marvins-lunchbox

Moon or Martian colonists may take some time to set up more elaborate greenhouse facilities after they land, but a good supply of nutritious food and oxygen needs to be already waiting for them when they arrive. We're designing a little insulated box that can be deployed onto a relatively flat landscape, and will automatically aim itself ideally to the sun's location. When dropped, it would immediately use the pivot point and wheel along with photosensors to orient optimally to the sun's location. The box would remain completely sealed until deployed.

Then would open the lid, which has an inner reflective surface, which would aim the light down at the water, nutrient, CO2 and spirulina mixture. When too much sun pours down, threatening to boil the water, the lid automatically closes somewhat, to block light to optimum levels. If there is very little light, the lid opens up, allowing more light in and focuses it downward into the water with a shaped mirror. When the sun is completely gone, the insulated lid closes down to hold in heat.

The sunlight comes to the Lunar pole almost horizontally, so the front of the box would be a perfect place for solar panels. Solar panels on the outside, along with a battery, collect and hold power to run the servos to open and close the lid, aim a shaped mirror, and provide low level heat if needed, to prevent the water, plant mixture from freezing until the sun returns. Excess power can be used to power operations at a colony and the greenhouse boxes can keep the batteries warm.

We have not tackled the challenges of filtering out the nutritious algae and re-loading the box with new nutrients for re-use, but suspect this would not be too difficult. Recycled, sterilized human waste could be used to replace many of the nutrients.

The prototype for the greenhouse box is made from insulation board to simulate the required thermal insulation. Controls, servos and sensors are from LEGO Mindstorms for ease of development, but a considerably simpler and/or robust control system could be used. At this point, due to time constraints, the greenhouse does not have anything growing in it, it's more of a platform in which the food can be grown.

An actual deployment of some food-growing apparatus on the Moon or on Mars would likely have additional challenges to overcome. The insulated containers would not necessarily be sturdy enough to take launch stresses if loaded with the tanks of growth media. The media itself should not be in liquid form during launch to avoid foaming and balance problems. The pivoting base plate would have to be deployed in a manner that allowed it to be levelled before the insulating box and tank of growth media are installed.

To address those issues, the system could be deployed in separate parts, the base, the container and the tank of media. The bases could be kept stacked on the deployment spacecraft, with ancillary hardware. The insulated containers could themselves be stacked if they are manufactured so that their sides tip out, like Tupperware. The growth media could be frozen before launch and kept in sturdy containers with transparent top covers to allow placing into the insulated containers. The media in their containers themselves would be somewhat of a radiation shield due to the large amount of water they contain, if deployed around the spacecraft during transit. Containers would need to be configured with ports for adding and removing gasses and liquids after they are in use by a colony.

The media containers would accumulate oxygen and process carbon dioxide as they grow the algae, and this could be enhanced by keeping a tank of carbon dioxide at each setup to add more as needed. The excess oxygen could be pumped and filtered out to a tank waiting for the colonists to use.

This type of portable, self-regulating greenhouse could be used in environments other than on other worlds; here on Earth it could be used in remote locations to provide food and help recycle wastes. Slight modifications would have to be made to adapt it to using vertical sunlight, among other considerations.

The deployment of a greenhouse of some sort, ahead of human colonization, would be necessary for most human space exploration missions. A self-regulating greenhouse that also produces oxygen would be very beneficial to our development of space habitats.

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