Towards an open source, systems-level mission planning and analysis tool

The traditional systems engineering workflow requires synthesis of subsystem design information into technical budgets, performance simulations, and other metrics of mission credibility and value. Projects often use a diverse mixture of spreadsheet calculators and custom and commercial simulation software to draw mission-level conclusions from subsystem-level design information and requirements. This approach suffers from two inefficiencies. First, heterogeneous design documentation approaches across subsystems and hardware providers makes combining design parameters at the systems-level a time-consuming and error-prone task. Second, the use of different tools for different analysis makes it challenging to co-optimize missions for multiple domains of interest.

To address this challenge, we develop a new, open source, mission-level simulation tool, called OpenSOAP. We model orbit dynamics, CONOPs, attitude dynamics, and onboard battery level and data storage consumption. As input, we can provide a master equipment list in a standard format, initial conditions, and ground- and space-based target objects of interest to the mission. Using this tool, we can rapidly investigate the effect of orbit selection, ground station selection, and hardware trades on key outcomes like power and data margins, ground station usage, and aggregate payload data downlinked.

We have used this tool in our development of the IMPAX mission—a 6U cubesat with a mission to measure electron microburst precipitation in Earth’s magnetosphere, and the X-rays that are emitted when those electrons collide in the atmosphere. The CONOPs for this mission involves frequent mode changes, each with different subsystems powered and different pointing requirements. Through OpenSOAP, we can readily estimate power and data margins across the mission lifetime, and perform orbit and ground station selection trade studies.