PRESS ASSOCIATION -- Astronauts travelling to Mars are likely to be farmers and chefs as well as spacefarers.

Supplying enough food for a round trip to the Red Planet is one of the greatest challenges facing mission planners, experts were told.

One solution under consideration is for astronauts to grow their own food in a hi-tech "kitchen garden". They would also need adequate cheffing skills to provide varied, tasty menus that lift spirits and ward off boredom.

Astronauts going to Mars would be far more food-savvy than their International Space Station colleagues.

Dr Maya Cooper, from the the American space agency Nasa's Space Food Systems Laboratory in Houston, Texas, said a five-year mission to Mars would require almost 7,000lb of food per person.

"That's a clear impediment to a lot of mission scenarios," she told the annual meeting of the American Chemical Society in Denver, Colorado.

"We need new approaches. Right now, we are looking at the possibility of implementing a bioregenerative system that would involve growing crops in space and possibly shipping some bulk commodities to a Mars habitat as well.

"This scenario involves much more food processing and meal preparation than the current food system developed for the space shuttles and the International Space Station."

Bioregenerative systems involve growing "multi-task" plants that not only provide food but also release oxygen for astronauts to breathe, remove the carbon dioxide they exhale, and even purify water.

Nasa expects to launch its first manned mission to Mars in the 2030s.