Monday Menu for ISS astronauts: Red lettuce grown in space

In a sumptuous feast that will help astronauts eat healthy on long-duration space missions like Mars, the crew members on board the International Space Station (ISS) are set to dine on fresh food grown in the micro-gravity environment of space for the first time on Monday.

Expedition 44 crew members, including NASA astronaut Scott Kelly, will on Monday sample the fruits of their labour after they harvested a crop of "Outredgeous" red romaine lettuce from the "veggie plant" growth system on the orbiting laboratory for 33 days.

Called Veg-01, NASA's plant experiment is being used to study the in-orbit function and performance of the plant growth facility and its rooting "pillows," which contain the seeds, the US space agency said in a statement.

The astronauts will clean the leafy greens with citric acid-based, food safe sanitizing wipes before consuming them.

They will eat half of the space bounty, setting aside the other half to be packaged and frozen on the station until it can be returned to Earth for scientific analysis.

Fresh foods such as tomatoes, blueberries and red lettuce are a good source of antioxidants.

"Having fresh food like these available in space could have a positive impact on people's moods and also could provide some protection against radiation in space," said Dr Ray Wheeler, head of advanced life support activities at NASA's Kennedy Space Centre in Florida.

The first "pillows" were activated, watered and cared for by Expedition 39 flight engineer Steve Swanson in May 2014.

After 33 days of growth, the plants were harvested and returned to Earth in October 2014.

At NASA's Kennedy Space Center in Florida, the plants underwent food safety analysis.

"Using LED lights to grow plants was an idea that originated with NASA as far back as the late 1990s," Dr Wheeler noted.

The purple/pinkish hue surrounding the plants is the result of a combination of the red and blue lights which by design emit more light than the green LEDs.

Green LEDS were added so the plants look like edible food rather than weird purple plants.

Besides the nutritional benefits, growing fresh produce in space may also provide a psychological benefit to astronauts.

The Veggie unit can also be used by astronauts for recreational gardening activities during deeper space missions.