On January 9th, China successfully launched the Einstein Probe satellite into space using the Long March-2C carrier rocket at the Xichang Satellite Launch Center. The satellite entered its designated orbit smoothly, and the launch mission was a complete success.
The Einstein Probe (EP for short) is essentially an X-ray scientific detection satellite dedicated to time-domain astronomy and high-energy astrophysics. Its mission is to conduct wide-field time-domain sky surveys in the soft X-ray band, with the aim of systematically discovering high-energy transient celestial objects in the universe, monitoring their activities, and exploring their nature and physical processes.
The Einstein Probe is another space science satellite developed by the Chinese Academy of Sciences as part of the second phase of the Space Science Pre-Research Program, following the success of ‘Taiji-1,’ ‘Huairou-1,’ and ‘KuaFu-1.’ The European Space Agency, Max Planck Institute for Extraterrestrial Physics in Germany, and French National Centre for Space Studies have jointly participated in this satellite project.
The Einstein Probe satellite has used the ‘lobster eye’ micro-pore array focusing imaging technology on a large scale for the first time internationally. It can achieve a sensitivity and spatial resolution 10 times higher, while conducting wide-field monitoring, it can accurately capture more distant and weak high-energy transient sources and fleeting unknown phenomena in the universe, and issue warnings to guide other astronomical devices on Earth to conduct subsequent observations.
The Einstein Probe project is one of the second-phase projects of the Chinese Academy of Sciences’ Space Science Pioneer Program. It was approved by the Chinese Academy of Sciences on December 29, 2017. The satellite has a mass of 1.45 tons and operates in a near-Earth orbit at an altitude of 600km with an inclination angle of 30 degrees. Its designed lifespan in orbit is not less than 3 years.
The Einstein Probe satellite payload consists of the Wide-field X-ray Telescope (WXT) and the Follow-up X-ray Telescope (FXT). The WXT is the first international large-scale adoption of lobster-eye micro-pore X-ray imaging technology and CMOS X-ray detectors. It utilizes 12 sub-telescopes to form a wide field of view for continuous monitoring. The FXT employs Wolter-I grazing incidence focusing telescope for detailed follow-up observations, and coordinates with other celestial devices through Beidou short messages, etc., for collaborative observations.
The EP satellite aims to study the merger of black holes with other celestial bodies, as well as the distribution, formation, and evolution of black holes in the universe. It will also investigate significant scientific questions such as gravitational wave sources and their electromagnetic counterparts, early universe phenomena, supernovae, and activity of compact celestial objects. The mission will collect time-domain astronomical observation data including all-sky X-ray timing panoramic images, X-ray spectra of celestial bodies, and temporal variations. This valuable data accumulation will contribute to the development of time-domain astronomy. Additionally, for the first time, the EP satellite will focus on studying dormant (inactive) black holes and open up a new research field regarding events where black holes consume stars.
It is worth mentioning that the EP satellite has a large and uniform field of view, as well as extremely high detection sensitivity. It will be able to detect rare X-ray transient sources and have the ability to discover unknown types of X-ray transient celestial bodies and phenomena. It is expected that the EP satellite will bring us more important scientific discoveries in the fields of time-domain astronomy, astrophysics, and cosmology.