In current CubeSat observation satellites, the main design constraint is the available space. Standards dictating the unit dimensions of the payload severely restrict the maximum aperture and focal length of the optical instrument. In this paper, the authors present the results of work to produce a novel DeploScope optical system for a CubeSat-type observation satellite with a segmented aperture of the primary mirror deployed in space. The telescope is designed for Earth observation and is expected to find its application in the military, precision agriculture or environmental disaster prevention. The work includes a detailed analysis of the segment aperture effect on image repeatability for different numbers of main mirror segments. Based on it, the optimal configuration of the optical model of the telescope with an aperture of 188.5 mm and a focal length of 1100 mm was selected. Based on this analysis, a so-called laboratory version of the telescope was built, providing the possibility of free correction of each segment of the primary mirror while maintaining a solid stable base for other components of the module. Imaging tests were carried out on the laboratory version of the instrument and the system was optimized for a version suitable for implementation in the payload structure of the microsatellite.

The objective of the research was to develop the Attitude Control System algorithm to be implemented in the Earth Observation Satellite System composed of leader-follower formation. The main task of the developed Attitude Control System is to execute attitude change manoeuvres required to point the axis of the image acquisition sensor to the fixed target on the Earth’s surface, while the satellite is within the segment of an orbit, where image acquisition is possible. Otherwise, the satellite maintains a nadir orientation. The control strategy is realized by defining the high-level operational modes and control laws to manage the attitude control actuators: magnetorquers used for desaturation of the reaction wheels and reaction wheels used for agile attitude variation. A six-degree-of-freedom satellite model was used to verify whether the developed Attitude Control System based on PID controllers for actuators performs attitude control in line with the requirements of an Earth Observation System. The simulations done for a variety of combinations of orbital parameters and surface target positions proved that the designed Attitude Control System fulfils the mission requirements with sufficient accuracy This high-level architecture supplemented by a more detailed control system model allowed proving efficient functionalities performance.

Water levels in freshwater resources have been descending daily as global temperatures have risen and a coastal recession has occurred. The losses in these water basins have a significant influence on natural life. While drought is a global environmental issue, its consequences may be seen in Turkey. This study looks at the loss of water areas in Burdur Lake, one of Turkey’s major lakes, between 2010 and 2021. The areas were identified using supervised classification, and the classification process was carried out for 2010, 2013, 2016, 2019, and 2021, respectively. Furthermore, several drought detection metrics, such as land surface temperature, soil moisture values, Normalized Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Palmer Drought Severity Index (PDSI), and precipitation amounts, have been evaluated for the study area between 2010 and 2021. The values of all drought detection indicators were also evaluated monthly for each year of the study. The analysis reveals abnormalities in all parameters, particularly in recent years, when compared to earlier years. Water areas decreased by 36.48% as a result of the classifications, whereas sandy areas increased by 89.85%. Again, the average values of various parameters used for drought detection over the years were compared. As a result, the indicator parameters gave reliable results as well as a means of monitoring the drought.