The International Space Station, or ISS has been orbiting the earth for over 20 years and as well as the normal scientific experiments being performed, the astronauts regularly make use of the onboard ham radio equipment to talk to interested parties back on Terra Firma.
Whilst transmissions are usually aimed at schools & colleges worldwide, it is not unknown for an astronaut to spend his/her spare time talking to fellow amateurs on the ground.
A separate activity looked after by the Russian Cosmonauts is the regular transmission of SSTV pictures, usually to commemorate a space related anniversary. Across the globe amateurs eagerly await the receipt of the signals to decode the pictures.
ARISS is the organisation formed to promote Amateur Radio on the ISS, please follow the links below for more information.