India’s Reusable Launch Vehicle Explained

The Reusable Launch Vehicle programme is the Indian Space Research Organisation’s long-term effort to make access to space cheaper by recovering and flying the most expensive parts of a rocket again and again. Most launch vehicles in the world, including ISRO’s workhorse PSLV and GSLV rockets, are expendable: their stages burn, separate and fall into the sea after a single use. A Reusable Launch Vehicle, or RLV, aims to change that by bringing hardware back intact, in the manner of an aircraft.

ISRO’s approach centres on a winged vehicle, often described as a spaceplane, that re-enters the atmosphere, glides to a precise point and lands horizontally on a runway. The effort has progressed through a technology demonstrator, a hypersonic flight experiment in 2016 and autonomous landing experiments from 2023. This explainer sets out the reasoning behind reusability, the vehicle’s design, each major test, and the roadmap toward a fully reusable, two-stage-to-orbit system.

Quick Facts

Why Reusability Matters

A rocket is among the most expensive machines humans build, and the bulk of its cost lies in the engines, structures and avionics rather than the propellant. When all of that hardware is discarded after a single flight, each launch has to pay for a new vehicle. Making a vehicle reusable spreads that cost over many flights, in the same way that an airline does not build a new aircraft for every journey.

Reusability is also important for launch frequency. Demand for satellites for communication, earth observation, navigation and broadband is growing worldwide, and cheaper, more frequent launches support that demand. For India, which wants to expand its role in the commercial space market and in its own human spaceflight and satellite programmes, reducing the cost per kilogram to orbit is a strategic priority.

Global background

The United States flew the Space Shuttle between 1981 and 2011, a partially reusable system whose orbiter returned to land on a runway, although refurbishment proved costly and slow. More recently, private companies have demonstrated that first stages of orbital rockets can land vertically and fly again. These examples show both the promise and the engineering difficulty of reusability, and they have shaped ISRO’s choices.

The RLV-TD Programme

ISRO began its dedicated reusable launch vehicle effort in the 2000s with the RLV Technology Demonstrator programme. The purpose of the demonstrator was not to reach orbit but to test, step by step, the critical technologies that a future orbital reusable vehicle would need. These include hypersonic flight, autonomous navigation, guidance and control, thermal protection, and landing on a runway.

Instead of building the full vehicle at once, ISRO planned a series of experiments, each with its own goal. The programme was organised around four main experiment types.

• HEX: Hypersonic Flight Experiment, which tested re-entry and gliding flight.
• LEX: Landing Experiment, which tests autonomous approach and landing on a runway.
• REX: Return Flight Experiment, which is meant to integrate the complete flight from launch to return.
• SPEX: Scramjet Propulsion Experiment, which aims to test air-breathing propulsion.

This stage-by-stage approach lets engineers learn from smaller, cheaper tests before committing to a full-scale vehicle.

Design of the RLV-TD

The RLV-TD resembles a small aircraft more than a conventional rocket. It has a slender fuselage, a delta wing, twin vertical tails and movable control surfaces that allow it to be steered during glide. The demonstrator was a scaled-down model, intended to test the aerodynamic behaviour and systems of the eventual operational vehicle rather than carry a payload.

The winged-body concept

A winged body offers a very different re-entry from a capsule. Instead of falling steeply and using parachutes, a spaceplane uses its wings to generate lift and fly along a controlled, shallow path. This allows it to manoeuvre sideways to reach the runway and land with a gentle touchdown, at the cost of more complex aerodynamics and thermal protection.

The 2016 HEX Hypersonic Flight Experiment

The first major milestone came on 23 May 2016, when the RLV-TD flew from the Satish Dhawan Space Centre at Sriharikota. The vehicle was mounted on the side of a solid rocket booster known as HS9, which lifted it to an altitude of about 65 kilometres, after which the booster separated and the vehicle continued upward under its own momentum before beginning its descent.

On the way down, the vehicle re-entered the atmosphere at hypersonic speed, roughly five times the speed of sound, and then used its control surfaces to glide and manoeuvre along a planned path. The flight lasted around thirteen minutes, and the vehicle splashed down in the Bay of Bengal several hundred kilometres from the launch site. It was not designed to be recovered after this test.

What HEX demonstrated

• Autonomous navigation, guidance and control during hypersonic re-entry.
• Performance of the thermal protection system under intense heating.
• Aerodynamic behaviour of a winged body at high speed and altitude.
• Integrated mission management software and flight control.

The flight established that India could design, launch and control a winged re-entry vehicle, and gave ISRO the data to refine its models.

Thermal Protection and Enabling Technologies

One of the hardest problems in reusability is surviving re-entry. As a vehicle plunges into the atmosphere at very high speed, friction with air heats its surface to extreme temperatures. A one-time capsule can use a thick ablative shield that burns away, but a reusable vehicle needs materials that endure repeated heating without being destroyed.

The RLV-TD used a combination of materials suited to the varying temperatures across its body. A carbon-based nose cap and silica tiles were fitted on the hottest regions, while lighter flexible insulation covered cooler areas. Developing these materials, and attaching them reliably to the structure, was a significant achievement in itself.

Other critical technologies

• Navigation: precise guidance using onboard sensors and satellite navigation signals to locate the runway.
• Autonomous control: software that decides and commands without human intervention during glide and landing.
• Aerodynamic design: shapes that provide stability across a range of speeds, from hypersonic to subsonic.
• Landing hardware: landing gear and braking systems able to handle high touchdown speeds.

The 2023 Landing Experiments at Chitradurga

The next major phase focused on the final and most delicate part of a reusable mission: landing. On 2 April 2023, ISRO carried out the first Landing Experiment, known as LEX-01, at the Aeronautical Test Range in Chitradurga, Karnataka. The test vehicle was lifted by an Indian Air Force Chinook helicopter as an underslung load, taken to an altitude of about 4.5 kilometres and released.

After release, the vehicle flew autonomously, corrected for the distance and wind, aligned with the runway and landed on its own at the planned point. It used its landing gear and a brake parachute to slow down on the runway. ISRO described the test as a first of its kind in the world, because a winged vehicle had been released from such a height and landed autonomously on a runway.

What the landing test proved

• The ability to manage the approach and landing phase under realistic conditions.
• The performance of the onboard navigation, guidance and control system without human input.
• The functioning of landing gear, brakes and the braking parachute at high landing speeds.
• The usefulness of a helicopter-based drop test as a cost-effective method of testing.

Further Landing Tests and the Pushpak Vehicle

ISRO followed the 2023 test with additional landing experiments in 2024, using a vehicle named Pushpak, after the mythical aerial vehicle of Indian tradition. In these tests, the vehicle was again released from a helicopter and landed on the runway at Chitradurga, with conditions made progressively more demanding, including different release points and stronger crosswinds.

The repeated tests showed that the vehicle could land accurately even with disturbances, and that the same vehicle could be reused for more than one landing experiment, a modest but real demonstration of reusability in practice. Each success has added to a data set used to fine-tune the control laws and the landing sequence.

Why a helicopter drop?

Releasing the vehicle from a helicopter recreates the conditions the winged body would experience in the final minutes of descent, without the cost of launching it on a rocket each time. It allows engineers to test landing repeatedly, to vary conditions, and to refine the system before a full orbital return.

Roadmap to a Two-Stage-to-Orbit Vehicle

The demonstrators are stepping stones. ISRO’s longer-term goal is a fully reusable two-stage-to-orbit vehicle, in which both stages return and can be flown again. In the concept, a large reusable first stage would carry a winged orbiter up and release it, after which the orbiter would continue to orbit, deliver its payload, and then re-enter and land horizontally on a runway. The first stage would also return to a landing site.

• Technology demonstrators: HEX and LEX tests that validate re-entry and landing.
• Return and propulsion experiments: integrated flights for return, and tests of air-breathing propulsion.
• Orbital re-entry vehicle: a larger vehicle that goes to orbit and returns, proving the full mission.
• Operational reusable vehicle: a vehicle designed for regular satellite launches at lower cost.

ISRO has described this as a long-term programme extending over many years, and has not tied it to fixed delivery dates. Related efforts, including a next-generation launch vehicle with reusability as a design objective, are also being developed alongside it.

Related Efforts: SRE-1, Scramjets and Private Players

The RLV programme builds on earlier recovery work. In January 2007, ISRO launched the Space Capsule Recovery Experiment, SRE-1, on a PSLV rocket. The small capsule orbited the Earth and then re-entered and splashed down in the Bay of Bengal, from where it was recovered. It gave ISRO experience in re-entry, heat shielding and recovery.

Air-breathing propulsion is another strand. In August 2016, ISRO tested a scramjet engine on a sounding rocket, igniting it at high speed and altitude for a few seconds. A scramjet draws oxygen from the atmosphere instead of carrying its own oxidiser, which could reduce the weight of a future launcher.

A changing space ecosystem

India opened its space sector to private companies through reforms from 2020, with the creation of IN-SPACe as a promotion and authorisation body. Indian start-ups working on small launchers have also spoken of reusability as a goal. Their work and ISRO’s programme are complementary, with ISRO providing infrastructure and research, and private firms bringing commercial energy and speed.

Challenges Ahead

Building a reusable orbital launch vehicle is difficult. The vehicle must withstand repeated launch loads and extreme heating, return accurately, and be turned around quickly and cheaply for the next flight. If the cost of inspection and refurbishment is too high, the economic advantage can vanish, as the Space Shuttle experience showed.

There are further engineering challenges: durable thermal protection, reliable engines that can be restarted, precise landing guidance in varied weather, and the weight penalty of carrying extra equipment such as wings and landing gear. Launch rates also matter, since a reusable vehicle pays off only if it flies often enough to spread its development cost.

Conclusion

India’s Reusable Launch Vehicle effort is a patient, step-by-step programme rather than a single leap. The 2016 hypersonic flight, the 2023 autonomous landing and the follow-up tests with the Pushpak vehicle have built a base of tested technology. If the roadmap to a two-stage-to-orbit vehicle is realised, it could lower launch costs, increase launch frequency and strengthen India’s position in the global space economy. This article was last reviewed on 4 October 2026.

Frequently Asked Questions

What is a reusable launch vehicle?

A reusable launch vehicle is a rocket or spaceplane designed to return to Earth intact after a mission so that it can be flown again. Unlike expendable rockets, whose stages are discarded after one use, reusable vehicles aim to cut costs by recovering expensive hardware.

What was the RLV-TD HEX flight in 2016?

The Hypersonic Flight Experiment took place on 23 May 2016 from Sriharikota. A winged test vehicle was lifted by a solid booster to about 65 kilometres, then re-entered at hypersonic speed, glided under autonomous control and splashed down in the Bay of Bengal.

What happened in the 2023 landing experiment?

On 2 April 2023, ISRO released a winged test vehicle from a helicopter at about 4.5 kilometres altitude over the Aeronautical Test Range at Chitradurga, Karnataka. The vehicle flew autonomously and landed on the runway, using landing gear and a brake parachute.

What is a winged-body spaceplane?

A winged-body spaceplane is a vehicle shaped like an aircraft, with wings and control surfaces, that can return from space by gliding. It lands horizontally on a runway, unlike capsules that descend under parachutes.

Has India’s reusable vehicle reached orbit?

No. The RLV-TD was a technology demonstrator that tested re-entry and landing, not orbital flight. ISRO’s roadmap aims at a later two-stage-to-orbit reusable vehicle that would carry payloads to orbit and return.

Why is reusability important for ISRO?

Reusability can lower the cost of reaching orbit and allow more frequent launches. It supports India’s growing needs in communication, earth observation, navigation and human spaceflight, and strengthens its place in the commercial launch market.

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