The long-waited Hard X-ray Modulation Telescope (HXMT) satellite, named Huiyan (‘Insight’), was launched atop a Long March 4B launch vehicle on Thursday, 15 June from Jiuquan Satellite Launch Centre (JSLC). The launch took place at 11:00 CST (03:00 UTC) from Pad 603 of the South Launch Site (SLS). In addition to the HXMT, the launch vehicle also carried small satellites on its piggyback. Some 25 minutes later, the satellite was successfully placed by the launch vehicle’s third-stage into a 550 km Earth orbit inclined at 43° from the Equator.
China’s first astronomical satellite, HXMT is a joint effort of the Chinese Ministry of Science and Technology, the China Academy of Sciences (CAS), and Tsinghua University. The satellite bus was developed and built by China Academy of Space Technology (the 5th Academy) of the China Aerospace Science & Technology Corporation (CASC) consortium. The 2,500-kg satellite carries three mission payloads: a high energy (HE) X-ray telescope, a medium energy (ME) X-ray telescope, and a low energy (LE) X-ray telescope, all of which were developed by the CAS Institute of High Energy Physics (IHEP). The main scientific objectives of HXMT are to scan the Galactic Plane to find new transient sources and to monitor the known variable sources, and to observe X-ray binaries to study the dynamics and emission mechanism in strong gravitational or magnetic fields.
The ground segment of HXMT includes two sections: operations and applications. The operations section consists of mission control, ground data receiver, data pre-processing, data archiving and distribution subsystems. The applications section consists of payload operations, advanced data production and calibration, scientific research support, and scientific user subsystems. The onboard mission payloads are operated from the CAS National Space Science Centre (NSSC) located in Huairou, Beijing.
The concept of an X-ray astronomical telescope was first proposed in the early 1990s, but it was not included in the country’s space and scientific research plan until the late 2000s. The HXMT project was first included in the Space Science Development Outline for China’s 11th Five-Year Plan (2007—2012), and subsequently the Aerospace Development Outline for the 11th Five-Year Plan. The development was then postponed due to funding being allocated to other projects with higher priority. Engineering development of the satellite finally began in 2011, and the satellite was completed in late 2016.