STRATHcube’s Secondary Payload: An Experiment to Better Understand Satellite Fragmentation During Re-entry

For a first look at the secondary payload, our previous blog: STRATHcube’s Secondary Payload: Development Through Semester 1, gives details of the initial inception and trade-offs considered during the project development. This blog picks up at the beginning of semester 2, with the over-arching requirements for the secondary payload. 

Aim

Following semester 1, our secondary payload aim was refined. The more detailed payload objective now includes the study of the CubeSat’s solar panel fragmentation during re-entry, and the conditions under which the re-entry event occurred.

Mission Outline

The secondary payload will be operational from approximately 150 – 80 km altitude, by which we expect solar panel fragmentation to occur around 90 km given the size of the satellite. The secondary payload will operate using the CubeSat battery for the duration. Data recorded will be relayed back.

The requirements for the payload are given in more detail below, and the mission outline will be updated further throughout the semester as we gain a greater understanding of the CubeSat’s position, attitude, available power and communication capabilities prior to the secondary payload operation.

Requirements for the Payload Experiment

Sensor Package

A sensor package including pressure sensors (and chambers), heat flux sensors and IR spectrometers will be further developed in the first weeks of the semester. With a selection of components allowing for greater trade-off of components, configuration checks and power calculations.

Stability

STRATHcube’s stability is essential for the successful operation of the fragmentation payload. The CubeSat must not tumble during re-entry to collect meaningful results that may be interpreted after the mission.

At this time the team is considering passive stabilization approaches, with further information required, working in collaboration with mission analysis and ADCS (Attitude Determination and Control System) to define the satellite attitude at the beginning of the experiment.

Communication Plan with Redundancy

       Relay with Constellation

The data collected from the fragmentation experiment must be transmitted prior to satellite demise. It will be challenging to relay data to the ground during re-entry. Therefore, we aim to transmit data to a constellation in orbit and relay it to ground. We will work closely with the Communications and Power subsystems this semester to achieve this requirement.

       Survival Cell

As a contingency for data transmission, we will design a section of the satellite, termed a ‘survival cell’ developed to survive the harsh re-entry environment. This will house key components, including the re-entry data. Allowing the survival cell to be located upon impact to access the data, if necessary. Of course, this generates a need to consider the location of re-entry for safe retrieval. Collaboration with the Structural, Configuration and Thermal subsystems will be required to develop this element of the design.

Next Steps

The secondary payload transformed during semester 1 to our current concept. I look forward in the coming weeks to gaining a better understanding of the key requirements and collaborating with the relevant subsystems to detail our design.

-       This is STRATHcube signing off, until next time.