January 28, 2021 – I sent this e-mail to our ARISS team today. I felt it is important that you see this too. ARISS will get through this issue. And, as you can see, we have some work arounds to keep our school contacts moving forward.

For those that do not know radio shortcuts—73 is short for “best regards.” It is a term amateur radio operators traditionally use at the end of our radio conversations.

ARISS thanks each of you for your tremendous interest and support to our program.

Frank Bauer


Today was a tough one for ARISS. Let me explain.

As you all know, an EVA (spacewalk) was conducted yesterday to install cabling on the exterior of Columbus to support the commissioning of the Bartolomeo attached payload capability mounted on the Columbus module. On January 26, prior to the EVA, 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. During the EVA, our current external antenna coaxial cable, installed in 2009, was replaced with another one built by ESA/Airbus with four RF connectors included, as compared to the current 2 RF connections. This change was made to allow ESA to connect ARISS and 3 additional customers to Bartolomeo, as compared to ARISS and one additional RF customer. As you might have seen yesterday, the EVA was conducted and our cable connection was swapped out. This morning, the crew restarted the radio system. Not hearing any Voice Repeater reports, we requested a switch to APRS packet. We still did not hear any downlink reports. At 1746 UTC we had a planned ARISS school contact between our certified telebridge station ON4ISS, operated by Jan in Belgium, and Mike Hopkins on ISS. No downlink signal was heard during the contact. The crew radioed down “no joy” on the contact about halfway through the contact and the Newcastle High School, Newcastle Wyoming, USA contact attempt ended.

Clearly, there is an issue. More troubleshooting will be required. It may be the new external RF cable that was installed during yesterday’s EVA. It might also be from the connect and disconnect of the interior coaxial (RF) cable. So the interior cable cannot not be totally discounted yet. The crew took pictures of 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. NASA has opened a Payload Anomaly Report on this issue. We have talked to both the NASA and ESA representatives. These are the same folks that worked with us on previous ARISS hardware systems as well as the ESA Bartolomeo integration initiative. We have also asked our Russian team lead, Sergey Samburov, if we can temporarily use the radio in the Service Module for school contacts until we are able to resolve this issue. As we gather more information, we will share it with you.

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

73, Frank