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Normalized, Weighted Rankings of Hybrid Leafy Asian Green Grown Under Varying CO2 and Radiation Treatments_
| 500 N | 1000 N | 1250 N | 1500 N | 500 I | 1000 I | 1250 I | 1500 I | |
|---|---|---|---|---|---|---|---|---|
| Germination | 1.43 | 0.00 | 1.50 | 1.50 | 1.50 | 0.74 | 1.50 | 1.12 |
| Edible Biomass | 0.11 | 1.63 | 2.00 | 0.23 | 0.05 | 0.21 | 1.86 | 0.00 |
| Volume | 1.40 | 0.36 | 0.44 | 0.44 | 1.50 | 1.46 | 0.00 | 1.37 |
| K | 0.00 | 0.22 | 2.00 | 1.93 | 0.01 | 1.92 | 1.15 | 1.42 |
| Mg | 0.32 | 1.50 | 1.21 | 1.35 | 0.26 | 1.50 | 1.24 | 0.00 |
| Ca | 1.00 | 0.55 | 0.00 | 0.17 | 0.97 | 0.12 | 0.03 | 0.48 |
| Fe | 0.00 | 1.21 | 0.95 | 0.65 | 0.46 | 1.50 | 0.49 | 0.03 |
| NO3− | n/a | 0.00 | 0.45 | 0.00 | n/a | 0.62 | 0.95 | 1.40 |
| Sum (Excl. NO3−) | 4.26 | 5.47 | 8.09 | 6.27 | 4.76 | 7.45 | 6.27 | 4.42 |
| Sum (Incl. NO3−) | n/a | 5.47 | 8.54 | 6.27 | n/a | 8.07 | 7.22 | 5.83 |
| Ranking (Excl. NO3−) | 8 | 5 | 1 | 3 | 6 | 2 | 3 | 7 |
| Ranking (Incl. NO3−) | 6 | 1 | 4 | 2 | 3 | 5 |
Experimental Design outlining control and experimental variables_
| Conditions | Control | Experimental |
|---|---|---|
| Photoperiod | 12/12 | 12/12 |
| Seeds | Non-irradiated | Irradiated |
| Light Intensity | 230 μmol·m−2·s−1 LED (R25G0B25W180) | 305 μmol·m−2·s−1 LED (R25G0B25W255) |
| CO2 (Light Intensity Trials) | ~ 500 ppm | ~ 500 ppm |
| CO2 (CO2 Trials) | ~ 500 ppm | Exp. 1: ~1000 ppm (+ 2500g dry ice) |
| Exp. 2: ~1250 ppm (+ 5000g dry ice) | ||
| Exp. 3: ~1500 ppm (+ 7500g dry ice) |
Spaceflight Suitability Matrix_
| Traits | Weight | Factor (Category) | Justification with References |
|---|---|---|---|
| Germination (%) | 1.5 | Plant growth (Establishment) | Ensures successful crop establishment under variable spaceflight conditions (Massa et al., 2015). |
| Edible Biomass (g) | 2 | Plant Growth (Yield) | Maximizes harvestable mass per unit area in bioregenerative systems (Darby et al., 2024; Massa et al., 2015). |
| Plant Volume (cm3) | 1.5 (inverted) | Plant Growth (Morphology) | Compact morphology supports limited-volume growth in spacecraft systems (Massa et al., 2015). |
| K (mg/g) | 2 | Nutritional (beneficial) | Essential for nerve function and cardiovascular regulation under microgravity (Darby et al., 2024). |
| Mg (mg/g) | 1.5 | Nutritional (beneficial) | Supports enzyme activity and chlorophyll production; however, this support may decline under elevated CO2 levels (Massa et al., 2015). |
| Ca (mg/g) | 1 | Nutritional (beneficial) | Protects bone health, which is compromised in microgravity (Darby et al., 2024; Massa et al., 2015). |
| Fe (μg/g) | 1.5 (inverted) | Nutritional (risk) | Excess Fe contributes to the risk of oxidative stress and bone loss (Darby et al., 2024; Smith & Zwart, 2020). |
| Nitrate (NO3−) (mg/g) | 1.5 (inverted) | Nutritional (risk) | High nitrate intake may form carcinogenic nitrosamines in space diets (Darby et al., 2024; Karwowska & Kononiuk, 2020). |
Summary of CO2 estimation parameters and modeled internal concentrations for each experimental chamber_
| Trial | Dry Ice (g) | Temp (°C) | RH (%) | CO2 (ppm) |
|---|---|---|---|---|
| Exp. 1 | 7725.4 | 16.3 ± 0.7 | 36.2 ± 1.2 | 1490 ± 188 |
| Exp. 2 | 4801.3 | 17.8 ± 0.5 | 38.3 ± 0.9 | 1192 ± 68 |
| Exp. 3 | 3997.0 | 20.3 ± 0.8 | 37.0 ± 1.0 | 1160 ± 145 |
Nutrient Ranking Matrix for Hybrid Leafy Asian Green Plant Leaf Tissue under Varying CO2 and Radiation Treatments_
| Treatment | K | Mg | Ca | Fe | Sum | Ranking |
|---|---|---|---|---|---|---|
| 500 ppm C02 non-IRR | 0.00 | 0.32 | 1.00 | 0.00 | 1.32 | 8 |
| 1000 ppm C02 non-IRR | 1.79 | 0.00 | 0.45 | 0.21 | 2.45 | 5 |
| 1250 ppm C02 non-IRR | 2.00 | 1.21 | 0.00 | 0.95 | 4.16 | 2 |
| 1500 ppm C02 non-IRR | 1.93 | 1.35 | 0.17 | 0.65 | 4.10 | 3 |
| 500 ppm C02 IRR | 0.01 | 0.27 | 0.97 | 0.46 | 1.71 | 7 |
| 1000 ppm C02 IRR | 1.92 | 1.50 | 0.12 | 1.50 | 5.04 | 1 |
| 1250 ppm C02 IRR | 1.15 | 1.24 | 0.03 | 0.49 | 2.91 | 4 |
| 1500 ppm C02 IRR | 1.42 | 0.00 | 0.48 | 0.03 | 1.93 | 6 |
Normalized, Weighted Rankings of Red Romaine Lettuce Grown Under Different Light Intensity and Radiation Treatments_
| 230 PPFD NonIRR | 230 PPFD IRR | 305 PPFD NonIRR | 305 PPFD IRR | |
|---|---|---|---|---|
| Germination ×1.5 | 0.17 | 1.50 | 0.00 | 0.00 |
| Edible Biomass ×2 | 0.00 | 0.39 | 1.27 | 2.00 |
| Volume ×1.5 (inverted) | 1.26 | 1.06 | 1.50 | 0.00 |
| K ×2 | 0.55 | 2.00 | 0.00 | 0.61 |
| Mg ×1.5 | 0.75 | 1.50 | 0.75 | 0.00 |
| Ca ×1 | 0.00 | 1.00 | 1.00 | 0.75 |
| Fe ×1.5 (inverted) | 1.49 | 1.50 | 0.00 | 1.34 |
| NO3− ×1.5 (Inverted) | 1.50 | 1.00 | 1.38 | 0.00 |
| Composite score (sum) | 5.71 | 9.95 | 5.89 | 4.70 |
| Ranking | 3 | 1 | 2 | 4 |
Cultivars Tested in This Study_ Seed selections were based on the Growing Beyond Earth (GBE) seed list from 2015–2022 and research protocol 2023_ Cultivars labeled with “IR” indicate neutron-irradiated seed groups_
| Species | Common name | Cultivar /Variety | Manufacturer (GBE ID) |
|---|---|---|---|
| Lactuca sativa | Red Romaine lettuce | ‘Outredgeous’ | Johnny's Seeds (GBE 1, GBE 1IR) |
| Brassica rapa var. nipposinica | Mizuna | ‘Mizuna’ | Johnny's Seeds (GBE 24, GBE24IR) |
| Brassica rapa var. chinensis | Pak Choi | ‘Extra dwarf’ | Kitazawa Seeds Co. (GBE 56, GBE56IR) |
| Brassica carinata | Mustard (JS) | ‘Amara’ | Johnny's Seeds (GBE 113, GBE113IR) |
| Brassica rapa var. chinensis | Hybrid Leafy Asian Green/Pak Choi | ‘Rosie F1’ | Johnny's Seeds (GBE 120, GBE120IR) |
| Brassica juncea | Mustard Green | ‘Scarlet Frills’ | Johnny's Seeds (GBE 195, GBE195IR) |
| Brassica juncea | Mustard Green | ‘Garnet Giant’ | Johnny's Seeds (GBE 196, GBE196IR) |
Environmental Data: Average environmental growth conditions measured across all trials_ Chamber temperature (Temp °C), relative humidity (RH, %), total water usage (Water, mL), and external CO2 (ppm) were recorded on weekdays; values are reported as mean ± standard error of the mean (SEM)_
| Trials | Temp (°C) | RH (%) | Water (mL) | CO2 (ppm) |
|---|---|---|---|---|
| 86 GBE Schools (6 Testing Cultivars) | 23.8 ± 0.4 | 42.9 ± 1.3 | 5502.7 ± 339.9 | N/A |
| Light Intensity Trial: Control | 21.9 ± 0.2 | 35.2 ± 2.0 | 4708.3 ± 809.3 | 505.6 ± 6.1 |
| Light Intensity Trial: Exp. | 26.4 ± 0.4 | 28.0 ± 1.2 | 4408.3 ± 391.4 | 517.8 ± 16.0 |
| CO2 Trial: Control | 23.8 ± 0.2 | 33.6 ± 1.9 | 4700 ± 195.8 | 500 ± 20.0 |
| CO2 Trial: Exp. 1 | 16.3 ± 0.7 | 36.2 ± 1.2 | 9700.0 | 1135.4 ± 39.4 |
| CO2 Trial: Exp. 2 | 17.8 ± 0.5 | 38.3 ± 0.9 | 6450.0 | 1215.0 |
| CO2 Trial: Exp. 3 | 20.3 ± 0.8 | 37.0 ± 1.0 | 5000.0 | 1215.0 |