ISRO’s RLV-LEX-03 Successfully Demonstrates Advanced Autonomous Landing Capabilities.

The Indian Space Research Organisation (ISRO) completed the third Reusable Launch Vehicle (RLV) Landing Experiment (LEX) on June 23 at the Aeronautical Test Range (ATR) in Chitradurga, Karnataka. This is the third and final test in the series of LEX experiments, conducted at 7:10 a.m.

“Following the success of the RLV LEX-01 and LEX-02 missions, RLV LEX-03 re-demonstrated the autonomous landing capability of the RLV under more challenging release conditions, including a cross-range of 500 meters against 150 meters for LEX-02, and more severe wind conditions,” ISRO stated.

On Sunday morning, the winged vehicle, Pushpak, was released from an Indian Air Force Chinook Helicopter at an altitude of 4.5 km. ISRO reported that from a release point 4.5 km away from the runway, Pushpak autonomously executed cross-range correction maneuvers, approached the runway, and performed a precise horizontal landing at the runway centerline.

“Due to this vehicle’s low lift-to-drag ratio aerodynamic configuration, the landing velocity exceeded 320 kmph, compared to 260 kmph for a commercial aircraft and 280 kmph for a typical fighter aircraft. After touchdown, the vehicle velocity was reduced to nearly 100 kmph using its brake parachute, after which the landing gear brakes were employed for deceleration and stop on the runway. During this ground roll phase, Pushpak utilized its rudder and nose wheel steering system to autonomously maintain a stable and precise ground roll along the runway,” the space agency explained.

This mission simulated the approach and landing interface and high-speed landing conditions for a vehicle returning from space, reaffirming ISRO’s expertise in acquiring the most critical technologies required for the development of a Reusable Launch Vehicle (RLV).

“Through this mission, the advanced guidance algorithm catering to longitudinal and lateral plane error corrections, which is essential for the future Orbital Re-entry Mission, has been validated,” the space agency added.

The RLV-LEX uses multi-sensor fusion, including sensors like the Inertial sensor, Radar altimeter, Flush air data system, Pseudolite system, and NavIC. Notably, the RLV-LEX-03 mission reused the winged body and flight systems from the LEX-02 mission without any modifications, demonstrating ISRO’s robust capability to reuse flight systems for multiple missions.

“This mission simulates the approach and landing interface and high-speed landing conditions for a vehicle returning from space, reaffirming ISRO’s expertise in acquiring the most critical technologies required for the development of a Reusable Launch Vehicle (RLV),” ISRO concluded.