Antimony trisulfide (Sb₂Se₃), a non-toxic and accessible substance, has possibilities as a material for use in solar cells. The current study numerically analyses Sb₂Se₃ solar cells through the program Solar Cell Capacitance Simulator (SCAPS). A detailed simulation and analysis of the influence of the Sb₂Se₃ layer’s thickness, defect density, band gap, energy level, and carrier concentration on the devices’ performance are carried out. The results indicate that a good device performance is guaranteed with the following values in the Sb₂Se₃ layer: an 800 optimal thickness for the Sb₂Se₃ absorber; less than 10¹⁵ cm⁻³ for the absorber defect density; a 1.2 eV optimum band gap; a 0.1 eV energy level (above the valence band); and a 10¹⁴ cm⁻³ carrier concentration. The highest efficiency of 30% can be attained following optimization of diverse parameters. The simulation outcomes offer beneficial insights and directions for designing and engineering Sb₂Se₃ solar cells.

The Sustainable Development Goals (SDGs) play an essential role, emphasizing responsible resource use, production, and consumption, including waste management. In addition, SDG 3, 7, 11, 12, and 13 are directly/indirectly related to waste management. This study aims to determine a suitable waste-to-energy (WtE) technology in Chittagong City, Bangladesh, focusing on cleaner technology. Anaerobic digestion, gasification, incineration, and landfill gas (LFG) recovery were considered as possible alternatives. Technical, economic, environmental, and social issues have been considered as necessary criteria for evaluation. An analytical hierarchy process was applied to rank these technologies based on stakeholders’ perceptions. The study found that anaerobic digestion (AD) ranked first, receiving 38% of overall weight. The second preferred technology is LFG (27%). Gasification and incineration stood at third and fourth, respectively (21% and 14%). According to a sensitivity study, the decision is only sensitive to the economy. LFG will become the most favoured solution for WtE conversion if the economy prioritizes more than 38%. Subsequently, this study’s findings will help achieve Bangladesh’s SDG agenda.

The antimony sulphide (AnS) solar cell is a relatively new photovoltaic technology. Because of its attractive material, optical, and electrical qualities, Sb2Se3 is an excellent absorption layer in solar cells, with a conversion efficiency of less than 8%. The purpose of this research is to determine the best parameter for increasing solar cell efficiency. This research focused on the influence of absorber layer defect density and the n/i interface on the performance of antimony trisulfide solar cells. The researchers designed the absorber thickness values with the help of the SCAPS-1D (Solar Cell Capacitance Simulator-1D) simulation programme. For this purpose, they designed the ZnS/Sb₂Se₃/PEDOT: PSS planar p-i-n structure, and then simulated its performance. This result confirms a Power Conversion Efficiency (PCE) of ≥25% at an absorber layer thickness of >300 nm and a defect density of 10¹⁴ cm⁻³, which were within the acceptable range. In this experiment, the researchers hypothesised that the antimony triselenide conduction band possessed a typical energy of ≈0.1 eV and an energetic defect level of ≈0.6 eV. At the n/i interface, every condition generated a similar result. However, the researchers noted a few limitations regarding the relationship between the defect mechanism and the device performance.

In near future, commercial companies have proposed to launch the extreme large constellation of small to medium-sized satellites over new 20,000 satellites in orbit. As a result, satellite operators will face a new challenge and have to prepare some solutions to mitigate huge potential collision risks. Under current practices, operators receive collision warning messages (Conjunction Data Messages: CDMs) generated by the Combined Space Operations Center (CSpOC). It is possibly to receive huge conjunctions that exceed warning threshold control each day but many of them are false conjunctions because the result of a combination of inaccuracies in the sensor measurements, predicting error and especially inadequacy of satellite information (e.g., GPS data and satellite size) To reduce the false CDMs and effectively mitigate the potential risk in time, space traffic management system can minimize the problems. The key system capabilities are able to automatically screen potential risky objects and provide an analysis tool to decide effective maneuver planning. As a result, GISTDA initiates the project to develop the space traffic management system known as “ZIRCON” to monitor and mitigate the risk of GISTDA’s satellites and future satellites (e.g., THEOS2 project). This paper presents the operational collision avoidance process and algorithm analysis of space traffic management system. The accuracy of analysis results is validated by comparing the analyzed results of CSpOC and Space Data Association (SDA) serving the commercial space sector to monitor and provide warning message for membership. The last section describes the future development planning and services for satellite operators.

The growing number of space objects leads to increases in the potential risks of damage to satellites and generates space debris after colliding. Conjunction assessment analysis is the one of keys to evaluating the collision risk of satellites and satellite operators require the analyzed results as fast as possible to decide and execute collision maneuver planning. However, the computation time to analyze the potential risk of all satellites is proportional to the number of space objects. The conjunction filters and parallel computing techniques can shorten the computation cost of conjunction analysis to provide the analyzed results. Therefore, this paper shows the investigation of the conjunction filter performances (accuracy and computation speed): Smart Sieve, CSieve and CAOS-D (combination of both Smart Sieve and CSieve) in both a single satellite (one vs. all) and all space objects (all vs. all) cases. Then, all the screening filters are developed to implement an algorithm that executes General-purpose computing on graphics processing units (GPGPU) by using NVIDIAs Compute Unified Device Architecture (CUDA). The analyzed results show the comparison results of the accuracy of conjunction screening analysis and computation times of each filter when implemented with the parallel computation techniques.

Currently, Geo-Informatics and Space Technology Development Agency (GISTDA), National Astronomical Research Institute of Thailand (NARIT) and Synchrotron Light Research Institute (SLRI) have a co-operation on a project of developing a satellite for scientific research called Thai Space Consortium (TSC). The project is aiming at Earth remote sensing mission by a small satellite about 100 kg. The main payload of the satellite is an optical instrument with the secondary payload of energetic particle detector for space weather. The satellite is designed to be in a Sun Synchronous orbit due to requirement of same light condition throughout the operational lifetime. In the meantime, there is another project by GISTDA named THEOS-2. This project consists of two remote-sensing satellites, THEOS-2 MainSAT and THEOS-2 SmallSAT, under the development in Europe. The SmallSAT does not have the propulsion subsystem. So it cannot perform station-keeping maneuvers or maintain constellation with others. Therefore, in this paper, we analyze two scenarios that the TSC satellite flies as constellations with the MainSAT of THEOS2 project. The constellation is in the sense that the TSC satellite flies on the same ground track path with the MainSAT satellite with slightly differences in local solar time. The ground track sequencing is presented with a methodology for obtaining orbital parameters with a discussion on accuracy relating to Keplerian assumption.