Near-Zero Gravity Cryogenic Line Chilldown Experiment in a Suborbital Reusable Launch Vehicle

The extension of human space exploration from low-Earth orbit to high-Earth orbit, then to the Moon, Mars, and possibly asteroids and moons of other planets is one of NASA’s biggest challenges. Integral to this is the effective, affordable, and reliable supply of cryogenic fluids. The efficient and safe utilization of cryogenic fluids in thermal management, power and propulsion, and life support systems of a spacecraft during space missions involves the transport, handling, and storage of these fluids in terrestrial, reduced gravity, and near zero-gravity conditions. Chilldown is the process of introducing cryogenic liquid into the cryogenic system, and allowing the hardware to cool down to several hundred degrees Kelvin below the ambient temperature. University of Florida researchers are building a line chilldown database from SRLV flight demonstrations with a duration long enough to cover the complete chilldown of a fluid transfer line or other hydraulic components. This effort is building on data collected in short-duration testing in drop towers (about 2 seconds of microgravity) and on parabolic flights (about 30 seconds of microgravity). The microgravity chilldown methodologies and engineering models are expected to have direct applications and benefits to both NASA and industry.