The two cosmonauts aboard the International Space Station (ISS) have placed an advert for photographic company Kodak on the outside of the orbiting platform.

It is not the first time that the Russian space agency has ventured into advertising.

"Pizza Hut had their advert on the side of a rocket which carried one of the components of the space station into orbit," David Wade, senior lecturer in space technology, satellite systems engineering and engineering design at Kingston University, UK, told BBC Radio Five Live.

"They filmed adverts on board the Mir space station," he said.

"At the moment, they're only seen on camera, so you have to take a photo or two to relay that information back to Earth. But there are plans for orbital billboards in the future - huge billboards kilometres wide which would possibly be seen from Earth," he said.

Mikhail Tyurin and Vladimir Dezhurov put the Kodak advert in place of a Russian flag on the outside of the space station on Monday.

Both the flag and the advert are made from a material that the Russian space agency wants to test for durability.

The ad is red and yellow, shows the Kodak logo and carries the words "Take Pictures. Further."