Ax-4 Update: Amateur Radio Contacts Set to Begin July 3rd

July 2, 2025—NASA has confirmed the six expected ham radio contacts for the Axiom Space Ax-4 crew onboard the International Space Station, starting July 3. Each of the three first-time astronauts—Shubhanshu Shukla (VU2TNI), Sławosz Uznański-Wiśniewski (SQ7AS) and Tibor Kapu (HA5TRO)—will have two 10-minute contacts with communities in their home countries during the remainder of their two-week stay on the ISS.

Contact Schedule:

  • On Thursday, July 3, starting at 7:05 am ET (11:05 UTC), Tibor Kapu (HA5TRO), representing Hungary, will have a 10-minute radio contact with Hungarian students in Budapest, Debrecen, and Mezőberény. Kapu will use the ISS call sign NA1SS and ARISS ground station K6DUE in Greenbelt, Maryland. Amateur radio enthusiasts in the eastern portions of North America can listen on 145.800 MHz FM.
  • On Friday, July 4, starting at 4:41 am ET (08:41 UTC), Sławosz Uznański-Wiśniewski (SQ7AS) will have a 10-minute radio contact with the University of Wrocław in Poland. Uznański-Wiśniewski will use the ISS call sign NA1SS and ARISS ground station K6DUE in Greenbelt, Maryland. Amateur radio enthusiasts in the eastern portions of North America can listen on 145.800 MHz FM.
  • Also on Friday, July 4, starting at 6:17 am ET (10:17 UTC), Shubhanshu Shukla (VU2TNI), representing India, will have a 10-minute radio contact with the UR Rao Satellite Centre in Bengaluru, Karnataka, India. Shukla will use the ISS call sign NA1SS and ARISS ground station K6DUE in Greenbelt, Maryland. Amateur radio enthusiasts in the eastern portions of North America can listen on 145.800 MHz FM.
  • On Saturday, July 5, starting at 5:28 am ET (09:28 UTC), Sławosz Uznański-Wiśniewski (SQ7AS) will have a 10-minute radio contact with Rzeszow University of Technology in Rzeszow, Poland. Uznański-Wiśniewski will use the ISS call sign NA1SS and ARISS ground station K6DUE in Greenbelt, Maryland. Amateur radio enthusiasts in the eastern portions of North America can listen on 145.800 MHz FM.
  • On Tuesday, July 8, starting at 4:38 am ET (08:38 UTC), Shubhanshu Shukla (VU2TNI) will have a 10-minute radio contact with the Human Spaceflight Center—North Eastern Space Applications Centre (NESAC) in Meghalaya, India. Shukla will use the ISS call sign NA1SS and ARISS ground station K6DUE in Greenbelt, Maryland. Amateur radio enthusiasts in the eastern portions of North America can listen on 145.800 MHz FM.On Wednesday, July 9, starting at 3:49 am ET (07:49 UTC), Tibor Kapu (HA5TRO), will have a 10-minute radio contact with the University of Gyor in Gyor, Hungary. Kapu will use the ISS call sign NA1SS and ARISS ground station K6DUE in Greenbelt, Maryland. Amateur radio enthusiasts in the eastern portions of North America can listen on 145.800 MHz FM

Ax-4 launched on June 25 and docked with the ISS on June 26. The mission is expected to last for approximately two weeks.

ARISS has been a partner for all four Axiom Space flights to the ISS, dating back to the Ax-1 in 2022, and three of the four missions to date have featured all-ham crews. Our participation in Ax-4 aligns with our broader goal of using amateur radio to connect youth, educators, and members of the public with the International Space Station. Find out more at our website www.ariss.org and on our social media feeds at Facebook, X, and YouTube.