Demonstration of charge-hold-vent (CHV) and no-vent-fill (NVF) in a simulated propellent storage tank during tank-to-tank cryogen transfer in microgravity.

The space exploration from a low earth orbit to a high earth orbit, then to Moon, Mars, and possibly asteroids and moons of other planets is one of the biggest challenges for scientists and engineers for the new millennium. The enabling of in-space cryogenic rocket engines and the Lower-Earth-Orbit (LEO) cryogenic fuel depots for these future manned and robotic space exploration missions begins with the technology development of advanced cryogenic thermal-fluid management systems for the propellant transfer line and storage tank system. One of the key thermal-fluid management operations is the chilldown and filling of the propellant storage tank in space.

Synthesis, Optical Performance Characterization, and Durability of Electrospun PTFE-PEO Materials for Space Applications.

Passive heat management is crucial in space, especially for extended missions involving protection from sunlight. Thermal coatings with desirable optical properties can drastically reduce the power consumed by active cooling systems, thereby reserving more resources for other critical systems onboard. Specifically, materials with wavelength-dependent reflectance and emittance are desirable for managing incident sunlight and self-cooling by thermal emission.

Nitrogen flow boiling and chilldown experiments in microgravity using pulse flow and low-thermally conductive coatings.

The enabling of in-space cryogenic engines and cryogenic fuel depots for future manned and robotic space exploration missions begins with technology development of advanced cryogenic fluid management systems upstream in the propellant feed system. Before single-phase liquid can flow to the engine or customer spacecraft receiver tank, the connecting transfer line must first be chilled down to cryogenic temperatures. The most direct and simplest method to quench the line is to use the cold propellant itself.

Acetone Tracer Laser-Induced Fluorescence (LIF) at 282 nm Excitation as a Diagnostic Tool in Elevated Pressure and Temperature Systems.

This paper provides new data at constant pressure, variable temperature and constant temperature, variable pressure over the range of temperature (295-750 K) and pressure (0.5-40 atm), in air and nitrogen bath gases at both constant number density and constant mole fraction needed to enable acetone laser-induced fluorescence (LIF) as a diagnostic tool in an elevated temperature and pressure environment. Results clearly indicate that the effect of elevated pressure on the temperature sensitivity of acetone LIF is negligible when the excitation wavelength is chosen near the absorption maximum, making acetone LIF ideal for measuring temperature fields in high-pressure systems.

System Validation Experiments for Obtaining Tracer Laser-Induced Fluorescence Data at Elevated Pressure and Temperature.

This paper presents a set of system validation experiments that can be used to qualify either static or flow experimental systems for gathering tracer photophysical data or conducting laser diagnostics at high pressure and temperature in order to establish design and operation limits and reduce uncertainty in data interpretation. Tests demonstrated here quantify the effect of tracer absorption at the test cell walls, stratification, photolysis, pyrolysis, adequacy of mixing and seeding, and reabsorption of laser light using acetone as the tracer and 282 nm excitation. Results show that acetone exhibits a 10% decrease in fluorescence signal over 36 000 shots at 127.

The effect of reduced gravity on cryogenic nitrogen boiling and pipe chilldown.

Manned deep space exploration will require cryogenic in-space propulsion. Yet, accurate prediction of cryogenic pipe flow boiling heat transfer is lacking, due to the absence of a cohesive reduced gravity data set covering the expected flow and thermodynamic parameter ranges needed to validate cryogenic two-phase heat transfer models. This work provides a wide range of cryogenic chilldown data aboard an aircraft flying parabolic trajectories to simulate reduced gravity.