return to main page
Black Soldier Fly Hydroponics - going to Mars?
I've submitted BSF Hydro for the NASA Deep Space Food Challenge
- and hence this page to document my progress and ideas.
There are many challenges of humans going to Mars, one of those is how to feed those humans in route and once arrived for the duration of their stay.
One of the issues with any crop production system is that the explorers will take with them 100% of all the nutrients they will need for their entire journey. Think of this like energy - energy is never created or destroyed, just transformed. The nutrients will be the same, the dirt on Mars has little to no nutrients and other issues
, so the explorers would need to take with them 100% of their nutrient needs for the entire duration off-earth. This also means that they will need to recycle absolutely as much of the available sources of nutrients as possible. Any failure to do so will likely mean their mission will fail - unless it's short enough that they can take all their food with them. If there were to be resupply arrivals, and likely this would be packaged foods, these nutrients in the form of humanure can contribute to the existing available nutrients.
Any Mars food crop system must supply enough food to have excess/waste. If the explorers only grow enough that they eat 100% of their crop, that means they are right on the cusp of starvation if there is the slightest hiccup.
It's extremely likely that any explorers will have to be vegans (and possibly entomophagy
) - except for packaged foods brought from Earth.
NASA has been vigilant to avoid taking along any microbial life to space except for tightly controlled experiments - which needs to change. Any explorers to Mars will need to at minimum be able to compost their human waste and plant waste.
BSF Hydro has some possible benefits in this scenario, while some real challenges exist as well.
- Less than 24 hour conversion of food waste into nutrients to grow new food crops.
- BSF can also (happily) process human feces (humanure) - solving another problem. While this isn't sexy, it will be important to recycle 100% of the available nutrients possible. The humanure is also processed in hours by BSF, but should remain fallow for 3 months to allow bacteria to complete processing into basically soil, which can then be used for non-hydroponic crops and/or "compost-tea" for the hydro system. Since 100% of any system will need to be indoors on Mars, it should be noted that the processed humanure is immediately not stinky, but just smells Earthy (Marsy?).
- Processing the food waste and humanure by BSF will significantly reduce the methane or other decomposition gasses since the food waste will not be composted. These gases might be an issue since 100% of the system and human existence will be indoors.
- BSF, and their included microbial family, has been shown (multiple scientific studies) to reduce 'bad' bacteria, namely e-coli and salmonella, and much research has been done with BSF and no known pathogens exist in common with them.
- The BSF themselves could be (maybe should be) processed and eaten as a protein source after they have reproduced. This could be either larva or fly stages, and people today are already making human food products from both stages of BSF.
- The BSF eggs, laid generally 1,000 at a time, can be successfully frozen, then are still viable when defrosted. There is a company that has based their business model on this exact venture with BSF. The reason this is important is that explorers would carry with them huge numbers of frozen eggs (but would already have live active BSF going) as a backup for any future BSF colony losses. They would want to regularly also harvest and freeze eggs once on Mars. One grain of rice is about the size of 50+ eggs, so fortunately they don't require much space.
- BSF generally live 4-6 months, eating for the first 3/4 of their lifespan, so their turnover is relatively low (at least in the fly/larva kingdom). This is good since we need hungry larva to process our waste. The flies lay eggs within a day or two, and would naturally expire by day 5ish.
- BSF colony size is easily maintained even if only a few BSF procreate (1k eggs each clutch). This means there could be significant harvests of larva or flies.
- The generated BSF nutrient water is very concentrated- and so your food crops can be grown right in and on top of each other since the nutrients come to the plants, and there won't be any competition. As long as they can get enough light, you can pack in the plants.
- Unlike "traditional" hydroponics system which use chemicals, and so eventually poison the water, the BSF nutrient water is alive with microbial life, and does not need to be (should not be) changed.
- Unlike "traditional" hydroponics chemicals, the BSF nutrient water is naturally ph balanced and non-reactive, and plants can take what they need from the water without toxicity from too much of any nutrient and likely without missing nutrients - the more variety of food waste, the more complete the nutrient water.
- BSF reduce the volume of waste by 80%+
- Low power requirements - typically a 15 minute cycle of water pump flooding tray, then a 15 minute cycle for a small aerator adds oxygen to the water for the beneficial bacteria. The system does not need to run at all overnight.
- If there were any meat sources, BSF readily devour raw or cooked.
- Of course the typical "hydroponic" system as BSF Hydro uses conserves water, and NASA has already experimented with hydroponics systems in space.
- Radiation in space during transit - my guess is that during the flight to Mars, the BSF would encounter more radiation than when on Mars. There have been a number of insect studies at this point by NASA, so NASA may have some ideas of how this may affect the BSF health and vitality. Fortunately, with frozen eggs, even if their overall quality is decreased, frozen eggs could be used for new stock until they reach Mars. Ideally, the eggs will be stored in a manner to significantly limit the amount of radiation they are exposed to.
- The crops grown will have woody parts, stems, etc. that the BSF will not process - so a more traditional compost system will be necessary to recapture these nutrients. Ideally, these would be mixed with the BSF processed humanure. Some other traditional compost system will be needed for any long duration stays, so this is not necessarily a problem, but is facilitated by the humanure. I suggest also taking earthworms to facilitate this composting.
- The BSF do like certain temperature and humidity ranges, but since the human enclosures on Mars will be 100% climate controlled, this should not be a problem - but something to pay attention to.
- Requires food waste (and/or humanure) - BSF will not (can not) eat woody parts of plants. No food waste means system failure. Fortunately the BSF are able to endure a dormant period of several weeks without eating if necessary.
- My assumption would be that for in-flight use, NASA would also stock the vehicle with dehydrated nutrients that could be added to the system in the event of a temporary BSF Hydro setback - enough to get them through time to nurture a new batch of eggs into larva.
- For processing humanure, it would be simple to have a 2 chamber system where only one is used for 3 months, then switch chambers for 3 months, where you would harvest the compost before starting to use the resting chamber again. The BSF will have processed the humanure within hours, so this is just time for microbial life to do processing so that it reaches the point of basically soil.
- High yield per plant crops would be required. Tomatoes, cucumbers, bell peppers, green beans, etc. are the most likely crops since single serving plants like carrots tend to be slower growing, take up more space for providing a single serving. Crops like lettuce grow quickly, but take up allot of space for their low nutrient value.
- Of course initially the explorers will take plant seeds with them, but they should also collect seeds from the plants they grow