To achieve the repeatability of aerospace thermal components, C/TaC-SiC composites were fabricated. Cycle ablation and bending tests were carried out. After 3 x 60 s of ablation beyond 2100 degrees C, the mechanical property retention rate was 80.9%. Interestingly, a reaction similar to ouroboros ring, in which the cyclic reactions of TaC being oxidized to Ta2O5 and Ta2O5 being reduced to TaC, occurred in the central ablation region of C/TaC-SiC composites. On the one hand, the continuous generation of TaC could prevent liquid state Ta2O5 from being blown off central ablation region, playing a similar role in water and soil conservation. On the other hand, liquid Ta2O5 covered the surface of C/TaC-SiC composites during ablation process, contributing to block the inward permeation of oxidized gases. In addition, novel Grotto structures were detected in the transitional ablation region of C/TaC-SiC composites. The formation reason of the Grotto structure has also been discussed.