On Tuesday, ISRO's Liquid Propulsion Systems Centre (LPSC) sent out the Crew Module for Gaganyaan's first uncrewed mission (G1). This came after successfully completing the integration of its liquid propulsion system.
"The liquid propulsion system is a type of rocket engine that uses liquid fuel and an oxidizer to create thrust. The liquids are mixed and burned inside the engine, producing hot gases that propel the spacecraft forward. This system is commonly used in space missions because it provides efficiency and precise control," said space expert Girish Linganna.
Explaining further, Linganna said the Crew Module Propulsion System (CMPS) uses a bi-propellant-based Reaction Control System (RCS) to control the movement of the crew module. It helps steer and stabilise the module in three directions: up and down (pitch), side to side (yaw), and rotation (roll).
All this is very significant as the control system will activate after the service module separates from the crew module. It will guide and stabilise the crew module during its descent and re-entry into the atmosphere, working until the parachutes are deployed to slow it down.
The system is equipped with 12 thrusters, each capable of generating 100 Newtons (N) of force. It also includes a pressurisation system with high-pressure gas bottles, a propellant feed system, and other fluid control components to ensure smooth and efficient operation. Together, these systems play a critical role in guiding and stabilising the spacecraft.
"Thrusters are small but powerful engines designed to control a spacecraft’s movement and direction. They work by ejecting gas or liquid in one direction, creating an equal and opposite force that adjusts the spacecraft’s position. In the Crew Module, the 12 thrusters are used for precise control, helping it make small adjustments to its movement and stay stable," added Linganna.
Experts point out that these thrusters are crucial during the descent and re-entry phase. They ensure the Crew Module follows the correct path while maintaining stability, allowing for a safe and controlled return to Earth. This precise control is especially important until the parachutes deploy to slow down the module for landing.
The Crew Module Uprighting System (CMUS), developed by the Vikram Sarabhai Space Centre (VSSC), was also added to the module at the Liquid Propulsion Systems Centre (LPSC). This system is designed to ensure that the crew module turns upright and remains stable after landing in water. It helps position the module correctly, ensuring safety and ease of recovery after its descent.
Next, the Crew Module will go through additional integration work at the Vikram Sarabhai Space Centre (VSSC). This includes assembling the avionics package, installing electrical wiring, and performing necessary checks. Once these tasks are complete, it will be sent to the U R Rao Satellite Centre in Bangalore for the final stage of integration with the Orbital Module.
The Orbital Module is a critical part of the Gaganyaan spacecraft. It consists of two main sections namely the crew module where astronauts will sit during future mission and the TTe service module which contains essential systems like propulsion, power supply, and life-support equipment.
Together, these components allow the spacecraft to perform key tasks such as maneuvering, maintaining orientation, and creating a safe environment for astronauts in orbit.