Context: A Green Propulsion System, developed under the Technology Development Fund (TDF) scheme of DRDO, has successfully demonstrated in-orbit functionality on a payload launched by PSLV C-58 mission.
Propulsion systems
Working Principle of Propulsion System
A general concept of propulsion is that the mass of the rocket, in terms of fuel, burns with an existing velocity, generating thrust that moves the rocket upward against gravity.
Why do we need different types of propulsion systems, or what are the basic requirements for a propulsion system to work?
When a rocket moves, it does so by the thrust opposing the drag provided by the air. The propulsion system must perform two tasks while operating: first, it should counteract the drag from the air, and second, it should surpass the drag to facilitate movement.
Different Types of Propulsion System
In-space spacecraft propulsion technologies are generally categorised as
Chemical Propulsion:
- Chemical propulsion systems use the energy released in a chemical reaction to produce thrust.
- They are typically simple, reliable, and have high thrust, making them ideal for launch vehicles and other applications where high power is needed for a short time.
- For example, monopropellant and bipropellant systems are common types of chemical propulsion used in small spacecraft.
- These systems use propellants primarily saturated liquids: Refrigerants – R134a – used in air conditioning systems; R236fa – used in fire extinguishers; Sulphur Dioxide; Isobutane etc.
Electric Propulsion:
- Electric propulsion systems use electric energy to accelerate ions or plasma to generate thrust.
- They are more fuel-efficient than chemical systems and can provide thrust over a long duration, making them ideal for missions requiring fine control or long lifespan.
- However, they typically require significant electrical power and produce lower thrust than chemical systems.
- It also releases following chemicals to the space such as Electrospray ions (iodine, or noble gas (xenon, krypton, etc.)); Electrothermal (refrigerants, ammonia, sulphur dioxide, isobutene); Field Emission Electric Propulsion (liquid metal).
Propellantless Propulsion:
- Propellantless propulsion systems do not rely on ejecting mass to generate thrust.
- Examples include solar sails, which use the pressure of sunlight, and electrodynamic tethers, which interact with a planet’s magnetic field.
- A cutting-edge concept in this category is the Air-scooping electric propulsion (ASEP) system, which ingests scarce air molecules from the upper atmosphere for propellant, extending the lifetime of satellites in very low Earth orbits.
Green Propulsion:
- Green propulsion technology is an umbrella term for the various strategies used to reduce the environmental impact of air and space travel.
- They usually blend ionic liquid to create green propellants. It includes the use of green propellants like liquid methane and liquid hydrogen.
- Green propulsion technologies refer to those that are environmentally friendly. The aim is to increase specific impulse, improve storability performance, decrease volumes, and reduce life cycle costs.
- They are often low toxicity and are seen as an emerging technology in the space industry.
Technology Development Fund Scheme (TDF)
The Technology Development Fund (TDF) scheme, under the Ministry of Defence (MoD) and executed by the Defence Research and Development Organisation (DRDO), plays a crucial role in promoting self-reliance in defence technology. Here are some key points about the TDF scheme:
- Objective: The primary objective of the Technology Development Fund (TDF) is to bolster self-reliance in defence technology in line with the 'Make in India' initiative aiming to reduce dependency on foreign sources for critical defence technologies and equipment.
- Execution and Oversight: The TDF program is executed by the Ministry of Defence (MoD) with active involvement and implementation by the Defence Research and Development Organisation (DRDO).
- Scope and Target Areas: The TDF scheme is designed to meet the requirements of the Tri-Services (Army, Navy, and Air Force), Defence Production, and DRDO itself.
- Inclusivity: One of the notable features of the TDF scheme is its encouragement of participation from both public and private industries, with a special emphasis on Micro, Small, and Medium Enterprises (MSMEs).
- Collaboration: The scheme aims to create an ecosystem that fosters collaboration between the government, research institutions, and industry players to enhance cutting-edge technology capabilities.
- R&D Culture in Industry: By promoting and supporting research initiatives, the scheme contributes to the development of advanced technologies that are applicable to defence requirements.
About Defence Research and Development Organisation (DRDO)
DRDO was established in 1958 through the amalgamation of the existing Technical Development Establishment (TDEs) of the Indian Army and the Directorate of Technical Development & Production (DTDP) with the Defence Science Organisation (DSO).
- Premier Research and Development Organization: under the Ministry of Defence DRDO is playing a crucial role in driving technological advancements and innovations in the defence sector.
- Extensive Network of Laboratories: DRDO operates a network of more than 50 laboratories that cover various disciplines, including aeronautics, armaments, electronics, combat vehicles, engineering systems, and simulation, special materials, naval systems etc.
- Diverse Technological Focus: DRDO is engaged in the development of defence technologies across a wide range of areas, including missiles, armaments, light combat aircraft, radars, electronic warfare systems, and more.
- Major Projects and Achievements: DRDO is actively involved in major projects aimed at developing advanced technologies for missiles, armaments, light combat aircraft, radars, electronic warfare systems, and other defence-related applications.
DRDO is associated with the Technology Development Fund (TDF) Scheme, and Invest India serves as the Supporting Agency for the implementation of the TDF Scheme. This highlights DRDO's commitment to promoting self-reliance in defence technology through collaboration and support from various stakeholders.
About Invest India
Invest India was established in 2009 as a non-profit venture under the Department for Promotion of Industry and Internal Trade (DPIIT), Ministry of Commerce and Industry, Government of India.
- National Investment Promotion and Facilitation Agency: with a primary focus is on sector-specific investor targeting and the development of new partnerships to attract sustainable investments to the country.
- Partnerships and Collaborations: The organisation operates with a core team dedicated to promoting sustainable investments. Additionally, Invest India collaborates with significant investment promotion agencies and multilateral organisations to enhance its reach and impact.
- State Collaboration and Capacity Building: Invest India collaborates with Indian states to enhance capacity and adopt global best practices in investment targeting, promotion, and facilitation.
- Government Projects and Initiatives: It is involved in implementing several key government projects and initiatives related to start-ups and innovation.