Nasa astronauts discover space-grown lettuce 'just as safe and nutritious as Earth-grown vegetables'

Nasa astronauts have claimed that lettuce grown entirely in space is as nutritious and safe to eat as those grown on Earth.

The crew on the International Space Station have been experimenting grown the leafy base for any good salad because growing food in space could be crucial for Nasa's first crewed mission to Mars or, eventually, long interstellar missions.

A report published in the journal Frontiers In Plant Science revealed that the space-grown lettuce was similar in composition to Earth-grown control samples, while some plants were even richer in a number of elements, including potassium, sodium and zinc.

The experiment involved crops being grown in individual sealed units of ceramic soil under red LED lighting for 33 to 56 days.

Astronauts on board the International Space Station (ISS) intermittently watered the crops by injecting them through a tube.

In the film The Martian, Matt Damon's character grew food on the red planet

Once fully grown, the plants were then harvested and either eaten, deep-frozen or returned to Earth for analysis.

Although the lettuce did have higher levels of bacteria, the crops were not found to carry any dangerous bacteria such as E.coli or salmonella.

It remains unconfirmed whether the astronauts are planning to next try to grow, ahem, rocket.

PA Media contributed to this article