Day: November 17, 2019

Sun 17 Nov Sol 7
by Guy Murphy

Illustrations of an early Mars landing often show a Habitat, Earth return vehicle, solar plant or a nuclear reactor, supply landers and a small greenhouse ‘for growing the mission’s food’. Usually, the greenhouses shown are way too small to meaningfully grow anything, but a real Mars base is going to need fresh produce to supplement the crew’s diet and to pioneer the growth of large scale crops.

The Greenhab at the MDRS is a good size for demonstrating the range of crops that can be grown in greenhouse conditions, and after a few months should be able to provide something for the crew’s
meal plates at least once a day. I have commenced as Greenhab Officer at the start of the field season. I am therefore planting crops with a time horizon lasting till May 2020. (There are no perennial plants here).

Some crops such as radishes and lettuces will be ready to harvest very quickly. It is best to plant these every month or so in modest quantities, so the crew doesn’t suddenly have more on hand than it can eat or store. Species with long yield times should be planted as soon as possible to allow time to mature. These include tomatoes, capsicums, onions and members of the cucurbit family such as pumpkins, zucchini, cucumbers, and melons. Some of these can be stored as harvested, or dried or frozen.

There are no bees or other insects to pollinate flowers, which means there will need to be hand-pollinated instead. Larger growing plants will need larger pots. Trailing plants are good because they can grow over a much larger area than their soil container, running over the ground or up over frames. The legume family will produce its own nitrogen in its roof system, providing benefits to the soil that can be available to other plants. On Mars, species where all the plants can be eaten (or fed to other edible creatures) will be given preference, as these will help minimize waste.

With these considerations, we now have tomatoes, capsium, cucumbers, snow peas, onions, carrots, radishes, strawberries, spinach and rocket currently growing in the Greenhab, with more to be planted with the next soil delivery. As long as the Greenhab officer in the future crews tends the crops, a bountiful harvest should be possible here.

On Mars, the crew will need larger greenhouses to establish a more reliable food supply and allow for crop failures, including accidental pressurisation. Artificial soils based on the surface regolith will need to be created, with reliable heating, water sources, pressurisation, and lighting. Some argue hydroponic systems might be more efficient.

Future Martian gardeners should not have to worry about insects and rodents at least. We, on the other hand, saw a wild white-tailed antelope squirrel, which had wandered inside from the adjacent plain. Before I leave here I will pot up the bag of narcissus bulbs, like a pot or 2 of these inside the Hab would bring some cheer.