DRDO’s HAPS Reaches 21 km in Stratospheric Flight Test
DRDO has successfully flight-tested an indigenous High-Altitude Platform System (HAPS) to 21 km, maintaining around 20 km for over 30 minutes. Developed by ADRDE, the lighter-than-air platform demonstrated controlled stratospheric flight, real-time data transmission and successful recovery, marking progress toward persistent ISR, communications relay and remote sensing capabilities for India.
DEFENCE NEWS
India has taken another step towards developing an indigenous stratospheric surveillance platform, with the Defence Research and Development Organisation (DRDO) successfully flight-testing its High-Altitude Platform System (HAPS) at 21 km above mean sea level.
The experimental flight was conducted on 6 October 2026 by DRDO’s Aerial Delivery Research and Development Establishment (ADRDE), Agra. The platform climbed to 21 km and subsequently maintained an altitude of approximately 20 km for more than 30 minutes before being commanded to descend and successfully recovered.
Real-time video and vehicle parameters were transmitted to a ground control station throughout the flight. The platform carried an inertial measurement unit, GPS receiver, onboard cameras, altitude-control mechanism and other instrumentation and control systems.
The test was conducted in coordination with the Indian Air Force, CEMILAC, DGCA, Airports Authority of India and other concerned authorities.
From 17 km to 21 km
The latest flight builds on ADRDE’s first stratospheric airship trial in May 2025, when an earlier prototype reached approximately 17 km during a 62-minute flight from Sheopur, Madhya Pradesh.
That trial focused on fundamental technologies including envelope-pressure control and emergency deflation, while onboard sensor data was collected to support further development and modelling.
The latest test pushes the demonstrated altitude roughly 4 km higher and, more importantly, demonstrates controlled operation around 20 km.
For a platform intended to eventually remain in the stratosphere for prolonged periods, maintaining altitude and control is just as important as reaching it.
Why put an airship at 20 km?
A HAPS essentially occupies an intermediate layer between conventional aircraft and satellites.
At around 20 km, the platform can operate above most commercial air traffic and much of the weather, while remaining considerably closer to the ground than an orbital satellite. This combination offers the potential for a large field of view and the ability to remain focused over a particular region.
That is where the concept becomes particularly relevant for India.
How could India use it?
Consider a future HAPS positioned over the Ladakh sector for an extended period. Instead of repeatedly deploying conventional aircraft or UAVs to obtain imagery of the Line of Actual Control, a persistent stratospheric platform could continuously monitor selected areas using electro-optical, infrared or other sensors.
It could potentially monitor troop movements, logistics routes, road construction and activity around sensitive areas, while also acting as a high-altitude communications relay for forces operating in difficult terrain.
The same concept could apply along the LoC and international border with Pakistan. A HAPS operating over areas of interest could provide persistent wide-area surveillance and complement satellites, manned aircraft and UAVs. It could potentially support monitoring of military infrastructure and movement without requiring a conventional aircraft to remain airborne continuously.
The primary advantage is persistence.
A satellite can provide excellent imagery, but an orbital platform follows a predetermined track. A conventional UAV, meanwhile, eventually has to return for recovery, maintenance and replenishment.
A sufficiently mature HAPS could potentially remain over or near an area of interest for prolonged periods, creating a persistent surveillance layer between low-altitude unmanned systems and space-based assets.
The platform could also serve as a communications and data relay. Information collected by lower-altitude UAVs operating in mountainous terrain, for example, could potentially be relayed through the HAPS to ground stations or command networks.
The Indian Air Force has also identified HAPS-type systems for applications including persistent ISR, telecommunications and remote sensing.
For maritime operations, the same architecture could provide persistent observation over India’s Arabian Sea and Indian Ocean approaches, supporting maritime domain awareness and monitoring of activity across key sea lanes.
These remain future applications, however. The current ADRDE vehicle has not yet demonstrated an operational ISR payload. The October flight was primarily a platform and flight-control demonstration.
The real challenge is endurance
Reaching 21 km is an important achievement. But for a HAPS, the harder challenge is staying there.
The platform will eventually need to progress from a 30-minute stratospheric hold towards much longer endurance. That will require advances in envelope durability, altitude control, autonomous station-keeping, power management, communications and mission-payload integration.
At around 20 km, the atmosphere is extremely thin. This makes aerodynamic control more challenging while the platform still has to operate its avionics, communications systems and, eventually, high-performance mission sensors reliably.
The lighter-than-air architecture does offer an inherent advantage, however. Buoyancy provides the primary lift, meaning the system does not need to continuously generate aerodynamic lift in the same way as a conventional aircraft.
That could make prolonged station-keeping significantly more efficient once the platform matures.
Building an indigenous stratospheric capability
ADRDE’s latest flight is an important step towards turning the HAPS concept into a practical capability.
The 2025 test established fundamental high-altitude airship technologies at around 17 km. The 2026 flight has now demonstrated 21 km altitude, controlled operation around 20 km, real-time data transmission and successful recovery.
The next major milestone will therefore be less about altitude and much more about endurance and payload.
If DRDO can eventually combine prolonged stratospheric persistence with useful ISR and communications payloads, HAPS could become a valuable layer in India’s surveillance architecture—sitting between UAVs, conventional aircraft and satellites while providing persistent coverage over strategically important areas.