Design and Test of a Multi-Layer Insulation Integrated Heat Shield for the Second-Stage Base of a Reusable Launch Vehicle
- Paper ID
96412
- DOI
- author
- company
LandSpace Technology Corporation Ltd.
- country
China
- year
2025
- abstract
ZQ-3 Reusable Launch Vehicle is a first-stage reusable liquid oxygen-methane (LOX/LCH4) launch vehicle with a launcher body diameter of 4.5 meters, which is believed to be China's first LOX/LCH4 reusable rocket model that will fly its debut mission in 2025. It can accommodate payload fairings with a diameter of 5.2 meters and cylindrical section heights of 6 meters and 9 meters, enabling it to perform missions to various orbits. The base of the second stage of the launch vehicle accomadates multiple types of equipment, which traditionally employs separate thermal protection. This means that the components such as devices, cables, gas cylinders, and frames are individually insulated. However, this approach presents challenges, including difficulties in thermal environment analysis and poor adaptability to adjustments in the operating duration of the second-stage main engine. Multi-layer insulation (MLI) components, consisting of alternating layers of low-emissivity reflective screens and low-thermal-conductivity spacer materials, exhibit excellent thermal insulation performance under low-pressure or vacuum conditions. Since the second-stage main engine operates at altitudes above 70 kilometers, where the environment is near-vacuum, MLI can be utilized for integrated thermal protection of the second-stage base. This approach blocks heat flux at the outer surface of the thermal protection shield, simplifying the thermal environment analysis of the second-stage base. Additionally, it offers advantages such as lightweight construction and ease of installation. Ground mechanical and thermal tests have demonstrated that using just two reflective screens and one spacer layer can reduce the heat flux reaching the surface of the base equipment by more than 90%, while also withstanding internal and external pressure differentials. This validates the effectiveness of the integrated thermal protection design for the second-stage base.