Landmark Achievement For Isro's Pushpak-Passes Final 3rd Testing Phase With Flying Colors

Hello, Everyone!

The 23rd of June marked a groundbreaking achievement for the Indian Space Research Organisation ISRO after clinching achievement in its RLV (Reusable launch vehicle -Pushpak) 3rd and final testing phase. The testing marked the autonomous landing proficiency without external control of the reusable launch vehicle.

The versions of the landing experiment -LEX03 were executed at the Aeronautical Test Range (ATR) located in Chitradurga district of Karnataka.

The 23rd of June marked a groundbreaking achievement for the Indian Space Research Organisation ISRO after clinching achievement in its RLV (Reusable launch vehicle -Pushpak) 3rd and final testing phase. The testing marked the autonomous landing proficiency without external control of the reusable launch vehicle. The versions of the landing experiment -LEX03 were executed at the Aeronautical Test Range (ATR) located in Chitradurga district of Karnataka.

Pic Source: https://www.financialexpress.com/life/science-isros-rlv-pushpak-completes-final-autonomous-landing-test-successfully-3532456/

In this blog post, we will delve into the intricacies of the mission of Pushpak RLV-LEX03 and its key achievements. So, let us get started.

But first, we will understand what is a RLV-Reusable Launch Vehicle.

What is an RLV -Reusable Launch Vehicle?

A reusable launch vehicle system (RLV) is a spacecraft or a rocket engineered for the sake of using it repetitively for numerous missions, unlike traditional rockets which are discarded after a single use.

RLVs are engineered in a way that they return to Earth's surface automatically either intact or after a little refurbishment post deploying payloads into space. This approach aims to lower the cost of space access by minimizing both manufacturing and launch expenses for each mission. As a result, this improves the sustainability and economic viability of space travel. Examples of such reusable launch vehicles are Space X's Falcon 9 rocket and Blue Origin's New Shepard vehicle.

What Did The Mission Pushpak RLV LEX03 Incorporated?

->1. The mission tested the approach and landing interface under high-speed conditions for a vehicle returning from space, hailing Bharat's prowess in acquiring crucial technologies pivotal for developing a reusable launch vehicle.

->2. During Pushpak RLV-LEXO3, the autonomous landing capability of the RLV was successfully demonstrated under challenging release conditions including a cross range of 500 meters in LEX 02

-landing experiment 02, and more severe wind conditions.

What is the milestone achievement of the mission?

According to ISRO, the advanced guidance algorithms mandated for aiding longitudinal and lateral plane error rectifications that are pivotal for upcoming re-entry missions have been authorized.

A collective endeavor of numerous ISRO space centers:

The Pushpak testing mission RLV LEX03 has been headed by Vikram Sarabhai Space Centre (VSSC) and has incorporated collective endeavors of numerous ISRO centers such as:-

->Space Applications Centre(SAC)

->ISRO Telemetry

->ISRO Tracking And Command Network (ISTRAC)

->Satish Dhawan Space Centre (SDSC) SHAR -Shriharikota Range ,Shriharikota.

SDSC and SHAR are not different entities but are names referring to the same spaceport.

How the PUSHPAK RLV LEX03 mission was conducted?

Let us understand the mission in the steps indicated below:

-> 1. ISRO's Pushpak is a winged vehicle deployed from an Indian Air Force Chinook helicopter from a height of 4.5 Km. It autonomously corrected its cross range and approached the runway from a release point 4.5 Km away from the runway. Pushpak independently, without any external control executed maneuvers to correct its cross range, approached the runway, and successfully executed a precise horizontal landing at the centreline of the runway.

Let us understand cross-range as well.

Cross-Range Capability :

Cross-range capability refers to the proficiency of a Reusable launch vehicle (RLV) to maneuver within the Earth's atmosphere when returning from space, which is different from changing its orbital path while in space a task dependent on the propulsion system and available fuel. Even though an RLV can trade payload weight for more fuel to increase its space maneuverability is crucial, providing significant advantages during emergencies such as aborting ascent or changing landing locations upon return. This capability is especially beneficial for military uses. This implies, that while an RLV can theoretically carry extra fuel instead of a payload to improve its ability to change direction in space, this trade-off often results in minimal improvement.But, the ability to maneuver within the Earth's atmosphere rather than in space is highly pivotal.This atmospheric maneuverability is especially valuable during an emergency for instance -if the RLV needs to abort its mission during ascent or even when to change its landing location while returning.

->2. Because of the design and low lift-to-drag ratio of the RLV-Pushpak, the landing velocity exceeded 320 Kmph, compared to a fighter aircraft, or 280 Kmph.

But what is the landing velocity and lift-to-drag ratio (L/D) ? What is the relation between landing velocity and the lift-to-drag ratio (L/D)?

Landing Velocity refers to the speed at which the aircraft touches down the runway while it's landing. It is the velocity at which the aircraft's wheels contact the ground after descending from the final approach phase. It is a critical parameter in aviation, as it affects the safety, control, and comfort of the landing.

Lift-to-drag ratio (L/D) refers to the highly crucial aerodynamics parameter which is a measure to quantify the efficiency of an aircraft's wing design. It represents the ratio of the lift force generated by the wings to the aerodynamic drag force experienced by the aircraft during flight.

An aircraft with a low L/D generates more drag for a given amount of lift. This results in higher approach and landing speeds to maintain sufficient lift during ascent and landing. The higher approach refers to the landing of the aircraft at a higher altitude. Higher landing velocities are pivotal for preventing the aircraft from losing control.

However, a high L/D refers to an aircraft experiencing lower drag for a given amount of lift. This typically allows for smoother and more efficient flight operations such as lower approach and landing speeds. Lower landing velocities can be achieved because the aircraft can maintain lift at lower speeds without excessive drag.

->3. The most interesting part is the brake parachute employed in Pushpak. After landing on the runway the vehicle velocity dropped to 100 Kmph from more than 320 Kmph due to the brake parachute. Post leveraging the brake parachute, the landing gear brakes were used to slow down and finally come to a standstill position on the runway.

Conclusively, we can say that the mission Pushpak-RLV LEX03 signifies Bharat's aerospace and aviation prowess which is unleashing a new vista of technological and innovation brilliance in the space realm.

Thank You.

References :

Physical copy of Hindustan Times dated 24th June 2024.