Bioregenerative Life Support for Humans in Space

R M Wheeler

NASA NTRS · 20205008786

Bioregenerative Life Support for Humans in Space

Abstract

To date, human life support in space has been achieved through physico-chemical methods along with stowage and resupply. But biological approaches could be used as well, such as growing plants (crops) to produce oxygen and food, while removing carbon dioxide generated by the humans. The plants and their associated microbiome could also be used to help recycle wastewater. These so-called bioregenerative approaches for human life support become more favorable as mission durations and distances increase. For example, a baseline mission to Mars would require about 3 years, including transit time to and from Mars, and living on the surface. For these and longer durations missions, life support approaches will need to be highly closed and sustainable, with minimal mass and power requirements. Based on testing by NASA and other space agencies around the world, about 20-25 m2 of crops could provide the oxygen needs for one human, while about 50 m2 of crops could provide the food(dietary calories) for one person. But this is dependent on lighting provided to the crops and optimizing the agricultural practices. In many ways, these goals for space agriculture have similar challenges to sustainable agriculture and living on Earth. The talk will review some of NASA’s research on biological life support and its potential for future space exploration.

Explore related subjects

Life Support Crop Food

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

R M Wheeler. Bioregenerative Life Support for Humans in Space. https://ntrs.nasa.gov/citations/20205008786

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

NASA NTRS2019

Dwarf Tomato and Dwarf Pepper as Potential Space Crops

Crops for space life support systems and in particular, early supplemental food production systems must be able to fit into the confined volume of space craft or space habitats. For example, spaceflight plant chambers such as Svet, Lada, Astroculture, BPS, and Veggie provided approximately 15-40 cm of growing height for plant shoots. Six cultivars each of tomato and pepper were selected for initial study based on their advertised dwarf growth and high yields. Plants were grown in 10-cm pots with solid potting medium and controlled-release fertilizer to simulate the rooting constraints that might be faced in space environments. Lighting was provided by fluorescent lamps (~300 umol m(exp -1) s(exp -1) and a 16 h light / 8 h dark photoperiod. Cultivars were then down selected to three each for pepper (cvs. Red Skin, Pompeii, and Fruit Basket) and tomato (cvs. Red Robin, Mohamed, and Sweet n' Neat). In all cases (pepper and tomato), the plants grew to an approximate height of 20 cm and produced between 200 and 300 g fruit fresh mass per plant. In previous hydroponic studies with unrestricted root growth, Fruit Basket pepper and Red Robin tomato produced much larger plants with taller shoots. The findings suggest that high value, nutritious crops like tomato and pepper could be grown within small volumes of space habitats, but horticultural issues, such as rooting volume could be important in controlling plant size.

Life Support↗

NASA NTRS2018

Solid State Air Purification System

Life support systems in spacecraft are designed to provide a safe, habitable environment for the astronauts, and one of the most significant challenges is managing acceptable air quality. Carbon dioxide (CO2) is respired normally by humans at concentrations that are toxic if inhaled directly, and as a result cabin air must be tightly managed. The Carbon Dioxide Removal Assembly (CDRA) currently on board the ISS is the best functioning technology for manned space cabins, but has two significant drawbacks:1. The CDRA requires that air be dried prior to CO2 capture, and this costs energy _ in fact, the system spends 4X more energy drying the air than in actually capturing and releasing carbon dioxide. 2. The CDRA works in batch mode, while downstream CO2 processing systems require a continuous stream of CO2. This adds unnecessary complexity, as well as a second parasitic energy loss.An ideal system would process CO2 continuously without any need for drying of the air, and without any moving parts. Such a system would require a fraction of the size and weight of the CDRA while dropping the cost of CO2 capture by 5X or more. Such a technology would be enabling for future long term manned flight missions, such as a mission to Mars. eSionic is developing a new electrochemical membrane technology using its patented innovations in electrolyte materials. In Phase I of this program eSionic has demonstrated continuous gas separation using only electricity to drive the separation, with no moving parts or pressure drops. In Phase II, eSionic will demonstrate long-term operation of the membranes consistent with the needs of NASA for this development program.

Life Support↗

NASA NTRS2017

Space Pomology: Dwarf Plums for Fresh Food Production

Recently, USDA ARS researchers genetically modified plums for rapid breeding work and noticed the plants could flower and develop fruit rapidly on relatively small plants. We have tested several of these genetically modified (GM) plums in plant chambers to assess their potential as a space crop. We have been able to clone these genetic lines using cuttings that are rooted using growth regulating compounds. Results showed that the GM plums indeed flower and fruit on small plants in controlled environments similar to what might be used in space, but they require cross-pollination with pollen from a standard plum. Analysis of stomatal conductance and leaf transpiration showed that water use went up in the light period, as expected, and but that GM types typically showed higher conductance than a standard plum. Analysis of tissue showed that fruit could be a good source of potassium and phenolic compounds, which could be beneficial as a bone loss countermeasure (Smith et al., 2014). These findings are all promising for using dwarf GM plums as a supplemental food for space, but further horticultural testing is needed before they are ready.

Life Support↗