102-576: The Space Shuttle Solid Rocket Booster ( SRB ) was the first solid-propellant rocket to be used for primary propulsion on 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
204-413: A casing, nozzle , grain ( propellant charge ), and igniter . The solid grain mass burns in a predictable fashion to produce exhaust gases, the flow of which is described by Taylor–Culick flow . The nozzle dimensions are calculated to maintain a design chamber pressure, while producing thrust from the exhaust gases. Once ignited, a simple solid rocket motor cannot be shut off, as it contains all
306-487: A control moment. For example, the Titan III C solid boosters injected nitrogen tetroxide for LITV; the tanks can be seen on the sides of the rocket between the main center stage and the boosters. An early Minuteman first stage used a single motor with four gimballed nozzles to provide pitch, yaw, and roll control. A typical, well-designed ammonium perchlorate composite propellant (APCP) first-stage motor may have
408-514: 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
510-541: A high-energy (yet unstable) monopropellant and the other acts as a lower-energy stabilizing (and gelling) monopropellant. In typical circumstances, nitroglycerin is dissolved in a nitrocellulose gel and solidified with additives. DB propellants are implemented in applications where minimal smoke is required yet a medium-high I sp of roughly 235 s (2.30 km/s) is required. The addition of metal fuels (such as aluminium ) can increase performance to around 250 s (2.5 km/s), though metal oxide nucleation in
612-502: 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
714-571: 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
816-441: 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
918-564: A long history as the final boost stage for satellites due to their simplicity, reliability, compactness and reasonably high mass fraction . A spin-stabilized solid rocket motor is sometimes added when extra velocity is required, such as for a mission to a comet or the outer solar system, because a spinner does not require a guidance system (on the newly added stage). Thiokol's extensive family of mostly titanium-cased Star space motors has been widely used, especially on Delta launch vehicles and as spin-stabilized upper stages to launch satellites from
1020-499: A loss in motor performance. Polyurethane-bound aluminium-APCP solid fuel was used in the submarine-launched Polaris missiles . APCP used in the space shuttle Solid Rocket Boosters consisted of ammonium perchlorate (oxidizer, 69.6% by weight), aluminium (fuel, 16%), iron oxide (a catalyst, 0.4%), polybutadiene acrylonitrile (PBAN) polymer (a non-urethane rubber binder that held the mixture together and acted as secondary fuel, 12.04%), and an epoxy curing agent (1.96%). It developed
1122-483: 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
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#17327721281211224-440: 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
1326-594: A propellant mass fraction of 92.23% while the 14,000-kilogram (31,000 lb) Castor 30 upper stage developed for Orbital Science's Taurus II COTS (Commercial Off The Shelf) (International Space Station resupply) launch vehicle has a 91.3% propellant fraction with 2.9% graphite epoxy motor casing, 2.4% nozzle, igniter and thrust vector actuator, and 3.4% non-motor hardware including such things as payload mount, interstage adapter, cable raceway, instrumentation, etc. Castor 120 and Castor 30 are 2.36 and 2.34 meters (93 and 92 in) in diameter, respectively, and serve as stages on
1428-895: A range of 5,500 metres (3.4 mi). By the end of World War II total production of rocket launchers reached about 10,000. with 12 million rockets of the RS type produced for the Soviet armed forces. In the United States modern castable composite solid rocket motors were invented by the American aerospace engineer Jack Parsons at Caltech in 1942 when he replaced double base propellant with roofing asphalt and potassium perchlorate . This made possible slow-burning rocket motors of adequate size and with sufficient shelf-life for jet-assisted take off applications. Charles Bartley , employed at JPL (Caltech), substituted curable synthetic rubber for
1530-654: 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
1632-492: A simple, solid-propellant rocket tube that was filled with gunpowder. One open end allowed the gas to escape and was attached to a long stick that acted as a guidance system for flight direction control. The first rockets with tubes of cast iron were used by the Kingdom of Mysore under Hyder Ali and Tipu Sultan in the 1750s. These rockets had a reach of targets up to a mile and a half away. These were extremely effective in
1734-414: A single-piece nozzle or 304 s (2.98 km/s) with a high-area-ratio telescoping nozzle. Aluminium is used as fuel because it has a reasonable specific energy density, a high volumetric energy density, and is difficult to ignite accidentally. Composite propellants are cast, and retain their shape after the rubber binder, such as Hydroxyl-terminated polybutadiene (HTPB), cross-links (solidifies) with
1836-943: A small charge that is set off when the propellant is exhausted after a time delay. This charge can be used to trigger a camera , or deploy a parachute . Without this charge and delay, the motor may ignite a second stage (black powder only). In mid- and high-power rocketry , commercially made APCP motors are widely used. They can be designed as either single-use or reloadables. These motors are available in impulse ranges from "A" (1.26 Ns– 2.50 Ns) to "O" (20.48 kNs – 40.96 kNs), from several manufacturers. They are manufactured in standardized diameters and varying lengths depending on required impulse. Standard motor diameters are 13, 18, 24, 29, 38, 54, 75, 98, and 150 millimeters. Different propellant formulations are available to produce different thrust profiles, as well as special effects such as colored flames, smoke trails, or large quantities of sparks (produced by adding titanium sponge to
1938-476: 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
2040-406: A specific impulse of 242 seconds (2.37 km/s) at sea level or 268 seconds (2.63 km/s) in a vacuum. The 2005-2009 Constellation Program was to use a similar PBAN-bound APCP. In 2009, a group succeeded in creating a propellant of water and nanoaluminium ( ALICE ). Typical HEC propellants start with a standard composite propellant mixture (such as APCP) and add a high-energy explosive to
2142-466: A sugar fuel (typically dextrose , sorbitol , or sucrose ) that are cast into shape by gently melting the propellant constituents together and pouring or packing the amorphous colloid into a mold. Candy propellants generate a low-medium specific impulse of roughly 130 s (1.3 km/s) and, thus, are used primarily by amateur and experimental rocketeers. DB propellants are composed of two monopropellant fuel components where one typically acts as
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#17327721281212244-478: 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
2346-751: 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
2448-684: A vacuum specific impulse ( I sp ) as high as 285.6 seconds (2.801 km/s) (Titan IVB SRMU). This compares to 339.3 s (3.327 km/s) for RP1/LOX (RD-180) and 452.3 s (4.436 km/s) for LH 2 /LOX (Block II RS-25 ) bipropellant engines. Upper stage specific impulses are somewhat greater: as much as 303.8 s (2.979 km/s) for APCP (Orbus 6E), 359 s (3.52 km/s) for RP1/LOX (RD-0124) and 465.5 s (4.565 km/s) for LH 2 /LOX (RL10B-2). Propellant fractions are usually somewhat higher for (non-segmented) solid propellant first stages than for upper stages. The 53,000-kilogram (117,000 lb) Castor 120 first stage has
2550-619: A very primitive form of solid-propellant rocket. Illustrations and descriptions in the 14th century Chinese military treatise Huolongjing by the Ming dynasty military writer and philosopher Jiao Yu confirm that the Chinese in 1232 used proto solid propellant rockets then known as " fire arrows " to drive back the Mongols during the Mongol siege of Kaifeng . Each arrow took a primitive form of
2652-492: Is another pressed propellant that does not find any practical application outside specialized amateur rocketry circles due to its poor performance (as most ZS burns outside the combustion chamber) and fast linear burn rates on the order of 2 m/s. ZS is most often employed as a novelty propellant as the rocket accelerates extremely quickly leaving a spectacular large orange fireball behind it. In general, rocket candy propellants are an oxidizer (typically potassium nitrate) and
2754-552: Is cheap and fairly easy to produce. The fuel grain is typically a mixture of pressed fine powder (into a solid, hard slug), with a burn rate that is highly dependent upon exact composition and operating conditions. The specific impulse of black powder is low, around 80 s (0.78 km/s). The grain is sensitive to fracture and, therefore, catastrophic failure. Black powder does not typically find use in motors above 40 newtons (9.0 pounds-force) thrust. Composed of powdered zinc metal and powdered sulfur (oxidizer), ZS or "micrograin"
2856-473: 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
2958-408: Is equal to the volumetric rate times the fuel density ρ {\displaystyle \rho } : Several geometric configurations are often used depending on the application and desired thrust curve : The casing may be constructed from a range of materials. Cardboard is used for small black powder model motors, whereas aluminium is used for larger composite-fuel hobby motors. Steel
3060-400: 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
3162-574: 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
Space Shuttle Solid Rocket Booster - Misplaced Pages Continue
3264-434: 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
3366-428: Is non-polluting: acid-free, solid particulates-free, and lead-free. It is also smokeless and has only a faint shock diamond pattern that is visible in the otherwise transparent exhaust. Without the bright flame and dense smoke trail produced by the burning of aluminized propellants, these smokeless propellants all but eliminate the risk of giving away the positions from which the missiles are fired. The new CL-20 propellant
3468-411: Is shock-insensitive (hazard class 1.3) as opposed to current HMX smokeless propellants which are highly detonable (hazard class 1.1). CL-20 is considered a major breakthrough in solid rocket propellant technology but has yet to see widespread use because costs remain high. Electric solid propellants (ESPs) are a family of high performance plastisol solid propellants that can be ignited and throttled by
3570-434: Is to achieve mid-course exo-atmospheric ABM capability from missiles small enough to fit in existing ship-based below-deck vertical launch tubes and air-mobile truck-mounted launch tubes. CL-20 propellant compliant with Congress' 2004 insensitive munitions (IM) law has been demonstrated and may, as its cost comes down, be suitable for use in commercial launch vehicles, with a very significant increase in performance compared with
3672-664: The Battle of Khalkhin Gol . In June 1938, the RNII began developing a multiple rocket launcher based on the RS-132 rocket. In August 1939, the completed product was the BM-13 / Katyusha rocket launcher . Towards the end of 1938 the first significant large scale testing of the rocket launchers took place, 233 rockets of various types were used. A salvo of rockets could completely straddle a target at
3774-668: The Reactive Scientific Research Institute (RNII) with the development of the RS-82 and RS-132 rockets , including designing several variations for ground-to-air, ground-to-ground, air-to-ground and air-to-air combat. The earliest known use by the Soviet Air Force of aircraft-launched unguided anti-aircraft rockets in combat against heavier-than-air aircraft took place in August 1939 , during
3876-541: 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 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
3978-788: The Second Anglo-Mysore War that ended in a humiliating defeat for the British East India Company . Word of the success of the Mysore rockets against the British triggered research in England, France, Ireland and elsewhere. When the British finally conquered the fort of Srirangapatana in 1799, hundreds of rockets were shipped off to the Royal Arsenal near London to be reverse-engineered. This led to
4080-500: The fuel and oxidizer mass. Grain geometry and chemistry are then chosen to satisfy the required motor characteristics. The following are chosen or solved simultaneously. The results are exact dimensions for grain, nozzle, and case geometries: The grain may or may not be bonded to the casing. Case-bonded motors are more difficult to design, since the deformation of the case and the grain under flight must be compatible. Common modes of failure in solid rocket motors include fracture of
4182-582: The 2010s include the European Ariane 5 , US Atlas V and Space Shuttle , and Japan's H-II . The largest solid rocket motors ever built were Aerojet's three 6.60-meter (260 in) monolithic solid motors cast in Florida. Motors 260 SL-1 and SL-2 were 6.63 meters (261 in) in diameter, 24.59 meters (80 ft 8 in) long, weighed 842,900 kilograms (1,858,300 lb), and had a maximum thrust of 16 MN (3,500,000 lbf). Burn duration
Space Shuttle Solid Rocket Booster - Misplaced Pages Continue
4284-605: The Athena IC and IIC commercial launch vehicles. A four-stage Athena II using Castor 120s as both first and second stages became the first commercially developed launch vehicle to launch a lunar probe ( Lunar Prospector ) in 1998. Solid rockets can provide high thrust for relatively low cost. For this reason, solids have been used as initial stages in rockets (for example the Space Shuttle ), while reserving high specific impulse engines, especially less massive hydrogen-fueled engines, for higher stages. In addition, solid rockets have
4386-567: 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
4488-424: 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
4590-486: 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
4692-493: The aid of a curative additive. Because of its high performance, moderate ease of manufacturing, and moderate cost, APCP finds widespread use in space, military, and amateur rockets, whereas cheaper and less efficient ANCP finds use in amateur rocketry and gas generators . Ammonium dinitramide , NH 4 N(NO 2 ) 2 , is being considered as a 1-to-1 chlorine-free substitute for ammonium perchlorate in composite propellants. Unlike ammonium nitrate, ADN can be substituted for AP without
4794-1310: The ancient Chinese, and in the 13th century, the Mongols played a pivotal role in facilitating their westward adoption. All rockets used some form of solid or powdered propellant until the 20th century, when liquid-propellant rockets offered more efficient and controllable alternatives. Because of their simplicity and reliability, solid rockets are still used today in military armaments worldwide, model rockets , solid rocket boosters and on larger applications. Since solid-fuel rockets can remain in storage for an extended period without much propellant degradation, and since they almost always launch reliably, they have been frequently used in military applications such as missiles . The lower performance of solid propellants (as compared to liquids) does not favor their use as primary propulsion in modern medium-to-large launch vehicles customarily used for commercial satellites and major space probes. Solids are, however, frequently used as strap-on boosters to increase payload capacity or as spin-stabilized add-on upper stages when higher-than-normal velocities are required. Solid rockets are used as light launch vehicles for low Earth orbit (LEO) payloads under 2 tons or escape payloads up to 500 kilograms (1,100 lb). A simple solid rocket motor consists of
4896-459: The application of electric current. Unlike conventional rocket motor propellants that are difficult to control and extinguish, ESPs can be ignited reliably at precise intervals and durations. It requires no moving parts and the propellant is insensitive to flames or electrical sparks. Solid propellant rocket motors can be bought for use in model rocketry ; they are normally small cylinders of black powder fuel with an integral nozzle and optionally
4998-442: 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
5100-422: 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
5202-467: The cargo bay of the Space Shuttle. Star motors have propellant fractions as high as 94.6% but add-on structures and equipment reduce the operating mass fraction by 2% or more. Higher performing solid rocket propellants are used in large strategic missiles (as opposed to commercial launch vehicles). HMX , C 4 H 8 N 4 (NO 2 ) 4 , a nitramine with greater energy than ammonium perchlorate,
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#17327721281215304-452: The casing is often implemented, which ablates to prolong the life of the motor casing. A convergent-divergent design accelerates the exhaust gas out of the nozzle to produce thrust. The nozzle must be constructed from a material that can withstand the heat of the combustion gas flow. Often, heat-resistant carbon-based materials are used, such as amorphous graphite or reinforced carbon–carbon . Some designs include directional control of
5406-489: 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
5508-454: The currently favored APCP solid propellants. With a specific impulse of 309 s already demonstrated by Peacekeeper's second stage using HMX propellant, the higher energy of CL-20 propellant can be expected to increase specific impulse to around 320 s in similar ICBM or launch vehicle upper stage applications, without the explosive hazard of HMX. An attractive attribute for military use is the ability for solid rocket propellant to remain loaded in
5610-511: 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
5712-474: 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
5814-611: The exhaust can turn the smoke opaque. A powdered oxidizer and powdered metal fuel are intimately mixed and immobilized with a rubbery binder (that also acts as a fuel). Composite propellants are often either ammonium-nitrate -based (ANCP) or ammonium-perchlorate -based (APCP). Ammonium nitrate composite propellant often uses magnesium and/or aluminium as fuel and delivers medium performance (I sp of about 210 s (2.1 km/s)) whereas ammonium perchlorate composite propellant often uses aluminium fuel and delivers high performance: vacuum I sp up to 296 s (2.90 km/s) with
5916-542: The exhaust. This can be accomplished by gimballing the nozzle, as in the Space Shuttle SRBs, by the use of jet vanes in the exhaust as in the V-2 rocket, or by liquid injection thrust vectoring (LITV). LITV consists of injecting a liquid into the exhaust stream after the nozzle throat. The liquid then vaporizes, and in most cases chemically reacts, adding mass flow to one side of the exhaust stream and thus providing
6018-563: The first industrial manufacture of military rockets with the Congreve rocket in 1804. In 1921 the Soviet research and development laboratory Gas Dynamics Laboratory began developing solid-propellant rockets, which resulted in the first launch in 1928, that flew for approximately 1,300 metres. These rockets were used in 1931 for the world's first successful use of rockets to assist take-off of aircraft . The research continued from 1933 by
6120-401: 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,
6222-476: 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,
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#17327721281216324-407: 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
6426-445: The functional definition of double base propellants. One of the most active areas of solid propellant research is the development of high-energy, minimum-signature propellant using C 6 H 6 N 6 (NO 2 ) 6 CL-20 nitroamine ( China Lake compound #20), which has 14% higher energy per mass and 20% higher energy density than HMX. The new propellant has been successfully developed and tested in tactical rocket motors. The propellant
6528-470: The gooey asphalt, creating a flexible but geometrically stable load-bearing propellant grain that bonded securely to the motor casing. This made possible much larger solid rocket motors. Atlantic Research Corporation significantly boosted composite propellant I sp in 1954 by increasing the amount of powdered aluminium in the propellant to as much as 20%. Solid-propellant rocket technology got its largest boost in technical innovation, size and capability with
6630-440: The grain, failure of case bonding, and air pockets in the grain. All of these produce an instantaneous increase in burn surface area and a corresponding increase in exhaust gas production rate and pressure, which may rupture the casing. Another failure mode is casing seal failure. Seals are required in casings that have to be opened to load the grain. Once a seal fails, hot gas will erode the escape path and result in failure. This
6732-411: 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
6834-409: The ground station. The RSS was used only when the shuttle vehicle violates a launch trajectory red line. Solid-propellant rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants ( fuel / oxidizer ). The earliest rockets were solid-fuel rockets powered by gunpowder . The inception of gunpowder rockets in warfare can be credited to
6936-430: 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
7038-402: 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
7140-658: The ingredients necessary for combustion within the chamber in which they are burned. More advanced solid rocket motors can be throttled , or extinguished and re-ignited, by control of the nozzle geometry or through the use of vent ports. Further, pulsed rocket motors that burn in segments, and that can be ignited upon command are available. Modern designs may also include a steerable nozzle for guidance, avionics , recovery hardware ( parachutes ), self-destruct mechanisms, APUs , controllable tactical motors, controllable divert and attitude control motors, and thermal management materials. The medieval Song dynasty Chinese invented
7242-478: 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
7344-537: The mix). Almost all sounding rockets use solid motors. Due to reliability, ease of storage and handling, solid rockets are used on missiles and ICBMs. Solid rockets are suitable for launching small payloads to orbital velocities, especially if three or more stages are used. Many of these are based on repurposed ICBMs. Propellants Too Many Requests If you report this error to the Wikimedia System Administrators, please include
7446-560: The mix. This extra component usually is in the form of small crystals of RDX or HMX , both of which have higher energy than ammonium perchlorate. Despite a modest increase in specific impulse, implementation is limited due to the increased hazards of the high-explosive additives. Composite modified double base propellants start with a nitrocellulose/nitroglycerin double base propellant as a binder and add solids (typically ammonium perchlorate (AP) and powdered aluminium ) normally used in composite propellants. The ammonium perchlorate makes up
7548-411: 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
7650-492: The most powerful solid rocket motors to ever launch humans. The Space Launch System (SLS) SRBs, adapted from 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,
7752-420: The next 50 years. By the later 1980s and continuing to 2020, these government-developed highly-capable solid rocket technologies have been applied to orbital spaceflight by many government-directed programs , most often as booster rockets to add extra thrust during the early ascent of their primarily liquid rocket launch vehicles . Some designs have had solid rocket upper stages as well. Examples flying in
7854-467: 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,
7956-431: 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
8058-417: 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
8160-495: 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
8262-569: The oxygen deficit introduced by using nitrocellulose , improving the overall specific impulse. The aluminium improves specific impulse as well as combustion stability. High performing propellants such as NEPE-75 used to fuel the Trident II D-5 SLBM replace most of the AP with polyethylene glycol -bound HMX , further increasing specific impulse. The mixing of composite and double base propellant ingredients has become so common as to blur
8364-463: The propellant surface area exposed to the combustion gases. Since the propellant volume is equal to the cross sectional area A s {\displaystyle A_{s}} times the fuel length, the volumetric propellant consumption rate is the cross section area times the linear burn rate b ˙ {\displaystyle {\dot {b}}} , and the instantaneous mass flow rate of combustion gases generated
8466-542: 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
8568-415: 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
8670-589: 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
8772-442: 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
8874-417: The retired Peacekeeper ICBMs). The Naval Air Weapons Station at China Lake, California, developed a new compound, C 6 H 6 N 6 (NO 2 ) 6 , called simply CL-20 (China Lake compound 20). Compared to HMX, CL-20 has 14% more energy per mass, 20% more energy per volume, and a higher oxygen-to-fuel ratio. One of the motivations for development of these very high energy density military solid propellants
8976-403: The rocket for long durations and then be reliably launched at a moment's notice. Black powder (gunpowder) is composed of charcoal (fuel), potassium nitrate (oxidizer), and sulfur (fuel and catalyst). It is one of the oldest pyrotechnic compositions with application to rocketry. In modern times, black powder finds use in low-power model rockets (such as Estes and Quest rockets), as it
9078-418: 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
9180-689: The spent SRBs, was USBI, a subsidiary of Pratt & Whitney . The contract was subsequently transitioned to United Space Alliance , 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
9282-493: 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
9384-468: 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
9486-644: 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
9588-616: The various mid-20th century government initiatives to develop increasingly capable military missiles. After initial designs of ballistic missile military technology designed with liquid-propellant rockets in the 1940s and 1950s, both the Soviet Union and the United States embarked on major initiatives to develop solid-propellant local , regional , and intercontinental ballistic missiles, including solid-propellant missiles that could be launched from air or sea . Many other governments also developed these military technologies over
9690-404: 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
9792-502: 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
9894-468: 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
9996-507: 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
10098-412: Was the cause of the Space Shuttle Challenger disaster . Solid rocket fuel deflagrates from the surface of exposed propellant in the combustion chamber. In this fashion, the geometry of the propellant inside the rocket motor plays an important role in the overall motor performance. As the surface of the propellant burns, the shape evolves (a subject of study in internal ballistics), most often changing
10200-423: Was two minutes. The nozzle throat was large enough to walk through standing up. The motor was capable of serving as a 1-to-1 replacement for the 8-engine Saturn I liquid-propellant first stage but was never used as such. Motor 260 SL-3 was of similar length and weight but had a maximum thrust of 24 MN (5,400,000 lbf) and a shorter duration. Design begins with the total impulse required, which determines
10302-407: Was used for the space shuttle boosters . Filament-wound graphite epoxy casings are used for high-performance motors. The casing must be designed to withstand the pressure and resulting stresses of the rocket motor, possibly at elevated temperature. For design, the casing is considered a pressure vessel . To protect the casing from corrosive hot gases, a sacrificial thermal liner on the inside of
10404-673: Was used in the propellant of the Peacekeeper ICBM and is the main ingredient in NEPE-75 propellant used in the Trident II D-5 Fleet Ballistic Missile. It is because of explosive hazard that the higher energy military solid propellants containing HMX are not used in commercial launch vehicles except when the LV is an adapted ballistic missile already containing HMX propellant (Minotaur IV and V based on
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