Astronauts yesterday took the first bites of food grown in entirely in space and harvested from their own space garden on board the International Space Station.

NASA astronauts Kjell Lindgren and Scott Kelly, along with Japanese astronaut Kimiya Yui were all laughs while they toasted their three pieces of lettuce together with a quick "cheers" before they took their first bites.

"That's awesome," said Lindgren, giving a thumbs up to the camera. "It's fresh," he added.

"Tastes good. Kind of like arugula," said Kelly.

The harvest comes from NASA's Veg-01 experiment, aimed at studying how plants grow in orbit in order to give astronauts on possible longer missions in the future the ability to grow their own meals and fresh produce in space.

"Having lived on the space station here for awhile I understand the logistical complexity of having people live and work in space for long periods and the supply chain that is required to keep us going," said Kelly, as Lindgren processed the leafy greens behind him.

"And if we're ever going to go to Mars someday, and we will, but whenever that is, we're going to have to have a spacecraft that is much more sustainable with regards to its food supply," said Kelly.

Before dining on the leafy vegetable, Lindgren first cleaned the lettuce with citric acid-based sanitising wipes.

This isn't the first time astronauts have harvested greens in space, but it is the first time astronauts were allowed to dine on the fresh space-grown produce.

The first set of harvested greens were sent back to Earth in October of last year for safety analysis.

Half of the produce will be packaged, frozen and sent back to Earth at a later date where it will be analysed by scientists.

Displaying their teamwork spirit the astronauts said they would be saving some of the leafy greens for their cosmonaut colleagues who were busy conducting a spacewalk outside the International Space Station.