There are not only a huge 3600° field of view array to patrol the universe, but also a focused lens accurate to 1° to stare at the fleeting "cosmic fireworks" - at 15:03 yesterday, the Einstein probe space science satellite was successfully launched into orbit by the Long March-2C carrier rocket at the Xichang Satellite Launch Center.
As the mainland's first large-field X-ray survey telescope, this satellite is called "the catcher of cosmic celestial explosions" by scientists. Over its five-year design lifespan, it will accurately capture more distant and faint transient sources and eruptive objects, explore X-ray signals from gravitational wave sources, and collect more evidence for studying major scientific questions such as stellar activity, the formation, evolution, and merger of compact objects such as black holes and neutron stars.
"Cosmic Fireworks Catcher" is equipped with 14 "eyes"
As one of the tasks of the Space Science Pilot Project (Phase II) of the Chinese Academy of Sciences, the Einstein Probe (EP) satellite has gone to space with three major scientific goals: discovering the temporary source of X-rays and exploding objects in the universe, discovering and exploring the flare of silent black holes in the universe, and exploring X-ray signals from gravitational wave sources.
"Because black holes and gravitational waves are both important predictions of Einstein's general theory of relativity, but a satellite can only solve the 'tip of the iceberg' of the mysteries of the universe, like a small probe, so we named this satellite 'Einstein probe'. Yuan Weimin, chief scientist of EP satellite and researcher at the National Astronomical Observatories of the Chinese Academy of Sciences, said that the celestial explosion is a spectacular and mysterious phenomenon in the universe, like fleeting fireworks.
For this purpose, the EP satellite is equipped with 12 lobster-eye X-ray telescopes, which form a huge field of view array of more than 3600°, gazing at the night sky area. When the "cosmic fireworks" appear, X-ray photons from the erupting objects will pass through the "lobster eyes" and gather on the detector into cross-shaped spots.
"The EP satellite will autonomously capture and identify the source of a 'flash in the pan' celestial body, calculate its position on the celestial sphere, and release information to ground-based telescopes around the world to guide their joint observations. Zhang Yonghe, chief designer of the EP satellite and researcher of the Institute of Microsatellite Innovation of the Chinese Academy of Sciences, introduced that it only takes 1 minute for the astronomical position information of these temporary sources to be sent to global astronomical equipment; within 3 minutes, two Wolter-I X-ray telescopes on the EP satellite can accurately point to the "cosmic fireworks", carry out high-precision follow-up observations, obtain early information of the temporary source explosion, and finally form a global joint observation model.
Ten years of creation, the detection ability has been increased tenfold
The sudden explosion of cosmic celestial bodies is called "guest star" in the ancient classics of the mainland, that is, visitors from outside the sky. The earliest relevant record on the mainland, the "Tianguan Guest Star" in the "History of the Song Dynasty and Astronomical Chronicles", refers to the explosion of a supernova. These X-rays from the depths of the universe carry a wealth of information and are important clues to help scientists solve the mysteries of the universe.
"Compared with the existing similar equipment in the world, the detection capability of EP satellites for erupting celestial bodies has been increased by more than ten times. Zhang Yonghe revealed that in order to achieve a series of challenging performance indicators, the EP satellite R&D team spent ten years, "whether it is a scientific payload or a satellite platform, it has carried out a fully autonomous, fast response, high-precision and stable innovative design for extremely complex observation needs." For example, in order to achieve a fast, accurate and smooth switch between "large field of view discovery" and "small field of view tracking", the EP satellite is integrated with the payload as the center, and the integrated truss optical platform supports 14 "eyes" - from the front of the satellite, the telescope modules are staggered and arranged, like a blooming lotus.
In the past ten years, the European Space Agency, the Max Planck Institute for Extraterrestrial Physics in Germany, and the French Space Agency have been attracted by the scientific value of EP satellites and have participated in the development of satellites or ground systems in the form of international cooperation. In the future, more European scientists will be involved in the later stage of the data study.
The Sino-French astronomical satellite will also be launched this year
The launch of the EP satellite into orbit is only the first step in success. After that, the satellite platform will perform several attitude maneuvers in order to point 14 telescopes at the night sky region for testing.
It is reported that another scientific satellite, the Sino-French Astronomical Satellite (SVOM), developed by the Institute of Microsatellite Innovation of the Chinese Academy of Sciences, will be launched in the middle of this year, and its scientific goal is gamma burst observation. At that time, the mainland will have the ability to simultaneously observe the temporary sources of astronomical phenomena in the time domain and gamma bursts, providing scientists with more abundant scientific data for revealing the mysteries of the universe.
The EP satellite project is carried out by the National Space Science Center of the Chinese Academy of Sciences, the Institute of Microsatellite Innovation of the Chinese Academy of Sciences is responsible for the overall development of the satellite, the lobster eye X-ray telescope is developed by the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences and the National Astronomical Observatories, and the X-ray telescope is developed by the Institute of High Energy Physics of the Chinese Academy of Sciences.