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Space Launch System core stage AI simulator
(@Space Launch System core stage_simulator)
Hub AI
Space Launch System core stage AI simulator
(@Space Launch System core stage_simulator)
Space Launch System core stage
The Space Launch System core stage, or simply core stage, is the main stage of the American Space Launch System (SLS) rocket, built by The Boeing Company in the NASA Michoud Assembly Facility. At 65 m (212 ft) tall and 8.4 m (27.6 ft) in diameter, the core stage contains approximately 987 t (2,177,000 lb) of its liquid hydrogen and liquid oxygen cryogenic propellants. Propelled by 4 RS-25 engines, the stage generates approximately 7.44 MN (1,670,000 lbf) of thrust, about 25% of the Space Launch System's thrust at liftoff, for approximately 500 seconds, propelling the stage alone for the last 375 seconds of flight. The stage lifts the rocket to an altitude of approximately 162 km (531,380 ft) before separating, reentering the atmosphere over the Pacific Ocean.
The core stage originated in 2011, when the architecture of the Space Launch System as a whole was defined. In the aftermath of the end of the Space Shuttle program and the cancellation of its prospective replacement the Constellation program, the SLS emerged, a super-heavy lift launch vehicle intended for human spaceflight to the Moon. The core stage is the first newly-developed stage of the SLS; the ICPS (Interim Cryogenic Propulsion Stage) and five-segment boosters are adaptations of existing hardware, to be replaced by the Exploration Upper Stage and BOLE boosters respectively.
Production of core stages began by 2014, but was beset by numerous difficulties in production and testing which delayed the readiness of the first core stage by several years. The core stage first flew on November 16, 2022, on the Artemis I mission, in which it performed successfully. As of 2024, the second core stage is completed, with the third and fourth core stages in production and while work has begun for the fifth and sixth, their production pending the transfer of SLS operations to Deep Space Transport, the vehicle's future operator.
The core stage comprises five major sections: the engine section, the liquid hydrogen (LH2) tank, the intertank, the liquid oxygen (LOx) tank, and the forward skirt. These elements can be further divided into ten barrel sections, four domes, and seven rings, together forming the structure of the rocket stage.
The core stage is powered by 4 RS-25 engines housed inside the engine section at the base of the stage. The engines are associated with the main propulsion system, which support the engines in their operation, allowing them to gimbal, or deflect, to control the rocket, supply them with liquid hydrogen and liquid oxygen propellants, and keep the propellant tanks pressurized. In service of this role, the main propulsion system is outfitted with hydraulic systems that move the engine bells to allow them to gimbal, pneumatics to actuate the numerous valves within the rocket, a pressurant system to feed gaseous propellants into their tanks, and large amounts of ducting. The pneumatic system is kept pressurized by helium stored in five composite-overwrapped pressure vessels within the engine section, while hydraulic power is provided by an auxiliary power unit called the CAPU, which on the first two core stages is directly reused Space Shuttle hardware. The CAPU is a turbine which is spun by pressurized gaseous helium during vehicle startup, then by hydrogen gas, as opposed to its Space Shuttle usage when it was powered by the flow of hydrazine. The hydraulic system powered by the CAPU also includes the gimbal actuators which themselves deflect the RS-25 engines. These actuators, like the CAPUs, are directly reused Space Shuttle parts on early-production core stages. The main propulsion system works to reduce the risk of fire in the engine section: while staged for work and servicing, the engine section is purged with clean air; on the launch pad, during flight preparations, the space is filled with nitrogen gas supplied from ground support equipment to mitigate the buildup of hazardous gases like hydrogen or oxygen. Before flight, the core stage also receives all of its supplies through the MPS, with propellants and helium pressurant flowing through quick-disconnect connections of the tail service mast umbilical, interfacing with the vehicle on a plate located on the engine section.
The engine section and intertank of the core stage both feature large thrust structures, which transmit thrust forces (the former from the core stage's RS-25 engines, the latter from the twin boosters of an SLS vehicle) through the vehicle. The engine thrust structure also enables the stage's RS-25 engines to be gimballed. Each engine is mounted an attachment point at the base of the thrust structure, while its hydraulic thrust vectoring system is installed on top of that same structure. The engine section thrust structure is bolted together and attached inside the cylindrical engine section barrel. The intertank thrust beam, mounted with the intertank much higher up on the vehicle, is a single beam, which, in conjunction with the thickened and strengthened bolted structure of the intertank itself, allows the thrust of the solid rocket boosters to be transmitted through the stage.
The largest structures of the core stage are its propellant tanks, built to carry approximately 987 tonnes of cryogenic propellants, liquid hydrogen and liquid oxygen. The extremely low cryogenic temperatures of these fluids – −182.8 °C (−297.0 °F) for liquid oxygen and −252.8 °C (−423 °F) for liquid hydrogen – causes substantial shrinkage in the propellant tanks. The liquid hydrogen tank shrinks about 15 cm (6 in) in length and 2.5 cm (1 in) in diameter after being filled, while the liquid oxygen tank's size decreases by 3.8 cm (1.5 in) lengthwise and 1.3 cm (0.5 in) across. Therefore, all hardware attached to the propellant tanks must be mounted using bellows that allow them to flexibly adjust to the shifting size of the propellant tanks.
The design of the core stage was intended to make use of knowledge and experience gained from the Space Shuttle program, similarly to the rest of the Space Launch System. This is reflected in aspects such as the rocket's 8.4 m (27.6 ft) diameter, identical to that of the Space Shuttle's external tank, while feedlines and ducts are designed to make use of existing valve designs and connectors. However, the core stage is also significantly different from the external tank. There is no structure on the external tank comparable to the core stage's main propulsion section, which is analogous to the main propulsion section which occupied the tail of the Shuttle orbiter. The core stage is also made from a different, harder aluminum alloy than that in the definitive version of the external tank, which was lighter but more difficult to work with. Structural construction of the core stage's propellant tanks is also dissimilar to that of the Shuttle external tank, partly through more extensive use of friction-stir welding, while the core stage's stringers are milled out of the workpiece instead of riveted in.
Space Launch System core stage
The Space Launch System core stage, or simply core stage, is the main stage of the American Space Launch System (SLS) rocket, built by The Boeing Company in the NASA Michoud Assembly Facility. At 65 m (212 ft) tall and 8.4 m (27.6 ft) in diameter, the core stage contains approximately 987 t (2,177,000 lb) of its liquid hydrogen and liquid oxygen cryogenic propellants. Propelled by 4 RS-25 engines, the stage generates approximately 7.44 MN (1,670,000 lbf) of thrust, about 25% of the Space Launch System's thrust at liftoff, for approximately 500 seconds, propelling the stage alone for the last 375 seconds of flight. The stage lifts the rocket to an altitude of approximately 162 km (531,380 ft) before separating, reentering the atmosphere over the Pacific Ocean.
The core stage originated in 2011, when the architecture of the Space Launch System as a whole was defined. In the aftermath of the end of the Space Shuttle program and the cancellation of its prospective replacement the Constellation program, the SLS emerged, a super-heavy lift launch vehicle intended for human spaceflight to the Moon. The core stage is the first newly-developed stage of the SLS; the ICPS (Interim Cryogenic Propulsion Stage) and five-segment boosters are adaptations of existing hardware, to be replaced by the Exploration Upper Stage and BOLE boosters respectively.
Production of core stages began by 2014, but was beset by numerous difficulties in production and testing which delayed the readiness of the first core stage by several years. The core stage first flew on November 16, 2022, on the Artemis I mission, in which it performed successfully. As of 2024, the second core stage is completed, with the third and fourth core stages in production and while work has begun for the fifth and sixth, their production pending the transfer of SLS operations to Deep Space Transport, the vehicle's future operator.
The core stage comprises five major sections: the engine section, the liquid hydrogen (LH2) tank, the intertank, the liquid oxygen (LOx) tank, and the forward skirt. These elements can be further divided into ten barrel sections, four domes, and seven rings, together forming the structure of the rocket stage.
The core stage is powered by 4 RS-25 engines housed inside the engine section at the base of the stage. The engines are associated with the main propulsion system, which support the engines in their operation, allowing them to gimbal, or deflect, to control the rocket, supply them with liquid hydrogen and liquid oxygen propellants, and keep the propellant tanks pressurized. In service of this role, the main propulsion system is outfitted with hydraulic systems that move the engine bells to allow them to gimbal, pneumatics to actuate the numerous valves within the rocket, a pressurant system to feed gaseous propellants into their tanks, and large amounts of ducting. The pneumatic system is kept pressurized by helium stored in five composite-overwrapped pressure vessels within the engine section, while hydraulic power is provided by an auxiliary power unit called the CAPU, which on the first two core stages is directly reused Space Shuttle hardware. The CAPU is a turbine which is spun by pressurized gaseous helium during vehicle startup, then by hydrogen gas, as opposed to its Space Shuttle usage when it was powered by the flow of hydrazine. The hydraulic system powered by the CAPU also includes the gimbal actuators which themselves deflect the RS-25 engines. These actuators, like the CAPUs, are directly reused Space Shuttle parts on early-production core stages. The main propulsion system works to reduce the risk of fire in the engine section: while staged for work and servicing, the engine section is purged with clean air; on the launch pad, during flight preparations, the space is filled with nitrogen gas supplied from ground support equipment to mitigate the buildup of hazardous gases like hydrogen or oxygen. Before flight, the core stage also receives all of its supplies through the MPS, with propellants and helium pressurant flowing through quick-disconnect connections of the tail service mast umbilical, interfacing with the vehicle on a plate located on the engine section.
The engine section and intertank of the core stage both feature large thrust structures, which transmit thrust forces (the former from the core stage's RS-25 engines, the latter from the twin boosters of an SLS vehicle) through the vehicle. The engine thrust structure also enables the stage's RS-25 engines to be gimballed. Each engine is mounted an attachment point at the base of the thrust structure, while its hydraulic thrust vectoring system is installed on top of that same structure. The engine section thrust structure is bolted together and attached inside the cylindrical engine section barrel. The intertank thrust beam, mounted with the intertank much higher up on the vehicle, is a single beam, which, in conjunction with the thickened and strengthened bolted structure of the intertank itself, allows the thrust of the solid rocket boosters to be transmitted through the stage.
The largest structures of the core stage are its propellant tanks, built to carry approximately 987 tonnes of cryogenic propellants, liquid hydrogen and liquid oxygen. The extremely low cryogenic temperatures of these fluids – −182.8 °C (−297.0 °F) for liquid oxygen and −252.8 °C (−423 °F) for liquid hydrogen – causes substantial shrinkage in the propellant tanks. The liquid hydrogen tank shrinks about 15 cm (6 in) in length and 2.5 cm (1 in) in diameter after being filled, while the liquid oxygen tank's size decreases by 3.8 cm (1.5 in) lengthwise and 1.3 cm (0.5 in) across. Therefore, all hardware attached to the propellant tanks must be mounted using bellows that allow them to flexibly adjust to the shifting size of the propellant tanks.
The design of the core stage was intended to make use of knowledge and experience gained from the Space Shuttle program, similarly to the rest of the Space Launch System. This is reflected in aspects such as the rocket's 8.4 m (27.6 ft) diameter, identical to that of the Space Shuttle's external tank, while feedlines and ducts are designed to make use of existing valve designs and connectors. However, the core stage is also significantly different from the external tank. There is no structure on the external tank comparable to the core stage's main propulsion section, which is analogous to the main propulsion section which occupied the tail of the Shuttle orbiter. The core stage is also made from a different, harder aluminum alloy than that in the definitive version of the external tank, which was lighter but more difficult to work with. Structural construction of the core stage's propellant tanks is also dissimilar to that of the Shuttle external tank, partly through more extensive use of friction-stir welding, while the core stage's stringers are milled out of the workpiece instead of riveted in.
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