Amateur Radio on the International Space Station (ARISS) and its partners are troubleshooting a failure within the on-board NA1SS amateur station in the ISS Columbus module. The problem does not appear to be with the radio equipment in Columbus, however. ARISS realized the problem when a contact with a school in Wyoming, between ON4ISS on Earth and astronaut Mike Hopkins, KF5LJG, at NA1SS, had to abort when no downlink signal was heard.

“Today was a tough one for ARISS,” ARISS-International Chair Frank Bauer, KA3HDO, began in a message on January 28 to the ARISS team. Bauer explained that during a January 27 spacewalk to install exterior cabling on the ISS Columbus module, the current coax feed line installed 11 years ago was replaced with another built by the European Space Agency (ESA) and Airbus. It included two additional RF connectors to support the commissioning of the Bartolomeo payload-hosting platform installed last spring on Columbus.

“On January 26, prior to the EVA [extravehicular activity], our Columbus next-generation radio system was shut off and the ISS-internal coaxial cable to the antenna was disconnected from the ARISS radio as a safety precaution for the EVA,” Bauer said. During the spacewalk, an external four-connector coax feed line replaced one with two RF connections.

“This change was made to allow ESA to connect ARISS and three additional customers to Bartolomeo, as compared to ARISS and one additional RF customer,” Bauer explained.

With the spacewalk completed, the ISS crew restarted the ISS ham radio station on January 28, but no voice repeater or automatic packet repeater system (APRS) downlink reports were heard. During a scheduled school contact at 1746 UTC, no downlink signal was heard either, and the attempted contact had to be terminated.

“Clearly, there is an issue,” Bauer continued. “More troubleshooting will be required. It may be the new external RF cable that was installed during yesterday’s EVA. It might also [have been caused by] the connect and disconnect of the interior coaxial (RF) cable. So, the interior cable cannot be totally discounted yet.”

Bauer said the crew photographed the coaxial cable and connector attached to the ARISS radio inside the ISS. “Because the exterior cable is a Bartolomeo cable and not an ARISS cable, we are working with ESA and NASA on a way forward,” he said. “NASA has opened a Payload Anomaly Report on this issue. We have talked to both the NASA and ESA representatives.”

Bauer said ARISS has asked its Russian team lead Sergey Samburov, RV3DR, if ARISS could temporarily use the RS0ISS radio in the ISS Service Module for school contacts that are already scheduled until ARISS can resolve the issue.

“On behalf of the ARISS International Board, the ARISS Delegates, and the entire team, I want to thank all of you for your tremendous volunteer support to ARISS,” Bauer said. We will get through this and be more resilient as a result.”