STRATHcube’s Secondary Payload: Development Through Semester 1

STRATHcube’s secondary payload aims to gather atmospheric data as the satellite’s orbit decays and it re-enters earth’s atmosphere. The objective is to use this data to improve and validate current orbit propagation and re-entry analysis models. Our aim primarily during semester 1 was to consider a range of experiments that may be suitable as our secondary payload. Our objectives were adjusted following the definition of the experiment, its scientific relevance, the complexities it introduces to the design, and a trade-off to ensure it integrates well with our primary payload.

If you’ve had the chance to read our previous blog: Satellites Falling from the Sky? You’ll understand the relevance of re-entry models and some of our considerations when developing our secondary payload. However, orbit propagation models were also considered during semester 1, as briefly mentioned in the previous blog. These models are used to define the satellite’s position as its orbit naturally decays. Atmospheric density in the lower thermosphere has more significant uncertainties in these models and therefore, a payload configuration to measure this quantity was also considered and developed.

In total, three payload configurations were developed and assessed for their suitability as the secondary payload during semester 1. The premise of each, as well as its scientific objective, are documented in the following figure:

We discarded the aerothermal re-entry experiment during the semester. This was largely because of the mass and volume required for the heat shield needed for the CubeSat to survive through the communications blackout zone. This was expected to be expensive, hard to test locally and limited the capabilities of the primary payload.

This left both the fragmentation and upper atmosphere experiments. It was concluded during the last design iteration in semester 1, that the fragmentation payload experiment shall be taken forward as the best choice for the secondary payload. Balancing scientific value, design complexity and suitability with the primary payload. However, with the upper atmosphere payload having a similar sensor package, it will remain as a baseline options in case it is required as the detailed design progresses.

-      This is STRATHcube signing off.