A staff member works on the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members work on the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Photo taken with a fisheye lens on March 28, 2021 shows a staff member conducting maintenance work on the feed cabin of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

A staff member works on the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

A staff member checks reflector panels during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members work on the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Photo taken with a fisheye lens on March 28, 2021 shows a staff member entering the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Photo taken with a fisheye lens on March 28, 2021 shows staff members conducting maintenance work on the feed cabin of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

A staff member enters the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members check the reflector panels during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Photo taken with a fisheye lens on March 28, 2021 shows staff members conducting maintenance work on the feed cabin of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members check the reflector panels during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members enter the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

A staff member works during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Photo taken with a fisheye lens on March 28, 2021 shows a staff member conducting maintenance work on the feed cabin of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members check the reflector panels during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

A staff member checks the reflector panels during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Staff members enter the feed cabin during a regular maintenance operation to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, March 28, 2021. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)

Photo taken with a fisheye lens on March 28, 2021 shows staff members conducting maintenance work on the feed cabin of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Pingtang County, southwest China's Guizhou Province. Starting formal operations in Jan. 11, 2020, the FAST is believed to be the largest and most sensitive radio telescope in the world, which has a huge potential for verifying and exploring mysteries of the universe. (Xinhua/Ou Dongqu)