Technological experiments on SiriusSat-1,2 satellites
The operation in space of the SiriusSat-1 and SiriusSat-2 satellites launched from the ISS 1 year and 8 months ago (August 15, 2018) continues. Currently, the satellites are in orbit at an altitude of 360-370 km.
Cubesats operate normally, constantly measuring fast variations of electron fluxes on the inner boundary of the external radiation belt and on the border of the South Atlantic Anomaly. The payload of the SiriusSat satellites is the detector of charged particles and gamma radiation developed at the Research Institute of Nuclear Physics of Moscow State University and created jointly by the SINP MSU and SPUTNIX.
From time to time, specialists conduct technological experiments on satellites. So, on the SiriusSat-1 nanosatellite, autonomous determination of angular motion is currently being tested using only magnetometer measurements. A magnetometer is an obligatory sensor on any spacecraft, with the help of which it is possible to measure the Earth’s magnetic field and use this data to evaluate the orientation of the spacecraft. As a rule, on large devices it is carried out on a bar, but on cubesat it is located inside the satellite. Therefore, in the measurements there is a component of the magnetic field of the spacecraft itself. The intrinsic field can change when the on-board devices are turned on/off, therefore it is important to evaluate the contribution of this field to the magnetometer measurements.
The program for the on-board control system, based on a special algorithm developed at the Keldysh Institute of Applied Mathematics, prepared by SPUTNIX specialists in conjunction with colleagues from the institute, allows satellites to estimate in real time both orientation and angular velocity, and magnetometer zero offset.
Processing the results of flight experiments showed that the estimates of the onboard algorithm adequately estimate angular motion with an accuracy of several degrees in orientation and about half a degree per second in angular velocity. Evaluation of angular motion will allow testing the SiriusSata orientation control algorithms using magnetic coils at the next stage of the experiments. Algorithms tested at SiriusSats will be used on new SPUTNIX satellites.