Measurements of the reduced force coefficients for H-2, N-2, CO, and CO2 incident upon a solar panel array material, SiO2-coated Kapton, Kapton, and Z-93-coated Al

摘要

The reduced force coefficients were measured for H-2, N-2, CO, and CO2 incident upon a solar panel array material, SiO2-coated Kapton, Kapton, and Z-93-coated Al. The coefficients were determined by measuring both the magnitude and direction of the force exerted on the surfaces by molecular beams of the gases. Measurements were made at angles of incidence of 0 degrees, 25 degrees, 50 degrees, 75 degrees: and 85 degrees. The forces were measured using a torsion balance with the surfaces mounted on the end of the lever arm. The absolute flux densities of the molecular beams were measured using a second torsion balance with a beam stop mounted on the lever arm that nullified the force of the scattered molecules. Flux measurements were also made using the effusive method. Standard time-of-flight techniques were used to determine the flux-weighted average velocities of the molecular beams. These velocities ranged from 1670 to 4620 m/s. The overall uncertainty in the reduced force coefficient measurements was estimated to be less than +/-10%. These measurements were used to obtain the magnitude and direction of the flux-weighted average velocity of the scattered molecules, and also the flux-weighted translational kinetic energy of the scattered molecules. Analysis of this information provided insight into the microscopic details of the gas-surface interaction potential energy surface. [References: 32]