Neptune-01, the first satellite of a radar constellation using parabolic antenna to image the Earth in space, was sent into planned orbit on Tuesday by China's Long March-6C in the new rocket's maiden flight.
The Neptune-01 satellite carries an umbrella-shaped antenna with an unfolded diameter of about four meters, which is a core device for Earth imaging.
Different from cameras of optical remote sensing satellites, the parabolic antenna emits electromagnetic waves to the Earth, and then receives and analyzes the electromagnetic waves reflected from the Earth to obtain radar images that contain a large amount of information.
"The satellite has the ability to image in a 24-hour and all-weather manner. This means that day or night, even in cloudy, rainy and sandy days, we can still use it to image," said Xiao Dengjun, payload chief designer of the satellite.
Boasting such capability, Neptune-01 can serve in land resources monitoring, disaster prevention and mitigation, environmental protection, maritime safety and other fields.
In addition to functions of traditional radar satellites, Neptune-01 can also determine the direction of slow-moving targets by taking videos.
"The satellite can grasp the dynamic characteristics of the target in a short period of time. This is very useful. For example, it's vital for traffic and port management," said Ren Wei, technical director of the satellite project.
The Neptune constellation initially plans to launch 13 satellites in orbit to form a network, which will greatly improve the response capabilities of the satellites upon its completion, according to Yao Xingfu, person in charge of the Neptune-01 satellite project.
"The second phase will be completed in 2028, with 36 satellites in orbit to provide high-resolution intelligent remote sensing services for the users," Yao said.
The Long March-6C carrier rocket blasted off at 11:21 (Beijing Time) from the Taiyuan Satellite Launch Center in north China's Shanxi Province, sending Neptune-01 and Smart-1C, as well as a wide-band optical satellite and a high-resolution video satellite into planned orbits.
Neptune-01 satellite sent into space by China’s new Long March-6C rocket
The endangered Tibetan antelopes have started their annual mass migration after the first batch of 47 female Tibetan antelopes passed through the Hoh Xil National Nature Reserve in northwest China's Qinghai Province on May 7.
To protect the rare species that are under top-class state protection, the management team of Hoh Xil in the province's Yushu Tibetan Autonomous Prefecture has set up the Wudaoliang protection station along the migration route. As of noon on Sunday, over 700 Tibetan antelopes had been spotted passing through the station.
The Tibetan antelope, known as the "fairies of the plateau", undertakes a migration from May to July each year. Female antelopes from the Sanjiangyuan region of Qinghai, parts of Qiangtang Terrane in Tibet, and the Arjin Mountains in Xinjiang Uygur Autonomous Region, would travel to the Zhuonai Lake in Hoh Xil to give birth before returning to their original habitats with their newborns.
"For Tibetan antelopes, we divide them into six species groups according to their geographical distribution. For example, Qinghai and Xinjiang have one group each. For Xizang (Tibet), there are three species groups in the east, central and west of the Qiangtang Terrane. And there is also one group in southern Qiangtang Terrane, which don't migrate," said Lian Xinming, researcher at the Northwest Institute of Plateau Biology under the Chinese Academy of Sciences.
With an average altitude of over 4,600 meters, the Hoh Xil Nature Reserve is known as a "no-life zone" due to its thin air and low oxygen levels.
However, it is an important habitat for Tibetan antelopes, which can reach top speeds of up to 80 kilometers per hour while running. Lian explained the reasons behind the antelopes' remarkable speed.
"I think one of the reasons why they run so fast is that they've got underfur. The warmth of its underfur is one of the characteristics of its ability to adapt to alpine cold and high altitudes. The diameter of its fur can be as thin as about one-seventh of our human hair on the temples. Secondly, its has been found in physiology that the hemoglobin of Tibetan antelope has a blood oxygen capacity that is more than 30 percent higher than that of other plain animals, which proves that the same number of red blood cells has stronger ability to carry oxygen. That should enable the Tibetan antelope to reach 70 or 80 kilometers per hour in a short time," Lian said.
After years of conservation efforts, the Tibetan antelope population in the Hoh Xil region has increased from less than 20,000 in the late 1980s to currently over 70,000.
Tibetan antelopes on migration journey to Hoh Xil Nature Reserve
