# US 5,564,648 A · High altitude launch platform payload launching apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,564,648 A - Document ID: US5564648A - Status: Granted - Kind: A - Application number: 08/504,261 - Filed: 1995-07-19 - Granted: 1996-10-15 - Earliest claimed: 1991-11-08 - Assignees: Spread Spectrum - Inventors: William R. Palmer - Web page: https://patentgrep.com/patent/US5564648A ## CPC - B64G 1/401: {Liquid propellant rocket engines (Ion or plasma engines B64G1/413; Arcjets and other resistojets B64G1/415)} - B64D 39/00: Refuelling during flight - B64G 1/005: {Air launch} - B64G 1/14: Space shuttles {(reusable launch rockets B64G1/006)} - B64G 1/2427: {Transfer orbits} - B64G 1/4005: {Air-breathing propulsion} - B64G 1/402: {Propellant tanks; Feeding propellants} - B64G: COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT ## Abstract A high altitude launch platform, used to launch a payload into earth orbit, is part of a payload launch system having a payload launching rocket with an engine carried by the high altitude launch platform. A first amount of fuel, substantially less than the capacity of the fuel tanks, is provided to the fuel tanks of the engines for the launch platform while the launch platform is on the ground. The launch platform is flown to a first altitude and the fuel tanks are provided with a second amount of fuel while the high altitude launch platform is at the first altitude. The addition of the second amount of fuel is sufficient to allow the payload to be launched into orbit. ## Claims ### Claim 1 A method of placing a payload into earth orbit, comprising the steps of: (a) providing a high altitude launch platform having a fuel-consuming propulsion system; (b) fueling said high altitude launch platform with a quantity of fuel for operating said propulsion system that is less than the total quantity of fuel necessary to operate said propulsion system to fly said high altitude launch platform from the earth to a first altitude above the earth; (b) flying said high altitude launch platform from a location on the earth to said first altitude above the earth; and (c) at said first altitude above the earth, refueling said high altitude launch platform from a fuel supply external to said high altitude launch platform with a further quantity of fuel that is sufficient to operate said propulsion system for flying said high altitude launch platform to a second altitude, higher than said first altitude, from which said payload is placed into earth orbit by a payload launch system therefor. ### Claim 2 (depends on 1) A method according to claim 1, further comprising the steps of: (d) operating said propulsion system using said further quantity of fuel refueled with which said high altitude launch platform has been refueled in step (c) so as to propel said high altitude launch platform and said payload launch system carried thereby from said first altitude to said second altitude higher than said first altitude; and (e) at said second altitude, separating said payload launch system from said high altitude launch platform and causing said payload launch system to travel to a third altitude higher than said second altitude and place said payload into earth orbit. ### Claim 3 (depends on 2) A method according to claim 2, wherein step (e) comprises separating said payload launch system from said high altitude launch platform in such a manner as to minimize structural loading of said high altitude launch platform by a propulsion system plume of said payload launch system, and to minimize structural loading of said payload launch system by a propulsion system plume of said high altitude launch platform. ### Claim 4 (depends on 2) A method according to claim 2, wherein step (e) comprises separating said payload launch system from said high altitude launch platform with a similar impulse relative to weight applied to each of said high altitude launch platform and said payload launch system, until said payload launch system separates from said high altitude launch platform by a distance that is effective to prevent structural loading of said payload launch system by a propulsion system plume of said high altitude launch platform, and to prevent structural loading of said high altitude launch platform by a propulsion system plume of said payload launch system. ### Claim 5 (depends on 1) A method according to claim 1, wherein step (e) comprises establishing the attitude and acceleration of said payload launch system with respect to said high altitude launch platform with a similar impulse relative to weight applied to each of said high altitude launch platform and said payload launch system, such that said payload launch'system and said high altitude launch platform are separated from one another by a distance sufficient to avoid structural loading of said payload launch system by a propulsion system plume of said high altitude launch platform, and to avoid structural loading of said high altitude launch platform by a propulsion system plume of said payload launch system. ### Claim 6 (depends on 1) A method according to claim 1, wherein said high altitude launch platform propulsion system includes an air-breathing engine, and wherein said high altitude launch platform employs air as a lifting medium for attaining said first altitude. ### Claim 7 (depends on 1) A method according to claim 1, wherein step (c) comprises performing in-flight refueling Of said high altitude launch platform and said payload launch system at said first altitude from an in-flight refueling vehicle flying at said first altitude. ### Claim 8 (depends on 1) A method according to claim 1, wherein said high altitude launch platform propulsion system includes an air-breathing engine. ### Claim 9 (depends on 1) A method according to claim 1, wherein said second altitude is between 135,000 and 180,000 feet. ### Claim 10 (depends on 9) A method according to claim 9, wherein said first altitude is above 25,000 feet. ### Claim 11 (depends on 9) A method according to claim 9, wherein step (d) comprises propelling said high altitude launch platform and said payload launch system to a velocity in excess of Mach 3.2. ### Claim 12 A method of placing a payload into earth orbit, comprising the steps of: (a) providing a quantity of fuel for operating a propulsion system of a high altitude launch platform, that is less than the total quantity of fuel necessary for said engine to propel said high altitude launch platform from the earth to a first altitude above the earth; (b) flying a refueling platform from a location on the earth to said first altitude above the earth; (c) flying said high altitude launch platform from a location on the earth to said first altitude above the earth; and (d) at said first altitude above the earth, performing in-flight refueling of said high altitude launch platform from said refueling platform, so as to refuel said high altitude launch platform with a further quantity of fuel that is sufficient to enable said propulsion system to propel said high altitude launch platform to a second altitude, higher than said first altitude, from which said payload is placed into earth orbit by a payload launch system therefor. ### Claim 13 (depends on 12) A method according to claim 12, further comprising the steps of: (e) operating said propulsion system using said further quantity of fuel refueled from said refueling platform in step (d), so as to propel said high altitude launch platform and said payload launch system carried thereby from said first altitude to said second altitude higher than said first altitude; and (f) at said second altitude, separating said payload launch system from said high altitude launch platform and causing said payload launch system to travel to a third altitude higher than said second altitude and place said payload into earth orbit. ### Claim 14 (depends on 13) A method according to claim 13, wherein step (f) comprises separating said payload launch system from said high altitude launch platform so as to minimize structural loading of said high altitude launch platform by a propulsion system plume of said payload launch system, and to minimize structural loading of said payload launch system by a propulsion system plume of said high altitude launch platform. ### Claim 15 (depends on 13) A method according to claim 13, wherein step (f) comprises separating said payload launch system from said high altitude launch platform with a similar impulse relative to weight applied to each of said high altitude launch platform and said payload launch system, until said payload launch system separates from said high altitude launch platform by a distance that is effective to prevent structural loading of said payload launch system by a propulsion system plume of said high altitude launch platform, and to prevent structural loading of said high altitude launch platform by a propulsion system plume of said payload launch system. ### Claim 16 (depends on 13) A method according to claim 13 wherein step (f) comprises establishing the attitude and acceleration of said payload launch system with respect to said high altitude launch platform with a similar impulse relative to weight applied to each of said high altitude launch platform and said payload launch system, such that said payload launch system and said high altitude launch platform are separated from one another by a distance sufficient to avoid structural loading of said payload launch system by a propulsion system plume of said high altitude launch platform, and to avoid structural loading of said high altitude launch platform by a propulsion system plume of said payload launch system. ### Claim 17 (depends on 12) A method according to claim 12, wherein said high altitude launch platform propulsion system includes an air-breathing engine, and wherein said high altitude launch platform employs air as a lifting medium for attaining said first altitude. ### Claim 18 (depends on 13) A method according to claim 13, wherein said high altitude launch platform propulsion system includes an air-breathing engine. ### Claim 19 (depends on 13) A method according to claim 13, wherein said second altitude is between 135,000 and 180,000 feet. ### Claim 20 (depends on 19) A method according to claim 19, wherein said first altitude is above 25,000 feet. ### Claim 21 (depends on 13) A method according to claim 13, wherein step (e) comprises propelling said high altitude launch platform and said payload launch system to a velocity in excess of Mach 3.2.