519: Retaining Water Ice in Regolith at Vacuum

Funded by NASA, our project goal was to design a test fixture that would mimic the space environment on the Moon’s surface. Space is a vacuum, where pressure is zero and temperature is below zero in the Celsius degree range. Regolith, which is soil on the Moon’s surface, contains 95% dirt and 5% water (as ice). NASA wants to extract hydrogen and oxygen from the water in the regolith and use it to make spacecraft fuel. This would allow spacecraft to refuel while in space and increase the travel duration.

Earth is warmer than its Moon, so the test box first needed to cool down the regolith. To do this, liquid nitrogen slowly dripped onto the soil and expanded into a gas. This expansion occurs because the surrounding temperature is warmer, so the liquid nitrogen evaporates. Then the nitrogen gas flowed through the soil. Liquid nitrogen also flowed through two plates to conduct heat from the sides.

We used temperature sensors to measure the temperature at various locations throughout the soil. To achieve water content, we evenly mixed water with sand and used moisture sensors at several places to measure how much water was still present in the dirt. This was important because the water would also evaporate out of the dirt. To reach vacuum pressure, we placed the test box inside NASA’s vacuum chamber and pumped it down. 

The project was important because it allowed NASA to perform tests on the regolith with realistic conditions to achieve the most accurate data possible. This will help NASA develop and improve technology for space travel to the moon, and space exploration to other planets in the future.