RLV Technology Demonstration Programme
Reusable Launch Vehicle—Technology Demonstration Programme or RLV–TD is a series of technology demonstration missions that has been conceived by ISRO as a first step towards realising a Two Stage To Orbit (TSTO) re-usable launch vehicle, an intermediate step towards the creation of an SSTO Avatar.
For this purpose a Winged Reusable Launch Vehicle technology Demonstrator (RLV-TD) has been configured. The RLV-TD will act as a flying test bed to evaluate various technologies like hypersonic flight, autonomous landing, powered cruise flight and hypersonic flight using air-breathing propulsion.
In the 1990s India had plans to develop a small space shuttle named Hyperplane that would to be orbited by non-reusable launchers. Then plans changed to project Avatar as a single-stage system. The Indian Space Research Organisation indicates that this vehicle was planned for development after 2010.
In parallel, India has more realistic and currently working the programme of manned spaceflights from 2014 to 2015 with non-reusable conventional spacecraft Orbital Vehicle launched by non-reusable launcher GSLV.
In 2011, ISRO gave more details on its shuttle programme.
- HEX (Hypersonic Flight Experiment)
- LEX (Landing Experiment)
- REX (Return Flight Experiment)
- SPEX (Scramjet Propulsion Experiment)
In January 2012, ISRO announced that a scaled prototype, called Reusable Launch Vehicle-Technology Demonstrator (RLV-TD), was approved to be built and tested. The aerodynamics characterization of the RLV-TD prototype was done by National Aerospace Laboratories in India. The unmanned scaled-down prototype has a diameter of 0.56 m and a length of 10 m. The RLV-TD is in the last stages of construction by a Hyderabad-based private company called CIM Technologies.
By May 2015, engineers at the Vikram Sarabhai Space Centre (VSSC) in Thumba Equatorial Rocket Launching Station were installing thermal tiles on the outer surface of the 'RLV-TD', so it can withstand the intense heat during atmospheric reentry. This prototype weighs around 1.5 tonnes and would fly up to an altitude of 70 km. ISRO has tentatively slated the prototype's test flight from the first launchpad of Satish Dhawan Space Centre for October 2015. The RLV-TD will be mounted on top of a rocket and launched beyond the atmosphere, after which the RLV-TD will separate and reenter the atmosphere while traveling through the hypersonic regime. The rocket is expendable while the RLV would glide back to Earth and fall in Bay of Bengal as there are no airstrips that are 5 km long in India that could be used to land such aircraft. ISRO has made detailed reports to construct an airstrip greater than 4 km long in the Sriharikota island and it will be built in near future. 
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- RLV-TD test flight animation
- Brief description of RLV-TD Programme
- Development update on HEX
- Image showing future RLV-TD flights