# US 10,308,377 B2 · Propellant tank and loading for electrospray thruster > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,377 B2 - Document ID: US10308377B2 - Status: Granted - Kind: B2 - Application number: 14/681,264 - Filed: 2015-04-08 - Published: 2016-10-13 - Granted: 2019-06-04 - Earliest claimed: 2015-04-08 - Assignees: Massachusetts Institute of Technology - Applicants: Massachusetts Institute of Technology - Inventors: Paulo C. Lozano; Corey Patrick Fucetola - Web page: https://patentgrep.com/patent/US10308377B2 ## CPC - F03H 1/0012: {Means for supplying the propellant} - B64G 1/413: {Ion or plasma engines} - F03H: PRODUCING A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR (from combustion products F02K) - B64G: COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR ## Abstract Methods and apparatus of adding propellant to a thruster assembly are described. A first end of a beaker is disposed in an opening of the tank, where the beaker contains propellant and the first end of the beaker includes a breakaway bottom. The thruster assembly and beaker are placed in a first environment, where the first environment is substantially a vacuum and/or an environment composed substantially of gases that can be absorbed by the propellant. A plunger in the beaker is depressed to cause the breakaway bottom of the beaker to break and the propellant to flow into the tank of the thruster assembly. The thruster assembly is removed from the first environment and the beaker is removed from the opening. A cap is added to complete the assembly. The assembly contains a vent to allow gases to escape the interior of the tank. ## Claims ### Claim 1 A method of adding propellant to a thruster assembly, wherein the thruster assembly comprises a tank comprising a first opening and a second opening; a porous emitter array disposed over the first opening; a porous reservoir disposed within an interior of the tank, wherein the porous reservoir is in fluid communication with the porous emitter array through the first opening, the method comprising: disposing a first end of a beaker in the second opening of the tank, wherein the beaker contains the propellant, and wherein the first end of the beaker comprises a breakaway bottom; placing the thruster assembly and beaker in a first environment, wherein the first environment is at least one of a vacuum or an environment composed of gases that can be absorbed by the propellant; depressing a plunger in the beaker to cause the breakaway bottom of the beaker to break and cause the propellant to flow into the tank; removing the thruster assembly from the first environment; and removing the beaker from the second opening. ### Claim 2 (depends on 1) The method of claim 1, further comprising: affixing a cap to the second opening of the tank. ### Claim 3 (depends on 2) The method of claim 2, wherein the cap comprises a porous membrane that permits gas to pass therethrough and blocks the propellant from passing therethrough. ### Claim 4 (depends on 3) The method of claim 3, wherein first pores of the porous membrane are larger than second pores of the porous emitter array. ### Claim 5 (depends on 3) The method of claim 3, wherein the porous membrane is made from at least one of polytetrafluoroethylene, PEEK and polyethylene. ### Claim 6 (depends on 1) The method of claim 1, wherein the tank comprises a porous membrane that permits gas to pass therethrough and blocks the propellant from passing therethrough. ### Claim 7 (depends on 1) The method of claim 1, further comprising: extending the plunger into the tank to compress the porous reservoir, thereby at least partially submerging the porous reservoir in the propellant; and retracting the plunger from the tank. ### Claim 8 An assembly comprising: a thruster assembly comprising: a tank comprising a first opening and a second opening; a porous emitter array disposed over the first opening; and a porous reservoir disposed within an interior of the tank, wherein the porous reservoir is in fluid communication with the porous emitter array through the first opening; a beaker having a first end comprising a breakaway bottom, wherein the first end of the beaker is disposed in the second opening, wherein prior to the breakaway bottom breaking, liquid propellant is retained in the beaker, and wherein when the breakaway bottom breaks, the liquid propellant flows into the tank. ### Claim 9 (depends on 8) The assembly of claim 8, wherein the beaker is filled with the liquid propellant, the assembly further comprising: a plunger disposed in the beaker to cause the breakaway bottom of the beaker to break and cause the liquid propellant to flow into the tank when depressed. ### Claim 10 (depends on 8) The assembly of claim 8, wherein the beaker is selectively removable from the second opening. ### Claim 11 (depends on 8) The assembly of claim 8, wherein the breakaway bottom is constructed and arranged such that when the breakaway bottom is broken, the beaker is removable from the second opening. ### Claim 12 (depends on 8) The assembly of claim 8, wherein the beaker is filled with liquid propellant disposed between the second opening and a plunger, and wherein the plunger is depressible toward the second opening. ### Claim 13 (depends on 8) The assembly of claim 8, wherein the porous reservoir is adapted to transport the liquid propellant to the porous emitter array through capillarity. ### Claim 14 A thruster assembly comprising: a tank comprising a first opening and a vent; a porous emitter array disposed over the first opening; a porous reservoir disposed within an interior of the tank, wherein the porous reservoir is in fluid communication with the porous emitter array through the first opening; and a liquid propellant disposed within the porous reservoir, wherein the vent comprises a porous membrane that permits gas to pass therethrough and blocks the liquid propellant from passing therethrough. ### Claim 15 (depends on 14) The thruster assembly of claim 14, wherein first pores of the porous membrane are larger than second pores of the porous emitter array. ### Claim 16 (depends on 14) The thruster assembly of claim 14, wherein the porous membrane is made from at least one of polytetrafluoroethylene, PEEK and polyethylene. ### Claim 17 A thruster assembly comprising: a tank comprising a first opening, wherein the tank is formed from one or more semi-permeable materials that permits gas to pass therethrough and blocks a liquid propellant from passing therethrough; a porous emitter array disposed over the first opening; a porous reservoir disposed within an interior of the tank, wherein the porous reservoir is in fluid communication with the porous emitter array through the first opening; and the liquid propellant disposed within the porous reservoir. ### Claim 18 (depends on 17) The thruster assembly of claim 17, wherein first pores of the tank are larger than second pores of the porous emitter array. ### Claim 19 (depends on 17) The thruster assembly of claim 17, wherein the tank is formed from at least one of porous polytetrafluoroethylene (PTFE) and hydrophobic solgel. ### Claim 20 (depends on 17) The thruster assembly of claim 17, further comprising: a propellant container disposed within the interior of the tank, wherein the propellant container is formed from another one or more semi-permeable materials that permit gas to pass therethrough and block the liquid propellant from passing therethrough; and wherein the porous reservoir is disposed within an interior of the propellant container. ### Claim 21 (depends on 20) The thruster assembly of claim 20, wherein first pores of the propellant container are larger than second pores of the porous emitter array. ### Claim 22 (depends on 21) The thruster assembly of claim 21, wherein the propellant container is formed from at least one of porous polytetrafluoroethylene and hydrophobic solgel. ### Claim 23 (depends on 12) The assembly of claim 12, wherein depressing the plunger toward the second opening causes the liquid propellant to flow into the tank.