Orbital Sciences Corp. believes it can sell space on the commercial cargo vehicle it has developed with NASA seed money as an orbiting laboratory once it is unloaded and unberthed from the International Space Station.

The Orbital Sciences Antares medium-lift launch vehicle set for its inaugural flight next week won’t carry the Cygnus capsule developed to deliver cargo to the ISS, but the instrumented mass simulator it is set to place in orbit will remain there for several months before re-entering the atmosphere.

So will future full-up Cygnus vehicles, which will be outfitted to support both the cargo they carry for the space station and any hosted payloads Orbital can find. The company already has a contract with NASA’s Glenn Research Center to conduct a combustion experiment on an emptied Cygnus once Orbital begins flying out its $1.9 billion, eight-mission Commercial Resupply Services (CRS) contract.

“We expect we will have a pretty sophisticated spacecraft that can operate on orbit for upward of a year,” said Michael Hamel, Orbital’s senior vice president for corporate strategy and development. “Now, this becomes a very interesting platform for being able to provide routine spaceflight opportunities for various technology and operational demonstrations, so we’re actively looking at down-the-road missions with CRS becoming a hosted payload platform.”

The Glenn experiment will study how fires can propagate and be extinguished in a spacecraft, on a scale that would be unsafe to attempt on an occupied vehicle. In the future, Hamel said Orbital hopes to use the Cygnus to create a market once filled by the Get Away Special (GAS) canisters in the space shuttle payload bay.

The so-called GAS cans carried a variety of stand-alone space experiments that were jettisoned once the payload bay doors were opened, giving researchers a way to expose experiments to the space environment. Potential customers for Cygnus payload space include civilian and military government agencies and commercial researchers.

The Cygnus/Antares stack will fly two or three missions a year to the ISS. Initially it will be able to deliver 2,000 kg (4,400 lb.) of cargo to the station, a capability that will grow to 2,700 kg after planned improvements in the spacecraft and launcher after the third CRS flight.

Unlike the SpaceX Dragon capsule, which was also developed with Commercial Orbital Transportation Services seed money from NASA, the Orbital vehicle does not carry thermal protection for re-entry, and is not designed to eventually accommodate humans. Instead, Hamel said during the National Space Symposium here, it is “optimized for cargo,” and so can fulfill its 20,000-metric-ton delivery requirement in eight flights instead of the 12 it will take the Dragon.

“We can take about 50% more cargo than the Dragon,” he said.