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141-488: A mobile launcher platform ( MLP ), also known as mobile launch platform , is a structure used to support a large multistage space vehicle which is assembled (stacked) vertically in an integration facility (e.g. the Vehicle Assembly Building ) and then transported by a crawler-transporter (CT) to a launch pad . This becomes the support structure for launch . The use of mobile launcher platform

282-478: A mechanical advantage of 3:1, it has been calculated that a single man working the winch could raise 150 kg (330 lb) (3 pulleys x 50 kg or 110 lb = 150), assuming that 50 kg (110 lb) represent the maximum effort a man can exert over a longer time period. Heavier crane types featured five pulleys ( pentaspastos ) or, in case of the largest one, a set of three by five pulleys ( Polyspastos ) and came with two, three or four masts, depending on

423-674: A Reimbursable Space Act Agreement in August 2019. Under the Agreement, Vehicle Assembly Building High Bay 2 would be used to assemble the rocket, while MLP-3 and crawler-transporter 1 would be used to move the rocket to LC-39B for launch. From 2019 to 2020, the OmegA launch tower was under construction on MLP-3. Following the cancellation of OmegA in September 2020, work began to demolish the half-completed launch tower. As of January 2021, MLP-3

564-570: A central vertical axle, were commonly found at the Flemish and Dutch coastside, German sea and inland harbors typically featured tower cranes where the windlass and treadwheels were situated in a solid tower with only jib arm and roof rotating. Dockside cranes were not adopted in the Mediterranean region and the highly developed Italian ports where authorities continued to rely on the more labor-intensive method of unloading goods by ramps beyond

705-656: A concerted action required a great amount of coordination between the work groups applying the force to the capstans. During the High Middle Ages , the treadwheel crane was reintroduced on a large scale after the technology had fallen into disuse in western Europe with the demise of the Western Roman Empire . The earliest reference to a treadwheel ( magna rota ) reappears in archival literature in France about 1225, followed by an illuminated depiction in

846-526: A constant pressure, thus increasing the crane's load capacity considerably. One of his cranes, commissioned by the Italian Navy in 1883 and in use until the mid-1950s, is still standing in Venice , where it is now in a state of disrepair. There are three major considerations in the design of cranes. First, the crane must be able to lift the weight of the load; second, the crane must not topple; third,

987-604: A contract for the design and construction of the Mobile Launcher-2 (ML-2) for SLS Block 1B. Construction of the ML-2 began in July 2020, with the planned completion in 2023. The total cost of the ML-2 was originally estimated to be $ 450 million, however cost overruns have seen this increase to a projected $ 1.8 to $ 2.7 billion, and a delay until 2027 or 2029 The Atlas V utilizes an MLP when launching from SLC-41 . The rocket

1128-417: A crane. This is generally not practical for larger space vehicles, which are assembled off the pad and moved into place on the launch site by various methods. NASA's Apollo / Saturn V crewed Moon landing vehicle, and Space Shuttle , were assembled vertically onto mobile launcher platforms with attached launch umbilical towers, in a Vehicle Assembly Building , and then a special crawler-transporter moved

1269-510: A dragon's head with an open mouth. The British scientist and historian Joseph Needham points out that the written material and depicted illustration of this rocket come from the oldest stratum of the Huolongjing , which can be dated roughly 1300–1350 AD (from the book's part 1, chapter 3, page 23). Another example of an early multistaged rocket is the Juhwa (走火) of Korean development. It

1410-407: A height of about 34 m (111.5 ft) (see construction of Trajan's Column ). It is assumed that Roman engineers lifted these extraordinary weights by two measures (see picture below for comparable Renaissance technique): First, as suggested by Heron, a lifting tower was set up, whose four masts were arranged in the shape of a quadrangle with parallel sides, not unlike a siege tower , but with

1551-408: A higher cost for deployment. Hot-staging is a type of rocket staging in which the next stage fires its engines before separation instead of after. During hot-staging, the earlier stage throttles down its engines. Hot-staging may reduce the complexity of stage separation, and gives a small extra payload capacity to the booster. It also eliminates the need for ullage motors , as the acceleration from

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1692-415: A higher specific impulse means a more efficient rocket engine, capable of burning for longer periods of time. In terms of staging, the initial rocket stages usually have a lower specific impulse rating, trading efficiency for superior thrust in order to quickly push the rocket into higher altitudes. Later stages of the rocket usually have a higher specific impulse rating because the vehicle is further outside

1833-453: A limitation imposed by the laws of physics on the velocity change achievable by a rocket stage. The limit depends on the fueled-to-dry mass ratio and on the effective exhaust velocity of the engine. This relation is given by the classical rocket equation : where: The delta v required to reach low Earth orbit (or the required velocity of a sufficiently heavy suborbital payload) requires a wet to dry mass ratio larger than has been achieved in

1974-529: A manuscript of probably also French origin dating to 1240. In navigation, the earliest uses of harbor cranes are documented for Utrecht in 1244, Antwerp in 1263, Bruges in 1288 and Hamburg in 1291, while in England the treadwheel is not recorded before 1331. Generally, vertical transport could be done more safely and inexpensively by cranes than by customary methods. Typical areas of application were harbors, mines, and, in particular, building sites where

2115-577: A memorial to Project Apollo. The crew access arm is preserved at the Kennedy Space Center Visitor Complex on the upper level of the gift shop. Following the launch of Apollo-Soyuz, ML-1 was the last Mobile Launcher to be converted for use by the Space Shuttle. The LUT and Milkstool were dismantled and placed into storage, and the base of the launch platform was modified to accommodate the locations of engines on

2256-441: A mission is the burn time, which is the amount of time the rocket engine will last before it has exhausted all of its propellant. For most non-final stages, thrust and specific impulse can be assumed constant, which allows the equation for burn time to be written as: Where m 0 {\displaystyle m_{\mathrm {0} }} and m f {\displaystyle m_{\mathrm {f} }} are

2397-609: A much greater lifting capability than was previously possible, although manual cranes are still utilized where the provision of power would be uneconomic. There are many different types of cranes, each tailored to a specific use. Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. Mini-cranes are also used for constructing high buildings, to facilitate constructions by reaching tight spaces. Large floating cranes are generally used to build oil rigs and salvage sunken ships. Some lifting machines do not strictly fit

2538-472: A multistage rocket introduces additional risk into the success of the launch mission. Reducing the number of separation events results in a reduction in complexity . Separation events occur when stages or strap-on boosters separate after use, when the payload fairing separates prior to orbital insertion, or when used, a launch escape system which separates after the early phase of a launch. Pyrotechnic fasteners , or in some cases pneumatic systems like on

2679-408: A point over the center of gravity, they are regarded by archaeologists as the positive evidence required for the existence of the crane. The introduction of the winch and pulley hoist soon led to a widespread replacement of ramps as the main means of vertical motion. For the next 200 years, Greek building sites witnessed a sharp reduction in the weights handled, as the new lifting technique made

2820-466: A rocket system will be when performing optimizations and comparing varying configurations for a mission. For initial sizing, the rocket equations can be used to derive the amount of propellant needed for the rocket based on the specific impulse of the engine and the total impulse required in N·s. The equation is: where g is the gravity constant of Earth. This also enables the volume of storage required for

2961-402: A single rocket stage. The multistage rocket overcomes this limit by splitting the delta-v into fractions. As each lower stage drops off and the succeeding stage fires, the rest of the rocket is still traveling near the burnout speed. Each lower stage's dry mass includes the propellant in the upper stages, and each succeeding upper stage has reduced its dry mass by discarding the useless dry mass of

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3102-399: A technical algorithm that generates an analytical solution that can be implemented by a program, or simple trial and error. For the trial and error approach, it is best to begin with the final stage, calculating the initial mass which becomes the payload for the previous stage. From there it is easy to progress all the way down to the initial stage in the same manner, sizing all the stages of

3243-443: A vertical lift, and not used to move loads for a considerable distance horizontally as well. Accordingly, lifting work was organized at the workplace in a different way than today. In building construction, for example, it is assumed that the crane lifted the stone blocks either from the bottom directly into place, or from a place opposite the centre of the wall from where it could deliver the blocks for two teams working at each end of

3384-483: Is a commonly used rocket system to attain Earth orbit. The spacecraft uses three distinct stages to provide propulsion consecutively in order to achieve orbital velocity. It is intermediate between a four-stage-to-orbit launcher and a two-stage-to-orbit launcher. Other designs (in fact, most modern medium- to heavy-lift designs) do not have all three stages inline on the main stack, instead having strap-on boosters for

3525-581: Is a part of the Integrate-Transfer-Launch (ITL) system, which involves vertical assembly, transport, and launch of rockets. The concept was first implemented in the 1960s for the United States Air Force 's Titan III rocket, and it was later used by NASA for Saturn V , Space Shuttle , and Space Launch System . There are alternatives to ITL. Horizontal assembly and transport to the pad is used by Russia, by ULA for

3666-415: Is a safe and reasonable assumption to say that 91 to 94 percent of the total mass is fuel. It is also important to note there is a small percentage of "residual" propellant that will be left stuck and unusable inside the tank, and should also be taken into consideration when determining amount of fuel for the rocket. A common initial estimate for this residual propellant is five percent. With this ratio and

3807-453: Is generally assembled at its manufacturing site and shipped to the launch site; the term vehicle assembly refers to the mating of all rocket stage(s) and the spacecraft payload into a single assembly known as a space vehicle . Single-stage vehicles ( suborbital ), and multistage vehicles on the smaller end of the size range, can usually be assembled directly on the launch pad by lifting the stage(s) and spacecraft vertically in place by means of

3948-577: Is impractical to directly compare the rocket's certain trait with the same trait of another because their individual attributes are often not independent of one another. For this reason, dimensionless ratios have been designed to enable a more meaningful comparison between rockets. The first is the initial to final mass ratio, which is the ratio between the rocket stage's full initial mass and the rocket stage's final mass once all of its fuel has been consumed. The equation for this ratio is: Where m E {\displaystyle m_{\mathrm {E} }}

4089-428: Is intermediate between a five-stage-to-orbit launcher and a three-stage-to-orbit launcher, most often used with solid-propellant launch systems. Other designs do not have all four stages inline on the main stack, instead having strap-on boosters for the "stage-0" with three core stages. In these designs, the boosters and first stage fire simultaneously instead of consecutively, providing extra initial thrust to lift

4230-458: Is near the deck. Additionally, the DLF increases further when lifting objects that are underwater or going through the splash zone. The wind speeds tend to be higher than onshore as well. Though actual DLF values are determined through crane tests under representative operational conditions, design specifications can be used for guidance. The values vary according to the specification, which reflects

4371-418: Is noteworthy that medieval cranes rarely featured ratchets or brakes to forestall the load from running backward. This curious absence is explained by the high friction force exercised by medieval tread-wheels which normally prevented the wheel from accelerating beyond control. According to the "present state of knowledge" unknown in antiquity, stationary harbor cranes are considered a new development of

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4512-751: Is planned to be placed in storage in High Bay 2 of the Vehicle Assembly Building. Between 2009 and 2010, a mobile launcher platform called the Mobile Launcher-1 (ML-1) was constructed as part of the Constellation program . Since the cancellation of the program in 2010, ML-1 was converted for the Space Launch System Block 1, with various phases of construction between 2013 and 2018. The total cost of

4653-427: Is repeated until the desired final velocity is achieved. In some cases with serial staging, the upper stage ignites before the separation—the interstage ring is designed with this in mind, and the thrust is used to help positively separate the two vehicles. Only multistage rockets have reached orbital speed . Single-stage-to-orbit designs are sought, but have not yet been demonstrated. Multi-stage rockets overcome

4794-586: Is stacked on its MLP in the 280-foot-tall (85.4 m) Vertical Integration Facility (VIF), and is then rolled-out over 600 yards (550 m) to the launch pad. The design of this MLP is derived from the MLPs used by the Titan III and IV rockets. Titan III and Titan IV rockets launched from SLC-40 and SLC-41 utilized MLPs to decouple assembly of the launch vehicle from launch. This was meant to enable simultaneous assembly of multiple launch vehicles as part of

4935-514: Is the empty mass of the stage, m p {\displaystyle m_{\mathrm {p} }} is the mass of the propellant, and m P L {\displaystyle m_{\mathrm {PL} }} is the mass of the payload. The second dimensionless performance quantity is the structural ratio, which is the ratio between the empty mass of the stage, and the combined empty mass and propellant mass as shown in this equation: The last major dimensionless performance quantity

5076-402: Is the mass of the oxidizer and m f u e l {\displaystyle m_{\mathrm {fuel} }} is the mass of the fuel. This mixture ratio not only governs the size of each tank, but also the specific impulse of the rocket. Determining the ideal mixture ratio is a balance of compromises between various aspects of the rocket being designed, and can vary depending on

5217-455: Is the payload ratio, which is the ratio between the payload mass and the combined mass of the empty rocket stage and the propellant: After comparing the three equations for the dimensionless quantities, it is easy to see that they are not independent of each other, and in fact, the initial to final mass ratio can be rewritten in terms of structural ratio and payload ratio: These performance ratios can also be used as references for how efficient

5358-405: Is usually part of the crane's type approval . In offshore lifting, where the crane and/or lifted object are on a floating vessel, the DLF is higher compared to onshore lifts because of the additional movement caused by wave action. This motion introduces additional acceleration forces and necessitates increased hoisting and lowering speeds to minimize the risk of repeated collisions when the load

5499-584: The Apollo program lunar landing missions of the 1960s and 1970s. Each ML originally had a single exhaust vent for the Saturn V's engines. The Mobile Launchers also featured a 380-foot-tall (120 m) Launch Umbilical Tower ( LUT ) with nine swing arms that permitted servicing of the vehicle on the launch pad, and swung away from it at launch. The Mobile Launchers were built by Ingalls Iron Works . The swing arms were constructed by Hayes International . After

5640-708: The Apollo program , the bases of the Mobile Launchers were modified for the Space Shuttle . The Launch Umbilical Towers from ML-2 and ML-3 were removed. Portions of these tower structures were erected at the two launch pads, 39A and 39B. These permanent structures were known as the Fixed Service Structures (FSS). The LUT from ML-1 was taken apart and stored in the Kennedy Space Center's industrial area. Efforts to preserve

5781-684: The Delta IV family, and by SpaceX for the Falcon 9 family. Vertical assembly on the launch pad is used for smaller launch vehicles and for the SpaceX Starship . From 1967 to 2011, three platforms were used at the LC-39 to support NASA's launch vehicles. Formerly called Mobile Launchers ( ML ), the mobile launcher platforms were constructed for transporting and launching the Saturn V rocket for

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5922-549: The Elswick works at Newcastle , to produce his hydraulic machinery for cranes and bridges in 1847. His company soon received orders for hydraulic cranes from Edinburgh and Northern Railways and from Liverpool Docks , as well as for hydraulic machinery for dock gates in Grimsby . The company expanded from a workforce of 300 and an annual production of 45 cranes in 1850, to almost 4,000 workers producing over 100 cranes per year by

6063-428: The Falcon 9 Full Thrust , are typically used to separate rocket stages. A two-stage-to-orbit ( TSTO ) or two-stage rocket launch vehicle is a spacecraft in which two distinct stages provide propulsion consecutively in order to achieve orbital velocity. It is intermediate between a three-stage-to-orbit launcher and a hypothetical single-stage-to-orbit (SSTO) launcher. The three-stage-to-orbit launch system

6204-482: The National Aeronautics and Space Administration . Multistage rocket By jettisoning stages when they run out of propellant, the mass of the remaining rocket is decreased. Each successive stage can also be optimized for its specific operating conditions, such as decreased atmospheric pressure at higher altitudes. This staging allows the thrust of the remaining stages to more easily accelerate

6345-734: The RTV-G-4 Bumper rockets tested at the White Sands Proving Ground and later at Cape Canaveral from 1948 to 1950. These consisted of a V-2 rocket and a WAC Corporal sounding rocket. The greatest altitude ever reached was 393 km, attained on February 24, 1949, at White Sands. In 1947, the Soviet rocket engineer and scientist Mikhail Tikhonravov developed a theory of parallel stages, which he called "packet rockets". In his scheme, three parallel stages were fired from liftoff , but all three engines were fueled from

6486-509: The Singijeon , or 'magical machine arrows' in the 16th century. The earliest experiments with multistage rockets in Europe were made in 1551 by Austrian Conrad Haas (1509–1576), the arsenal master of the town of Hermannstadt , Transylvania (now Sibiu/Hermannstadt, Romania). This concept was developed independently by at least five individuals: The first high-speed multistage rockets were

6627-490: The Soviet and U.S. space programs, were not passivated after mission completion. During the initial attempts to characterize the space debris problem, it became evident that a good proportion of all debris was due to the breaking up of rocket upper stages, particularly unpassivated upper-stage propulsion units. An illustration and description in the 14th century Chinese Huolongjing by Jiao Yu and Liu Bowen shows

6768-612: The Yoshinobu Launch Complex . The PSLV , GSLV , and GSLV Mark III rockets utilize an MLP called the Mobile Launch Pedestal. The rockets are stacked on the Mobile Launch Pedestal in the Vehicle Assembly Building (VAB; not to be confused with the NASA building with the same name ), and are then rolled-out towards the launch pad. Once delivered to the pad, the mobile launcher platform is connected to

6909-586: The lever and pulley , to create mechanical advantage to do its work. Cranes are commonly employed in transportation for the loading and unloading of freight, in construction for the movement of materials, and in manufacturing for the assembling of heavy equipment . The first known crane machine was the shaduf , a water-lifting device that was invented in ancient Mesopotamia (modern Iraq) and then appeared in ancient Egyptian technology . Construction cranes later appeared in ancient Greece , where they were powered by men or animals (such as donkeys), and used for

7050-484: The polyspastos indicate that the overall lifting capability of the Romans went far beyond that of any single crane. At the temple of Jupiter at Baalbek , for instance, the architrave blocks weigh up to 60 tons each, and one corner cornice block even over 100 tons, all of them raised to a height of about 19 m (62.3 ft). In Rome , the capital block of Trajan's Column weighs 53.3 tons, which had to be lifted to

7191-523: The "stage-0" with two core stages. In these designs, the boosters and first stage fire simultaneously instead of consecutively, providing extra initial thrust to lift the full launcher weight and overcome gravity losses and atmospheric drag. The boosters are jettisoned a few minutes into flight to reduce weight. The four-stage-to-orbit launch system is a rocket system used to attain Earth orbit. The spacecraft uses four distinct stages to provide propulsion consecutively in order to achieve orbital velocity. It

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7332-455: The 15th century also by windlasses shaped like a ship's wheel . To smooth out irregularities of impulse and get over 'dead-spots' in the lifting process flywheels are known to be in use as early as 1123. The exact process by which the treadwheel crane was reintroduced is not recorded, although its return to construction sites has undoubtedly to be viewed in close connection with the simultaneous rise of Gothic architecture. The reappearance of

7473-460: The 361 t heavy Vatican obelisk in Rome. From his report, it becomes obvious that the coordination of the lift between the various pulling teams required a considerable amount of concentration and discipline, since, if the force was not applied evenly, the excessive stress on the ropes would make them rupture. Cranes were also used domestically during this period. The chimney or fireplace crane

7614-418: The 5 percent grade leading to the top of the launch pad. Two 2,750 horsepower (2.05 MW) diesel engines power each crawler. The MLPs were designed as part of NASA's strategy for vertical assembly and transport of space vehicles. Vertical assembly allows the preparation of the spacecraft in a ready-for-launch position, and avoids the additional step of lifting or craning a horizontally-assembled vehicle onto

7755-426: The DLF. More sophisticated methods, such as finite element analysis or other simulation techniques, may also be used to model the crane's behavior under various loading conditions, as deemed appropriate by the designer or certifying authority.To verify the actual DLF, control load tests can be conducted on the completed crane using instrumentation such as load cells , accelerometers , and strain gauges . This process

7896-471: The LUT in the 1990s failed due to a lack of funding, and it was scrapped. In addition to removal of the umbilical towers, each Shuttle-era MLP was extensively reconfigured with the addition of two Tail Service Masts (TSM), one on either side of the main engine exhaust vent. These 9.4 m (31 ft) masts contained the feed lines through which liquid hydrogen (LH 2 ) and liquid oxygen (LOX) were loaded into

8037-489: The ML-1 is estimated to be $ 1 billion. The biggest modification to the ML-1 was on the platform's base, where engineers increased the size of a 22 square feet (2.0 m) exhaust duct to a rectangle stretching 60 by 30 feet (18.3 by 9.1 m) and strengthened the surrounding structure. SLS weighs more than twice as much as the planned Ares I rocket. The Ares I rocket would have featured a single solid-fueled first stage, while

8178-659: The ML-1 was modified by the addition of a structure known as the Milkstool , which allowed the Saturn IB to use the same Launch Umbilical Tower as the much larger Saturn V. Three crewed flights to Skylab , and the Apollo launch for the Apollo-Soyuz Test Project , were conducted from the ML-1 using the Milkstool . Prior to the scrapping of the LUT in 2004, there was a campaign to rebuild and preserve it as

8319-689: The MLP-1 was used for 52 Shuttle launches between 1981 and 2009. It was used for the first Space Shuttle launch, STS-1 , in April 1981. Following the launch of STS-119 in March 2009, it was transferred to the Constellation program . The platform was used only for the Ares I-X and the MLP-1 suffered substantial damage. The canceled Ares I-Y would have used the same MLP. However, the Constellation program

8460-698: The MLP-2 for liquid-propellant rockets , but in January 2021, NASA announced that due to lack of storage space, the massive structure would be demolished. The first launch from the Mobile Launcher Platform-3 (MLP-3) (formerly called the Mobile Launcher-1 or ML-1) was the maiden flight of the Saturn V, and the first launch from LC-39, Apollo 4 . Following this, it was used for two crewed Apollo launches: Apollo 8 and Apollo 11 . After NASA decided to move Saturn IB launches from LC-34 to LC-39B,

8601-888: The Middle Ages. Unlike construction cranes where the work speed was determined by the relatively slow progress of the masons, harbor cranes usually featured double treadwheels to speed up loading. The two treadwheels whose diameter is estimated to be 4 m or larger were attached to each side of the axle and rotated together. Their capacity was 2–3 tons, which apparently corresponded to the customary size of marine cargo. Today, according to one survey, fifteen treadwheel harbor cranes from pre-industrial times are still extant throughout Europe. Some harbour cranes were specialised at mounting masts to newly built sailing ships, such as in Gdańsk , Cologne and Bremen . Beside these stationary cranes, floating cranes , which could be flexibly deployed in

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8742-411: The Middle Ages. The typical harbor crane was a pivoting structure equipped with double treadwheels. These cranes were placed docksides for the loading and unloading of cargo where they replaced or complemented older lifting methods like see-saws , winches and yards . Two different types of harbor cranes can be identified with a varying geographical distribution: While gantry cranes, which pivoted on

8883-465: The SLS includes two large solid rocket boosters and a powerful core with four RS-25 engines. The base of the ML-1 is 25 feet (7.6 m) high, 158 feet (48 m) long, and 133 feet (41 m) wide. The ML-1 also features a 355-foot-tall (108 m) Launch Umbilical Tower (LUT) with several arms that permit servicing of the SLS on the launch pad, and swing away from it at launch. In June 2019, NASA awarded

9024-490: The Shuttle. The platform was redesignated MLP-2. In total, MLP-2 was used for 44 Shuttle launches, starting in 1983. All of the orbiters except Columbia made their maiden flights from MLP-2. It was also the launch site for the ill-fated STS-51L mission, when Space Shuttle Challenger disintegrated shortly after launch, killing all seven crew members. Following the Space Shuttle retirement , NASA kept

9165-628: The Titan's Integrate-Transfer-Launch (ITL) concept, allowing a high flight rate from a small number of launch pads. United Launch Alliance 's Vulcan will use an MLP similar in design to the one used by the Atlas V when launching from SLC-41, altered to support the former's larger design. The VLP (Vulcan Launch Platform) stands 183 ft (56 m) tall, and when complete will weigh 1.3 million pounds (590 tonnes). It will be equipped with various electronics, power-lines, and cables to support and control

9306-606: The above definition of a crane, but are generally known as cranes, such as stacker cranes and loader cranes. Cranes were so called from the resemblance to the long neck of the bird , cf. Ancient Greek : γερανός , French grue . The first type of crane machine was the shadouf , which had a lever mechanism and was used to lift water for irrigation . It was invented in Mesopotamia (modern Iraq) circa 3000 BC. The shadouf subsequently appeared in ancient Egyptian technology circa 2000 BC. A crane for lifting heavy loads

9447-462: The atmosphere and the exhaust gas does not need to expand against as much atmospheric pressure. When selecting the ideal rocket engine to use as an initial stage for a launch vehicle, a useful performance metric to examine is the thrust-to-weight ratio, and is calculated by the equation: The common thrust-to-weight ratio of a launch vehicle is within the range of 1.3 to 2.0. Another performance metric to keep in mind when designing each rocket stage in

9588-478: The autocratic societies of Egypt or Assyria . The first unequivocal literary evidence for the existence of the compound pulley system appears in the Mechanical Problems ( Mech . 18, 853a32–853b13) attributed to Aristotle (384–322 BC), but perhaps composed at a slightly later date. Around the same time, block sizes at Greek temples began to match their archaic predecessors again, indicating that

9729-401: The breakup of a single upper stage while in orbit. After the 1990s, spent upper stages are generally passivated after their use as a launch vehicle is complete in order to minimize risks while the stage remains derelict in orbit . Passivation means removing any sources of stored energy remaining on the vehicle, as by dumping fuel or discharging batteries. Many early upper stages, in both

9870-405: The column in the middle of the structure ( Mechanica 3.5). Second, a multitude of capstans were placed on the ground around the tower, for, although having a lower leverage ratio than treadwheels, capstans could be set up in higher numbers and run by more men (and, moreover, by draught animals). This use of multiple capstans is also described by Ammianus Marcellinus (17.4.15) in connection with

10011-603: The coming of the Industrial Revolution . For many centuries, power was supplied by the physical exertion of men or animals, although hoists in watermills and windmills could be driven by the harnessed natural power. The first mechanical power was provided by steam engines , the earliest steam crane being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century. Modern cranes usually use internal combustion engines or electric motors and hydraulic systems to provide

10152-518: The construction of buildings. Larger cranes were later developed in the Roman Empire , employing the use of human treadwheels , permitting the lifting of heavier weights. In the High Middle Ages , harbour cranes were introduced to load and unload ships and assist with their construction—some were built into stone towers for extra strength and stability. The earliest cranes were constructed from wood, but cast iron , iron and steel took over with

10293-451: The construction of the ancient Egyptian pyramids , where about 50 men were needed to move a 2.5 ton stone block up the ramp (50 kg (110 lb) per person), the lifting capability of the Roman polyspastos proved to be 60 times higher (3,000 kg or 6,600 lb per person). However, numerous extant Roman buildings which feature much heavier stone blocks than those handled by

10434-467: The crane must not fail structurally. For stability, the sum of all moments about the base of the crane must be close to zero so that the crane does not overturn. In practice, the magnitude of load that is permitted to be lifted (called the "rated load" in the US) is some value less than the load that will cause the crane to tip, thus providing a safety margin. Under United States standards for mobile cranes,

10575-409: The cylinder and a valve regulated the amount of fluid intake relative to the load on the crane. This mechanism, the hydraulic jigger , then pulled on a chain to lift the load. In 1845 a scheme was set in motion to provide piped water from distant reservoirs to the households of Newcastle . Armstrong was involved in this scheme and he proposed to Newcastle Corporation that the excess water pressure in

10716-474: The design dynamic factor, is a critical parameter in the crane design and operation. It accounts for the dynamic effects that can increase the load on a crane's structure and components during lifting operations. These effects include: The DLF for a new crane design can be determined with analytical calculations and mathematical models following the relevant design specifications . If available, data from previous tests of similar crane types can be used to estimate

10857-419: The different stages of the rocket should be clearly defined. Continuing with the previous example, the end of the first stage which is sometimes referred to as 'stage 0', can be defined as when the side boosters separate from the main rocket. From there, the final mass of stage one can be considered the sum of the empty mass of stage one, the mass of stage two (the main rocket and the remaining unburned fuel) and

10998-404: The drawbacks of a less efficient specific impulse rating. But suppose the defining constraint for the launch system is volume, and a low density fuel is required such as hydrogen. This example would be solved by using an oxidizer-rich mixture ratio, reducing efficiency and specific impulse rating, but will meet a smaller tank volume requirement. The ultimate goal of optimal staging is to maximize

11139-417: The dynamic load on the crane due to vessel motion. Additionally, the stability of the vessel or platform must be considered. For stationary pedestal or kingpost mounted cranes, the moment produced by the boom, jib, and load is resisted by the pedestal base or kingpost. Stress within the base must be less than the yield stress of the material or the crane will fail. The dynamic lift factor (DLF), also known as

11280-469: The early 1860s. Armstrong spent the next few decades constantly improving his crane design; his most significant innovation was the hydraulic accumulator . Where water pressure was not available on site for the use of hydraulic cranes, Armstrong often built high water towers to provide a supply of water at pressure. However, when supplying cranes for use at New Holland on the Humber Estuary , he

11421-400: The end of the rocket stage's motion, as the vehicle will still have a velocity that will allow it to coast upward for a brief amount of time until the acceleration of the planet's gravity gradually changes it to a downward direction. The velocity and altitude of the rocket after burnout can be easily modeled using the basic physics equations of motion. When comparing one rocket with another, it

11562-462: The engineers Vitruvius ( De Architectura 10.2, 1–10) and Heron of Alexandria ( Mechanica 3.2–5). There are also two surviving reliefs of Roman treadwheel cranes , with the Haterii tombstone from the late first century AD being particularly detailed. The simplest Roman crane, the trispastos , consisted of a single-beam jib, a winch , a rope , and a block containing three pulleys. Having thus

11703-598: The entire vehicle stack to the launch pad in an upright position. In contrast, vehicles such as the Russian Soyuz rocket and the SpaceX Falcon 9 are assembled horizontally in a processing hangar, transported horizontally, and then brought upright at the pad. Spent upper stages of launch vehicles are a significant source of space debris remaining in orbit in a non-operational state for many years after use, and occasionally, large debris fields created from

11844-411: The equations for determining the burnout velocities, burnout times, burnout altitudes, and mass of each stage. This would make for a better approach to a conceptual design in a situation where a basic understanding of the system behavior is preferential to a detailed, accurate design. One important concept to understand when undergoing restricted rocket staging, is how the burnout velocity is affected by

11985-456: The exact circumstances of the shift from the ramp to the crane technology remain unclear, it has been argued that the volatile social and political conditions of Greece were more suitable to the employment of small, professional construction teams than of large bodies of unskilled labour, making the crane preferable to the Greek polis over the more labour-intensive ramp which had been the norm in

12126-569: The external fuel tank. The Space Shuttle assembly was held to the MLP at eight holddown points using large studs , four on the aft skirt of each Solid Rocket Booster. Immediately before SRB ignition, frangible nuts attached to the top of these studs were detonated, releasing the Shuttle assembly from the platform. Each MLP weighed 8.23 million pounds (3,730 tonnes) unloaded and roughly 11 million pounds (5,000 tonnes) with an unfueled Shuttle aboard, measured 160 by 135 feet (49 by 41 m), and

12267-486: The first stage of the American Atlas I and Atlas II launch vehicles, arranged in a row, used parallel staging in a similar way: the outer pair of booster engines existed as a jettisonable pair which would, after they shut down, drop away with the lowermost outer skirt structure, leaving the central sustainer engine to complete the first stage's engine burn towards apogee or orbit. Separation of each portion of

12408-441: The first-stage and booster engines fire to propel the entire rocket upwards. When the boosters run out of fuel, they are detached from the rest of the rocket (usually with some kind of small explosive charge or explosive bolts ) and fall away. The first stage then burns to completion and falls off. This leaves a smaller rocket, with the second stage on the bottom, which then fires. Known in rocketry circles as staging , this process

12549-467: The fuel to be calculated if the density of the fuel is known, which is almost always the case when designing the rocket stage. The volume is yielded when dividing the mass of the propellant by its density. Asides from the fuel required, the mass of the rocket structure itself must also be determined, which requires taking into account the mass of the required thrusters, electronics, instruments, power equipment, etc. These are known quantities for typical off

12690-476: The full launcher weight and overcome gravity losses and atmospheric drag. The boosters are jettisoned a few minutes into flight to reduce weight. Crane (machine)#Hammerhead A crane is a machine used to move materials both vertically and horizontally, utilizing a system of a boom , hoist , wire ropes or chains , and sheaves for lifting and relocating heavy objects within the swing of its boom. The device uses one or more simple machines , such as

12831-483: The future. NASA stated that re-conditioning of the crawlerway will be required periodically in the future, and MLP-1 will be retained for that purpose. MLP-1 will be stored in High Bay 1 of the Vehicle Assembly Building when not in use for crawlerway maintenance. Mobile Launcher Platform-2 (MLP-2) (formerly called the Mobile Launcher-2 or ML-2) was used for the uncrewed Apollo 6 mission, followed by three crewed Apollo launches; Apollo 9 , Apollo 12 and Apollo 14 . It

12972-405: The initial and final masses of the rocket stage respectively. In conjunction with the burnout time, the burnout height and velocity are obtained using the same values, and are found by these two equations: When dealing with the problem of calculating the total burnout velocity or time for the entire rocket system, the general procedure for doing so is as follows: The burnout time does not define

13113-456: The initial stages of construction on the ground, often within the building. When a new floor was completed, and massive tie beams of the roof connected the walls, the crane was dismantled and reassembled on the roof beams from where it was moved from bay to bay during construction of the vaults. Thus, the crane "grew" and "wandered" with the building with the result that today all extant construction cranes in England are found in church towers above

13254-457: The larger sound suppression system by large pipes which deliver a deluge of water from an adjacent water tower. Six 12-foot-high (3.7 m) towers known as "rainbirds" spray water over the MLP and into the flame deflector trenches below it, absorbing acoustic waves. The suppression system reduced the acoustic sound level to approximately 142 dB . [REDACTED]  This article incorporates public domain material from websites or documents of

13395-443: The largest rocket ever to do so, as well as the first reusable vehicle to utilize hot staging. A rocket system that implements tandem staging means that each individual stage runs in order one after the other. The rocket breaks free from the previous stage, then begins burning through the next stage in straight succession. On the other hand, a rocket that implements parallel staging has two or more different stages that are active at

13536-450: The launch of Apollo 17, the ML-3 was the first of the Mobile Launchers to be converted for use by the Space Shuttle. The Launch Umbilical Tower was dismantled and later partially reassembled on LC-39A as that pad's Fixed Service Structure (FSS) and the base of the launch platform was modified to accommodate the locations of engines on the Shuttle. The platform was redesignated MLP-1. In total,

13677-701: The launchpad (as the engineers of the Soviet space program chose to do). Construction of the Mobile Launcher Platform-1 (MLP-1) (formerly called the Mobile Launcher-3 or ML-3) began in 1964 and was completed with the installation of the Launch Umbilical Tower hammerhead crane on 1 March 1965. The swing arms were added at a later date. The ML-3 was used for five crewed Apollo launches; Apollo 10 , Apollo 13 , Apollo 15 , Apollo 16 and Apollo 17 . Following

13818-580: The lifting of the Lateranense obelisk in the Circus Maximus (c. 357 AD). The maximum lifting capability of a single capstan can be established by the number of lewis iron holes bored into the monolith. In case of the Baalbek architrave blocks, which weigh between 55 and 60 tons, eight extant holes suggest an allowance of 7.5 ton per lewis iron, that is per capstan. Lifting such heavy weights in

13959-583: The lower masts of the vessel under construction or repair. These lower masts were the largest and most massive single timbers aboard a ship, and erecting them without the assistance of either a sheer hulk or land-based masting sheer was extremely difficult. The concept of sheer hulks originated with the Royal Navy in the 1690s, and persisted in Britain until the early nineteenth century. Most sheer hulks were decommissioned warships; Chatham , built in 1694,

14100-548: The lower part of town could be used to power one of his hydraulic cranes for the loading of coal onto barges at the Quayside . He claimed that his invention would do the job faster and more cheaply than conventional cranes. The corporation agreed to his suggestion, and the experiment proved so successful that three more hydraulic cranes were installed on the Quayside. The success of his hydraulic crane led Armstrong to establish

14241-403: The mass of the payload. High-altitude and space-bound upper stages are designed to operate with little or no atmospheric pressure. This allows the use of lower pressure combustion chambers and engine nozzles with optimal vacuum expansion ratios . Some upper stages, especially those using hypergolic propellants like Delta-K or Ariane 5 ES second stage, are pressure fed , which eliminates

14382-464: The mass of the propellant calculated, the mass of the empty rocket weight can be determined. Sizing rockets using a liquid bipropellant requires a slightly more involved approach because there are two separate tanks that are required: one for the fuel, and one for the oxidizer. The ratio of these two quantities is known as the mixture ratio, and is defined by the equation: Where m o x {\displaystyle m_{\mathrm {ox} }}

14523-491: The maximum load. The polyspastos , when worked by four men at both sides of the winch, could readily lift 3,000 kg (6,600 lb) (3 ropes x 5 pulleys x 4 men x 50 kg or 110 lb = 3,000 kg or 6,600 lb). If the winch was replaced by a treadwheel, the maximum load could be doubled to 6,000 kg (13,000 lb) at only half the crew, since the treadwheel possesses a much bigger mechanical advantage due to its larger diameter. This meant that, in comparison to

14664-418: The more sophisticated compound pulley must have found its way to Greek construction sites by then. The heyday of the crane in ancient times came during the Roman Empire , when construction activity soared and buildings reached enormous dimensions. The Romans adopted the Greek crane and developed it further. There is much available information about their lifting techniques, thanks to rather lengthy accounts by

14805-566: The nearly spent stage keeps the propellants settled at the bottom of the tanks. Hot-staging is used on Soviet-era Russian rockets such as Soyuz and Proton-M . The N1 rocket was designed to use hot staging, however none of the test flights lasted long enough for this to occur. Starting with the Titan II, the Titan family of rockets used hot staging. SpaceX retrofitted their Starship rocket to use hot staging after its first flight , making it

14946-708: The need for complex turbopumps . Other upper stages, such as the Centaur or DCSS , use liquid hydrogen expander cycle engines, or gas generator cycle engines like the Ariane 5 ECA's HM7B or the S-IVB 's J-2 . These stages are usually tasked with completing orbital injection and accelerating payloads into higher energy orbits such as GTO or to escape velocity . Upper stages, such as Fregat , used primarily to bring payloads from low Earth orbit to GTO or beyond are sometimes referred to as space tugs . Each individual stage

15087-419: The number of stages that split up the rocket system. Increasing the number of stages for a rocket while keeping the specific impulse, payload ratios and structural ratios constant will always yield a higher burnout velocity than the same systems that use fewer stages. However, the law of diminishing returns is evident in that each increment in number of stages gives less of an improvement in burnout velocity than

15228-442: The observation of the labor-saving qualities of the waterwheel with which early treadwheels shared many structural similarities. The medieval treadwheel was a large wooden wheel turning around a central shaft with a treadway wide enough for two workers walking side by side. While the earlier 'compass-arm' wheel had spokes directly driven into the central shaft, the more advanced "clasp-arm" type featured arms arranged as chords to

15369-454: The oldest known multistage rocket; this was the " fire-dragon issuing from the water " (火龙出水, huǒ lóng chū shuǐ), which was used mostly by the Chinese navy. It was a two-stage rocket that had booster rockets that would eventually burn out, yet, before they did so, automatically ignited a number of smaller rocket arrows that were shot out of the front end of the missile, which was shaped like

15510-525: The outer two stages, until they are empty and could be ejected. This is more efficient than sequential staging, because the second-stage engine is never just dead weight. In 1951, Soviet engineer and scientist Dmitry Okhotsimsky carried out a pioneering engineering study of general sequential and parallel staging, with and without the pumping of fuel between stages. The design of the R-7 Semyorka emerged from that study. The trio of rocket engines used in

15651-632: The overall payload ratio of the entire system. It is important to note that when computing payload ratio for individual stages, the payload includes the mass of all the stages after the current one. The overall payload ratio is: Where n is the number of stages the rocket system comprises. Similar stages yielding the same payload ratio simplify this equation, however that is seldom the ideal solution for maximizing payload ratio, and ΔV requirements may have to be partitioned unevenly as suggested in guideline tips 1 and 2 from above. Two common methods of determining this perfect ΔV partition between stages are either

15792-573: The payload ratio (see ratios under performance), meaning the largest amount of payload is carried up to the required burnout velocity using the least amount of non-payload mass, which comprises everything else. This goal assumes that the cost of a rocket launch is proportional to the total liftoff mass of the rocket, which is a rule of thumb in rocket engineering. Here are a few quick rules and guidelines to follow in order to reach optimal staging: The payload ratio can be calculated for each individual stage, and when multiplied together in sequence, will yield

15933-402: The previous increment. The burnout velocity gradually converges towards an asymptotic value as the number of stages increases towards a very high number. In addition to diminishing returns in burnout velocity improvement, the main reason why real world rockets seldom use more than three stages is because of increase of weight and complexity in the system for each added stage, ultimately yielding

16074-401: The rocket to its final velocity and height. In serial or tandem staging schemes, the first stage is at the bottom and is usually the largest, the second stage and subsequent upper stages are above it, usually decreasing in size. In parallel staging schemes solid or liquid rocket boosters are used to assist with launch. These are sometimes referred to as "stage 0". In the typical case,

16215-427: The rocket system. Restricted rocket staging is based on the simplified assumption that each of the stages of the rocket system have the same specific impulse, structural ratio, and payload ratio, the only difference being the total mass of each increasing stage is less than that of the previous stage. Although this assumption may not be the ideal approach to yielding an efficient or optimal system, it greatly simplifies

16356-532: The rocket. For the initial Vulcan-Centaur configuration, the MLP will supply liquefied natural gas and liquid oxygen to the first stage, and liquid hydrogen and liquid oxygen to the Centaur upper stage. As of October 24, 2019, the basic structure has been completed, but the umbilicals and equipment have yet to be installed. As of 2024, there are two VLP’s allowing for parallel processing. Japanese H-IIA and H-IIB rockets utilize an MLP when launching from

16497-456: The same time. For example, the Space Shuttle has two Solid Rocket Boosters that burn simultaneously. Upon launch, the boosters ignite, and at the end of the stage, the two boosters are discarded while the external fuel tank is kept for another stage. Most quantitative approaches to the design of the rocket system's performance are focused on tandem staging, but the approach can be easily modified to include parallel staging. To begin with,

16638-416: The savings are so great that every rocket ever used to deliver a payload into orbit has had staging of some sort. One of the most common measures of rocket efficiency is its specific impulse, which is defined as the thrust per flow rate (per second) of propellant consumption: When rearranging the equation such that thrust is calculated as a result of the other factors, we have: These equations show that

16779-518: The shelf hardware that should be considered in the mid to late stages of the design, but for preliminary and conceptual design, a simpler approach can be taken. Assuming one engine for a rocket stage provides all of the total impulse for that particular segment, a mass fraction can be used to determine the mass of the system. The mass of the stage transfer hardware such as initiators and safe-and-arm devices are very small by comparison and can be considered negligible. For modern day solid rocket motors, it

16920-561: The shuttle's external fuel tank, as well as electrical hookups and flares that were used to burn off any ambient hydrogen vapors at the launch site immediately prior to Main Engine start. The main engines vented their exhaust through the original opening used for the Saturn rocket exhaust. Two additional exhaust ports were added to vent exhaust from the Space Shuttle Solid Rocket Boosters (SRBs) that flanked

17061-533: The shuttle. The platform was redesignated MLP-3. In total, MLP-3 was used for 29 Shuttle launches, starting in 1990. It was the least used of the three MLPs. Following the Space Shuttle retirement , NASA kept the MLP-3 for solid-propellant rockets . Usage of MLP-3 to launch the OmegA rocket was granted to Orbital ATK (later bought out by Northrop Grumman ) following discussions in 2016, and later formalized through

17202-414: The spent lower stages. A further advantage is that each stage can use a different type of rocket engine, each tuned for its particular operating conditions. Thus the lower-stage engines are designed for use at atmospheric pressure, while the upper stages can use engines suited to near vacuum conditions. Lower stages tend to require more structure than upper as they need to bear their own weight plus that of

17343-554: The stability-limited rated load for a crawler crane is 75% of the tipping load. The stability-limited rated load for a mobile crane supported on outriggers is 85% of the tipping load. These requirements, along with additional safety-related aspects of crane design, are established by the American Society of Mechanical Engineers in the volume ASME B30.5-2018 Mobile and Locomotive Cranes . Standards for cranes mounted on ships or offshore platforms are somewhat stricter because of

17484-486: The stages above them. Optimizing the structure of each stage decreases the weight of the total vehicle and provides further advantage. The advantage of staging comes at the cost of the lower stages lifting engines which are not yet being used, as well as making the entire rocket more complex and harder to build than a single stage. In addition, each staging event is a possible point of launch failure, due to separation failure, ignition failure, or stage collision. Nevertheless,

17625-404: The treadwheel crane may have resulted from a technological development of the windlass from which the treadwheel structurally and mechanically evolved. Alternatively, the medieval treadwheel may represent a deliberate reinvention of its Roman counterpart drawn from Vitruvius ' De architectura which was available in many monastic libraries. Its reintroduction may have been inspired, as well, by

17766-568: The treadwheel crane played a pivotal role in the construction of the lofty Gothic cathedrals . Nevertheless, both archival and pictorial sources of the time suggest that newly introduced machines like treadwheels or wheelbarrows did not completely replace more labor-intensive methods like ladders , hods and handbarrows . Rather, old and new machinery continued to coexist on medieval construction sites and harbors. Apart from treadwheels, medieval depictions also show cranes to be powered manually by windlasses with radiating spokes , cranks and by

17907-436: The type of crane and its usage. Here are some example typical values: The methods for determining the DLF vary in the different crane specifications. The following formulas are examples from one specification. The working load (suspended load) is the total weight that a crane is designed to safely lift under normal operating conditions. It is W = g ⋅ ( m w l l + m

18048-406: The type of fuel and oxidizer combination being used. For example, a mixture ratio of a bipropellant could be adjusted such that it may not have the optimal specific impulse, but will result in fuel tanks of equal size. This would yield simpler and cheaper manufacturing, packing, configuring, and integrating of the fuel systems with the rest of the rocket, and can become a benefit that could outweigh

18189-475: The use of several smaller stones more practical than fewer larger ones. In contrast to the archaic period with its pattern of ever-increasing block sizes, Greek temples of the classical age like the Parthenon invariably featured stone blocks weighing less than 15–20 metric tons. Also, the practice of erecting large monolithic columns was practically abandoned in favour of using several column drums. Although

18330-467: The vaulting and below the roof, where they remained after building construction for bringing material for repairs aloft. Less frequently, medieval illuminations also show cranes mounted on the outside of walls with the stand of the machine secured to putlogs . In contrast to modern cranes, medieval cranes and hoists — much like their counterparts in Greece and Rome  — were primarily capable of

18471-538: The wall. Additionally, the crane master who usually gave orders at the treadwheel workers from outside the crane was able to manipulate the movement laterally by a small rope attached to the load. Slewing cranes which allowed a rotation of the load and were thus particularly suited for dockside work appeared as early as 1340. While ashlar blocks were directly lifted by sling, lewis or devil's clamp (German Teufelskralle ), other objects were placed before in containers like pallets , baskets , wooden boxes or barrels . It

18612-477: The wheel rim, giving the possibility of using a thinner shaft and providing thus a greater mechanical advantage. Contrary to a popularly held belief, cranes on medieval building sites were neither placed on the extremely lightweight scaffolding used at the time nor on the thin walls of the Gothic churches which were incapable of supporting the weight of both hoisting machine and load. Rather, cranes were placed in

18753-451: The whole port basin came into use by the 14th century. A sheer hulk (or shear hulk) was used in shipbuilding and repair as a floating crane in the days of sailing ships , primarily to place the lower masts of a ship under construction or repair. Booms known as sheers were attached to the base of a hulk's lower masts or beam, supported from the top of those masts. Blocks and tackle were then used in such tasks as placing or removing

18894-402: Was 25 feet (7.6 m) high. They were carried by one of two crawler-transporters (CT), which measure 131 by 114 feet (40 by 35 m), and 20 feet (6.1 m) high. Each crawler weighs about 6 million pounds (2,700 tonnes) unloaded, has a maximum speed of about 1 mile per hour (1.6 km/h) loaded, and has a leveling system designed to keep the launch vehicle vertical while negotiating

19035-543: Was canceled and the MLP was left unused. Following the STS-135 , usable parts from the MLP-1 were removed and stored in the Vehicle Assembly Building, with no plans to use the MLP again. In 2021, NASA began rolling out Mobile Launch Platform-1 on Crawler transporter-2 with a concrete ballast on the top to condition the crawlerway to handle the combined weight of the Space Launch System and Orion spacecraft in

19176-467: Was developed by the Ancient Greeks in the late 6th century BC. The archaeological record shows that no later than c. 515 BC distinctive cuttings for both lifting tongs and lewis irons begin to appear on stone blocks of Greek temples. Since these holes point at the use of a lifting device, and since they are to be found either above the center of gravity of the block, or in pairs equidistant from

19317-515: Was proposed by medieval Korean engineer, scientist and inventor Ch'oe Mu-sŏn and developed by the Firearms Bureau (火㷁道監) during the 14th century. The rocket had the length of 15 cm and 13 cm; the diameter was 2.2 cm. It was attached to an arrow 110 cm long; experimental records show that the first results were around 200m in range. There are records that show Korea kept developing this technology until it came to produce

19458-492: Was subsequently used for the launch of Skylab on a Saturn V in 1973. Following the launch of Skylab, ML-2 was the second of the Mobile Launchers to be converted for use by the Space Shuttle. The Launch Umbilical Tower was dismantled and partially reassembled to become the LC-39B Fixed Service Structure (FSS), and the base of the launch platform was modified to accommodate the locations of engines on

19599-461: Was the first of only three purpose-built vessels. There were at least six sheer hulks in service in Britain at any time throughout the 1700s. The concept spread to France in the 1740s with the commissioning of a sheer hulk at the port of Rochefort. A lifting tower similar to that of the ancient Romans was used to great effect by the Renaissance architect Domenico Fontana in 1586 to relocate

19740-441: Was unable to do this, because the foundations consisted of sand. He eventually produced the hydraulic accumulator, a cast-iron cylinder fitted with a plunger supporting a very heavy weight. The plunger would slowly be raised, drawing in water, until the downward force of the weight was sufficient to force the water below it into pipes at great pressure. This invention allowed much larger quantities of water to be forced through pipes at

19881-413: Was used to swing pots and kettles over the fire and the height was adjusted by a trammel . With the onset of the Industrial Revolution the first modern cranes were installed at harbours for loading cargo. In 1838, the industrialist and businessman William Armstrong designed a water-powered hydraulic crane . His design used a ram in a closed cylinder that was forced down by a pressurized fluid entering

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