OTHER-WORLD GREENHOUSES

To settle on another planet we will need to grow plants there, but how?

It’s generally accepted that planetary colonies will have to grow their own food, and no colony illustration is complete without an astronaut tending to some crops. But like everything in space, this is not as easy as it looks.

Various plants have been grown on the International Space Station, but the problem for planetary greenhouses is not the lack of gravity, but the lack of pressure. In the initial stages of colonisation, most materials and equipment will have to be brought from Earth, and if you can grow plants at a lower atmospheric pressure, it will save a lot of mass.

Air may need to be transported from Earth, and even if there are convenient deposits of ice to split oxygen from, you still need nitrogen and carbon dioxide to make plant-friendly air, which add mass. Greenhouses on the Moon and Mars would need to operate under little or no atmospheric pressure. Until colonies can make engineering materials, the structure will need to be transported. If the pressure inside can be minimised, it will make it much lighter.