Extra-terrestrial 'tweet-up' links Tokyo with the International Space Station

An unusual "Tweet-up" -- a meeting of people who know each other on Twitter -- involving an ambassador, an astronaut and a prime minister has taken place on a video-link between Japan and the International Space Station.

Prime Minister Shinzo Abe and US ambassador to Japan Caroline Kennedy chatted with the Japanese commander of the ISS, Koichi Wakata, as he circled the Earth hundreds of miles up.

The three, who are all active on the micro-blogging site, talked on Thursday evening about daily life aboard the station, while Kennedy and Wakata traded compliments on their activities in the blogosphere.

"It's an honour to be able to speak with you," Kennedy, the only surviving daughter of assassinated US president John F. Kennedy said.

"Congratulations Commander Wakata on being the first Japanese commander of the space station and I am glad that we follow each other on Twitter," Kennedy said.

"Ambassador Kennedy, it's quite an honour that you follow my tweets," Wakata replied.

Wakata who was flanked by fellow space-farers from Russia and the US, battled with zero-gravity to grab the microphone and make himself heard back on Earth as Abe addressed him.

"You are the first Asian to become commander of the ISS," the Japanese PM said. "Are there days when you think that it is hard work?"

Wakata, a practised diplomat as well as an astronaut said the multi-national crew was an effective unit.

"I think we really work well as a team," he said. "But we are more than just crew mates, qualities from all the countries we represent complete each other and we can communicate perfectly," he added.

The conversation took place hours after a a Russian cargo ship docked with the ISS, bringing the crew crucial supplies and water.

Earlier this month NASA announced that it was cutting space cooperation with Russia -- except over the ISS -- because of Moscow's actions in Ukraine, including the takeover of Crimea last month.

NASA has been wholly reliant on Russia for delivering astronauts to the space station since the US retired its space shuttles in 2011.