With the development of deep-space exploration

low-density ablators have received increased attention due to their distinguished features such as good ablation performance and low structure weight to fulfill the requirement of lightweight

low ablation rate

low thermal conductivity and long re-entry time of thermal protection for heatshield and backshell of planetary entry probes and re-entry capsules. The historical prospects on development of low-density ablative thermal protection systems and materials were introduced with emphasis on low-density honeycomb reinforced silicon rubber

phenolic and organic silicone resin ablators

as well as the typical representative of light weight ceramic ablators (LCAs) such as silicone impregnated reusable ceramic ablator (SIRCA) and phenolic impregnated carbon ablator (PICA). According to the task requirements of China's new-generation manned spacecraft

including low earth orbit flight mission

as well as manned flights to the Moon

the asteroid and the Mars

the progress of basic and applied research on lightweight thermal protection system for the spacecraft was presented. And then

it analyzes the technology gap between domestic and foreign

and provides several suggestions concerning the prospects of China's low-density ablators.