Misplaced Pages

#241758

122-494: The Space Launch System ( SLS ) is an American super heavy-lift expendable launch vehicle used by NASA . Development of SLS began in 2011 as a replacement for the retiring Space Shuttle as well as the canceled Ares I and Ares V launch vehicles. SLS was built using existing Shuttle technology, including solid rocket boosters and RS-25 engines. As the primary launch vehicle of the Artemis Moon landing program, SLS

244-413: A "super heavy" because recovery of the center core was attempted. ^G Apollo 6 was a "partial failure": It reached orbit, but had problems with the second and third stages. ^I Estimate by third party. ^J Flight 6 entered a Transatmospheric Earth orbit , an orbit, though one that results in rapid decay and reentry. ^K Block 1 boosters were proven to be recoverable in

366-405: A flight, the rocket would have continued to fly normally. There was no sign of damage to the core stage or the engines, contrary to initial concerns. The second fire test was completed on 18 March 2021, with all four engines igniting, throttling down as expected to simulate in-flight conditions, and gimballing profiles. The core stage was shipped to Kennedy Space Center to be mated with the rest of

488-514: A gearbox. The waste gas, now cooler and at low pressure, was passed back over the gas generator housing to cool it before being dumped overboard. The gearbox drove the fuel pump, its own lubrication pump, and the HPU hydraulic pump. A startup bypass line went around the pump and fed the gas generator using the nitrogen tank pressure until the APU speed was such that the fuel pump outlet pressure exceeded that of

610-502: A hydraulic pump that produced hydraulic pressure for the SRB hydraulic system. The two separate HPUs and two hydraulic systems were located on the aft end of each SRB between the SRB nozzle and aft skirt. The HPU components were mounted on the aft skirt between the rock and tilt actuators. The two systems operated from T minus 28 seconds until SRB separation from the orbiter and external tank. The two independent hydraulic systems were connected to

732-429: A joint venture between Boeing and Northrop Grumman. The SLS is a Space Shuttle-derived launch vehicle . The rocket's first stage is powered by one central core stage and two outboard solid rocket boosters . All SLS Blocks share a common core stage design but differ in their upper stages and boosters. Together with the solid rocket boosters, the core stage is responsible for propelling the upper stage and payload out of

854-610: A joint venture of Boeing and Lockheed Martin . Out of 270 SRBs launched over the Shuttle program, all but four were recovered – those from STS-4 (due to a parachute malfunction) and STS-51-L ( terminated by the range during the Challenger disaster ). Over 5,000 parts were refurbished for reuse after each flight. The final set of SRBs that launched STS-135 included parts that had flown on 59 previous missions, including STS-1 . Recovery also allowed post-flight examination of

976-453: A journalist, a NASA spokesperson did not deny this per-flight cost estimate. The NASA Office of Inspector General has conducted several audits of the SLS program. A November 2021 report estimated that, at least for the first four launches of Artemis program, the per-launch production and operating costs would be $ 2.2 billion for SLS, plus $ 568 million for Exploration Ground Systems . Additionally,

1098-530: A larger launch vehicle. Numerous super-heavy-lift vehicles have been proposed and received various levels of development prior to their cancellation. As part of the Soviet crewed lunar project to compete with Apollo/Saturn V, the N1 rocket was secretly designed with a payload capacity of 95 t (209,000 lb). Four test vehicles were launched from 1969 to 1972, but all failed shortly after lift-off. The program

1220-571: A launch hold. Electrical power distribution in each SRB consisted of orbiter-supplied main DC bus power to each SRB via SRB buses labeled A, B and C. Orbiter main DC buses A, B and C supplied main DC bus power to corresponding SRB buses A, B and C. In addition, orbiter main DC bus C supplied backup power to SRB buses A and B, and orbiter bus B supplied backup power to SRB bus C. This electrical power distribution arrangement allowed all SRB buses to remain powered in

1342-442: A liftoff thrust of approximately 2,800,000 pounds-force (12  MN ) at sea level, increasing shortly after liftoff to about 3,300,000 lbf (15 MN). They were ignited after the three RS-25 main engines' thrust level was verified. Seventy-five seconds after SRB separation, SRB apogee occurred at an altitude of approximately 220,000 ft (42 mi; 67 km); parachutes were then deployed and impact occurred in

SECTION 10

#1732773094242

1464-483: A manual lock pin from each SRB safe and arm device has been removed. The ground crew removes the pin during prelaunch activities. At T−5:00, the SRB safe and arm device is rotated to the arm position. The solid rocket motor ignition commands are issued when the three Space Shuttle Main Engines (SSMEs) are at or above 90% of rated thrust, no SSME fail and/or SRB ignition Pyrotechnic Initiator Controller (PIC) low voltage

1586-501: A modified solid rocket booster with lighter casing, more energetic propellant, and four segments instead of five, and Pratt & Whitney Rocketdyne and Dynetics proposed a liquid-fueled booster named Pyrios . However, this competition was planned for a development plan in which Block 1A would be followed by Block 2A, with upgraded boosters. NASA canceled Block 1A and the planned competition in April 2014, in favor of simply remaining with

1708-669: A nuclear powered variant of the UR-700, and UR-700M, a LOx/Kerosene variant to assemble the 1,400 t (3,100,000 lb) MK-700 spacecraft in earth orbit in two launches. The UR-700M would have a payload capacity of 750 t (1,650,000 lb). The only Universal Rocket to make it past the design phase was the UR-500 while the N1 was selected to be the Soviets' HLV for lunar and Martian missions. The UR-900 , proposed in 1969, would have had

1830-457: A payload capacity of 240 t (530,000 lb) to low earth orbit. It never left the drawing board. The General Dynamics Nexus was proposed in the 1960s as a fully reusable successor to the Saturn V rocket, having the capacity of transporting up to 450–910 t (990,000–2,000,000 lb) to orbit. The American Saturn MLV family of rockets was proposed in 1965 by NASA as successors to

1952-440: A predetermined time, an isolating valve would be selected, excluding it from the force-sum entirely. Failure monitors were provided for each channel to indicate which channel had been bypassed, and the isolation valve on each channel could be reset. Each actuator ram was equipped with transducers for position feedback to the thrust vector control system. Within each servoactuator ram was a splashdown load relief assembly to cushion

2074-457: A projected development cost of US$ 18 billion through 2017, with $ 10 billion for the SLS rocket, $ 6 billion for the Orion spacecraft , and $ 2 billion for upgrades to the launch pad and other facilities at Kennedy Space Center . These costs and schedules were considered optimistic in an independent 2011 cost assessment report by Booz Allen Hamilton for NASA. An internal 2011 NASA document estimated

2196-654: A rocket or part of it with on-board explosives by remote command if the rocket is out of control, in order to limit the danger to people on the ground from crashing pieces, explosions, fire, poisonous substances, etc. The RSS was only activated once – during the Space Shuttle Challenger disaster (37 seconds after the breakup of the vehicle, when the SRBs were in uncontrolled flight). The shuttle vehicle had two RSS, one in each SRB. Both were capable of receiving two command messages (arm and fire) transmitted from

2318-478: A specific energy density of about 31.0 MJ/kg . The propellant had an 11-pointed star-shaped perforation in the forward motor segment and a double-truncated- cone perforation in each of the aft segments and aft closure. This configuration provided high thrust at ignition and then reduced the thrust by approximately a third 50 seconds after lift-off to avoid overstressing the vehicle during maximum dynamic pressure (max. Q). SRB ignition can occur only when

2440-571: A state permitting reuse on Starship flight test 5 , but it was decided they would not be reused regardless. Long March 10 was first proposed in 2018 as a concept for the Chinese Lunar Exploration Program . Long March 9 , an over 150 t (330,000 lb) to LEO capable rocket was proposed in 2018 by China , with plans to launch the rocket by 2028. The length of the Long March-9 will exceed 114 meters, and

2562-478: A switching valve that allowed the hydraulic power to be distributed from either HPU to both actuators if necessary. Each HPU served as the primary hydraulic source for one servoactuator, and a secondary source for the other servoactuator. Each HPU possessed the capacity to provide hydraulic power to both servoactuators within 115% operational limits in the event that hydraulic pressure from the other HPU should drop below 2,050 psi (14.1 MPa). A switch contact on

SECTION 20

#1732773094242

2684-754: A switchover was made from the SRB RGAs to the orbiter RGAs. The SRB RGA rates passed through the orbiter flight aft multiplexers/demultiplexers to the orbiter GPCs. The RGA rates were then mid-value-selected in redundancy management to provide SRB pitch and yaw rates to the user software. The RGAs were designed for 20 missions. Made out of 2-cm-thick D6AC high-strength low-alloy steel . The rocket propellant mixture in each solid rocket motor consisted of ammonium perchlorate ( oxidizer , 69.6% by weight), atomized aluminum powder ( fuel , 16%), iron oxide ( catalyst , 0.4%), PBAN (binder, also acts as fuel, 12.04%), and an epoxy curing agent (1.96%). This propellant

2806-658: A temporary solution and slated to be replaced on the Block 1B version of the SLS by the next-generation Exploration Upper Stage, under design by Boeing. The ICPS used on the Artemis I mission was powered by a single RL10B-2 engine, while the ICPS for Artemis II and Artemis III will use the RL10 C-2 variant. Block 1 is intended to be capable of lifting 209,000 lb (95 t) to low Earth orbit (LEO) in this configuration, including

2928-621: A test flight in fall 2022, and NASA and Boeing are constructing the next three rockets for Artemis II , Artemis III , and Artemis IV . Boeing stated in July 2021 that while the COVID-19 pandemic had affected their suppliers and schedules, such as delaying parts needed for hydraulics, they would still be able to provide the Artemis II SLS core stage per NASA's schedule, with months to spare. The spray-on foam insulation process for Artemis II

3050-688: A variant with five main engines, a Block 1A variant with upgraded boosters instead of the improved second stage, and a Block 2 with five main engines plus the Earth Departure Stage , with up to three J-2X engines. In the initial announcement of the design of the SLS, NASA also announced an "Advanced Booster Competition", to select which boosters would be used on Block 2 of the SLS. Several companies proposed boosters for this competition, all of which were indicated as viable: Aerojet and Teledyne Brown proposed three booster engines each with dual combustion chambers, Alliant Techsystems proposed

3172-564: A vehicle used for human spaceflight . A pair of them provided 85% of the Space Shuttle 's thrust at liftoff and for the first two minutes of ascent. After burnout, they were jettisoned, and parachuted into the Atlantic Ocean, where they were recovered , examined, refurbished, and reused . The Space Shuttle SRBs were the most powerful solid rocket motors to ever launch humans. The Space Launch System (SLS) SRBs, adapted from

3294-762: Is about 122.4 t (270,000 lb). ^B Required upper stage or payload to perform final orbital insertion. ^C Side booster cores recoverable, center core intentionally expended. First re-use of the side boosters was demonstrated in 2019 when the ones used on the Arabsat-6A launch were reused on the STP-2 launch. ^D Includes mass of Orion spacecraft , European Service Module , Interim Cryogenic Propulsion Stage , and propellant for translunar injection . ^E Does not include dry mass of spaceship. ^F Falcon Heavy has launched 11 times since 2018, but first three times did not qualify as

3416-497: Is also preparing to begin construction of the Exploration Upper Stage (EUS), which is planned to be used on Artemis IV . Originally planned for late 2016, the uncrewed first flight of SLS slipped more than twenty-six times and almost six years. As of earlier that month, the first launch was originally scheduled for 8:30 am EDT, 29 August 2022. It was postponed to 2:17 pm EDT (18:17 UTC), 3 September 2022, after

3538-474: Is commonly referred to as ammonium perchlorate composite propellant (APCP). This mixture gave the solid rocket motors a specific impulse of 242 seconds (2.37 km/s) at sea level or 268 seconds (2.63 km/s) in a vacuum. Upon ignition, the motor burned the fuel at a nominal chamber pressure of 906.8 psi (6.252 MPa). Aluminum was chosen as a propellant due to high volumetric energy density, and its resilience to accidental ignition. Aluminum has

3660-633: Is designed to launch the crewed Orion spacecraft on a trans-lunar trajectory. The first SLS launch was the uncrewed Artemis I , which took place on 16 November 2022. All Space Launch System flights are to be launched from Launch Complex 39B at the Kennedy Space Center in Florida. The first three SLS flights are expected to use the Block 1 configuration, comprising a core stage , extended Space Shuttle boosters developed for Ares I and

3782-653: Is developing a new composite-based fuel tank for the EUS that would increase Block 1B's overall payload mass capacity to TLI by 40 percent. The improved upper stage was originally named the Dual Use Upper Stage (DUUS, pronounced "duce"), but was later renamed the Exploration Upper Stage (EUS). During the joint Senate-NASA presentation in September 2011, it was stated that the SLS program had

Space Launch System - Misplaced Pages Continue

3904-400: Is held for four seconds, and SRB thrust drops to less than 60,000 lbf (270 kN). The SRBs separate from the external tank within 30 milliseconds of the ordnance firing command. The forward attachment point consists of a ball (SRB) and socket (External Tank; ET) held together by one bolt. The bolt contains one NSD pressure cartridge at each end. The forward attachment point also carries

4026-574: Is indicated and there are no holds from the Launch Processing System (LPS). The solid rocket motor ignition commands are sent by the orbiter computers through the Master Events Controllers (MECs) to the safe and arm device NASA standard detonators (NSDs) in each SRB. A PIC single-channel capacitor discharge device controls the firing of each pyrotechnic device. Three signals must be present simultaneously for

4148-434: Is less than or equal to 50 psi (340 kPa). A backup cue is the time elapsed from booster ignition. The separation sequence is initiated, commanding the thrust vector control actuators to the null position and putting the main propulsion system into a second-stage configuration (0.8 seconds from sequence initialization), which ensures the thrust of each SRB is less than 100,000 lbf (440 kN). Orbiter yaw attitude

4270-404: Is planned to first fly on Artemis IV . The EUS will complete the SLS ascent phase and then re-ignite to send its payload to destinations beyond LEO. It is expected to be used by Block 1B and Block 2. The EUS shares the core stage diameter of 8.4 meters, and will be powered by four RL10 C-3 engines. It will eventually be upgraded to use four improved RL10 C-X engines. As of March 2022, Boeing

4392-538: The Ares I Crew Launch Vehicle, funded from 2006 to 2010 for a total of $ 4.8 billion in development, including the 5-segment Solid Rocket Boosters used on the SLS. The SLS was created by an act of the U.S. Congress in the NASA Authorization Act of 2010 , Public Law 111–267, in which NASA was directed to create a system for launching payloads and crew into space that would replace the capabilities lost with

4514-426: The Ares I 's five-segment solid rocket boosters, themselves modified from the Space Shuttle 's solid rocket boosters, until at least the late 2020s. The overly powerful advanced booster would have resulted in unsuitably high acceleration, and would need modifications to Launch Complex 39B , its flame trench, and Mobile Launcher . On 31 July 2013, the SLS passed Preliminary Design Review. The review included not only

4636-615: The Comet HLLV . The Comet would have been capable of injecting 230.8 t (508,800 lb) into low earth orbit and 88.5 t (195,200 lb) on a TLI making it one of the most capable vehicles ever designed. FLO was cancelled during the design process along with the rest of the Space Exploration Initiative . The U.S. Ares V for the Constellation program was intended to reuse many elements of

4758-584: The Constellation Program , including tests at low and high core temperatures, to validate performance at extreme temperatures. The 5-segment solid rocket booster would be carried over to SLS. Northrop Grumman Innovation Systems has completed full-duration static fire tests of the five-segment solid rocket boosters. Qualification Motor 1 was tested on 10 March 2015. Qualification Motor 2 was successfully tested on 28 June 2016. NASA has been reluctant to provide an official per-flight cost estimate for

4880-543: The Interim Cryogenic Propulsion Stage (ICPS) upper stage. The improved Block 1B configuration, with the powerful and purpose-built Exploration Upper Stage (EUS), is planned to be introduced on the fourth flight; a further improved Block 2 configuration with new solid rocket boosters is planned for the ninth flight. After the launch of Artemis IV , NASA plans to transfer production and launch operations of SLS to Deep Space Transport LLC ,

5002-481: The Orion spacecraft on the SLS, the Artemis II mission , no earlier than September 2025. Included in the above SLS costs above are (1) the Interim Cryogenic Propulsion Stage (ICPS) , a $ 412 million contract and (2) the costs of developing the Exploration Upper Stage (below). Excluded from the SLS cost above are the costs to assemble, integrate, prepare and launch the SLS and its payloads, funded separately in

Space Launch System - Misplaced Pages Continue

5124-633: The Space Shuttle program, both on the ground and flight hardware, to save costs. The Ares V was designed to carry 188 t (414,000 lb) and was cancelled in 2010. The Shuttle-Derived Heavy Lift Launch Vehicle ("HLV") was an alternate super heavy-lift launch vehicle proposal for the NASA Constellation program, proposed in 2009. A 1962 design proposal, Sea Dragon , called for an enormous 150 m (490 ft) tall, sea-launched rocket capable of lifting 550 t (1,210,000 lb) to low Earth orbit. Although preliminary engineering of

5246-473: The stringers . The first four flights will each use and expend four of the remaining sixteen RS-25D engines previously flown on Space Shuttle missions. Aerojet Rocketdyne refits these engines with modernized engine controllers, higher throttle limits, as well as insulation for the high temperatures the engine section will experience due to their position adjacent to the solid rocket boosters. Later flights will switch to an RS-25 variant optimized for expended use,

5368-488: The $ 11.9 billion spent on the SLS as of August 2018. By 2021, development of the core stage was expected to have cost $ 8.9 billion, twice the initially planned amount. In December 2018, NASA estimated that yearly budgets for the SLS will range from $ 2.1 to $ 2.3 billion between 2019 and 2023. In March 2019, the Trump administration released its fiscal year 2020 budget request for NASA, which notably proposed dropped funding for

5490-739: The 1960s, including the Sea Dragon . During the Space Race , the Saturn V and N1 were built by the United States and Soviet Union, respectively. After the Saturn V's successful Apollo program and the N1's failures, the Soviets' Energia launched twice in the 1980s, once bearing the Buran spaceplane . The next two decades saw multiple concepts drawn out once again, most notably Space Shuttle-derived vehicles and Rus-M , but none were built. In

5612-643: The 2010s, super heavy-lift launch vehicles received interest once again, leading to the launch of the Falcon Heavy , the Space Launch System , and Starship , and the beginning of development of the Long March and Yenisei rockets . ^A Includes mass of Apollo command and service modules, Apollo Lunar Module, Spacecraft/LM Adapter , Saturn V Instrument Unit , S-IVB stage, and propellant for translunar injection ; payload mass to LEO

5734-463: The BOLE program is under development, with first firing expected in 2024. The Interim Cryogenic Propulsion Stage (ICPS) is a temporary upper stage for Block 1 versions of SLS, built by United Launch Alliance , a joint venture of Boeing and Lockheed Martin . The ICPS is essentially an "off-the-shelf" Delta Cryogenic Second Stage , with minimal modifications for SLS integration. The ICPS is intended as

5856-547: The Block 1B and Block 2 variants of SLS. Congressional action ultimately included the funding in the passed budget. One Gateway component that had been previously planned for the SLS Block 1B is expected to fly on the SpaceX Falcon Heavy rocket. On 1 May 2020, NASA awarded a contract extension to Aerojet Rocketdyne to manufacture 18 additional RS-25 engines with associated services for $ 1.79 billion, bringing

5978-557: The EUS with upgraded boosters. The ICPS for Artemis 1 was delivered by ULA to NASA about July 2017 and was housed at Kennedy Space Center as of November 2018. In mid-November 2014, construction of the first core stage hardware began using a new friction stir welding system in the South Vertical Assembly Building at NASA's Michoud Assembly Facility . Between 2015 and 2017, NASA test fired RS-25 engines in preparation for use on SLS. The core stage for

6100-510: The Energia booster was proposed in 2016, also to avoid pushing the Angara project. If developed, this vehicle could allow Russia to launch missions towards establishing a permanent Moon base with simpler logistics, launching just one or two 80-to-160-tonne super-heavy rockets instead of four 40-tonne Angara A5Vs implying quick-sequence launches and multiple in-orbit rendezvous. In February 2018,

6222-591: The European Vinci instead of the RL10 , which offered the same specific impulse but with 64% greater thrust, which would allow for the same performance at a lower cost. In 2018, Blue Origin submitted a proposal to replace the EUS with a cheaper alternative to be designed and fabricated by the company, but it was rejected by NASA in November 2019 on multiple grounds; these included lower performance compared to

SECTION 50

#1732773094242

6344-512: The NASA Exploration Ground Systems , currently at about $ 600 million per year, and anticipated to stay there through at least the first four launches of SLS. Also excluded are payloads that launch on the SLS, such as the Orion crew capsule, the predecessor programs that contributed to the development of the SLS, such as the Ares V Cargo Launch Vehicle project, funded from 2008 to 2010 for a total of $ 70 million, and

6466-476: The NASA Office of Inspector General has called NASA's cost savings goals highly unrealistic and other potential government customers have made it clear they have no interest in using SLS. As of 2020, three SLS versions are planned: Block 1, Block 1B, and Block 2. Each will use the same Core stage with its four main engines, but Block 1B will feature the Exploration Upper Stage (EUS), and Block 2 will combine

6588-567: The PIC to generate the pyro firing output. These signals, arm, fire 1 and fire 2, originate in the orbiter general-purpose computers (GPCs) and are transmitted to the MECs. The MECs reformat them to 28 volt DC signals for the PICs. The arm signal charges the PIC capacitor to 40 volts DC (minimum of 20 volts DC). The GPC launch sequence also controls certain critical main propulsion system valves and monitors

6710-602: The RS-25E, which will lower per-engine costs by over 30%. The thrust of each RS-25D engine has been increased from 492,000 lbf (2,188 kN), as on the Space Shuttle, to 513,000 lbf (2,281 kN) on the sixteen modernized engines. The RS-25E will further increase per-engine thrust to 522,000 lbf (2,321 kN). Blocks 1 and 1B of the SLS will use two five-segment solid rocket boosters. They use casing segments that were flown on Shuttle missions as parts of

6832-475: The SLS program passed its Key Decision Point C review and was deemed ready to enter full development, costs from February 2014 until its planned launch in September 2018 were estimated at $ 7.021 billion. Ground systems modifications and construction would require an additional $ 1.8 billion over the same time. In October 2018, NASA's Inspector General reported that the Boeing core stage contract had made up 40% of

6954-668: The SLS. However, independent agencies, such as the White House Office of Management and Budget and the NASA Office of Inspector General , have offered their own estimates. A White House Office of Management and Budget letter to the Senate Appropriations Committee in October 2019 estimated that SLS's total cost to the taxpayer was estimated at "over $ 2 billion" per launch. When questioned by

7076-424: The SRB. The solid rocket motor ignition commands were issued by the orbiter's computers through the master events controllers to the hold-down pyrotechnic initiator controllers (PICs) on the mobile launcher platform . They provided the ignition to the hold-down NSDs. The launch processing system monitored the SRB hold-down PICs for low voltage during the last 16 seconds before launch. PIC low voltage would initiate

7198-486: The SRBs from the external tank. The solid rocket motors in each cluster of four are ignited by firing redundant NSD pressure cartridges into redundant confined detonating fuse manifolds. The separation commands issued from the orbiter by the SRB separation sequence initiate the redundant NSD pressure cartridge in each bolt and ignite the BSMs to effect a clean separation. A range safety system (RSS) provides for destruction of

7320-505: The Saturn V rocket. It would have been able to carry up to 160,880 kg (354,680 lb) to low Earth orbit. The Nova designs were also studied by NASA before the agency chose the Saturn V in the early 1960s Nova was cancelled in 1964 and had reusable variants. Based on the recommendations of the Stafford Synthesis report, First Lunar Outpost (FLO) would have relied on a massive Saturn-derived launch vehicle known as

7442-422: The amount of time the solid rocket boosters can remain stacked to "about a year" from the time two segments are joined. The first and second segments of the Artemis I boosters were joined on 7 January 2021. NASA could choose to extend the time limit based on an engineering review. On 29 September 2021, Northrop Grumman indicated that the limit could be extended to eighteen months for Artemis I, based on an analysis of

SECTION 60

#1732773094242

7564-513: The atmosphere to near orbital velocity. It contains the liquid hydrogen and liquid oxygen tanks for the ascent phase, the forward and aft solid rocket booster attach points, avionics, and the Main Propulsion System (MPS), an assembly of the four RS-25 engines, associated plumbing and hydraulic gimbal actuators , and equipment for autogenous pressurization of the vehicle's tanks. The core stage provides approximately 25% of

7686-444: The boosters, identification of anomalies, and incremental design improvements. The two reusable SRBs provided the main thrust to lift the shuttle off the launch pad and up to an altitude of about 150,000 ft (28 mi; 46 km). While on the pad, the two SRBs carried the entire weight of the external tank and orbiter and transmitted the weight load through their structure to the mobile launcher platform . Each booster had

7808-423: The bypass line, at which point all the fuel was supplied to the fuel pump. When the APU speed reached 100%, the APU primary control valve closed, and the APU speed was controlled by the APU controller electronics. If the primary control valve logic failed to the open state, the secondary control valve assumed control of the APU at 112% speed. Each HPU on an SRB was connected to both servoactuators on that SRB by

7930-489: The commands to each servoactuator of the main engines and SRBs. Four independent flight control system channels and four ATVC channels controlled six main engine and four SRB ATVC drivers, with each driver controlling one hydraulic port on each main and SRB servoactuator. Each SRB servoactuator consisted of four independent, two-stage servovalves that received signals from the drivers. Each servovalve controlled one power spool in each actuator, which positioned an actuator ram and

8052-573: The consistency of a rubber eraser and is packed into each segment. The five-segment solid rocket boosters provide approximately 25% more total impulse than the Shuttle Solid Rocket Boosters. The stock of SLS Block 1 to 1B boosters is limited by the number of casings left over from the Shuttle program, which allows for eight flights of the SLS. On 2 March 2019, the Booster Obsolescence and Life Extension program

8174-568: The contract, saving the agency an estimated US$ 2 billion in direct launch costs over SLS, albeit at an increase to mission control costs due to longer flight. Super heavy-lift launch vehicle Only 14 such payloads were successfully launched before 2022: 12 as part of the Apollo program before 1972 and two Energia launches, in 1987 and 1988. Most planned crewed lunar and interplanetary missions depend on these launch vehicles. Several super heavy-lift launch vehicle concepts were produced in

8296-402: The cost of the program through 2025 to total at least $ 41 billion for four 209,000 lb (95 t) launches (1 uncrewed, 3 crewed), with the 290,000 lb (130 t) version ready no earlier than 2030. The Human Exploration Framework Team estimated unit costs for 'Block 0' at $ 1.6 billion and Block 1 at $ 1.86 billion in 2010. However, since these estimates were made, the Block 0 SLS vehicle

8418-497: The crewed Artemis II and III flights. The SLS Block 1 has a conical frustum -shaped interstage called the Launch Vehicle Stage Adapter between the core stage and the ICPS. It consists of sixteen aluminum-lithium panels made of 2195 aluminum alloy . Teledyne Brown Engineering is its builder. The first one cost $ 60 million, and the next two cost $ 85 million together. The Exploration Upper Stage (EUS)

8540-595: The data collected when the boosters were being stacked; an analysis weeks before the actual launch date later extended that to December 2022 for the boosters of Artemis I, almost two years after stacking. In late 2015, the SLS program was stated to have a 70% confidence level for the first Orion flight that carries crew , the second SLS flight overall, to happen by 2023; as of November 2021, NASA delayed Artemis II from 2023 to May 2024. In March 2023, NASA announced they had delayed Artemis II to November 2024 and in January 2024

8662-410: The design for the SLS, with the Orion spacecraft as payload. The SLS has considered several future development routes of potential launch configurations, with the planned evolution of the blocks of the rocket having been modified many times. Many options, all of which just needed to meet the congressionally mandated payload minimums, were considered, including a Block 0 variant with three main engines,

8784-466: The design was done by TRW , the project never moved forward due to the closing of NASA's Future Projects Branch . The Rus-M was a proposed Russian family of launchers whose development began in 2009. It would have had two super heavy variants: one able to lift 50–60 tons, and another able to lift 130–150 tons. SpaceX Interplanetary Transport System was a 12 m (39 ft) diameter launch vehicle concept unveiled in 2016. The payload capability

8906-511: The engine ready indications from the SSMEs. The MPS start commands are issued by the onboard computers at T−6.6 seconds (staggered start engine three, engine two, engine one all approximately within 0.25 of a second), and the sequence monitors the thrust buildup of each engine. All three SSMEs must reach the required 90% thrust within three seconds; otherwise, an orderly shutdown is commanded and safing functions are initiated. Normal thrust buildup to

9028-474: The event one orbiter main bus failed. The nominal operating voltage was 28 ± 4 volts DC. There were two self-contained, independent Hydraulic Power Units (HPUs) on each SRB, used to actuate the thrust vector control (TVC) system. Each HPU consisted of an auxiliary power unit (APU), fuel supply module, hydraulic pump , hydraulic reservoir and hydraulic fluid manifold assembly. The APUs were fueled by hydrazine and generated mechanical shaft power to drive

9150-494: The existing EUS design, incompatibility of the proposal with the height of the door of the Vehicle Assembly Building being only 390 feet (120 m), and unacceptable acceleration of Orion components such as its solar panels due to the higher thrust of the engines being used for the fuel tank. From 2009 to 2011, three full-duration static fire tests of five-segment solid rocket boosters were conducted under

9272-534: The first SLS, built at Michoud Assembly Facility by Boeing, had all four engines attached in November 2019, and it was declared finished by NASA in December 2019. The first core stage left Michoud Assembly Facility for comprehensive testing at Stennis Space Center in January 2020. The static firing test program at Stennis Space Center, known as the Green Run, operated all the core stage systems simultaneously for

9394-470: The first time. Test 7 (of 8), the wet dress rehearsal, was carried out in December 2020 and the fire (test 8) took place on 16 January 2021, but shut down earlier than expected, about 67 seconds in total rather than the desired eight minutes. The reason for the early shutdown was later reported to be because of conservative test commit criteria on the thrust vector control system, specific only for ground testing and not for flight. If this scenario occurred during

9516-401: The flight deck aboard the orbiter), as the flight reference computers translate navigation commands (steering to a particular waypoint in space, and at a particular time) into engine and motor nozzle gimbal commands, which orient the vehicle about its center of mass. As the forces on the vehicle change due to propellant consumption, increasing speed, changes in aerodynamic drag, and other factors,

9638-476: The flight stack (orbiter, external tank, SRBs) over onto the external tank. That rotating moment is initially countered by the hold-bolts. Prior to release of the vehicle stack for liftoff, the SRBs must simultaneously ignite and pressurize their combustion chambers and exhaust nozzles to produce a thrust-derived, net counter-rotating moment exactly equal to the SSME's rotating moment. With the SRBs reaching full thrust,

9760-407: The force to expel (positive expulsion) the fuel from the tank to the fuel distribution line, maintaining a positive fuel supply to the APU throughout its operation. In the APU, a fuel pump boosted the hydrazine pressure and fed it to a gas generator. The gas generator catalytically decomposed the hydrazine into hot, high-pressure gas; a two-stage turbine converted this into mechanical power, driving

9882-446: The four-segment Space Shuttle Solid Rocket Boosters . They possess an additional center segment, new avionics, and lighter insulation, but lack a parachute recovery system, as they will not be recovered after launch. The propellants for the solid rocket boosters are aluminum powder, which is very reactive, and ammonium perchlorate, a powerful oxidizer. They are held together by a binder, polybutadiene acrylonitrile (PBAN). The mixture has

10004-411: The ground launch sequence is terminated. Timing sequence referencing in ignition is critical for a successful liftoff and ascent flight. The explosive hold-down bolts relieve (through the launch support pedestals and pad structure) the asymmetric vehicle dynamic loads caused by the SSME ignition and thrust buildup, and applied thrust bearing loads. Without the hold-down bolts the SSMEs would violently tip

10126-430: The hold-down bolts are blown, releasing the vehicle stack, the net rotating moment is zero, and the net vehicle thrust (opposing gravity) is positive, lifting the orbiter stack vertically from the launch pedestal, controllable through the coordinated gimbal movements of the SSMEs and the SRB exhaust nozzles. During ascent, multiple all-axis accelerometers detect and report the vehicle's flight and orientation (referencing

10248-402: The hold-down stud. The stud traveled downward because of the release of tension in the stud (pretensioned before launch), NSD gas pressure and gravity. The stud was stopped by the stud deceleration stand, which contained sand. The hold-down stud was 28 in (710 mm) long and 3.5 in (89 mm) in diameter. The frangible nut was captured in a blast container mounted on the aft skirt of

10370-470: The launch director called a scrub due to a temperature sensor falsely indicating that an RS-25 engine's hydrogen bleed intake was too warm. The 3 September attempt was then scrubbed due to a hydrogen leak in the tail service mast quick disconnect arm, which was fixed; the next launch option was at first a period in late October and then a launch in mid-November, due to unfavorable weather during Hurricane Ian . It launched on 16 November. NASA originally limited

10492-479: The manufacturer and then shipped to Kennedy Space Center by rail for final assembly. The segments were fixed together using circumferential tang, clevis, and clevis pin fastening, and sealed with O-rings (originally two, changed to three after the Challenger Disaster in 1986) and heat-resistant putty. Each solid rocket booster had four hold-down posts that fit into corresponding support posts on

10614-432: The mass of the Shuttle stack at liftoff. The motor segments of the SRBs were manufactured by Thiokol of Brigham City, Utah , which was later purchased by ATK . The prime contractor for most other components of the SRBs, as well as for the integration of all the components and retrieval of the spent SRBs, was USBI, a subsidiary of Pratt & Whitney . The contract was subsequently transitioned to United Space Alliance ,

10736-463: The mission was further delayed to September 2025. Efforts have been made to expand the usage of SLS beyond the Artemis missions to launching NASA's robotic space probes and observatories . While the vibrations of SLS's large solid-rocket boosters have been at first thought to be incompatible with many scientific payloads due to the excessive vibration they generate, but on later analysis “[it] really

10858-411: The mobile launcher platform. Hold-down studs held the SRB and launcher platform posts together. Each stud had a nut at each end, the top one being a frangible nut . The top nut contained two explosive charges initiated by NASA standard detonators (NSDs), which were ignited at solid rocket motor ignition commands. When the two NSDs were ignited at each hold down, the frangible nut fractured, releasing

10980-467: The nozzle at water splashdown and prevent damage to the nozzle flexible bearing. Each SRB contained three rate gyro assemblies (RGAs), with each RGA containing one pitch and one yaw gyro. These provided an output proportional to angular rates about the pitch and yaw axes to the orbiter computers and guidance, navigation and control system during first-stage ascent flight in conjunction with the orbiter roll rate gyros until SRB separation. At SRB separation,

11102-432: The nozzle rock and tilt servoactuators . The HPU controller electronics were located in the SRB aft integrated electronic assemblies (IEAs ) on the aft external tank attach rings. The HPUs and their fuel systems were isolated from each other. Each fuel supply module (tank) contained 22 lb (10.0 kg) of hydrazine. The fuel tank was pressurized with gaseous nitrogen at 400  psi (2.8  MPa ), which provided

11224-417: The nozzle to control the direction of thrust. The four servovalves operating each actuator provided a force-summed majority-voting arrangement to position the power spool. With four identical commands to the four servovalves, the actuator force-sum action prevented, instantaneously, a single erroneous input affecting power ram motion. If differential-pressure sensing detected the erroneous input persisting over

11346-495: The ocean approximately 122 nautical miles (226  km ) downrange, after which the two SRBs were recovered. The SRBs helped take the Space Shuttle to an altitude of 28 miles (45 km) and a speed of 3,094 mph (4,979 km/h) along with the main engines. The SRBs committed the shuttle to liftoff and ascent, without the possibility of launch abort, until both motors had fully consumed their propellants and had simultaneously been jettisoned by explosive jettisoning bolts from

11468-582: The payload would cost $ 1 billion for Orion and $ 300 million for the European Service Module . An October 2023 report found that recurring production costs for SLS, excluding development and integration costs, are estimated to be at least $ 2.5 billion per launch. NASA has said that it is working with Boeing to bring down the cost of SLS launches and that a higher launch frequency could potentially lead to economies of scale, and would allow fixed costs to be spread out over more launches. However,

11590-542: The range safety system cross-strap wiring connecting each SRB Range Safety System (RSS) and the ET RSS with each other. The aft attachment points consist of three separate struts: upper, diagonal and lower. Each strut contains one bolt with an NSD pressure cartridge at each end. The upper strut also carries the umbilical interface between its SRB and the external tank and on to the orbiter. There are four booster separation motors (BSMs) on each end of each SRB. The BSMs separate

11712-415: The redundant NSDs to fire through a thin barrier seal down a flame tunnel. This ignites a pyro. booster charge, which is retained in the safe and arm device behind a perforated plate. The booster charge ignites the propellant in the igniter initiator; and combustion products of this propellant ignite the solid rocket motor initiator, which fires down the entire vertical length of the solid rocket motor igniting

11834-591: The remainder of the vehicle. Only then could any conceivable set of launch or post-liftoff abort procedures be contemplated. In addition, failure of an individual SRB's thrust output or ability to adhere to the designed performance profile was probably not survivable. The SRBs were the largest solid-propellant motors ever flown and the first of such large rockets designed for reuse. Each is 149.16 ft (45.46 m) long and 12.17 ft (3.71 m) in diameter. Each SRB weighed approximately 1,300,000 lb (590 t) at launch. The two SRBs constituted about 69% of

11956-442: The required 90% thrust level will result in the SSMEs being commanded to the lift off position at T−3 seconds as well as the fire 1 command being issued to arm the SRBs. At T−3 seconds, the vehicle base bending load modes are allowed to initialize (referred to as the "twang", movement of approximately 25.5 in (650 mm) measured at the tip of the external tank, with movement towards the external tank). The fire 2 commands cause

12078-451: The retirement of the Space Shuttle . The act set out certain goals, such as being able to lift 70–100 tons into low earth orbit with evolvability to 130 tons, a target date of 31 December 2016 for the system to be fully operational, and a directive to use "to the extent practicable" existing components, hardware, and workforce from the Space Shuttle and from Ares I . On 14 September 2011, NASA announced their plan to meet these requirements:

12200-565: The rocket and boosters but also ground support and logistical arrangements. On 7 August 2014, the SLS Block 1 passed a milestone known as Key Decision Point C and entered full-scale development, with an estimated launch date of November 2018. In 2013, NASA and Boeing analyzed the performance of several Exploration Upper Stage (EUS) engine options. The analysis was based on a second-stage usable propellant load of 105 metric tons, and compared stages with four RL10 engines, two MARC-60 engines, or one J-2X engine. In 2014, NASA also considered using

12322-481: The rocket for Artemis I. It left Stennis on 24 April and arrived at Kennedy on 27 April. It was refurbished there in preparation for stacking. On 12 June 2021, NASA announced the assembly of the first SLS rocket was completed at the Kennedy Space Center. The assembled SLS was used for the uncrewed Artemis I mission in 2022. The first SLS, for Artemis I, launched an Orion spacecraft into a lunar orbit on

12444-510: The rocket would have a core stage with a diameter of 10 meters. Long March 9 is expected to carry a payload of over 150 tonnes into low-Earth orbit, with a capacity of over 50 tonnes for Earth-Moon transfer orbit. Development was approved in 2021. Yenisei , a super heavy-lift launch vehicle using existing components instead of pushing the less-powerful Angara A5 V project, was proposed by Russia's RSC Energia in August 2016. A revival of

12566-519: The shuttle, surpassed it as the most powerful solid rocket motors ever flown, after the launch of the Artemis 1 mission in 2022. Each Space Shuttle SRB provided a maximum 14.7  MN (3,300,000  lbf ) thrust, roughly double the most powerful single- combustion chamber liquid-propellant rocket engine ever flown, the Rocketdyne F-1 . With a combined mass of about 1,180 t (1,160 long tons; 1,300 short tons), they comprised over half

12688-418: The solid rocket motor propellant along its entire surface area instantaneously. At T−0, the two SRBs are ignited, under command of the four onboard computers; separation of the four explosive bolts on each SRB is initiated; the two T-0 umbilicals (one on each side of the spacecraft) are retracted; the onboard master timing unit, event timer and mission event timers are started; the three SSMEs are at 100%; and

12810-495: The switching valve closed when the valve was in the secondary position. When the valve was closed, a signal was sent to the APU controller, that inhibited the 100% APU speed control logic and enabled the 112% APU speed control logic. The 100-percent APU speed enabled one APU/HPU to supply sufficient operating hydraulic pressure to both servoactuators of that SRB. The APU 100-percent speed corresponded to 72,000 rpm, 110% to 79,200 rpm, and 112% to 80,640 rpm. The hydraulic pump speed

12932-468: The terms solid rocket motor and solid rocket booster are often used interchangeably, in technical use they have specific meanings. The term solid rocket motor applied to the propellant, case, igniter and nozzle. Solid rocket booster applied to the entire rocket assembly, which included the rocket motor as well as the recovery parachutes, electronic instrumentation, separation rockets, range safety destruct system, and thrust vector control. Each booster

13054-631: The total RS-25 contract value to almost $ 3.5 billion. NASA has spent $ 26.4 billion on SLS development since 2011, through 2023, in nominal dollars. This is equivalent to $ 32 billion in 2024 dollars using the NASA New Start Inflation Indices. In 2024, the US Congress approved "up to" $ 2,600 million for the NASA Space Launch System. In January 2024 NASA announced plans for a first crewed flight of

13176-644: The total lift-off mass. The primary propellants were ammonium perchlorate ( oxidizer ) and atomized aluminum powder ( fuel ), and the total propellant for each solid rocket motor weighed approximately 1,100,000 lb (500 t) (see § Propellant ). The inert weight of each SRB was approximately 200,000 pounds (91 t). Primary elements of each booster were the motor (including case, propellant, igniter, and nozzle ), structure, separation systems, operational flight instrumentation, recovery avionics, pyrotechnics , deceleration system, thrust vector control system, and range safety destruct system. While

13298-404: The vehicle automatically adjusts its orientation in response to its dynamic control command inputs. The SRBs are jettisoned from the space shuttle at an altitude of about 146,000 ft (45 km). SRB separation is initiated when the three solid-rocket motor-chamber pressure transducers are processed in the redundancy-management middle-value select and the head-end chamber pressure of both SRBs

13420-502: The vehicle in all three axes (roll, pitch, and yaw). The ascent thrust vector control portion of the flight control system directed the thrust of the three shuttle main engines and the two SRB nozzles to control shuttle attitude and trajectory during lift-off and ascent. Commands from the guidance system were transmitted to the Ascent Thrust Vector Control (ATVC) drivers, which transmitted signals proportional to

13542-424: The vehicle's thrust at liftoff, the rest coming from the solid rocket boosters. The stage measures 213 ft (65 m) long by 28 ft (8.4 m) in diameter and is visually similar to the Space Shuttle external tank . It is made mostly of 2219 aluminum alloy , and contains numerous improvements to manufacturing processes, including friction stir welding for the barrel sections, and integrated milling for

13664-464: The weight of the ICPS as part of the payload. At the time of SLS core stage separation, Artemis I was travelling on an initial 1,806 by 30 km (1,122 by 19 mi) transatmospheric orbital trajectory. This trajectory ensured safe disposal of the core stage. ICPS then performed orbital insertion and a subsequent translunar injection burn to send Orion towards the Moon. The ICPS will be human-rated for

13786-479: The КРК СТК (space rocket complex of the super-heavy class) design was updated to lift at least 90 tonnes to LEO and 20 tonnes to lunar polar orbit, and to be launched from Vostochny Cosmodrome . The first flight is scheduled for 2028, with Moon landings starting in 2030. It looks like this proposal has been at least paused. Blue Origin has plans for a project following their New Glenn rocket, termed New Armstrong , which some media sources have speculated will be

13908-470: Was 3,600 rpm and supplied hydraulic pressure of 3,050 ± 50 psi (21.03 ± 0.34 MPa). A high pressure relief valve provided overpressure protection to the hydraulic system and relieved at 3,750 psi (25.9 MPa). The APUs/HPUs and hydraulic systems were reusable for 20 missions. Each SRB had two hydraulic gimbal servoactuators, to move the nozzle up/down and side-to-side. This provided thrust vectoring to help control

14030-539: Was a nonissue at the end of the day.” As of October 2024, NASA has studied using SLS for Neptune Odyssey , Europa Lander , Enceladus Orbilander , Persephone, HabEx , Origins Space Telescope , LUVOIR , Lynx , and Interstellar probe . Initially, Congress mandated that NASA use the SLS to launch the Europa Clipper probe. However, concerns about the SLS's availability led NASA to seek congressional approval for competitive launch bids. SpaceX ultimately won

14152-478: Was announced, with the goal of developing new solid rocket boosters for SLS Block 2. These boosters will be built by Northrop Grumman Space Systems , and will be derived from the composite-casing solid rocket boosters then in development for the canceled OmegA launch vehicle, and are projected to increase Block 2's payload to 290,000 lb (130 t) to low Earth orbit (LEO) and at least 101,000 lb (46 t) to trans-lunar injection . As of July 2021,

14274-508: Was attached to the external tank at the SRB's aft frame by two lateral sway braces and a diagonal attachment. The forward end of each SRB was attached to the external tank at the forward end of the SRB's forward skirt. On the launch pad, each booster also was attached to the mobile launcher platform at the aft skirt by four holddown studs, with frangible nuts that were severed at liftoff. The boosters were composed of seven individually manufactured steel segments. These were assembled in pairs by

14396-463: Was automated for most sections of the core stage, saving 12 days in the schedule. The Artemis II forward skirt, the foremost component of the core stage, was affixed on the liquid oxygen tank in late May 2021. By 25 September 2023 the core stage was functionally complete, as all sections were assembled and the four RS-25 engines had been installed. As of May 2023, the complete core stage was set to ship to NASA in late fall 2023, eight months later than

14518-556: Was dropped in late 2011, and the design was not completed. In September 2012, an SLS deputy project manager stated that $ 500 million is a reasonable target average cost per flight for the SLS program. In 2013, the Space Review estimated the cost per launch at $ 5 billion, depending on the rate of launches. NASA announced in 2013 that the European Space Agency will build the Orion service module . In August 2014, as

14640-496: Was predicted originally. The complete core stage was delivered in July 2024. For Artemis III, assembly of elements of the thrust structure began at Michoud Assembly Facility in early 2021. The liquid hydrogen tank for Artemis III was originally planned to be the Artemis I tank, but it was set aside as the welds were found to be faulty. Repair techniques were developed, and the tank re-entered production and will be proof tested for strength, for use on Artemis III. As of July 2021, Boeing

14762-613: Was suspended in May 1974 and formally cancelled in March 1976. The Soviet UR-700 rocket design concept competed against the N1, but was never developed. In the concept, it was to have had a payload capacity of up to 151 t (333,000 lb) to low earth orbit. During project Aelita (1969–1972), the Soviets were developing a way to beat the Americans to Mars. They designed the UR-700 A,

14884-506: Was to be 550 t (1,210,000 lb) in an expendable configuration or 300 t (660,000 lb) in a reusable configuration. In 2017, the 12 m evolved into a 9 m (30 ft) diameter concept Big Falcon Rocket , which became the SpaceX Starship . Space Shuttle Solid Rocket Booster The Space Shuttle Solid Rocket Booster ( SRB ) was the first solid-propellant rocket to be used for primary propulsion on

#241758