Hypersonic Flight Experiment or HEX was the first test flight in the

RLV Technology Demonstration Programme Reusable Launch Vehicle–Technology Demonstration Programme is a series of technology demonstration missions that has been conceived by the Indian Space Research Organisation (ISRO) as a first step towards realising a Two Stage To Orbit (TSTO) re ...

of the Indian Space Research Organisation (ISRO). The demonstration trials will pave the way for a

two-stage-to-orbit A two-stage-to-orbit (TSTO) or two-stage rocket launch vehicle is a spacecraft in which two distinct stages provide propulsion consecutively in order to achieve orbital velocity. It is intermediate between a three-stage-to-orbit launcher and a hy ...

(TSTO) fully re-usable launch vehicle. HEX was launched on 23 May 2016.RLV-TD
ISRO. 23 May 2016. Includes diagrams.

Configuration

* First stage: live, 9 ton solid booster (S-9) * Second stage: winged test vehicle, no main engines (scramjet will be used in the future) In 2009, an airframe engineering model, axisymmetric proto nose cap after graphitisation (C-C) and slow burn rate propellant were completed. Aerodynamic characterization of technology demonstration vehicle was completed at

National Aerospace Laboratories The National Aerospace Laboratories (NAL) is India's first and largest aerospace research firm established by the Council of Scientific and Industrial Research (CSIR) in Delhi in 1959. The firm closely operates with HAL, DRDO, and ISRO and ha ...

(NAL),

Vikram Sarabhai Space Centre The Vikram Sarabhai Space Centre (VSSC) is a major space research centre of the Indian Space Research Organisation (ISRO), focusing on rocket and space vehicles for India's satellite programme. It is located in Thiruvananthapuram, in the India ...

(VSSC) and

Indian Institute of Space Science and Technology Indian Institute of Space Science and Technology (IIST) is a government-aided institute and deemed university for the study and research of space science, located at Valiamala, Nedumangad, Thiruvananthapuram, Kerala. It is the first universit ...

(IIST). Computational flow simulation and supersonic combustion in ground testing were also completed. RLV-TD consists of a fuselage (body), a nose cap, double delta wings and twin vertical rudders. It has active control surfaces called Elevons and Rudders. Apart from the twin rudders it is similar in shape and operation to a small Space Shuttle Orbiter.

Thermal Protection System

TDV uses 600 or so heat resistant silica tiles and Flexible External Insulation, nose-cap is made out Carbon-Carbon composite with SiC coating. The leading edges of twin rudders are Inconel-718, wing leading edges of 15CDV6.

Objectives

HEX was the first test flight of a reusable launch vehicle developed by India. The test flight objectives included:''An Indian space shuttle takes shape'' 2009
/ref> * Validating the aerodynamic design characteristics during

hypersonic flight Hypersonic flight is flight through the atmosphere below altitudes of about 90 km at speeds greater than Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Speeds of Mach 25+ have been achiev ...

* Characterize induced loads during the hypersonic descent through the atmosphere * Assess the performance of the

carbon fibre Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...

used in construction of the nose of the vehicle * Demonstrate first stage separation sequencing

Launch and flight

The Hypersonic Flight Experiment, or HEX, was the first test-flight in the

. The

RLV-TD RLV-TD is India's first uncrewed flying testbed developed for the Indian Space Research Organisation (ISRO)'s Reusable Launch Vehicle Technology Demonstration Programme. It is a scaled down prototype of an eventual two-stage-to-orbit (TSTO) reusa ...

vehicle was launched from the first launchpad of Satish Dhawan Space Centre on 23 May 2016 at 7:00 AM local time, on board an HS9 rocket booster. After a successful lift that lasted 91.1 seconds to a height of about 56 km, the RLV-TD separated from the 9-ton HS9 booster and further ascended to a height of about 65 km. The RLV-TD then began its descent at about Mach 5 (five times the speed of sound). The vehicle's navigation, guidance and control systems accurately steered the vehicle during this phase for a controlled

splashdown Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by crewed American space capsules prior to the Space Shuttle program, by SpaceX Dragon and Dragon 2 capsules and by NASA's Orion Multipurpose Crew ...

down to the defined landing spot over the

Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean, bounded on the west and northwest by India, on the north by Bangladesh, and on the east by Myanmar and the Andaman and Nicobar Islands of India. Its southern limit is a line betwee ...

, at a distance of about 450 km from Sriharikota, thereby fulfilling its mission objectives. The vehicle was tracked during its flight from ground stations at Sriharikota and a shipborne terminal. The total flight duration from launch to

lasted about 773.6 seconds. The unit was not planned to be recovered. ISRO plans to construct an airstrip greater than 4 km long in Sriharikota island in the "near future". Critical technologies such as autonomous navigation, guidance & control, reusable thermal protection system, and descent mission management were validated in this flight.

References

{{Spaceplanes Space programme of India

Configuration

Thermal Protection System

Objectives

Launch and flight

See also

References