Oxygen Boost for the Skies: Reviving Zeolites in MiG-29 Jets

Inside a MiG-29, safety is engineered from molecules and materials too. Now, rejuvenated zeolites are rewriting aviation safety.

At 35,000 feet high above the Earth’s surface, the air is much thinner than at the ground to support human life. Luckily, passengers inside commercial aircrafts do not suffocate at that height because air is pumped into the cabin and the air pressure is maintained.

However, fighter jets like Mig-29 fly as high as 50,000 feet. At that altitude, the level of breathable oxygen is low, and air pressure is also extremely low. Pilots of fighter jets depend on a critical life-support system called the On-Board Oxygen Generation System (OBOGS). This system generates breathable oxygen in real time, ensuring that pilots remain alert and safe during high-altitude flight and extreme maneuvers.

At the heart of the OBOGS lies a fascinating material that makes this possible—Zeolites.

Zeolites: The Microscopic Gatekeepers

Zeolites are crystalline materials filled with micro and nanoscale pores—so they can separate gases based on molecular interaction. They act like filters, selectively adsorbing nitrogen while allowing less adsorptive oxygen molecules to pass through.

When air passes through the OBOGS system in the aircraft, the zeolites trap nitrogen molecules due to higher molecular interaction and allow the less interactive oxygen molecules to flow freely. This excellent filtering allows the system to deliver oxygen rich air to the pilot. This selective behavior makes zeolites incredibly valuable in air purification and gas separation.

The Problem: Degradation in Efficiency of Zeolite

While zeolites are highly effective, they don’t function forever. With prolonged use, wear and tear and moisture accumulate on the surface. As a result, zeolites become less effective, leading to a noticeable drop in efficiency. The pores get clogged, their performance drops, and they no longer adsorb nitrogen efficiently. As a result, oxygen output from the OBOGS declines—posing a serious risk during missions.

Zeolite Rejuvenation Technology

The Council of Scientific and Industrial Research-National Chemical Laboratory (CSIR-NCL) has stepped in with a game-changing zeolite rejuvenation solution.

Scientists at CSIR-NCL have developed a new class of zeolites called Li-LSX (Lithium-exchanged Low Silica X). These specialized materials have enhanced adsorption capacity and can be regenerated to restore performance. In trials, the Li-LSX zeolite delivered oxygen with up to 94% purity.

When performance drops, the zeolites are treated with rejuvenation process to release the trapped gases/moisture etc. Once cleared, the zeolites are as good as new—ready to filter again. Think of it like washing and reusing a high-performance sponge or a coffee filter.

CSIR-NCL has successfully rejuvenated over 5 kg of used zeolites from a MiG-29 OBOGS unit. Post-rejuvenation, oxygen output jumped from 30% to 85%, enabling safe high-altitude operations once again. This effort has now scaled up to rejuvenate over 100 kg of zeolites, ensuring the readiness of multiple aircraft.

Broader Impact: Beyond the Cockpit

This innovation doesn’t just benefit fighter pilots. The rejuvenation technology has far-reaching applications, including spacecrafts, submarines, remote medical facilities, especially in rural or disaster-hit areas, industrial oxygen generators and so on.

Moreover, by eliminating the need to carry oxygen cylinders, this system reduces aircraft weight, improving fuel efficiency and lowering carbon emissions.

Science Serving the Skies and Beyond

The zeolite rejuvenation technology developed by CSIR-NCL is a powerful example of how materials science can enhance operational safety, sustainability, and strategic capabilities. By extending the life of vital components and ensuring uninterrupted oxygen supply at high altitudes, this breakthrough strengthens India's self-reliance in aerospace technology.

With applications that stretch from fighter jets to remote hospitals, this innovation highlights translation of cutting-edge research into real-world impact.

Dr. Sudip Karmakar
SCDD, CSIR HQ.