The Einstein Probe (EP) has passed an important ‘exam’ and gained the official approval to begin its nominal operational tasks of exploring and observing the dynamic X-ray universe.

On July 22, EP successfully passed the review of its in-orbit commissioning organized by the National Space Science Center (NSSC) of the Chinese Academy of Sciences (CAS). This marks the end of its commissioning phase and the start of the nominal operational phase. As the result from a series of functional and performance testing of its satellite platform, payloads and ground systems as outlined in the in-orbit testing plan, EP is confirmed to be in excellent condition. Its stable operation has already yielded promising scientific discoveries, further demonstrating its potential for successful long-term scientific observations.

Prof. Weimin Yuan, the PI of EP mission, expressed his gratitude to the engineering team for their dedicated efforts and impressive achievements during the in-orbit testing phase. He also stressed the importance of continued efforts towards achieving scientific goals, with emphasis on improving collaboration between the engineering team and the science team.

The EP is a mission of the CAS dedicated to time-domain high-energy astrophysics. Its primary goals are to discover high-energy transients and monitor variable objects. Since its launch on January 9, 2024, EP has detected more than 4,000 known X-ray sources, discovered over 30 transient sources and 300 stellar flares. EP has so far issued over 50 alerts, attracting the interest of international multi-band facilities, which subsequently conducted follow-up observations on the sources discovered by EP.  Such facilities include the European Southern Observatory's Very Large Telescope (VLT) , the US Radio Telescope Array's Very Large Array (VLA), and NASA's Chandra X-ray Observatory.