BENGALURU: Indian Space Research Organisation (Isro) has postponed the test launch of the key reusable launch vehicle technology demonstrator (RLVTD) to next year.

While the earlier test schedule of September was disrupted by the launch of Astrosat, India's first astronomy satellite other launches with societal application have delayed it further.

A source said the focus currently is on putting the payload for GPS Aided Geo Augmented Navigation (GAGAN) system which will be put in space by GSAT in November first week and the subsequent Indian Regional Navigation Satellite System (IRNSS) launch in December.

"Both these missions have direct societal applications, which Isro feels is important," the source said, reiterating that preparations for the RLVTD test were all ready. The reusable launch vehicle will reduce launching cost to one-tenth of what's incurred now.

Another source pointed out that even the eventual test of the RLVTD will be of a vehicle that's one fifth the original prototype and may not even require the PSLV. "A single-phase rocket will suffice," he said. Isro has already successfully completed testing the crew module, which is important for the human space programme.

