Implementing multifunctional bioregenerative technologies may provide mission carbon loop closure while simultaneously addressing multiple environmental control and life support system requirements. This paper proposes using water-based algal medium for thermal control of the spacecraft cabin, while taking advantage of the algae's photosynthetic activity for air revitalization. Consequently, this could expose the algal culture to transient thermal environments fluctuating between +4 °C and +30 °C, in the span of minutes, reflecting the operation of the International Space Station (ISS) internal thermal control and cabin system. This paper presents an initial investigation of the metabolic response of Chlorella vulgaris to transient environmental temperatures, reflecting temperature ranges and cycling frequency of the ISS cooling loop (+9 °C to +27 °C, 30 min). The constant 19 °C control represented the time-averaged temperature of the cycled condition. Growth and acclimation were observed in both tested conditions through pH, dissolved oxygen, optical density, and photosynthetic quantum yield measurements. However, there was significant reduction in the oxygen production rate, measured pH, and optical density for the cycled temperature condition when compared to the control (cycled temperature = 0.95 gO₂ L⁻¹ d⁻¹, pH = 6.75, OD = 0.05; control = 1.17 gO₂ L⁻¹ d⁻¹, pH = 8.20, OD = 0.08). No significant reduction in growth rate or photosynthetic quantum yield were recorded between the two tested conditions. Growth rate of the cycled temperature condition reflected those of psychrotolerant algae, suggesting some amount of culture acclimation to the rapidly dynamic environment. Results suggest that while C. vulgaris was viable within the tested temperature environment reflecting the ISS thermal control loop and cabin, there was a measurable reduction in the oxygen production rate.

实施多功能生物再生技术可以提供任务碳循环闭合，同时满足多种环境控制和生命支持系统要求。本文提出使用水基藻类介质对航天器舱进行热控制，同时利用藻类的光合作用活动使空气恢复活力。因此，这可能会在几分钟内将藻类培养物暴露于在 +4°C 和 +30°C 之间波动的瞬态热环境中，这反映了国际空间站 (ISS) 内部热控制和机舱系统的运行。本文对普通小球藻的代谢反应进行了初步研究。瞬态环境温度，反映 ISS 冷却回路的温度范围和循环频率（+9 °C 至 +27 °C，30 分钟）。恒定的 19 °C 控制代表循环条件的时间平均温度。通过 pH、溶解氧、光密度和光合量子产率测量，在两种测试条件下都观察到生长和驯化。然而，与对照（循环温度 = 0.95 gO ₂ L ^-1 d ^-1，pH = 6.75，OD = 0.05；对照 = 1.17 gO ₂ L ^-1 d ^-1，pH = 8.20，OD = 0.08）。在两种测试条件之间没有记录到生长速率或光合量子产率的显着降低。循环温度条件的生长速度反映了耐冷藻类的生长速度，表明一定程度的培养适应了快速动态的环境。结果表明，虽然C. vulgaris在反映国际空间站热控制回路和机舱的测试温度环境中是可行的，但氧气产生率却出现了可测量的降低。