NEW DELHI: The Indian Space Research Organisation (ISRO) will carry out a test flight of Reusable Launch Vehicle - Technology Demonstrator (RLV-TD) any day between April-June this year.The reusable vehicle will bring down the cost of satellite launches substantially in future, making such operations quite competitive in global commercial launch market."Technology Demonstrator winged body vehicle weighing 1.5T will be lofted to a height of 70 km using solid booster, thus attaining five times the speed of sound. Thereafter, it will descend by gliding and splashing down into the sea", said an official statement.This test flight would demonstrate the Hypersonic aerodynamics characteristics, Avionics system, Thermal protection system, Control system and Mission management."Development of Reusable Launch Vehicles is a technical challenge and it involves development of many cutting edge technologies. The magnitude of cost reduction depends on development and realization of fully reusable launch vehicle and its degree of reusability", said the statement issued on Wednesday.The ISRO has taken steps to develop next generation launch vehicle GSLV MkIII, capable of launching four ton class communication satellites to Geo-synchronous Transfer Orbit, which would bring down the cost of satellite launches.Besides, the ISRO is setting up Indian Regional Navigation Satellite System (IRNSS) to provide positioning and navigational services in Indian mainland and surrounding region up to 1,500km.The IRNSS consists of seven satellites in a constellation, three satellites in geostationary orbit and four satellites in geosynchronous orbit. The objective of IRNSS is to provide positioning services over Indian region with an absolute position accuracy of better than 20 metres."The IRNSS provides two services namely Standard Positioning Service (SPS) for Civilian users and Restricted Service (RS) for strategic users", said the statement.Out of the seven satellites required in the constellation, three satellites namely, IRNSS-1A, 1B & 1C have already been successfully placed in the orbit.The fourth satellite IRNSS-1D is scheduled for launch during March 2015.The work on remaining three satellites is in progress."The associated ground segment for maintaining the satellites in orbit, monitoring the constellation status, correction of the orbital parameters and navigation data uploading is in place", said the statement.