A crane is a type of machine equipped with a hoist rope, wire ropes or chains, sheaves, that can be used both to lift and lower materials and to move them horizontally. It is used for lifting heavy things and transporting them to other places; the device uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of a human. Cranes are employed in the transport industry for the loading and unloading of freight, in the construction industry for the movement of materials, in the manufacturing industry for the assembling of heavy equipment; the first known construction cranes were invented by the Ancient Greeks and were powered by men or beasts of burden, such as donkeys. These cranes were used for the construction of tall buildings. Larger cranes were developed, 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 and steel took over with 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 use internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capability than was possible, although manual cranes are still utilized where the provision of power would be uneconomic. Cranes exist in an enormous variety of forms – 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 used for constructing high buildings, in order to facilitate constructions by reaching tight spaces.
We can find larger floating cranes used to build oil rigs and salvage sunken ships. Some lifting machines do not fit the above definition of a crane, but are 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: γέρανος, French grue; the crane for lifting heavy loads was invented by the Ancient Greeks in the late 6th century BC. The archaeological record shows that no 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, since they are to be found either above the center of gravity of the block, or in pairs equidistant from 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 lead 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 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; the practice of erecting large monolithic columns was abandoned in favour of using several column drums. Although 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 more preferable to the Greek polis than the more labour-intensive ramp, the norm in 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 attributed to Aristotle, but composed at a later date.
Around the same time, block sizes at Greek temples began to match their archaic predecessors again, indicating that 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 developed it further. We are well informed about their lifting techniques, thanks to rather lengthy accounts by the engineers Vitruvius and Heron of Alexandria. There are two surviving reliefs of Roman treadwheel cranes, with the Haterii tombstone from the late first century AD being detailed; the simplest Roman crane, the trispastos, consisted of a single-beam jib, a winch, a rope, a block containing three pulleys. Having thus a mechanical advantage of 3:1, it has been calculated that a single man working the winch could raise 150 kg, assuming that 50 kg represent the maximum effort a man can exert over a longer time period.
Heavier crane types featured five pulleys or, in case of the largest one, a set of three by five pulleys and came with two, three or four masts, depending on the maximum load. The polyspastos, when worked by four men at both sides of the winch, could lift 3,000 kg (3 ropes x 5 pulleys x 4
The Space Shuttle was a reusable low Earth orbital spacecraft system operated by the U. S. National Aeronautics and Space Administration as part of the Space Shuttle program, its official program name was Space Transportation System, taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. In addition to the prototype whose completion was cancelled, five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center in Florida. Operational missions launched numerous satellites, interplanetary probes, the Hubble Space Telescope; the Shuttle fleet's total mission time was 19 hours, 21 minutes and 23 seconds. Shuttle components included the Orbiter Vehicle with three clustered Rocketdyne RS-25 main engines, a pair of recoverable solid rocket boosters, the expendable external tank containing liquid hydrogen and liquid oxygen.
The Space Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the OV's three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, the ET was jettisoned just before orbit insertion, which used the orbiter's two Orbital Maneuvering System engines. At the conclusion of the mission, the orbiter fired its OMS to re-enter the atmosphere; the orbiter glided as a spaceplane to a runway landing to the Shuttle Landing Facility at Kennedy Space Center, Florida or Rogers Dry Lake in Edwards Air Force Base, California. After landing at Edwards, the orbiter was flown back to the KSC on the Shuttle Carrier Aircraft, a specially modified Boeing 747; the first orbiter, was built in 1976, used in Approach and Landing Tests and had no orbital capability. Four operational orbiters were built: Columbia, Challenger and Atlantis. Of these, two were lost in mission accidents: Challenger in 1986 and Columbia in 2003, with a total of fourteen astronauts killed.
A fifth operational orbiter, was built in 1991 to replace Challenger. The Space Shuttle was retired from service upon the conclusion of Atlantis's final flight on July 21, 2011; the U. S. has since relied on the Russian Soyuz spacecraft to transport astronauts to the International Space Station, pending the Commercial Crew Development and Space Launch System programs on schedule for first flights in 2019 and 2020. The Space Shuttle was a reusable human spaceflight vehicle capable of reaching low Earth orbit and operated by the U. S. National Aeronautics and Space Administration from 1981 to 2011, it resulted from shuttle design studies conducted by NASA and the U. S. Air Force in the 1960s and was first proposed for development as part of an ambitious second-generation Space Transportation System of space vehicles to follow the Apollo program in a September 1969 report of a Space Task Group headed by Vice President Spiro Agnew to President Richard Nixon. Nixon's post-Apollo NASA budgeting withdrew support of all system components except the Shuttle, to which NASA applied the STS name.
The vehicle consisted of a spaceplane for orbit and re-entry, fueled from an expendable External Tank containing liquid hydrogen and liquid oxygen, with two reusable strap-on solid rocket boosters. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982, all launched from the Kennedy Space Center, Florida; the system was retired from service in 2011 after 135 missions, with Atlantis making the final launch of the three-decade Shuttle program on July 8, 2011. The program ended after Atlantis landed at the Kennedy Space Center on July 21, 2011. Major missions included launching numerous satellites and interplanetary probes, conducting space science experiments, servicing and construction of space stations; the first orbiter vehicle, named Enterprise, was used in the initial Approach and Landing Tests phase but installation of engines, heat shielding, other equipment necessary for orbital flight was cancelled. A total of five operational orbiters were built, of these, two were destroyed in accidents.
It was used for orbital space missions by NASA, the U. S. Department of Defense, the European Space Agency and Germany; the United States funded Shuttle development and operations except for the Spacelab modules used on D1 and D2—sponsored by Germany. SL-J was funded by Japan. At launch, it consisted of the "stack", including the dark orange external tank; some payloads were launched into higher orbits with either of two different upper stages developed for the STS. The Space Shuttle was stacked in the Vehicle Assembly Building, the stack mounted on a mobile launch platform held down by four frangible nuts on each SRB, which were detonated at launch; the Shuttle stack launched vertically like a conventional rocket. It lifted off under the power of its two SRBs and three main engines, which were fueled by liquid hydrogen and liquid oxygen from the ET; the Space Shuttle had a two-stage ascent. The SRBs provided additional thrust during first-stage flight. About two minutes after liftoff, frangible nuts were fired, releasing the SRBs, which parachuted into the ocean, to
Apollo 16 was the tenth manned mission in the United States Apollo space program, the fifth and penultimate to land on the Moon, the second to land in the lunar highlands. The second of the so-called "J missions," it was crewed by Commander John Young, Lunar Module Pilot Charles Duke and Command Module Pilot Ken Mattingly. Launched from the Kennedy Space Center in Florida at 12:54 PM EST on April 16, 1972, the mission lasted 11 days, 1 hour, 51 minutes, concluded at 2:45 PM EST on April 27. Young and Duke spent 71 hours—just under three days—on the lunar surface, during which they conducted three extra-vehicular activities or moonwalks, totaling 20 hours and 14 minutes; the pair drove the Lunar Roving Vehicle, the second produced and used on the Moon, for 26.7 kilometers. On the surface and Duke collected 95.8 kilograms of lunar samples for return to Earth, while Command Module Pilot Ken Mattingly orbited in the command and service module above to perform observations. Mattingly spent 64 revolutions in lunar orbit.
After Young and Duke rejoined Mattingly in lunar orbit, the crew released a subsatellite from the service module. During the return trip to Earth, Mattingly performed a one-hour spacewalk to retrieve several film cassettes from the exterior of the service module. Apollo 16's landing spot in the highlands was chosen to allow the astronauts to gather geologically older lunar material than the samples obtained in three of the first four Moon landings, which were in or near lunar maria. Samples from the Descartes Formation and the Cayley Formation disproved a hypothesis that the formations were volcanic in origin. Mattingly had been assigned to the prime crew of Apollo 13, but was exposed to rubella through Duke, at that time on the back-up crew for Apollo 13, who had caught it from one of his children, he never contracted the illness, but was removed from the crew and replaced by his backup, Jack Swigert, three days before the launch. Young, a captain in the United States Navy, had flown on three spaceflights prior to Apollo 16: Gemini 3, Gemini 10 and Apollo 10, which orbited the Moon.
One of 19 astronauts selected by NASA in April 1966, Duke had never flown in space before Apollo 16. He served on the support crew of Apollo 10 and was a capsule communicator for Apollo 11. Although not announced, the original backup crew consisted of Fred W. Haise, William R. Pogue and Gerald P. Carr, who were targeted for the prime crew assignment on Apollo 19. However, after the cancellations of Apollos 18 and 19 were finalized in September 1970 this crew would not rotate to a lunar mission as planned. Subsequently and Mitchell were recycled to serve as members of the backup crew after returning from Apollo 14, while Pogue and Carr were reassigned to the Skylab program where they flew on Skylab 4. Anthony W. England Karl G. Henize Henry W. Hartsfield Jr. Robert F. Overmyer Donald H. Peterson The insignia of Apollo 16 is dominated by a rendering of an American eagle and a red and blue shield, representing the people of the United States, over a gray background representing the lunar surface.
Overlaying the shield is a gold NASA vector, orbiting the Moon. On its gold-outlined blue border, there are 16 stars, representing the mission number, the names of the crew members: Young, Duke; the insignia was designed from ideas submitted by the crew of the mission. Apollo 16 was the second of the Apollo type J missions, featuring the use of the Lunar Roving Vehicle, increased scientific capability, lunar surface stays of three days; as Apollo 16 was the penultimate mission in the Apollo program and there was no new hardware or procedures to test on the lunar surface, the last two missions presented opportunities for astronauts to clear up some uncertainties in understanding the Moon's properties. Although previous Apollo expeditions, including Apollo 14 and Apollo 15, obtained samples of pre-mare lunar material, before lava began to upwell from the Moon's interior and flood the low areas and basins, none had visited the lunar highlands. Apollo 14 had visited and sampled a ridge of material, ejected by the impact that created the Mare Imbrium impact basin.
Apollo 15 had sampled material in the region of Imbrium, visiting the basin's edge. There remained the possibility, because the Apollo 14 and Apollo 15 landing sites were associated with the Imbrium basin, that different geologic processes were prevalent in areas of the lunar highlands far from Mare Imbrium. Several members of the scientific community remarked that the central lunar highlands resembled regions on Earth that were created by volcanic processes and hypothesized the same might be true on the Moon, they had hoped. Two locations on the Moon were given primary consideration for exploration by the Apollo 16 expedition: the Descartes Highlands region west of Mare Nectaris and the crater Alphonsus. At Descartes, the Cayley and Descartes formations were the primary areas of interest in that scientists suspected, based on telescopic and orbital imagery, that the terrain found there was formed by magma more viscous than that which formed the lunar maria; the Cayley Formation's age was approximated to be about the same as Mare Imbrium based on the local frequency of impact craters.
The considerable distance between the Descartes site and previous Apollo landing sites would be beneficial for the network of geophysical instruments, portions of which were deployed on each Apollo expedition beginning with Apollo 12. At the Alphonsus, three scientific objectives were determined to be of primary int
Apollo 17 was the final mission of NASA's Apollo program and the last mission as of 2019 in which humans have travelled to and walked on the Moon. Launched at 12:33 a.m. Eastern Standard Time on December 7, 1972, with a crew made up of Commander Eugene Cernan, Command Module Pilot Ronald Evans, Lunar Module Pilot Harrison Schmitt, it was the last use of Apollo hardware for its original purpose. Apollo 17 was the first night launch of a U. S. human spaceflight and the final manned launch of a Saturn V rocket. It was a "J-type mission" which included three days on the lunar surface, extended scientific capability, the third Lunar Roving Vehicle. While Evans remained in lunar orbit in the command and service module and Schmitt spent just over three days on the Moon in the Taurus–Littrow valley and completed three moonwalks, taking lunar samples and deploying scientific instruments. Evans took scientific measurements and photographs from orbit using a scientific instruments module mounted in the service module.
The landing site was chosen with the primary objectives of Apollo 17 in mind: to sample lunar highland material older than the impact that formed Mare Imbrium, investigate the possibility of new volcanic activity in the same area. Cernan and Schmitt returned to Earth on December 19 after a 12-day mission. Apollo 17 is the most recent manned Moon landing and the most recent time humans travelled beyond low Earth orbit, it was the first mission to have no one on board, a test pilot. The mission broke several records: the longest Moon landing, longest total extravehicular activities, largest lunar sample, longest time in lunar orbit. Eugene Cernan, Ronald Evans, former X-15 pilot Joe Engle were assigned to the backup crew of Apollo 14. Engle flew sixteen X-15 flights. Following the rotation pattern that a backup crew would fly as the prime crew three missions Cernan and Engle would have flown Apollo 17. Harrison Schmitt served on the backup crew of Apollo 15 and, following the crew rotation cycle, was slated to fly as Lunar Module Pilot on Apollo 18.
However, Apollo 18 was cancelled in September 1970. Following this decision, the scientific community pressured NASA to assign a geologist to an Apollo landing, as opposed to a pilot trained in geology. In light of this pressure, Harrison Schmitt, a professional geologist, was assigned the Lunar Module Pilot position on Apollo 17. Scientist-astronaut Curt Michel believed that it was his own decision to resign, after it became clear that he would not be given a flight assignment, that mobilized this action. Subsequent to the decision to assign Schmitt to Apollo 17, there remained the question of which crew would become prime crew of the mission. NASA Director of Flight Crew Operations Deke Slayton assigned the backup crew of Apollo 14, along with Schmitt, to the prime crew of Apollo 17; the Apollo 15 prime crew received the backup assignment since this was to be the last lunar mission and the backup crew would not rotate to another mission. However, when the Apollo 15 postage stamp incident became public in early 1972 the crew was reprimanded by NASA and the United States Air Force.
Director of Flight Crew Operations Deke Slayton removed them from flight status and replaced them with Young and Duke from the Apollo 16 prime crew and Roosa from the Apollo 14 prime and Apollo 16 backup crews. Robert F. Overmyer Robert A. Parker C. Gordon Fullerton The insignia's most prominent feature is an image of the Greek sun god Apollo backdropped by a rendering of an American eagle, the red bars on the eagle mirroring those on the flag of the United States. Three white stars above the red bars represent the three crewmen of the mission; the background includes the Moon, the planet Saturn, a galaxy or nebula. The wing of the eagle overlays the Moon, suggesting man's established presence there; the gaze of Apollo and the direction of the eagle's motion embody man's intention to explore further destinations in space. The patch includes, along with the colors of the U. S. flag, the color gold, representative of a "golden age" of spaceflight, to begin with Apollo 17. The image of Apollo in the mission insignia is a rendering of the Apollo Belvedere sculpture.
The insignia was designed with input from the crew. Like Apollo 15 and Apollo 16, Apollo 17 was slated to be a "J-mission," an Apollo mission type that featured lunar surface stays of three days, higher scientific capability, the usage of the Lunar Roving Vehicle. Since Apollo 17 was to be the final lunar landing of the Apollo program, high-priority landing sites that had not been visited were given consideration for potential exploration. A landing in the crater Copernicus was considered, but was rejected because Apollo 12 had obtained samples from that impact, three other Apollo expeditions had visited the vicinity of Mare Imbrium. A landing in the lunar highlands near the crater Tycho was considered, but was rejected because of the rough terrain found there and a landing on the lunar far side in the crater Tsiolkovskiy was rejected due to technical considerations and the operational costs of maintaining communication during surface operations. A landing in a region southwest of Mare Crisium was considered, but rejected on the grounds that a Soviet spacecraft could access t
The Saturn V was an American human-rated expendable rocket used by NASA between 1967 and 1973. The three-stage liquid-propellant super heavy-lift launch vehicle was developed to support the Apollo program for human exploration of the Moon and was used to launch Skylab, the first American space station; the Saturn V was launched 13 times from the Kennedy Space Center in Florida with no loss of crew or payload. As of 2019, the Saturn V remains the tallest and most powerful rocket brought to operational status, holds records for the heaviest payload launched and largest payload capacity to low Earth orbit of 140,000 kg, which included the third stage and unburned propellant needed to send the Apollo Command/Service Module and Lunar Module to the Moon; the largest production model of the Saturn family of rockets, the Saturn V was designed under the direction of Wernher von Braun and Arthur Rudolph at the Marshall Space Flight Center in Huntsville, with Boeing, North American Aviation, Douglas Aircraft Company, IBM as the lead contractors.
To date, the Saturn V remains the only launch vehicle to carry humans beyond low Earth orbit. A total of 15 flight-capable vehicles were built. An additional three vehicles were built for ground testing purposes. A total of 24 astronauts were launched to the Moon, three of them twice, in the four years spanning December 1968 through December 1972; the origins of the Saturn V rocket begin with the US government bringing Wernher von Braun along with about seven hundred German rocket engineers and technicians to the United States in Operation Paperclip, a program authorized by President Truman in August 1946 with the purpose of harvesting Germany's rocket expertise, to give the US an edge in the Cold War through development of intermediate-range and intercontinental ballistic missiles. It was known that America's rival, the Soviet Union, would try to secure some of the Germans. Von Braun was put into the rocket design division of the Army due to his prior direct involvement in the creation of the V-2 rocket.
Between 1945 and 1958, his work was restricted to conveying the ideas and methods behind the V-2 to the American engineers. Despite Von Braun's many articles on the future of space rocketry, the US Government continued funding Air Force and Navy rocket programs to test their Vanguard missiles in spite of numerous costly failures, it was not until the 1957 Soviet launch of Sputnik 1 atop an R-7 ICBM, capable of carrying a thermonuclear warhead to the US, that the Army and the government started taking serious steps towards putting Americans in space. They turned to von Braun and his team, who during these years created and experimented with the Jupiter series of rockets; the Juno I was the rocket that launched the first American satellite in January 1958, part of the last-ditch plan for NACA to get its foot in the Space Race. The Jupiter series was one more step in von Braun's journey to the Saturn V calling that first series "an infant Saturn"; the Saturn program was named Saturn. The Saturn's design stemmed from the designs of the Jupiter series rockets.
As the success of the Jupiter series became evident, the Saturn series emerged. Between 1960 and 1962, the Marshall Space Flight Center designed a series of Saturn rockets that could be used for various Earth orbit or lunar missions; the C-1 was developed into the Saturn I, the C-2 rocket was dropped early in the design process in favor of the C-3, intended to use two F-1 engines on its first stage, four J-2 engines for its second stage, a S-IV stage using six RL10 engines. NASA planned to use the C-3 as part of the Earth Orbit Rendezvous concept, with at least four or five launches needed for a single lunar mission, but MSFC was planning an bigger rocket, the C-4, which would use four F-1 engines on its first stage, an enlarged C-3 second stage, the S-IVB, a stage with a single J-2 engine, as its third stage. The C-4 would need only two launches to carry out an EOR lunar mission. On January 10, 1962, NASA announced plans to build the C-5; the three-stage rocket would consist of: the S-IC first stage, with five F-1 engines.
The C-5 was designed for a 90,000-pound payload capacity to the Moon. The C-5 would undergo component testing before the first model was constructed; the S-IVB third stage would be used as the second stage for the C-IB, which would serve both to demonstrate proof of concept and feasibility for the C-5, but would provide flight data critical to development of the C-5. Rather than undergoing testing for each major component, the C-5 would be tested in an "all-up" fashion, meaning that the first test flight of the rocket would include complete versions of all three stages. By testing all components at once, far fewer test flights would be required before a manned launch; the C-5 was confirmed as NASA's choice for the Apollo program in early 1963, was named the Saturn V. The C-1 became the Saturn I, C-1B became Saturn IB. Von Braun headed a team at the Marshall Space Flight Center in building a vehicle capable of launching a manned spacecraft to the Moon. Before they moved under NASA's jurisdiction, von Braun's team had begun work on improving the thrust, creating a less complex operating system, designing better mechanical systems.
It was during these revisions that the decision to reject the single engine of the V-2's design came about, the team moved to a multiple-engine design. The Saturn I and IB reflected these changes, but were not large enough to send a m