Demonstration of a Low Resource Lyophilizer Prototype for Spaceflight Applications

A way to investigate the possibility of extraterrestrial life on Jupiter’s moon Europa is to search for amino acids inside the surface ice using a Nuclear Magnetic Resonance (NMR) spectrometer. Any potential amino acids inside the ice sample must be concentrated in order to perform an NMR analysis given today’s state-of-the-art NMR sensitivity. One way to increase the concentration without damaging the sample is to remove the water through sublimation inside a lyophilizer, which is accomplished by reducing the temperature and pressure inside the lyophilizer below the triple point of water (0.01 °C/ 6 hPa). Conventional lyophilizers are typically equipped with a power-intensive vacuum pump and cooling unit. To reduce the consumed resources for a lander-mission on Europa’s surface, a spaceflight lyophilizer is proposed to use the in-situ available resources of space vacuum and cold temperatures, in place of a pump and cooling unit. The feasibility of such a low resource lyophilizer was investigated and demonstrated using a prototype tested under relevant and realistic environmental conditions. During the testing, an operational end-of-lyophilisation criteria was derived as well as the influences of temperature, pressure, and freezing rate on sublimation. The proposed low resource lyophilizer is scaled to freeze dry a 5 ml sample under 5 hours with a power consumption below 5 Watts.