Effect of helium permeability on working endurance high altitude long duration LTA vehicle

Helium permeability is one of key elements to design the envelope material of lighter-than-air vehicle (LTA), and affects the LTA runtime and costs, especially the high altitude LTA. A sphere LTA is analyzed as an example to estimate the effect of helium permeability. The relation between volume and differential pressure is deduced by the stress-strain characteristics of thin envelope. Based on the kinematics model, the micro-damnification model of helium permeability and change of the helium temperature changing in LTA, the effect of the helium permeability on the working performance of the sphere LTA such as stagnation altitude and stagnation time is investigated. The relationship between permeability, design altitude and thermodynamics is concluded.