Session
Session I: Year In Review
Location
Utah State University, Logan, UT
Abstract
N3SS is a triple Cubesat launched the 9th of October 2023. This in-orbit demonstrator embeds a miniaturized Software Developed Radio-Frequency payload that measures signals received in L and S bands. CNES, the French space agency, has been developing this satellite with the support of U-Space, a French company provider of next-generation nanosatellites. After about two weeks of commissioning, the spacecraft started its mission, which has been ongoing for six months now.
This article is focusing on the lessons learnt from the design, validation and commissioning of N3SS Guidance, Navigation and Control (GNC) system.
The GNC of N3SS includes attitude and orbit determination, on-board autonomous attitude guidance and a three axis stabilized control system that were described in a previous paper presented in 4S conference in 2022. This new paper now focuses on the robustness of the control design, especially against space environment (solar activity mainly). In particular, it is shown that the spacecraft attitude control is able to cope with a much higher level of solar activity than the satellite was expected to encounter during its mission at the time of design.
Second, this paper describes the impact of magnetic perturbation on N3SS GNC, and actions taken to mitigate it. In fact, a major lesson learnt from the previous cubesat launched by CNES (Eyesat) is that magnetization could be a major perturbation to satellite pointing and stability.
Several steps, from ground to commissioning, were performed to ensure the best pointing performance for the satellite, such as:
- Measurement of the residual magnetic moment of the complete satellite (on-ground, CNES facility)
- Demagnetization of the satellite (on-ground, CNES facility)
- Magnetometers calibration (on-ground, CNES facility)
- Magnetometers calibration (commissioning, in orbit)
The calibration algorithm, based on a non-linear least square algorithm (Gauss-Newton) is described in this article, as well as the in-orbit pointing performance gain from the calibration.
This article will also focus on a method to manage a cluster of reaction wheel during satellite lifetime to increase the reaction wheels lifetime in orbit, using the degree of freedom given by a cluster of four reaction wheels.
Finally, this document highlights how the design, validation and commissioning of the GNC N3SS were made possible with few human resources, making maximum use of CNES's assets and experience.
Lessons Learnt From N3SS GNC Operations
Utah State University, Logan, UT
N3SS is a triple Cubesat launched the 9th of October 2023. This in-orbit demonstrator embeds a miniaturized Software Developed Radio-Frequency payload that measures signals received in L and S bands. CNES, the French space agency, has been developing this satellite with the support of U-Space, a French company provider of next-generation nanosatellites. After about two weeks of commissioning, the spacecraft started its mission, which has been ongoing for six months now.
This article is focusing on the lessons learnt from the design, validation and commissioning of N3SS Guidance, Navigation and Control (GNC) system.
The GNC of N3SS includes attitude and orbit determination, on-board autonomous attitude guidance and a three axis stabilized control system that were described in a previous paper presented in 4S conference in 2022. This new paper now focuses on the robustness of the control design, especially against space environment (solar activity mainly). In particular, it is shown that the spacecraft attitude control is able to cope with a much higher level of solar activity than the satellite was expected to encounter during its mission at the time of design.
Second, this paper describes the impact of magnetic perturbation on N3SS GNC, and actions taken to mitigate it. In fact, a major lesson learnt from the previous cubesat launched by CNES (Eyesat) is that magnetization could be a major perturbation to satellite pointing and stability.
Several steps, from ground to commissioning, were performed to ensure the best pointing performance for the satellite, such as:
- Measurement of the residual magnetic moment of the complete satellite (on-ground, CNES facility)
- Demagnetization of the satellite (on-ground, CNES facility)
- Magnetometers calibration (on-ground, CNES facility)
- Magnetometers calibration (commissioning, in orbit)
The calibration algorithm, based on a non-linear least square algorithm (Gauss-Newton) is described in this article, as well as the in-orbit pointing performance gain from the calibration.
This article will also focus on a method to manage a cluster of reaction wheel during satellite lifetime to increase the reaction wheels lifetime in orbit, using the degree of freedom given by a cluster of four reaction wheels.
Finally, this document highlights how the design, validation and commissioning of the GNC N3SS were made possible with few human resources, making maximum use of CNES's assets and experience.
