Terms containing second order perturbation

Subject	English	Chinese
space	second order perturbation	二阶摄动
avia.	second order perturbation	二级微扰
space	second-order oblateness perturbation	二阶地球扁率摄动
tech.	second-order perturbation	二阶摄动
space	second-order perturbation guidance	二阶摄动制导