Early crewed missions back to the moon and on to Mars will be like 'camping
trips' in which processed food will be transported in forms that can be
stored without refrigeration for periods of time exceeding nominal mission
length. Some salad greens and vegetables may be grown on site during early
missions for dietary augmentation and to satisfy crew psychological needs.
As mission duration and crew size increase, and as available power and energy
issues are resolved, reliance upon photosynthetic organisms will have to
increase for both dietary and air-revitalization purposes. The ALS NSCORT
captures the spirit of both early and later advanced life-support scenarios
in its suite of research projects involving edible biomass production.
One such project emphasizes production of wood-rotting fungi whose fruiting
bodies are exotic, edible mushrooms. Mushrooms contribute vitamins, minerals,
and interest to the human diet. Can the hydrolytic enzymes of fungal mycelia
reduce the oxygen requirement external to the crew for breaking down biomass
that is not digestible or safe for direct human consumption by converting
it first to alternative food sources? In addressing that question, the
fungal/mushroom research project bridges solid-waste treatment and edible-biomass
production focus areas.
Fungal pretreatment also may enhance the digestibility of ligno-cellulosic
biomass by certain fresh-water fish that already have some capability
to do this by enzymatic and acid hydrolysis within their own digestive
tract. If such fish can be grown to a functional harvest size while being
fed mainly fungal-pretreated crop residues that humans cannot digest directly,
crew diets could be supplemented with protein and essential fatty acids
from an animal source. Both bridging projects of the NSCORT have potential
to demonstrate production of edible biomass while degrading recalcitrant
crop waste.
As ALS crew habitats progressively achieve higher degrees of mass closure,
photosynthetic sources of edible biomass for on-site food processing gradually
will replace food prepared on Earth. However, ALS has temporarily suspended
funding of new plant projects pending resolution of power and energy issues
surrounding crop production as the main source of food and oxygen for
human consumption. The ALS NSCORT crop-production project directly addresses
the specific issue that prevents early life-support scenarios from involving
substantial mass closure and production of crops for a mainly vegetarian
diet. Planetary surface dangers and environmental limitations preclude
reliance upon solar energy to consistently energize life support on both
Luna and Mars, which further exacerbates the operational energy dilemma.
Energetic penalties of crop quantum inefficiency as well as for heat rejection
related to traditional controlled environment crop growth and for condensation
of transpired water vapor account for the majority of energy costs in
closed systems. The NSCORT crop-production project aims to significantly
reduce these cropping penalties by taking a non-traditional approach to
light distribution requiring significantly lower electrical power input
than do traditional lighting systems.
Crop Group Leader
Cary Mitchell
Professor of Horticulture
Purdue University
Phone: 765.494.1347
e-Mail: mitchell@hort.purdue.edu
Project Lab
http://www.hort.purdue.edu/hort/research/mitchell/
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