Staging of space propulsion systems would allow lifetime limitations inherent to small propulsion systems to be bypassed in order to enable high-$\mathrm{\Delta }\mathrm{V}$ capabilities for small spacecraft, in particular mass and volume constrained CubeSats. In addition, staging can be used to provide redundancy in the propulsion system, counteract thruster degradation, or open up new avenues of mission optimization. Analytical approximations are developed in order to provide a computationally simple approach to the design, analysis, definition of propulsion technology requirements, and online autonomous decision making for systems that make use of staging of propulsion elements. In addition, the analytical approximations provide insight into the dependencies of performance metrics on system parameters. Equations are developed for any mission, defined by its $\mathrm{\Delta }\mathrm{V}$, and then specialized for escape trajectories.

空间推进系统的升级可以绕开小型推进系统固有的寿命限制，以实现$\mathrm{\Delta }\mathrm{V}$小型航天器的功能，特别是质量和体积受限制的立方体卫星。此外，分级可用于在推进系统中提供冗余，抵消推进器性能下降或开辟任务优化的新途径。开发分析近似法是为了提供一种计算上简单的方法来设计，分析，确定推进技术要求，以及为使用推进元件分级的系统进行在线自主决策。此外，解析近似值可以深入了解性能指标对系统参数的依赖性。为任何任务开发方程式，由其定义$\mathrm{\Delta }\mathrm{V}$，然后专门用于逃生轨迹。