A Russian military submarine could be the launch pad for an upcoming attempt to test an inflatable spacecraft initially conceived for missions to Mars.

A Moscow-based company called Lavochkin is preparing a Russian Naval sub for the $700,000 experiment known as Inflatable Reentry and Descend Technology, or IRDT.

The spacecraft took its maiden spaceflight in February as a piggyback payload on a Russian Soyuz-Fregat rocket. In the next test, set for May 2001, a ballistic missile would blast off from the navy sub carrying the spacecraft to a suborbital trajectory for a landing in Australia.

Lavochkin developed the IRDT technology in cooperation with Munich-based DaimlerChrysler Aerospace AG, which is now part of the European aerospace giant Astrium. The companies hope to use the technology as a cheap and simple way of returning cargo from space, including commercial payloads from the International Space Station.

The European Space Agency co-funded the original IRDT mission, together with the European Commission and DaimlerChrysler Aerospace. The International Science and Technology Center, a Moscow-based intergovernmental organization dedicated to keeping Russian rocket technology in Russia, awarded the contract to build the spacecraft to Lavochkin.

Konstantin Pichkhadze, who manages the IRDT project at Lavochkin, told SPACE.com on Wednesday that the company is seriously considering using a Russian sub as a launch pad for a converted submarine-based missile known as Volna.

Earlier plans called for the Volna launch with the IRDT from a land-based naval missile range, however, the use of a submarine would allow more flexibility in the choice of the landing site.

In the past, Russian subs have launched several suborbital and orbital missions.

Mixed results from the previous test

In the February launch, two IRDT devices landed in southern Russia within an area used by the Russian military to recover its payloads. Bad weather and deep snow, however, hampered Lavochkin's recovery efforts for days. The smaller IRDT device was eventually found, damaged. The search for the second reentry shield, which was supposed to return the Fregat upper stage, was delayed until spring.

When the search resumed, a few multiple pressurized tanks were found near the landing zone, but they provided too little information to discern the spacecraft's fate.

"There is no logical explanation of what happened [on landing]," Pichkhadze said.

Some surmised that local residents simply took the larger IRDT apart and stole its remains but left the tanks.

Despite promises of a reward for the recovered pieces of the Fregat or IRDT, nobody came forward.

A landing in a flat, deserted part of Australia could make it easier to recover the spacecraft. The Woomera launch site, located in the sparsely populated region of the continent, has been long used for rocket experiments in the past, including space launches.

The next IRDT test also will feature several upgrades aimed at preventing depressurization of the spacecraft -- basically a heat shield -- which had occurred at least in the small IRDT device flown in February.

The shield, along with a satellite mock-up it would carry, will weigh around 308 pounds (140 kilograms) and inflate to around 26 feet (8 meters) during landing. Preliminary analysis shows that Volna is capable of putting the experiment into orbit, but financial reasons prompted Lavochkin to drop this option and stick with the suborbital flight.

In the past, Russian subs have been used to launch suborbital research missions and satellites.