Microgravity Testing of Vapor Motion within Tapered Channels for Spaceflight Cryogenic Propellant Management

The use of cryogenic propellants in rocket fluid transfer and storage systems create safety and operational challenges for long-duration space missions. Screened-channel liquid acquisition devices (LADs) have long been used with storable propellants to deliver vapor-free liquid during spacecraft engine restart and liquid transfer processes. The use of LADs with cryogenic fluids is problematic due to low fluid temperatures, as external heat leaks will cause vapor bubbles to form that are difficult to remove in conventional LAD designs. A tapered LAD channel has been designed to reliably remove vapor bubbles within the device without costly thrusting maneuvers by the in-space vehicle or active separation systems. Microgravity testing of this tapered LAD technology was recently completed onboard the New Shepard suborbital launch vehicle with two different simulant cryogenic fluids. An analysis was performed on the image sequence taken of the fluid motion inside of the devices. The results of this analysis indicate that these new LADs can passively expel vapor bubbles within the channel without active measures.