Abstract: In the very low Earth orbit environment, the incoming gas flow directly collides with the surfaces of spacecraft in the form of collimated hyperthermal molecular beams. The gas surface interaction property plays a decisive role in determining the aerodynamic performance of very low earth orbit vehicles as well as the gas capture efficiency of the intake facility. This study employs molecular dynamics simulations to investigate the microscopic scattering processes of collimated gas molecular beams with amorphous solid surface. The momentum and energy accommodation coefficients together with the scattering angular distributions of gas molecules are obtained under various conditions of incident speed and angle. The results indicate that the gas-surface interaction accommodation coefficients vary significantly with the gas incident angle and frequently exceed the conventional range of 0, 1, which leads the failure of the traditional phenomenological gas surface interaction models in the hyperthermal flow applications. In contrast, the new physical based gas surface interaction model can accurately reproduce the reflected velocity distribution function of gas molecules, as well as the variation patterns of the momentum/energy accommodation coefficients and scattering angular distributions with respect to the gas incident speed and angle, which demonstrates superior accuracy and adaptability in the hyperthermal flow applications. Mechanism analysis reveals that the energy conversion between the different velocity components of gas molecules plays a key role in influencing the scattering characteristics at the gas-solid interface. To quantify this effect, this study proposes a new energy conversion coefficient to effectively characterize the efficiency of energy conversion between the different velocity components under varying gas incident angle and surface roughness conditions. These findings provide critical physical insights for developing high-fidelity boundary conditions in rarefied gas dynamics, which are of great significance for the aerodynamic design and performance optimization of advanced aerospace vehicles operating in the very low Earth orbit.