WASHINGTON — NASA plans to make a second attempt to deploy an expandable module attached to the International Space Station as early as May 28, confident that there is no fundamental problem keeping it from expanding.
NASA halted an initial effort to deploy the Bigelow Expandable Activity Module (BEAM) on May 26 when the module failed to increase in length and diameter as much as expected. After about two hours of manually adding air to the module, the agency halted those efforts in order to study why the module was not expanding.
In a conference call with reporters May 27, NASA and Bigelow Aerospace officials said that it’s likely friction between parts of the module’s fabric, folded up for more than a year, caused the module to expand more slowly than models projected. They added that they believe a second expansion attempt, after allowing that material to “relax,” would be more successful.
“The primary force that we believe that we’re working against is friction forces between the fabrics,” said Jason Crusan, director of NASA’s advanced exploration systems division. “Those fabric friction forces — soft goods friction forces — are most likely the contributing factor.”
In a press release issued just before the media teleconference, Bigelow Aerospace, which build BEAM under a NASA contract, suggested the materials in BEAM had “undergone a tremendous squeeze” by being its compact form for 15 months, three times longer than originally planned because of launch delays. “Therefore, there is a potential for the behavior of the materials that make up the outside of the spacecraft to act differently than expected,” the company stated.
Lisa Kauke, a Bigelow Aerospace engineer, said during the teleconference that the press release was referring to the “memory” that the fabric material has when folded. “The longer they’re packed, the more they’re compressed, and then it takes a little while for the shapes to return,” she said.
BEAM’s current status, in what NASA called a “partially deployed” state, is giving the material time to relax. Plans to depressurize and repressurize the module, she said, “can only be helpful in allowing those materials to have some time to relax.”
Adding to NASA and Bigelow’s confidence about BEAM was that the module continued to expand slightly after they stopped adding air inside the module. The module grew by several centimeters in length and diameter overnight.
NASA now plans to remove the air from BEAM and then make a second attempt to pressurize and expand it early May 28. NASA has not set an exact time for that second pressurization attempt, but said it would take place early enough in the crew’s workday to allow them to depressurize it later in the day if needed.
Should the May 28 effort not fully deploy BEAM, NASA plans to wait several days to further study the issue, while also allowing the crew to carry out some previously planned activities early next week. “We’re going to take tomorrow and going to go do this, and fingers crossed everything works out fine,” said Kenneth Todd, NASA ISS operations integration manager. “If not, we’ll probably scratch our heads a little bit about what it is we want to go do next.”
BEAM is designed to remain on the station for at least two years, primarily to test the performance of expandable structures that could be used for both commercial space stations and deep space habitation modules. Crusan noted that, given the time BEAM will remain on the station, NASA was not in a rush to deploy the module if they continued to experience problems.
“We’ve very confident that we’ll get it fully expanded at some point in time,” he said. “There’s no signs of anything that we’ve seen in the data that the BEAM module deployment is at any risk.”