June 30, 2025—NASA has confirmed five of 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 UznańskiWiśniewski (SQ7AS) and Tibor Kapu (HA5TRO)—is planning to 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 - 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 UznańskiWiśniewski (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. - An additional contact with Poland could take place pending schedule coordination.
Ax-4 launched on June 25 and docked with the ISS on June 26. The mission is expected to
last for approximately two weeks.
ISS crew welcoming the Ax-4 crew (from left in dark outfits: Kapu, Mission Commander
Whitson, Shukla and Uznański-Wiśniewski)
Credit: ESA/Axiom Space/SpaceX
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.
