The world's first robot astronaut has begun chatting to the Japanese commander of the International Space Station, in what was being touted as the first conversation of its kind.

Kirobo, a small android equipped with artificial intelligence and capable of learning how to respond appropriately to humans, even put in a request for Christmas, telling astronaut Koichi Wakata he wanted Santa to deliver him a toy rocket.

"Santa Claus will come to space," Kirobo told Wakata as they drifted in zero gravity hundreds of kilometres above the Earth.

"What will you ask for from Santa Claus, Kirobo?" asked the Japanese astronaut.

"I want a toy rocket," Kirobo responded.

The unscripted exercise is part of a longer-term project to see whether a robot can act as a companion for isolated people, particularly to see if it can develop conversational skills.

Kirobo - roughly the size of a chihuahua - left Earth on a cargo-carrying rocket and reached the space station on August 10.

"We've had some trouble before having the robot carry on the conversation smoothly," developer Tomotaka Takahashi said.

"When people develop a relationship, it is an accumulation of small bits of communication. Small things make it work or not work," he said.

"We've learnt important tips to develop a robot that can communicate with people more."

Kirobo and his interlocutor managed several minutes of conversation aboard the ISS, which included the robot giving very general opinions.

"How was it when the rocket launched?" Wakata asked the machine.

"It was exciting!" Kirobo replied.

Kirobo was created jointly by advertising firm Dentsu, the University of Tokyo, robot developer Robo Garage and Toyota.

AFP