BENGALURU, India — The Indian Space Research Organisation (ISRO) will conduct its long-delayed initial test flight of a reusable launcher technology demonstrator by midyear, a senior government official said.

The Reusable Launch Vehicle (RLV) Technology Demonstration Program, involving a series of experimental missions, was conceived by ISRO in 2009 as a first step toward a fully reusable, two-stage-to-orbit launcher.

Jitendra Singh, minister of state for science, told the Indian parliament March 4 that in the upcoming test, the 1.5-ton technology demonstrator will be launched to a height of 70 kilometers atop a solid-rocket booster, an ascent during which it will reach five times the speed of sound. “Thereafter it will descend by gliding and splashing down into the sea,” he said.

The flight will demonstrate the vehicle’s hypersonic aerodynamic properties, avionics, thermal protection and control systems, and mission management, Singh said. The entire flight will be autonomous, he said.

According to ISRO, four flights of the technology demonstrator are planned. The upcoming hypersonic flight will be followed by a landing experiment, a launch to orbit and return mission and a scramjet propulsion demonstration.

The initial RLV Technology Demonstration Program flight originally was scheduled for 2011 but was postponed multiple times. The exact date of the coming flight has not been announced.

According to Indian space officials, the experimental flights will show, in a cost effective way, the technologies that are required for taking decisions on the design and development of the full-scale two-stage-to-orbit RLV.

Based in Bangalore, Killugudi S. Jayaraman holds a doctorate in nuclear physics from the University of Maryland and a master's degree in journalism from the Medill School of Journalism at Northwestern University. He was formerly science editor of the...