Abstract: In actual use, the helium leakage of the aerostat is much larger than the theoretical value, which greatly affects the standing performance of the aerostat. In this paper, the mechanism of helium leakage at the envelope welding area was discussed based on the errors between the calculated and actual helium leakage values. Helium permeability tests in the envelope welding area were conducted, and improvement ideas and methods were proposed. Aiming at the design of the long-endurance aerostat, the forming technology of the low helium aerostat capsule was optimized by studying the influence of different structural forms and technological methods of the envelope welding on the helium leakage rate. The results show that optimizing the structural form and processing methods of the airship envelope, such as applying protective outer heat-sealing strips on the outside of the envelope heat-sealing seams, or using heat-sealing processes as much as possible, the barrier and shape retention capabilities of the envelope can be effectively improved, and the standing time of the aerostat can be increased.

Key words: aerostat, long endurance, envelope welding technology, leakage rate test