Patent ID: 8613188
Filing Date: 2013-12-24
Classification: B64G,F03H

Abstract:
1. A microthruster for a spacecraft, comprising: a supply of pressurized gas; a pressure vessel of the microthruster having an entrance for receiving the supply of gas and defining an exit for releasing the gas to ambient conditions, the pressure vessel defining an internal flowpath between the entrance and exit, and a generally cylindrical centerbody having an aft face extending through at least a portion of the flowpath and extending into the exit so as to form a generally annular throat, the generally cylindrical centerbody defining a central axis extending along the length of the generally cylindrical centerbody, the aft face of the generally cylindrical centerbody is coplanar with the exterior portion of the nozzle adjacent to and surrounding the exit; wherein the Reynolds number (Re) through the throat is less than about one thousand when the gas is released from the pressure vessel and travels through the throat to the exit, wherein the Reynolds number (Re) is m being the neutral particle mass of the gas, n ng being the neutral gas number density of the gas, V x being the velocity component of the gas parallel to the central axis, D th being the throat diameter, and u ref being reference viscosity of the gas at 300K.