The findings matter because geostationary satellites are essential for Indonesia’s communications, territorial monitoring, and national defense systems. Maintaining satellites in geostationary orbit requires continuous station-keeping maneuvers, and inefficient propulsion systems can rapidly consume onboard fuel and shorten mission lifespan.
RIDU-Sat 1, Indonesia’s nanosatellite developed by the Indonesian Defense University in collaboration with BRIN and Berliner Nanosatelliten Allianz, was launched on June 24, 2025. The 1U CubeSat serves educational, research, and emergency communication purposes. However, the first-generation satellite does not yet carry its own propulsion system, limiting maneuvering and orbital correction capabilities.
To address this challenge, Mahdin and colleagues designed a nozzle-thruster system aimed at supporting future RIDU-Sat missions. A nozzle is the key component of a thruster, converting pressurized gas into high-speed exhaust flow that generates thrust. In small satellites, nozzle geometry is especially critical because spacecraft volume, mass, and fuel storage are highly constrained.
The researchers employed Computational Fluid Dynamics (CFD) simulations using ANSYS Fluent rather than physical prototyping. Hydrogen peroxide (H₂O₂) was selected as the monopropellant because of its relatively high stability, environmental friendliness, and operational safety compared with hydrazine-based systems.
Three nozzle throat diameters were tested: 0.5 millimeter, 1 millimeter, and 2 millimeters. Each design maintained a 45-degree convergent angle and a 30-degree divergent angle to isolate the influence of throat size on propulsion performance.
The performance differences proved substantial.
The 0.5-millimeter throat configuration produced the strongest results:
- Exit velocity reached 1,740 meters per second
- Thrust reached approximately 609 milliNewtons
- Specific impulse achieved 177.4 seconds
By comparison, the 1-millimeter configuration produced only about 148 milliNewtons of thrust and 43 seconds of specific impulse, while the 2-millimeter version dropped to roughly 36 milliNewtons and 10 seconds respectively.
According to the researchers, reducing throat diameter increases the effectiveness of supersonic expansion inside the nozzle. This process improves the conversion of pressure energy into kinetic energy, producing faster exhaust flow and stronger thrust while consuming less propellant.
The researchers concluded that the 0.5-millimeter throat design represents the optimal configuration for future RIDU-Sat propulsion systems targeting geostationary deployment and station-keeping missions.
The study also acknowledged several limitations. Extremely small nozzles may face higher erosion risks and require advanced manufacturing precision. Furthermore, the current work remains simulation-based and has not yet undergone vacuum chamber or hot-fire experimental validation.
The research team recommends future cold-flow and hot-fire testing of the 0.5-millimeter prototype, along with hybrid chemical-electric propulsion studies and full mission simulations to evaluate long-term satellite performance.
Beyond engineering performance, the implications extend to national technology development. Satellite propulsion remains a strategically sensitive field often dependent on imported systems and foreign expertise. Developing indigenous nozzle technology could strengthen Indonesia’s aerospace independence while supporting communication, monitoring, and defense satellite programs.
Author Profile
Ahmad Dzakir Nurafif Mahdin is a researcher in Motion Power Technology, Faculty of Engineering and Defense Technology, Indonesian Defense University, specializing in propulsion systems, motion power technology, and aerospace engineering.
Sumaryadi and Ansori are researchers and academics affiliated with the Indonesian Defense University, contributing to defense technology and satellite engineering development.
Research Source
Mahdin, Ahmad Dzakir Nurafif; Sumaryadi; Ansori. 2026. Development of a Satellite Nozzle-Thruster Design for Geostationary Orbit Deployment: CFD-Based Geometric Optimization for RIDU-Sat. Indonesian Journal of Advanced Research (IJAR), Vol. 5 No. 5, pp. 531–542.
0 Komentar