HOUSTON — Space manufacturing, a field whose promise has gone unrealized for decades, is now offering new opportunities thanks to the use of the International Space Station and reduced space access costs, some experts believe.

The best near-term opportunity to demonstrate the ability of space manufacturing to produce products of value on Earth, according to a panel at the SpaceCom Expo here Dec. 6, may come from experiments flying to the station in the next year to test the production of high-quality optical fibers.

“The opportunities for in-space manufacturing have never been better,” said Lynn Harper of the Space Portal Office at NASA’s Ames Research Center. “Large-scale manufacturing could be tested and perfected on the ISS, and then implemented in the many commercial carriers that are starting to emerge.”

Manufacturing in space, taking advantage of its microgravity or vacuum conditions, has long been proposed as a key space industry, but has failed to materialize. Harper noted that, in 1973, a General Electric executive testified before Congress that his company had identified space manufacturing applications that could grow to a $2 billion a year market in the 1980s. Those applications did not emerge, and Harper said that the infrequent and expensive access to space provided by the shuttle was a major factor in that.

“The space station changed everything about we could do in space,” Harper said. The continuous presence on the station and versatility of its facilities is better suited to testing space manufacturing applications. Commercial cargo vehicles also provide more frequent and less expensive access to the station than the shuttle could offer.

One key demonstration of space manufacturing will take place on the ISS in the next year. Two companies plan to fly payloads on the station to test the ability to produce a high-quality optical fiber called ZBLAN, taking advantage of the microgravity conditions to make the fiber without the flaws created when such fiber is made on Earth.

“For this class of materials, gravity induces microcrystallization that really ruins the beneficial properties of these materials,” said Justin Kugler, new business development manager for Made In Space, one of the companies developing such payloads. The concept has been tested in the brief moments of microgravity on parabolic aircraft flights, he said, but longer durations of weightlessness are needed to pull fibers long enough to be useful

Made In Space’s experiment that will go to the station on a Dragon cargo mission scheduled for launch as soon as Dec. 12. “We’re using the space station as the testbed to prove out that you can actually make the product in space, bring it back down to Earth and sell it for a profit.”

Another company, FOMS Inc., is developing a similar payload that will fly to the ISS in 2018. Dmitry Starodubov, chief scientist of FOMS, said that high-quality ZBLAN fiber can sell for up to $2 million per kilogram. That high price per kilogram makes space manufacturing economical even at current costs to transport cargo to and from orbit.

“This is a unique opportunity to build a sustainable industry in low Earth orbit,” he said. “The key is to make the fiber better than we make it on the ground. Then it becomes a sustainable industry that could be profitable.”

Starodubov said they have built a payload that is capable of producing “multiple kilometers” of fiber. He said later a specific launch date for the payload hasn’t been set but would likely be mid to late 2018.

Even though the FOMS payload is flying after the Made In Space one, Starodubov said that it is “the first commercially feasible opportunity to have sustainable manufacturing on the International Space Station.” He didn’t elaborate on that assessment.

FOMS and Made In Space have had disagreements in the past, including a protest Made In Space filed with the Government Accountability Office on a NASA Small Business Innovation Research award to FOMS, arguing that the technology to produce such fibers already existed and did not need to be developed again. The GAO rejected the protest by arguing that Made In Space, which did not seek SBIR funding, was not an “interested party” to the award.

Starodubov mentioned the GAO protest in the panel but took an optimistic tack. “We believe that space is big enough for everybody,” he said.