When NASA engineers designed the International Space Station during the 1990s, they didn’t envision the orbital outpost becoming a hub of commercial activity; nevertheless, that has become one of the most important contributions of ISS to US spaceflight. And as it nurtures American enterprise in low-Earth orbit, the station is increasingly running into a bottleneck: getting scientific research and other payloads outside.

Now a Texas company, NanoRacks, has proposed a solution. It is offering to build an airlock that will be attached to the space station and provide the capability to deploy cubesats and larger satellites. The $12 million-15 million airlock would also allow NASA to bring in costly large pumps and storage tanks for repairs rather than disposing of them.

“We developed a commercial pathway to the station, and now we want to extend that pathway outside the station,” Jeff Manber, the company’s managing director, told Ars in an interview. “This is a sign that we believe in the future of the station.”

NanoRacks, founded to make it easier for companies, universities, and other governments to get their research into space, has become one of NASA’s most important partners in commercializing the space station. It regularly flies experimental payloads for paying customers to and from the station, and Manber said more of that business is now migrating outside the laboratory.

On board the station there is only one equipment airlock, inside Japan’s Kibo module. The Japanese airlock is fairly small, large enough to only accommodate items about the size of a miniature refrigerator. Although it opens 10 times a year, five of those openings are allocated to the Japanese space agency, JAXA, with the other five going to NASA and its commercial partners.

“It’s becoming a real bottleneck,” said Mike Johnson, chief designer of NanoRacks. “We were sitting around the table one day and we were like, you know if we had our own airlock this would make life a whole lot easier. We started thinking about it and realized we have enough business now where we could actually self-fund an airlock.”

NASA is interested, and it may give NanoRacks approval to proceed with developing the airlock as soon as next month. The agency and its primary station contractor, Boeing, are conducting a formal assessment to see if the airlock can be safely integrated into the station. “We’ve very intrigued by it, and we haven’t found any showstoppers so far,” Mike Read, manager of the space station National Lab Office at Johnson Space Center, told Ars.

If approved by NASA, the airlock, which NanoRacks has dubbed the “Doorway to Space,” could launch as early as 2018 inside the trunk of a SpaceX Dragon capsule. The company says it could use the airlock as many as 12 times a year.

NanoRacks

NanoRacks

NanoRacks

NanoRacks

NanoRacks is proposing to build a large, half-cylinder-shaped airlock about two meters in diameter and 1.8 meters long. The airlock would attach to the end of the station’s Node 3 module, near the cupola. It would connect via a common berthing mechanism, or CBM, and then be pressurized. After pressurization, the hatch could be opened and the airlock configured for various tasks.

For commercial opportunities, NanoRacks has a small satellite launcher, and it is also designing a “haybale” system to launch as many as 192 cubesats at a time. After the airlock is configured, it would be depressurized and sealed. Then a station robotic arm could grab it, move it away from the vehicle, and deploy its payloads.

NASA is also interested in the opportunity to potentially fix large, external components of the space station. Before the space shuttle’s retirement, NASA used the sizable delivery vehicle to stash dozens of replacement pumps, storage tanks, controller boxes, batteries, and other equipment on the station, known as ORUs. When one of these components broke, astronauts would conduct a spacewalk to install a replacement unit.

However sometimes the problem with a broken unit is relatively minor, such as a problematic circuit card. With a larger airlock, damaged components could be brought inside the station, assessed, and possibly fixed, saving NASA the expense of building and delivering a new unit to the station—or losing a valuable spare. Finally, the space agency could use the airlock to dispose of trash that accumulates on station and can be difficult to get rid of.

The symbolism of a commercial doorway on the space station is also important for NASA. The agency has made no secret of its desire for commercial companies to step up and use the space station as a test bed for everything from basic research to testing new modes of space exploration.

“From the national lab perspective, the attractive thing is that this leverages ISS in a commercial manner, built with commercial funds and operated as a commercial capability,” Read said. “That’s what the whole concept of the National Lab is. If this works, it’s an important step toward what an exploration partnership might look like. Not only are we using space station for research, we’re using it to test new business relationships for exploration, and this would be an important one.”