Introduction
“Systems Engineering” is a discipline not often encountered in university teams, but it is one that is prevalent across the aerospace sector.
Making a satellite, even one that is so small that you can carry around in a suitcase, is no easy task; it requires the perfect function and cooperation of different and complex subsystems, in order to create something that will survive the dangers of outer space for more than one year, without any physical intervention.
AcubeSAT’s Systems Engineering subteam is therefore responsible to ensure the correct and reliable functionality of the spacecraft, to coordinate the technical aspects of the subsystems, and to ensure compliance with a wide array of international and European standards.
Requirements
Before getting started with a space project, we have to know what we’re trying to achieve, and how we can be sure that we’ve achieved it. This is made by specifying the technical requirements of the AcubeSAT mission, which are then broken down into all the necessary subsystems.
AcubeSAT’s technical specification contains 291 requirements, each of which has to be verified through review, analysis or testing. Starting from the scientific objectives and concluding with the detailed specifications of the satellite platform, the requirements tree shows the hierarchical structure of the requirements and can take you through a short trip in mission design.
Concurrent Design
Despite constituting a complex device, each CubeSat subsystem must be developed within a certain timeframe, keeping in mind the demands and constraints of all other participants in the project, be it technical needs or programmatic limitations.
The Systems Engineering team is responsible to ensure that all disciplines work in unison and do not overstep the limits of the project. Furthermore, it has arranged over 30 concurrent design sessions, where the entire team discusses pressing design issues and takes informed decisions.
The shown design process culminates in the Critical Design Review, a process resulting in over 1000 pages of documentation which is then reviewed by ESA experts. Through this journey in the world of aerospace, Systems Engineers face the difficulties of getting many parts and people to work well together, but are rewarded with knowledge about many aspects of a space system, and the fun of designing one of their own.
Failures, Safety and Reliability
While it may be easy to make anything work, it can be much harder to make it work well. AcubeSAT’s Systems Engineers have to employ a large array of techniques to reduce risk and ensure mission success for our satellite, despite the unforgiving (and hard to emulate) space environment and the large distances involved.
To this end, the Systems Engineering team has catalogued over 900 different failure modes as part of the Failure Modes and Effects Analysis (FMEA) technique. Each of those has to be mitigated with a large variety of techniques, or even autonomously solved in orbit, as part of Failure Detection, Isolation and Recovery (FDIR).
Assembly and Testing (MAIV)
Systems Engineering is not just paperwork and endless PDF pages! The subsequent manufacturing phase may be well planned for in advance, but huge amounts of testing have to take place before anyone can be certain that what we created is suitable to be flown away.
Functional, environmental, vibration, thermal vacuum, EMC are only some of the tests that have to be performed on all subsystems and the entire satellite in various facilities around Europe. The manufacturing process can result in many design iterations and produced models, while it has to take place in a cleanroom, to prevent dust from contaminating the precious “FlatSat” and Flight Models.
