US 11,878,818 B2
Tunable water-based microthruster devices and methods
Steven M. Pugia, Lafayette, IN (US); Anthony G. Cofer, Lafayette, IN (US); and Alina Alexeenko, West Lafayette, IN (US)
Assigned to Purdue Research Foundation, West Lafayette, IN (US)
Filed by Purdue Research Foundation, West Lafayette, IN (US)
Filed on Sep. 7, 2021, as Appl. No. 17/447,061.
Prior Publication US 2023/0070933 A1, Mar. 9, 2023
Int. Cl. B64G 1/40 (2006.01); B64G 1/26 (2006.01); B64G 1/24 (2006.01)
CPC B64G 1/409 (2013.01) [B64G 1/244 (2019.05); B64G 1/26 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method of manufacturing a microthruster for a spacecraft, comprising:
forming a nozzle throat channel for a micronozzle in a first layer or a second layer;
forming a water reservoir channel in the first layer or the second layer, the water reservoir channel defined by a reservoir lower wall and a side surface;
forming a water supply port, the water supply port having a central axis;
forming a heating element, wherein the heating element is spaced at least 1 μm from the nozzle throat;
bonding the first layer and the second layer to one another, said bonding forming a nozzle throat between the first layer and the second layer for ejecting water from the microthruster, and said bonding forming a water reservoir between the first layer and the second layer, wherein the water reservoir is bounded by a reservoir upper wall and the reservoir lower wall, the water reservoir being in fluidic communication with the nozzle throat,
wherein the heating element partially covers the reservoir upper wall or the reservoir lower wall, the heating element is configured to contact water within the water reservoir, the heating element is positioned along the reservoir upper wall or the reservoir lower wall, and the central axis of the water supply port intersects the heating element.
 
9. A microthruster for a spacecraft, comprising:
a water supply port having a central axis;
a water reservoir bounded by a reservoir upper wall and a reservoir lower wall; and
a nozzle throat in fluid communication with the water reservoir, the nozzle throat defining a cross sectional area equal to or less than 20 square micrometers (20 μm2); and
a heating element in thermal communication with the water reservoir, wherein the reservoir upper wall or the reservoir lower wall is partially covered by the heating element, the heating element is configured to contact water within the water reservoir, the heating element is positioned along the reservoir upper wall or the reservoir lower wall, the central axis of the water supply port intersects the heating element, the heating element is spaced at least 1 μm from the nozzle throat, and the heating element is configured and adapted to heat water in the water reservoir, increase the pressure within the water reservoir, and cause the water to be expelled from the nozzle throat.