About Air Independent Propulsion (AIP) System:
- With the emergence of submarines, there was a problem finding satisfactory forms of propulsion underwater.
- AIP is mostly implemented as an auxiliary source, with the traditional diesel engine handling surface propulsion.
- Most of these systems generate electricity, which in turn drives an electric motor for propulsion or recharges the boat’s batteries.
- AIP allows longer submergence than a conventionally propelled submarine. A typical conventional power plant provides 3 megawatts maximum, and an AIP source around 10 per cent of that. A nuclear submarine’s propulsion plant is much greater than 20 megawatts.
Key features of the AIP system:
- It allows the submarines to stay for longer hours in water. The submarines need to come to the surface of the water to charge their batteries. This is reduced by AIP System.
- It decreases the noise levels made by the submarines. This makes it hard to detect the submarines.
- Types of AIP: Open-cycle systems, Closed-cycle diesel engines, Closed-cycle steam turbines Stirling cycle engines and Fuel cells.
What are the types of Submarines?
- Conventional or Diesel-electric submarine: They need atmospheric oxygen to run the diesel generator which in turn charges the batteries.
- Nuclear Submarine: It is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed. They have considerable performance advantages over conventional submarines.
Q1) What is Submarines?
Submarines are watercraft that are designed to operate underwater. They are a type of naval vessel that is capable of independent operation beneath the surface of the water. Submarines are used for various purposes, including military, scientific research, exploration, and rescue missions.
Source: L&T, DRDO sign contract for AIP System for submarines of Indian Navy
Last updated on January, 2026
→ Check out the latest UPSC Syllabus 2026 here.
→ Join Vajiram & Ravi’s Interview Guidance Programme for expert help to crack your final UPSC stage.
→ UPSC Mains Result 2025 is now out.
→ UPSC Notification 2026 is scheduled to be released on January 14, 2026.
→ UPSC Calendar 2026 has been released.
→ UPSC Prelims 2026 will be conducted on 24th May, 2026 & UPSC Mains 2026 will be conducted on 21st August 2026.
→ The UPSC Selection Process is of 3 stages-Prelims, Mains and Interview.
→ Prepare effectively with Vajiram & Ravi’s UPSC Prelims Test Series 2026 featuring full-length mock tests, detailed solutions, and performance analysis.
→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2026 for structured answer writing practice, expert evaluation, and exam-oriented feedback.
→ Join Vajiram & Ravi’s Best UPSC Mentorship Program for personalized guidance, strategy planning, and one-to-one support from experienced mentors.
→ UPSC Result 2024 is released with latest UPSC Marksheet 2024. Check Now!
→ UPSC Toppers List 2024 is released now. Shakti Dubey is UPSC AIR 1 2024 Topper.
→ Also check Best UPSC Coaching in India


