# US 11,305,895 B1 · Self-preserved amphibious landing of space hardware > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,895 B1 - Document ID: US11305895B1 - Status: Granted - Kind: B1 - Application number: 16/800,004 - Filed: 2020-02-25 - Granted: 2022-04-19 - Earliest claimed: 2018-02-21 - Assignees: United Launch Alliance, L.L.C. - Applicants: United Launch Alliance, L.L.C. - Inventors: Brendan M. Coyne; James Lampariello; Daniel A. Wehrwein - Web page: https://patentgrep.com/patent/US11305895B1 ## CPC - B64G 1/623: {Retarding devices, e.g. retrorockets} - B64G 1/006: {Reusable launch rockets or boosters} - B64G 1/401: {Liquid propellant rocket engines (Ion or plasma engines B64G1/413; Arcjets and other resistojets B64G1/415)} - B64G 1/402: {Propellant tanks; Feeding propellants} - B64G: COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR ## Abstract A method for preserving and recovering the main engine of the first stage of a multistage launch vehicle involves utilizing a portion of a first stage propellant tank together with a parachute and a deployed buoyancy device to float the engine in a body of water until the engine can be recovered. Controlled explosions remove portions of the propellant tank to permit it to stabilize the position of the engine relative to the water following splash down. ## Claims ### Claim 1 A method for returning a launch vehicle main engine to earth, comprising: launching a launch vehicle from a launch site, the launch vehicle having a first stage and a second stage, the first stage comprising: a first end; a second end; a main engine proximate the second end; a fuselage; and a propellant tank positioned within the fuselage, the propellant tank having a central section, a first closed end, and a second closed end; terminating operation of the main engine; separating the first stage from the second stage; deploying at least one parachute from the first stage; causing the first stage to separate into at least two sections, wherein a first section includes the main engine, a portion of the fuselage, and a portion of the propellant tank comprising the central section and the first closed end, and wherein a second section includes an end portion of the propellant tank comprising the second closed end, wherein the at least one parachute is connected to the first section; forming a plurality of apertures extending through the portion of the fuselage of the first section and the portion of the propellant tank remaining with the first section; and landing the first section of the first stage including the main engine in a body of water. ### Claim 2 (depends on 1) The method of claim 1 wherein the propellant tank comprises a main body portion, a first end portion affixed to one end of the main body proximate the engine and a second end portion fixed to the opposite end of the main body, and wherein causing a portion of the first stage including at least a portion of a propellant tank to separate from the remainder of the first stage comprises separating the second end portion of the propellant tank from the main body. ### Claim 3 (depends on 2) The method of claim 2, wherein the plurality of apertures is formed proximate the location where the main body of the propellant tank is joined to the first dome portion. ### Claim 4 (depends on 2) The method of claim 2, wherein the plurality of apertures is formed before the first stage is separated into at least two sections. ### Claim 5 (depends on 1) The method of claim 1, wherein deploying a buoyancy device comprises inflating a buoyancy device. ### Claim 6 (depends on 1) The method of claim 1, wherein deploying the at least one parachute orients the first stage such that the second end of the first stage is farther from the earth than is the first end of the first stage. ### Claim 7 (depends on 1) The method of claim 1, wherein the parachute is at least one parafoil. ### Claim 8 (depends on 1) The method of claim 1, further comprising tracking the location of the first section of the first stage. ### Claim 9 (depends on 8) The method of claim 8, further comprising recovering the main engine. ### Claim 10 (depends on 1) The method of claim 1, further comprising deploying a cover over the main engine. ### Claim 11 (depends on 1) The method of claim 1, further comprising at least one booster rocket associated with the first stage, separating the at least one booster rocket from the first stage, and deploying at least one parachute associated with the at least one booster rocket. ### Claim 12 A method for returning a launch vehicle engine to earth, comprising: providing a launch vehicle comprising: a fuselage; an engine positioned at a first end of the fuselage; and a propellant tank disposed within the fuselage; terminating operation of the engine; separating a first section from the fuselage, the first section comprising the engine and a portion of the propellant tank having a closed end; creating a severed open end of the first section when separating the first section, wherein the engine is positioned opposite the severed open end; deploying a buoyancy device proximate the engine; landing the first section of the fuselage including the engine in a body of water such that the severed open end contacts the body of water first; and controlling the flow of air from the portion of the propellant tank following landing the first section in the body of water. ### Claim 13 (depends on 12) The method of claim 12 wherein controlling the flow of air from the at least a portion of the propellant tank comprises forming a plurality of apertures extending through the fuselage of the first section and the portion of the propellant tank remaining with the first section. ### Claim 14 (depends on 12) The method of claim 12 wherein the launch vehicle comprises a first stage and a second stage, and the fuselage, at least one engine and at least one propellant tank are part of the first stage, further comprising separating the second stage from the first stage prior to deploying the at least one parachute. ### Claim 15 (depends on 12) The method of claim 12 further comprising deploying a cover to shield the at least one engine from water. ### Claim 16 A method for returning a launch vehicle main engine to earth, comprising: launching a launch vehicle from a launch site, the launch vehicle having a first stage and a second stage, the first stage comprising: a first end; a second end; a main engine proximate the second end; a fuselage; and a propellant tank positioned within the fuselage, the propellant tank having a central section, a first closed end, and a second end; terminating operation of the main engine; separating the first stage from the second stage; deploying at least one parachute from the first stage; causing the first stage to separate into at least two sections, wherein a first section includes the main engine, a portion of the fuselage, and a portion of the propellant tank comprising the central section and the first closed end, wherein a second section includes an end portion of the propellant tank comprising the second end, and wherein the at least one parachute is connected to the first section; creating a severed open end of the first section when separating the first stage into the at least two sections; orienting the first section generally vertically with the main engine farthest from earth, the first closed end of the propellant tank positioned proximate the main engine, and the severed open end of the first section positioned closest to earth; and landing the first section of the first stage including the main engine in a body of water.