Mechanical design and analysis of the eXTP satellite

The enhanced X-ray Timing and Polarimetry (eXTP) is an international cooperation flagship mission, equipped with four kinds of instruments, including 9 SFA (Spectroscopic Focusing Array) telescopes, 4 PFA (Polarimetry Focusing Array) telescopes, 6 WFM (Wide Field Monitor) cameras, and 40 LAD (Large Area Detector) modules. These payloads overall require about 11.5m2 for mounting on the same side of the satellite, with high alignment requirement between lines of sight of each instrument to guarantee the effective area and response performance of scientific payload, which is the most important driver for the satellite mechanical design. At the same time, the mirror assemblies and cameras of SFA and PFA telescopes are installed separately on the satellite, relying on the satellite structure to ensure the relative position accuracy. There are also factors such as payload field-of-view, sun shield, antenna accommodation, mechanical property to be taken care of in the satellite configuration design. According to the characteristics of payloads, an integrated configuration and structure design of eXTP satellite is proposed, with a high-rigid optical module providing large area for payload optics accommodation, a central cylinder as the primary force-taking structure of the satellite, a service module for platform equipment accommodation, and a detector module equipped with cameras of SFA and PFA. This paper introduces the mechanical design and analysis of eXTP satellite. The feasibility and performance of configuration and structure design are verified by simulation analysis.