SpIRIT CubeSat Demonstrates a Operational Gamma and X-Ray Detector

CubeSats are becoming more and more capable, and it seems like every month, another CubeSat is launched doing something new and novel. So far, technology demonstration has been one of the primary goals of those missions, though the industry is moving into playing an active role in scientific discovery. However, there are still some hurdles to jump before CubeSats have as many scientific tools at their disposal as larger satellites. That is where the Space Industry Responsive Intelligent Thermal (SpIRIT) CubeSat, the first from the Univeristy of Melbourne’s Space Lab, hopes to make an impact. Late in 2023, it launched with a few novel systems to operate new scientific equipment, and its leaders published a paper a few months ago detailing the progress of its mission so far.

SpIRIT represents a first not only for the Melbourne Space Lab but also for Australia as a whole. Their space agency was first set up in 2018 and began funding the SpIRIT project in 2020, as the COVID pandemic started making joint development efforts difficult. To contribute to the nation’s overall learning of how to build and control CubeSat, as much equipment as possible was sourced directly from Australian companies, including an ion drive from Neumann Space and a solar panel platform from Inovor Technologies.

However, the most exciting part of the SpIRIT mission was the instruments explicitly designed for it. There were several interesting ones, including HERMES, an X-ray and gamma-ray detector; TheMIS, a thermal management system used to cool HERMES; LORIS, an edge computing system; and Mercury, for use in low-latency communications.

Each system is designed to address a specific development problem plaguing CubeSats more generally. They aren’t typically able to capture light in specific wavelengths, such as gamma waves, because the sensors for those wavelengths, which include infrared, require active cooling systems that are too bulky to fit into a CubeSat’s space constraints.

Additionally, the sheer amount of data collected by modern sensors would be overwhelming for the communication links available to standard CubeSats. A single sensor could produce as much as 100Gb of data per day, while a standard downlink channel would allow only 1Gb of data to be sent back to Earth. Combining “edge computing,” where preliminary data processing is done on the CubeSat, with a low-latency communication line is SpIRIT’s solution to that problem. However, TheMIS would also have to deal with the additional heat generated by inefficiencies in the processing unit.

Preliminary results of the project look good, with HERMES beginning complete observations in March and TheMIS successfully managing thermal loads automatically. LORIS has successfully captured some camera images and started performing image recognition algorithms. Mercury has been more of a struggle, with intermittent communication happening throughout the satellite’s lifetime. Since the whole project has primarily been considered a technology demonstration mission, those growing pains are understandable and don’t seem to affect the overall mission operation.

In addition to technical derisking, many of the lessons the mission operators at the Melbourne Space Lab learned were about managing space projects more generally. Project management and personnel allocation might not be the most interesting topics, but they are necessary for completing a technical project like SpIRIT.

With over 2000 successful CubeSat launches, SpIRIT is another valuable industry contribution. As CubeSats become more widely used as scientific platforms, expect to see more and more efforts like SpIRIT reporting on their progress soon.

Learn More:
Trenti et al. – SpIRIT Mission: In-Orbit Results and Technology Demonstrations
UT – A Gamma Ray Burst Lasted So Long it Triggered a Satellite Twice
UT – A 2022 Gamma Ray Burst Was So Powerful, it was Detected by Spacecraft Across the Solar System
UT – What are CubeSats?

Lead Image:
Depiction of the SpIRIT CubeSat.
Credit – Trenti et al.