Researchers report water behavior study under lunar gravity in Microgravity Science and Technology

In Feb. 2025, Hasenstein’s experiment flew on a Blue Origin suborbital rocket aboard a New Shepard 29 flight; after capsule separation the vehicle experienced about two minutes of weightlessness (free fall) before post‑flight analysis of the mixtures.

Inside the capsule was a 3D‑printed housing containing 18 fluid‑filled test cavities, an Arducam camera and LED backlight. The cavities held deionized water tinted yellow, a glycerol solution at 30 % concentration tinted blue, and a saline solution at 0.8 % concentration tinted red, with wall orientations set to vertical, 15 degrees and 20 degrees.

Researchers simulated lunar gravity by using the New Shepard 29 mission in Feb. 2025. After booster separation the capsule fired reaction‑control thrusters and rotated at about 11 revolutions per minute, producing about 1.76 m/s² of acceleration for around two minutes.

Under lunar gravity the meniscus—the curved surface of a liquid in a container—appeared more rounded than the flatter profile seen in Earth gravity. After the flight researchers analyzed the recorded images with hydrodynamic equations to calculate surface tension, capillary length—the height liquid rises in a narrow tube due to capillary action—and related parameters.

Lower gravity allowed thicker liquid films to cling to the cavity walls, producing higher liquid columns than we would expect under Earth gravity. The glycerol solution wetted surfaces better than water or saline.

Measured surface tension and capillary length—the height liquid rises in a narrow tube due to capillary action—were smaller than textbook theoretical values. When the researchers applied the findings to actual lunar regolith, the top layer appeared dry and hydrophobic while deeper larger grains create drainage paths that can lead to stagnant water pools risking root oxygen deprivation.

The study found that water does not flow as freely under reduced gravity because of increased surface tension. This result indicates that irrigation system designs for lunar habitats must consider how water moves and interacts with surfaces under reduced gravity.

Researchers regard grasping how water behaves under low gravity as essential for designing irrigation and life‑support systems for Artemis lunar bases, as the Moon’s gravity is roughly one‑sixth of Earth’s. A six‑person crew would need roughly 650 square meters of growing area to support a lunar base, according to crop‑production estimates.

Karl Hasenstein, from the University of Louisiana at Lafayette, has more than three decades of experience studying plant growth in space, including experiments conducted on the International Space Station; John Kiss from the Florida Institute of Technology and Christopher McKay from NASA’s Ames Research Center co‑authored the study. The results appeared in the peer‑reviewed journal Microgravity Science and Technology.