DRDO DEVELOPED GREEN PROPULSION SYSTEM

• A Green Propulsion System was developed under the Technology Development Fund (TDF) scheme of the Defence Research and Development Organization (DRDO).
• It has demonstrated in-orbit functionality on a payload launched by the Polar Satellite Launch Vehicle (PSLV) - C58 Mission.

About the Green Propulsion System

1. It is developed by a Bengaluru-based start-up Bellatrix Aerospace Pvt Ltd (Development Agency).
2. It utilizes a 1N Class Green Monopropellant for altitude control and orbit keeping of microsatellites.

1. Green monopropellants are low toxicity, high energy liquid rocket propellants that could be an alternative to conventional chemical propellants in the future.

3. Components include indigenously-developed propellant, fill and drain valves, latch valve, solenoid valve, catalyst bed, drive electronics, etc. Fill and drain valves are used to load and vent propellants in spacecraft and satellites.

1. A latch valve is a two-position valve that can stay in either its open or closed position without continuous power.
2. Solenoid valves are control units which are electrically energized or de-energized to shut off/allow fluid flow.
3. A catalyst bed is a reactor system that controls reaction temperature by separating the catalyst mass.

4. Offers a non-toxic and environment-friendly propulsion system for low orbit space, unlike hazardous and polluting hydrazine-based propulsion systems. Ideal for space missions with high thrust requirements.

1. Hydrazine is a colorless, fuming, oily liquid with an Ammonia- like odor. It is used in boiler treatment, as a rocket propellant and blowing agent, and in making agricultural chemicals, pharmaceuticals and spandex fibers.

Technology Development Fund (TDF)

1. The TDF is a flagship programme of the Ministry of Defence executed by the DRDO under the “Make in India” initiative to fund innovation in defence and aerospace, especially for startups and MSMEs.
2. It specifically aims to assist start-ups and small to medium-sized enterprises in these sectors.
3. The recent success of the Green Propulsion System highlights the positive impact of such initiatives in advancing technological progress in space defence.

Propulsion System

1. Definition of Propulsion: Propulsion refers to pushing forward or driving an object forward. A propulsion system is a machine that generates thrust to propel an object.
2. Types of Propellants: Propellants are substances expelled or expanded to create thrust, and they can be gases, liquids, or solids. In rockets, propellants are chemical mixtures comprising fuel and an oxidizer.
3. Types of Propulsion Systems in Satellites

1. Chemical Propulsion

• Bi-Propellant Systems: Utilize two separate propellants that combine in a combustion chamber. Common combinations include liquid oxygen (LOX) and hydrazine.
• Mono-Propellant Systems: Use a single propellant that decomposes exothermically (process that releases energy) to produce thrust. Hydrogen peroxide is a common choice for mono-propellant systems.

2. Electric Propulsion

• Ion Thrusters: Expel ions at high speeds using electric or magnetic fields. Ideal for long-duration missions due to high specific impulse.
• Hall Effect Thrusters: Accelerate plasma using magnetic fields. Balances thrust and efficiency, suitable for station-keeping and orbit adjustments.

3. Green Propulsion

• Water Electrolysis Propulsion: Utilizes water as a propellant, separating it into hydrogen and oxygen through electrolysis. Environmentally friendly and suitable for small satellites.
• Green Mono-Propellants: Focuses on developing non-toxic, environmentally friendly mono-propellants. Aims to reduce the environmental impact of satellite propulsion.

4. ISRO's Development of Green Propellants: The Indian Space Research Organisation (ISRO) is developing green propellants for future rocket and satellite propulsion systems.

1. They have developed an eco-friendly solid propellant based on Glycidyl Azide Polymer (GAP) as fuel and Ammonium Di-Nitramide (ADN) as oxidizer at the laboratory level.
2. This development aims to eliminate the emission of chlorinated exhaust products from rocket motors.

PSLV-C58 Mission

1. X-ray Polarimeter Satellite (XPoSat) is India's first dedicated mission to study the polarization of cosmic X-rays, launched on January 1, 2024 on a PSLV rocket. It is expected to have an operational lifespan of at least five years.

1. Cosmic radiation is made up of high-energy charged particles, X-rays, and gamma rays produced in space that travel through space at nearly the speed of light.

2. Mission Aim: The mission aims to investigate the polarization of intense X-ray sources, which are characterized by electromagnetic radiation with wavelengths ranging from 0.01 to 10 nanometers.
3. Significance of X-ray Polarization: Measuring X-ray polarization helps astronomers study magnetic field orientations and strengths in celestial bodies.

1. This understanding is crucial for deciphering (understanding) phenomena like pulsars, black hole regions, and other X-ray-emitting cosmic phenomena.

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