ISRO Achieves Major Milestone With Gaganyaan Propulsion System Test
India’s prestigious human spaceflight program, Gaganyaan, has achieved another milestone as the Indian Space Research Organisation (ISRO) successfully test-fired the engines of its Service Module Propulsion System (SMPS). These crucial engine tests were conducted at the ISRO Propulsion Complex (IPRC) located in Mahendragiri, Tamil Nadu. With these successful trials, ISRO has moved a step closer to launching India’s first crewed mission into space.
The recent tests demonstrated the functionality and reliability of the engines that will manoeuvre the Gaganyaan capsule in orbit. The Service Module Propulsion System is an integral component of the Gaganyaan Orbital Module. Its successful performance is vital to ensure safe and precise orbital movement, emergency abort scenarios, and re-entry.
Gaganyaan Propulsion System Undergoes Hot-Fire Validation
ISRO carried out two hot-fire tests of the propulsion system one lasting 30 seconds and the other 100 seconds. These tests were designed to replicate the conditions the engines would face in space. The goal was to validate the test article configuration and the operational reliability of the entire propulsion system. The outcome of both tests was consistent with ISRO’s pre-test predictions, confirming that the propulsion system behaved as expected.
During the 100-second test, all five Liquid Apogee Motors (LAMs) and sixteen Reaction Control System (RCS) thrusters were fired simultaneously. The tests included different operational modes such as steady-state and pulsed modes, simulating complex manoeuvring scenarios in space. The Reaction Control System thrusters and LAMs worked in unison, showcasing the robustness of ISRO’s spacecraft control mechanisms.
These successful firings represent a critical achievement for ISRO, as the propulsion system’s performance is essential for Gaganyaan’s orbital operations. The Liquid Apogee Motors generate 440 Newtons of thrust each, while the Reaction Control System thrusters generate 100 Newtons each. Together, they provide Gaganyaan with the capability to change orientation, adjust its orbital path, and return safely to Earth.
Liquid Apogee Motor Performance After NVS-02 Concerns
The successful Gaganyaan engine tests also come after an earlier incident involving the NVS-02 satellite in January 2024. Although the NVS-02 satellite was launched into the correct orbit by ISRO’s GSLV Mk2 rocket, its liquid apogee motor failed to fire due to a technical issue. This failure left the satellite stranded in its initial orbit.
The issue in the NVS-02 mission was traced back to a malfunction in the oxidizer valve, which prevented fuel ignition. The propulsion system, which included the same 440 Newton engine used in the Gaganyaan module, did not function as intended. This event triggered a detailed internal review and led ISRO to enhance quality control, implement additional testing, and make significant hardware and software changes.
Despite the setback, ISRO responded swiftly by integrating enhanced verification processes. These included improved design protocols, detailed validation of engine components, and stricter safety mechanisms. These learnings have been directly applied to the Gaganyaan propulsion system, ensuring that future missions are more resilient and reliable.
SMPS: Core of Gaganyaan’s Orbital Maneuvering Capability
The Gaganyaan Service Module Propulsion System is a complex and highly engineered structure, designed to support human spaceflight. It is responsible for the critical tasks of orbital injection, course corrections, and controlled descent. The system combines five high-thrust Liquid Apogee Motors with sixteen Reaction Control System thrusters to ensure multi-directional control and stability in orbit.
The engines are powered by a hypergolic bipropellant system using Monomethyl Hydrazine (MMH) as fuel and Mixed Oxides of Nitrogen (MON) as the oxidizer. Hypergolic propellants ignite spontaneously when they come into contact, eliminating the need for ignition systems and ensuring quick response times. This combination is ideal for spacecraft propulsion due to its reliability, precision, and ease of operation in the vacuum of space.
To better simulate real mission conditions, ISRO made significant upgrades to the test articles used during the hot-fire tests. These upgrades were based on data from earlier tests and involved changes in engine configuration, material reinforcement, improved sealing systems, and more advanced monitoring equipment. The goal was to bring the test environment as close to actual flight conditions as possible.
Unmanned Gaganyaan G1 Mission Set for Launch
The successful engine tests are part of a comprehensive series of evaluations that ISRO is conducting in preparation for the Gaganyaan G1 mission. This will be the first unmanned flight of the Gaganyaan spacecraft. Instead of human astronauts, this mission will carry a humanoid robot named Vyommitra. The robot is designed to simulate astronaut behavior and monitor environmental and physiological parameters during the mission.
The G1 mission is expected to pave the way for future human spaceflights by validating critical systems under real launch conditions. ISRO has planned to conduct at least three such unmanned missions, each designed to test specific aspects of the Gaganyaan spacecraft and its components. Only after completing these missions successfully will ISRO proceed with launching Indian astronauts into space.
ISRO has also shared that the Gaganyaan spacecraft will undergo splashdown recovery after each uncrewed mission. These recovery operations will be coordinated with the Indian Navy and other agencies to ensure that the capsule and its contents are safely retrieved from the ocean.
Strengthening India’s Position in Global Space Exploration
With the Gaganyaan mission, India is set to join an elite group of nations capable of human spaceflight. Only a handful of countries the United States, Russia, and China have achieved this feat. ISRO’s progress on the Gaganyaan propulsion system brings India closer to realizing this ambitious goal.
This development not only reflects India’s technological advancement but also strengthens its position in the global space sector. The Gaganyaan mission is expected to inspire future collaboration with other space-faring nations, including potential partnerships with the UAE, which has shown growing interest in human space exploration.
The Indian government has allocated significant resources to the Gaganyaan program, recognizing its strategic and scientific importance. The mission aligns with India’s long-term space objectives, including establishing a human presence in low Earth orbit, developing space habitats, and eventually participating in lunar and interplanetary missions.
Propulsion Technology and Safety: Top Priorities for ISRO
In any human spaceflight mission, propulsion system reliability is paramount. The engines must perform flawlessly to ensure the safety of the crew and the success of the mission. ISRO’s current focus on testing every aspect of the SMPS reflects its commitment to ensuring zero margin for error.
The organization has introduced several safety protocols, including multiple levels of redundancy in engine control, real-time health monitoring systems, and autonomous fault detection. All components of the Gaganyaan propulsion system are being evaluated through rigorous thermal, vibration, and vacuum testing to simulate the harsh conditions of space.
ISRO has emphasized that each engine test adds valuable data and insights, contributing to better system design and operational procedures. Engineers are also reviewing lessons from past missions, including the Chandrayaan and Mars Orbiter Missions, to refine the technology and adapt it for crewed spaceflight.
ISRO’s Broader Vision for Human Spaceflight
While the immediate goal is to successfully execute the Gaganyaan G1 unmanned mission, ISRO’s long-term vision includes developing sustainable human spaceflight capabilities. This includes designing a space station, advanced life-support systems, reusable spacecraft, and deep-space exploration missions.
The current focus on SMPS development and testing fits into this broader roadmap. By mastering propulsion systems that can support human life and execute precise manoeuvres, ISRO is laying the foundation for a new era of Indian space exploration.
Additionally, India’s strides in space technology offer promising avenues for international cooperation. Countries in the Middle East, particularly the UAE, are also investing in astronaut programs and have demonstrated interest in space missions. ISRO’s expertise in low-cost, high-efficiency space missions presents opportunities for bilateral collaboration and knowledge sharing.
A Pivotal Leap for India’s Space Ambitions
The successful testing of the Gaganyaan propulsion system represents a critical step in India’s journey to launch its first astronauts into space. The twin engine tests conducted at IPRC Mahendragiri confirm the readiness of the SMPS system, a core component of the Gaganyaan mission. By demonstrating simultaneous operation of both Liquid Apogee Motors and Reaction Control System thrusters, ISRO has shown that it possesses the engineering capabilities required for complex orbital operations.
At the same time, the lessons learned from past challenges, such as the NVS-02 mission, have made ISRO’s testing procedures more rigorous and effective. With future full-duration engine tests on the horizon and unmanned missions like Gaganyaan G1 in advanced stages of preparation, India’s dream of human spaceflight is steadily turning into reality.
The next few years will be crucial for India’s space program. Every test and mission will take the country closer to putting its own astronauts in space, demonstrating India’s technological prowess on a global stage, and inspiring future generations to reach for the stars.
