrasting observational data with ΛCDM cosmological models. Exploration of pulsars is a crucial focus, leveraging FAST's extraordinary sensitivity to potentially discover new pulsar-black hole binaries and contribute to the physics of extreme states of matter. Moreover, FAST's ability to conduct SETI surveys at unprecedented volumes signifies its broader quest for extraterrestrial intelligence.

Anticipated Implications and Future Developments

The construction and operation of FAST reflect significant strides in radio astronomy, presenting both immediate scientific opportunities and long-term challenges in data management and interpretation. As it becomes operational, FAST is expected to act as a scientific catalyst, fostering international collaborations and inspiring advancements in associated technologies like signal processing and interferometric techniques.

On a theoretical level, FAST's contributions to studying the universe’s expansion, the dynamics of the ISM, and the fabric of cosmic structure are anticipated to refine existing models and possibly reveal new paradigms in our understanding of the cosmos. Practically, the insights gained from FAST's observations will likely have profound implications across scientific disciplines, enhancing our grasp of cosmic phenomena, and contributing to technological developments in related fields.

In conclusion, the FAST project encapsulates a combination of ambitious engineering and potent scientific inquiry, representing a significant commitment to exploring the radio universe. The anticipated outcomes, both in terms of technological innovations and scientific discoveries, hold promise for advancing our exploration of the cosmos. The long-term impacts of FAST will likely extend well beyond its operational timeline, shaping future radio astronomical endeavors and theories.