In weightlessness, fluids do not behave anything like they do within a gravitational field or under acceleration. Fluid mechanics are complicated and messy enough on Earth, but when you can’t count on convection to transmit heat, buoyancy to separate gas bubbles, or weight to settle fluids at the bottom of tanks, entirely new cans of worms open to bedevil the engineer. Near-term plans for both SpaceX’s Starship and Blue Origin’s lunar lander architecture require in-orbit bulk transfer of cryogenic propellants to accomplish their missions. This places understanding the behaviour of fluids in space and developing means to manage them squarely on the critical path of plans to return to the Moon and send humans to Mars.
Alvaro Romero-Calvo is director of the Low-Gravity Science and Technology Laboratory and member of the Space Systems Design Laboratory at the Georgia Institute of Technology. In this presentation, he discusses fluid mechanics in space and some of the approaches (including magnets!) to designing systems for that environment.