image: Mobile CubeSat Command and Control (MC3) Network is a DoD-based activity targeting satellite communications facilities in partner institutions to provide a shared infrastructure for small satellite missions.
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Credit: (US Navy Office of NPS Graphics)
Four students from the Naval Postgraduate School (NPS), representing the Navy and the Army, conducted each graduate study to improve and address the unique aspects of the Mobile CubeSat (MC3) command and control network, a network of ground stations of the Ministry of Defense. (DOD) provision of common infrastructure for small satellite research.
At almost 10 years old, MC3 has become a multinational network and is designed as a means of bringing together organizations that have developed their own CubeSat programs with a single community-based approach that focuses on a standard infrastructure that many governments could use over time. The NPS Space Systems Academic Group was used to carry out the construction, maintenance and operation of the network, given its strengths in CubeSat-related activities and its focus on practical military education.
The network has eight active sites, the ninth under construction, located in military, educational and commercial institutions. The network allows for a low-cost, fast-growing development environment in which satellite and terrestrial infrastructure technology can be developed without the burden of potentially impacting high-value missions that are crucial to national security.
The growth of the network and its capabilities are commensurate with the challenges posed by its expansion. The four students strive to turn the challenges of growth into opportunities with their respective diploma projects, focused on autonomy within the systems, towards the integration of hardware and software.
“Students have contributed to sophisticated capabilities with a reasonable scope that strengthen the network,” said Dr. Giovanni Minelli, a research fellow at the Faculty of Space Systems at NPS (SSAG). “Without the students in our dissertation to produce measurably useful results, small teams of faculty and staff researchers would not have been able to pay the necessary attention to these new development efforts, given the work involved in keeping the network operational. for our users in orbit. the work often leads to interesting follow-up work that can be taken by a prospective student or can spill over into other groups around the Ministry of Education. “
U.S. Army Major Timothy Marczewski is integrating a series of environmental sensors capable of monitoring the ground station’s thermal, power, humidity, vibration and even acoustic environment, so that real-time open source machine learning algorithms can be applied to to determine a normal operational baseline. Any reporting outside the limits would help to predict an imminent failure, thus allowing the operator to react faster and minimize downtime.
“This is a way to autonomously monitor these geographically dispersed ground stations,” Marchevski said. “The purpose here is to predict errors or malfunctions that could cause a leak related to a satellite passing where there is no data communication between the ground station and this satellite, due to something we did not identify before this pass. “
Using the sensors, Marchevski examined the clusters of datasets about the time of day and the temperature in the satellite dome of the ground station to get an idea of what “normal” looks like and allows users to see if normal conditions are present and eliminate potential errors.
Remaining in the field of autonomy, another student’s thesis seeks to develop software to autonomously characterize the sensitivity of the antenna to receive signals from space. The sun produces a significant amount of radio signals in the range used by MC3 stations. The developed algorithms can record the intensity of these readings and when compared to a baseline without the sun, they can extract the instantaneous sensitivity of the antenna. By repeating this process daily, degradation or sudden abnormalities can be identified autonomously. Currently, these measurements are performed manually, only once or twice a year when staff are on site and performing maintenance.
As important as ground stations are for the MC3 network, in-orbit equipment can also make or disrupt the efficiency of the entire network. U.S. Navy Lt. Col. Alison Claybow used his thesis to test end-to-end compatibility between the MC3 ground station and CubeSat’s CPSSat-defined software-defined radio (SDR), a payload designed and constructed through previous graduate research. The tests conducted in her study aimed to find the necessary parameters and related software configurations to achieve mission readiness interoperability between payload SDRs and commercial SDR receivers at the NPS MC3 ground station.
“XR-band SDRs offer enticing features such as higher bandwidth, higher data rates, advanced modulation schemes, and increased resistance to environmental disturbances such as attenuation,” says Claybo. “CubeSat’s proven form factor leads to increasingly ambitious payloads and mission requirements, leading to more data products and the subsequent need for higher data rates between space and land. Through the MC3 X- band and the CubeSat project, SSAG is developing an infrastructure that meets this emerging need for the small satellite community. “
Instead of focusing on one aspect of the overall network, U.S. Navy Lt. Anastasia Novoselovablat is working to integrate hardware and software to simulate the entire communication path of the upcoming CubeSat mission. This communication path consists of ground-based software that drives the vehicle, the spacecraft itself with its communication system and payload, which is currently being developed in New Zealand. The test, called FlatSatNet, is able to link the payload in New Zealand by NPS to enable mission software developers to develop software interfaces before the flight payload is sent to the NPS for satellite integration.
“This helps reduce the risk to the mission and sets a precedent that simultaneous development can take place in the oceans to maximize cooperation between Allied governments’ small satellite programs,” Minnelli said. “The FlatSatNet concept allows us to test the entire communication architecture of the mission, including components developed internationally, before launching the satellite into orbit.”
Because space missions have a degree of uncertainty, Minelli also notes SSAG projects, so students are not dependent on the outcome of an experiment or mission that is beyond their control. In this way, they ensure that these types of results are the “cherry on top” of an otherwise strong theoretical or experimental topic.
“I believe that the practical, comprehensive, project-oriented education we receive in the NPS space curriculum is one of the highest quality space education out there,” Claybo added. “The support I received from my diploma advisors, as well as the instructions and interaction with experienced teachers – this is really special and will set me up for my next tour, as well as for my future career in space.”
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