NEW DELHI: Hypersonic technology demonstrator vehicle (HSTDV) programme is being put back on track after the first developmental trial failed to meet test parameters. Scientists are expecting success within four months.The Defence Research and Development Organisation (DRDO) programme, which will have futuristic applications for next generation missiles and aerial systems, was reviewed by Union minister Rajnath Singh last week as part of a larger audit of the research body.Scientists are confident that another test can be carried out in less than four months after identifying what went wrong in the first trial last week, when Agni-I missile platform carrying HSTDV could not reach the desired altitude, sources said.Singh, who was present during the June 12 trial in Odisha, later reviewed the progress at DRDO headquarters and met scientists who had worked on HSTDV.Sources told ET that the June 12 trial was successful in the first and second stages when the Agni-I missile carrying the HSTDV took off from the Dr Abdul Kalam Island off the coast of Odisha but the test vehicle was not released. The missile lost control mid-way through the flight path and HSTDV could not be tested during the trial, indicating that the fault could be localised.While this could come as a worry for the strategic forces who have the Agni-I in active service, an investigation is on to find the exact reason for the failure. DRDO is testing HSTDV that has to demonstrate its ability to fly at speeds in excess of Mach 6 while using atmospheric oxygen as oxidizer. Other nations that have demonstrated this technology are the US, Russia, Japan, China and the European Agency.