# CubeSat Imaging Payload Design for Environmental Monitoring of Greenland
## 5 Discussion  
The current article presents the design process for a novel CubeSat Imaging payload capable of high-resolution image capture, with on-satellite image processing including the use of ML accelerators. The article follows a clear design methodology and presents results up until the development stage of the project. Clearly, the detailed design work, test schedule and presentation of the empirical validation of the design are out of the scope of this article, and while they are in progress, they are detailed as future work, as is publication on the software development. The scientific case for the satellite and the processor selection benchmarking are covered elsewhere.  
Typically satellite imagery is transmitted to Earth for processing and analysis, but in this design, we attempt to present a viable on-satellite analysis system that is feasible within the tight constraints of the CubeSat form factor.  
As we demonstrate here, recent advances in embedded processors such as the iMx8 are providing rich opportunities for powerful, compact and flexible systems, and multi-core systems such as the one demonstrated here can provide low-latency on-chip connection to both ML co-processor hardware, microcontrollers, and full operating system-capable microprocessors. This provides additional design flexibility in both software design and flight planning.  
In CubeSat development in general, COTS parts from industrial or automotive vendors are used as opposed to the space qualified equipment found in larger space programs. The advantages are in the wide range of product options available, as well as much lower cost and lead time, while disadvantages are lack of clear Technology Readiness Levels or conformance to rigorous published space-related standards.  
In particular, we find a proliferation of appropriate SOM module vendors. The use of SOM modules can reduce design complexity, development risk, and hence timelines by  
Figure 5: Full imaging payload with cameras, brackets and hardness.  
simplifying the custom electronic development needed to complete a module. Likewise, industrial machine vision cameras can provide a viable alternative to specific satellite imager designs.  
This approach is distinct from highly customized development approaches often found in scientific instrument making, where a scientific goal drives a highly specific instrument design. In the case of DISCO, we aim to provide a flexible platform for a range of future student experimentation, and the design approach focuses on building a system from a collection of existing hardware. In this case, a strong methodology of defining requirements and evaluating a wide range of devices is appropriate. It is our experience that it is not only the technical specifications that are important to recognize, but also what might be termed social aspects of vendor communication, documentation quality, lead times and user community. In future design processes, we would increase the range of this type of requirement, and also perhaps develop technical means to undertake systematic product searches.  
A large number of functional, integration, system, environmental and qualification tests are either completed, underway or planned before launch. Our test suite includes thermal, vacuum, vibration, electrical, communications, radio transmission, optical calibration, software performance, power consumption, networking and in some cases radiation testing. We look forward to presenting the results in future work.