Аннотация:—The time-dependent problem of the development of a rarefied flow in a plane channel formed
by two parallel infinite plates is considered on the basis of a kinetic model. At the initial moment of
time the gas at rest occupies half the channel and borders on a vacuum. The effect of gas deceleration
at the channel walls is studied as a function of the gas rarefaction degree under the conditions of the
diffuse reflection of molecules from the boundary. Emphasis is placed on the calculations of the time
dependence of the integral gas mass flux through the boundary separating the gas from the vacuum at the
initial moment. The deceleration of the conditional expansion wave front and the conditional front of
gas expansion into the vacuum is traced. The kinetic equation is numerically solved using a first-order
difference method.