"CQ - this is Canada calling Space"

Crandon said he knew from a tracking program on his computer that he had an 11 minute window to chat with Garriott as he heard the tourist call out 'CQ,' meaning that he was seeking contact.

"He just called, 'CQ, this is Richard Garriott, NA1SS aboard the International Space Station,' and then I just answered him with my own call sign," Crandon said.

"We didn't have a lot of time and I wanted to respect everybody else's opportunity to make a contact as well so we just exchanged our call signs ... and we just moved on from there."

Crandon is an 18-year ham radio veteran, so contacting Garriott was no new thing. He'd also been able to make contact with Charles Simonyi, another US space tourist on board the station, in April last year. He also had the opportunity to contact South Korea's Antarctic base in the South Shetland Islands in March 2003. Whilst these amateur radio feats are impressive, Crandon wants to receive signals from even farther afield. "I suppose if they ever put a human on Mars, I'll be listening," he said.