For 15 years, the 130-tonne Russian craft orbited 180 miles above the earth, providing accommodation and workshops for almost 100 visitors.

But when two cosmonauts involved in the mission toured schools this week, they knew it was not mind-boggling statistics the children were after.

"Typically, we are asked, 'How do you go to the toilet?'," said Dr Alexander Martynov, the former head of ballistics at Russian mission control centre, who designed re-entry spacecraft.

This week Dr Martynov and Colonel Alexander Volkov, a former commander of the Mir space station, have been speaking to pupils from schools in Nottingham and Devon about life in space.

"We like to tell the children about flights into space, how it can improve our life on earth, how important the experiments are on the space station and how they help progress," Dr Martynov said.

Organiser Peter Hicks, headteacher of Broadclyst primary school, in Devon, has been in contact with Dr Martynov since a school project to make radio contact with the cosmonauts on the space station several years ago.

The talk includes a film of life on board Mir - which answers the toilet question (you attach a device which works like a vacuum cleaner), and they bring along some space food, a spongy lump of dehydrated soup, for pupils to see.

Amy Troke, 11, of Big Wood comprehensive school, Nottingham, said: "I think it's cool. They get to go into space and see the world from a different angle."

Muhammed Abdullah, 12, of Hadden Park high school, Nottingham, said:

"Cosmonauts know more about nature and the planet. I would love to be a cosmonaut. I think you have to be strong and healthy."

The two cosmonauts began their tour at Nottingham Trent University, where children from 13 schools came to hear them speak as part of the "gifted and talented" strand of the Government's Excellence in Cities project. They then went to Devon, visiting eight schools in and around Exeter.

PUPILS' QUESTIONS ABOUT MIR

Q: "Is it true you grow taller in space?"

(Richard Ross, 12, William Sharp secondary school,Nottingham) A: Cosmonauts do grow one to two centimetres because of weightlessness, however this is soon lost upon returning to Earth and gravity.

Q: "After being in space for such a long time, what is it like being back on Earth?"

(Melanie Greenwood, 13, William Crane secondary, Nottingham) A: It takes a few days to get used to gravity. It is hard for cosmonauts to walk properly at first and drugs are needed to control their blood supply as they lose about half of their red blood cells after space flight.

Q: "When you are in space does it affect how you age?"

(Kevin Nyajeka, 13, Henry Mellish comprehensive school,Nottingham) A: The ageing process is not affected.

Q: "What are the psychological effects of being in space for a long time?"

(Scott Vardy, 13, Big Wood comprehensive school, Nottingham) A. The main problem people suffer from is isolation. Paradoxically, there is also the difficulty of getting time away from the others on the station.