For safety and for environmental considerations Airport Taxi Van in Westcliff, most airports are built far away from cities and other residential areas. This poses an issue of traveling to and from the airport. People need transportation to the airfield when they are flying out and need to reach the airfield in time to catch their flight. Likewise, Taxi To Airport Cost after landing at the airfield from a flight, transport from the airfield to the city is required. Both the issues are solved with private operators operating lax airfield car services.Transportation utilities provide luxury car services to and from the airport.
These are mainly chauffeur driven cars, for which travelers may book reservations online. This facility comes as a great advantage to the commuter. With an online reservation system, the traveler is confident that he will be picked up from his hotel, office or home by a cab and taken to the airport right on-time to catch his flight, the service being guaranteed.Most transportation utilities track national and international flights. Therefore, the commuter may rest assured that the transportation from the aerodrome will be available and waiting for him, even if the flight arrives late into the night.
The traveler no longer has to depend on rented cars and driving them through rush-hour traffic. After the long journey by flight, Airport Transfers Orlando he could take the luxurious, relaxing ride to his hotel, home or office.They have professional chauffeurs who have been trained to accommodate customer needs. They possess the required expertise and knowledge to conduct the traveler to and from the destination. They know the city roads like the back of their hands and can help the traveler reach his destination on time, even if the normal city roads are choked with traffic.
Airport car service providers value the relationship with their customers and strive to maintain the required professionalism that is expected from such executive luxury service. These smart luxury car services are hard to forget once their utility has been realized.
Airport Taxi Van in Westcliff ?
A car rapide
share taxi in Senegal
A share taxi (also called shared taxi) is a mode of transport which falls between a taxicab and a bus. These vehicles for hire are typically smaller than buses and usually take passengers on a fixed or semi-fixed route without timetables, but instead departing when all seats are filled. They may stop anywhere to pick up or drop off their passengers. Often found in developing countries, the vehicles used as share taxis range from four-seat cars to minibuses. They are often owner-operated.
The UITP term "informal transport" includes share taxis.
A given share taxi route may start and finish in fixed central locations, and landmarks may serve as route names or route termini. In some African cities routes are run between formal termini, where the majority of passengers board. In these places the share taxis wait for a full load of passengers prior to departing, and off-peak wait times may be in excess of an hour.
In other places there may be no formal termini, with taxis simply congregating at a central location, instead.
Even more-formal terminals may be little more than parking lots.
In South Africa, its also referred to as a rank, which denotes an area specifically built, by a municipality or city, for taxi operators, where commuters may start and end their journey.
Where they exist, share taxis provide service on set routes within and sometimes between towns.
After a share taxi has picked up passengers at its terminus, it proceeds along a semi-fixed route where the driver may determine the actual route within an area according to traffic condition. Drivers will stop anywhere to allow riders to disembark, and may sometimes do the same when prospective passengers want to ride.
While all share taxis share certain characteristics—and many regional versions exhibit peculiarities—some basic operational distinctions can be delineated.
Most share taxis are operated under one of two regimes. Some share taxis are operated by a company. For example, in Dakar there are company-owned fleets of hundred of car rapides. In Soviet Union, share taxis, known as marshrutka, were operated by state-owned taxi parks. There are also individual operators in many countries. In Africa, while there are company share taxis, individual owners are more common. Rarely owning more than two vehicles at a time, they will rent out a minibus to operators, who pay fuel and other running costs, and keep revenue.
In some places, like some African cities and also Hong Kong, share taxi minibuses are overseen by syndicates, unions, or route associations. These groups often function in the absence of a regulatory environment and may collect dues or fees from drivers (such as per-use terminal payments, sometimes illegally), set routes, manage terminals, and fix fares. Terminal management may include ensuring each vehicle leaves with a full load of passengers.
Because the syndicates represent owners, their regulatory efforts tend to favor operators rather than passengers, and the very termini syndicates upkeep can cost delays and money for passengers as well as forcing them to disembark at inconvenient locations, in a phenomenon called "terminal constraint".
In Africa, regulation is mainly something that pertains to the vehicle itself not its operator or its mode of operation.
In Kenya, regulation does extend to operators and mode of operation (such as routes used) as well as the vehicle
As of 2008, African minibuses are difficult to tax, and may operate in a "regulatory vacuum" perhaps because their existence is not part of a government scheme, but is simply a market response to a growing demand for such services. Route syndicates and operator's associations often exercise unrestricted control, and existing rules may see little enforcement.
Share taxi is a unique mode of transport independent of vehicle type. Minibuses, midibuses, covered pickup trucks, station wagons, and lorries see use as share taxis.
Certain vehicle types may be better-suited to current condition than others. In many traffic-choked, sprawling, and low-density African cities minibuses profit.
In Israel they were mostly the largest model of Mercedes, owned generally by Arabs, and very efficient, having space for 7-8 people, and having loosely fixed routes, dropping a passenger either at a specific terminus or going a little out of way to facilitate the passenger.
While carrying different names and distinguished by regional peculiarities, the share taxi is an everyday feature of life in many places throughout the world.
An Angkot in Bandung, West Java A three-wheeler Bemo
in Jakarta. It also serves as a share taxi like Angkots
Angkutan Kota abbreviated Angkot or Mikrolet are share taxis in Indonesia widely operating throughout the country usually with Mini vans. In some places there are also three-wheelers which are called Bemo (such as autorickshaws based on the Daihatsu Midget). The older version of Angkot is called Oplet. The name of this transportation differs from each different province or area in the country. In Jakarta, it is called Angkot, in other parts such as in Sulawesi, the term Mikrolet shortened Mikro is more widely used especially in Manado. In Makassar it is called "Pete-Pete", in Malang it is called "Angkota", in Medan it is called "Sudako".
It runs accordingly with its exact routes and passengers can stop the van anywhere according to its destination, and is not required to stop at a bus stop or station.
In some towns in Northern Ireland, notably certain districts in Ballymena, Belfast, Derry and Newry, share taxi services operate using Hackney carriages and are called black taxis. These services developed during The Troubles as public bus services were often interrupted due to street rioting. Taxi collectives are closely linked with political groups – those operating in Catholic areas with Sinn Féin, those in Protestant areas with loyalist paramilitaries and their political wings.
Typically, fares approximate to those of Translink operated bus services on the same route. Service frequencies are typically higher than on bus services, especially at peak times, although limited capacities mean that passengers living close to the termini may find it difficult to find a black taxi with seats available in the rush hour.
A Toyota Corolla estate bush taxi
Three main vehicle types are used as bush taxis (French taxi brousse, Mandinka tanka tanka): the station wagon, the minibus, and the lorry. Many are previously owned vehicles imported from Europe or Japan; others are assembled from parts in regional centres such as Nigeria or Kenya. The original seating of the vehicles is usually stripped out in order to fit benches with more passenger space. In addition, more people generally sit on each bench than would be the case in more-developed countries. They are often in poor condition, though wealthier countries tend to have better-maintained vehicles.
In the past, most station-wagon bush taxis were modified 1980s-model Peugeot 504s. In some countries they are known as "five-seaters" or "seven-seaters" (French sept-place), but in fact, they may seat nine passengers or more in three rows of seats. Other models, such as the Peugeot 505 or the Toyota Corolla have since supplanted the 504 in some countries, and are gaining ground in others.
The bush taxi, a type of public light bus frequently used in West-Africa
Typically two passengers are seated on the front seat next to the driver, and four passengers in each of the two back rows. Sometimes, in particular on less-frequented routes, bush taxis are more crowded, and passengers might even sit on the roof or the boot. Bush taxis in wealthier countries tend to be less crowded. For example, in Nigeria bush taxis (of both the station wagon or minibus type) are called three-across or four-across according to the number of passengers seated in each row.
The minibus (a van-like vehicle seating 12 to 20 passengers; French minicar) is quickly becoming the most common type of bush taxi in West and Central Africa, especially for longer trips. Due to the vehicles' larger size, drivers often employ a helper who rides in the back of the vehicle and tells the driver when to stop to let people off, and helps load and unload baggage. Minibuses tend to travel slower than cars, and they take longer to fill up and to pass through police checkpoints. These vehicles generally charge more than standard buses but less than Peugeot-type bush taxis. Frequently used models in West-Africa are the Renault Super Goélette, the Saviem Super Goelette 2, and the Isuzu Kitamura minibus. The Goelette is also used frequently in Vietnam and Madagascar as a share taxi.
Lorries are also used as bush taxis (French bâché): they are normal lorries (trucks) with benches along the sides of the bed for passengers. There is often a cover for the bed as well. Lorries are more robustly made (and give a rougher ride) than purpose-built passenger vehicles; routes over worse roads and to more remote areas are often serviced by lorries.
Carros Públicos (literally "Public Cars") are share taxis in the Dominican Republic and Puerto Rico.
In the Dominican Republic, these privately owned vehicles run fixed routes with no designated stops, and the ride is shared with other passengers.
Foreign Affairs and International Trade Canada advises against traveling in Dominican Republic carros públicos because doing so makes passengers targets for robbery, and because the taxis are known to, "disregard traffic laws, often resulting in serious accidents involving injuries and sometimes death." The US Department of State also warns that using them is hazardous, as passengers often have their pockets picked, and are sometimes robbed by the drivers themselves.
In Puerto Rico, carros públicos ply set routes with several passengers sharing the ride and others picked up throughout the journey.
The industry is regulated by the Puerto Rico Public Service Commission.
While these cars do travel inter-city, they may not be available for longer, cross-island travel. Stations may exist in cities, and Puerto Rican carros públicos may congregate in specific places around town.
Minibus public transports in Rwanda may be called coaster buses, share taxis, or twegerane. The latter could easily be a word meaning "stuffed" or "full".
As of 2011 in Kigali, Rwanda, syndicates include ATRACO and ONATRACOM, but an independent transport authority is absent.
Colectivos operated as share taxis from the late 1920s until the 1950s in Buenos Aires, Argentina when they were integrated into the public transportation system. Vehicles still known as colectivos operate throughout the country, but have long been indistinguishable from buses.
Main article: Dala-dala A dala dala
in the city of Dar es Salaam
Minivans (minibuses may be a more correct term here) are used as vehicles for hire and referred to as dala dala in Tanzania. While dala dala may run fixed routes picking up passengers at central locations, they will also stop along the route to drop someone off or allow a prospective passenger to board. Before minibuses became widely used, the typical dala dala was a pick-up truck with benches placed in the truck bed.
In Dar es Salaam, publicly operated minibus service may also exist as of 2008.
Usually run by both a driver and a conductor, the latter is called a mpigadebe, literally meaning "a person who hits a debe" (a 4-gallon tin container used for transporting gasoline or water). The name is in reference to the fact that conductors are often hitting the roof and side of the van to attract customers and notify the driver when to leave the station.
These often-crowded public transports have their routes allocated by a Tanzania transport regulator, Surface and Marine Transport Regulatory Authority (SUMATRA), but syndicates also exist and include DARCOBOA. Play media Play media
The danfo share taxi and molue minibuses are iconic of transport in Lagos, Nigeria.
In Nigeria, both minibuses (called danfo) and midibuses (molue) may be operated as share taxis. Such public transports may also be referred to as bolekaja, and many may bear slogans or sayings.[Thompson 1]
Lagos, Nigeria, has a transport-dedicated regulator, Lagos Metropolitan Area Transport Agency (LAMATA), its remit most probably includes share taxi activity. Outside of Lagos, most major cities in Africa have similar systems of transport.
Syndicates in Lagos may include National Union of Road and Transport Workers (NURTW).
Karsan-built Peugeot J9 Premier dolmuş
in Bodrum, Turkey
In Turkey and Turkish controlled Northern Cyprus dolmuş (pronounced "dolmush") are share taxis that run on set routes within and between cities. Each of these cars or minibuses displays their particular route on signboards behind the windscreen.
Some cities may only allow dolmuş to pick up and disembark passengers at designated stops, and terminals also exist. The word derives from Turkish for "full" or "stuffed", as these share taxis depart from the terminal only when a sufficient number of passengers have boarded. Visitors to Turkey have been surprised by the speed of dolmuş travel.
These share taxis are also found in Turkish-controlled, Northern Cyprus under the same name. Traveling intra and inter-city, the privately owned minibuses or aging Mercedes stretch limos are overseen by a governance institution; routes are leased and vehicles licensed. Passengers board anywhere along the route (you may have to get the driver to stop if he doesn't honk at you) as well as at termini and official stations. Dolmuş in Turkish-controlled, Northern Cyprus display their routes but don't follow timetables. Instead, they simply appear frequently.
Those in Kinshasa, DRC, (or perhaps just the Kongo people) may call share taxis fula fula meaning "quick quick".[Thompson 2]
There was no independent transport authority in the city of Kinshasa as of 2008.
In Côte d'Ivoire, gbaka are a name for minibus public transports.
The transport regulator in Abidjan, CI, is Agence de Gestion des Transports Urbains or AGETU.
As of 2008, Abidjan public transport was serviced by large buses as well as minibuses.
Syndicates include UPETCA, SNTMVCI.
In Morocco, grands taxis are the name for large, unmetered, shared taxicabs used for transportation between towns. Grands taxis are generally old full-size Mercedes-Benz sedans, and seat six or more passengers.
A typical jeepney Main article: Jeepney
The most popular means of public transportation in the Philippines as of 2007, jeepneys were originally made out of US military jeeps left over from World War II and are known for their color and flamboyant decoration. Today the jeepneys are built by local body shops from a combination of prefabricated elements (from handful Filipino manufacturers) and improvisation and in most cases equipped with "surplus" or used Japanese SUV or light truck engines, drive train, suspension and steering components (from recycled vehicles in Japan).
They have not changed much since their post-war creation, even in the face of an increased access to pre-made vehicles, such as minibuses.
Jeepneys have the entrance on the back, and there is space for two people beside the driver (or more if they are small). The back of the Jeepney is equipped with two long bench seats along the sides and the people seated closest to the driver are responsible for passing the fare of new passengers forward to the driver and the change back to the passenger. The start and end point of the Jeepney route is often a Jeepney terminal, where there is a queue system so only one Jeepney plying a particular route is filled at a time, and where a person helps the driver to collect fares and fill the vehicles with people, usually to more than comfortable capacity.
Preferring to leave only when full and only stop for a crowd of potential passengers, riders can nonetheless disembark at any time; and while jeepneys ply fixed routes, these may be subject to change over time. New ones may need approval from a Philippine transport regulator. Jeepney stations do exist.
Main article: Dollar van
Jitney is an American English term that originally referred to a vehicle for hire intermediate between a taxi and a bus. They are generally small-capacity vehicles that follow a rough service route, but can go slightly out of their way to pick up and drop off passengers. In many US cities (e.g. Pittsburgh and Detroit), the term jitney refers to an unlicensed taxi cab.
The name comes from an archaic, colloquial term for a five-cent piece in the US (the nickel). The common fare for the service when it first came into use was five cents, so the "five-cent cab" or "jitney cab" came to be known for the price charged.
In Rhode Island a jitney license plate is used for all public passenger buses, even for larger ones.
Jitney in Atlantic City, United States in 2008
While jitneys became fairly common in many other countries, such as the Philippines, they first appeared in the US and Canada. The first US jitneys ran in 1914 in Los Angeles, California. By 1915, there were 62,000 nationwide. Local regulations, demanded by streetcar companies, killed the jitney in most places. By the end of 1916, only 6,000 jitneys remained. Similarly, in Vancouver, Canada, in the 1920s, jitneys competed directly with the streetcar monopoly operating along the same routes as the streetcars, but jitneys were charging lower fares. Operators were referred to as "jitney men." They were so successful that the city government banned them at the request of the streetcar operators.
Since the 1973 oil crisis (as well as the mid-20th-century decline in transit service), jitneys have reappeared in some areas of the US, particularly in inner city areas once served by streetcars and private buses. An increase in bus fares usually leads to a significant rise in jitney usage. Liberalization of jitneys is often encouraged by libertarian urban economists, such as University of Chicago's Richard Epstein, Rutgers' James Dunn, and USC's Peter Gordon, as a more "market-friendly" alternative to public transportation. Concerns over fares, insurance liabilities, and passenger safety have kept legislative support for jitneys decidedly tepid. Nevertheless, in New York City and northern New Jersey, jitneys (known as "dollar vans" because of their original price) are regulated.
Miami has the country's most comprehensive jitney network, due to Caribbean influence. In Atlanta jitneys run along Buford Highway.
In Atlantic City the ACJA operates a jitney service that travels the main strip of casinos. One of the routes also services the new cluster of casinos west of Atlantic City proper.
In 2009, the Houston Waves, Houston's first jitney service in 17 years, started running. It has expanded into a network of buses operating within Loop 610 and to all special event venues in Houston.
The term kia kia may be used in Yorùbáland to refer to minibus public transports, and means "quick quick".[Thompson 1]
Share taxis in Estonia are mostly found in Tallinn, the capital. Called liinitakso, marsruuttakso, taksobuss or mikroautobuss depending on the language spoken, these minibuses run fixed routes and allow passengers to disembark at any time.
Share taxis in Tunisia are called louage and follow fixed or semi-fixed routes, departing from stations when full. Usually minibuses or compact cars, although some louage are station wagons, passengers may board and disembark at any point during travel.
They run between towns and within cities.
in Bishkek, Kyrgyzstan Main article: Marshrutka
Marshrutka or marshrutnoe taksi are share taxis found in Eastern Europe and the republics of the former Soviet Union. Usually vans, they drive along set routes, usually depart only when all seats are filled, and may have higher fares than buses. Passengers can board a marshrutka anywhere along its route if there are seats available.
As fares are usually paid before the marshrutka leaves, which seat you choose can have consequences. Riders nearer the driver are responsible for handing up the other passengers' fares and passing back change.
In Lithuania, share taxis are called maršrutinis taksi.
Main article: Matatu
In Kenya, Uganda, and neighboring nations matatu are privately owned minibuses, although pick-up trucks were in the past pressed into service as these East African public transports whose decoration often features portraits of the famous. Slogans and sayings also appear, some religious. In addition to a driver, matatu may be staffed by a tout, conductor, or porter.
They may ply set routes, display this route, run from termini, run both inter and intra-city, and may stop along said route to purchase or collect money from passengers.
As of 1999, matatu could have been the only form of public transport in Nairobi, Kenya, but this may not have been the case in 2006 and 2008. As of 2008, Kampala, Uganda, may only be serviced by minibuses.
The name is a Swahili colloquialism, and were it convenient, passengers could even pay for their journeys via cell phone. The name is literally a conjugation of the word "three", and derives from their original price, three shillings "mashilingi matatu".
In Kenya, this industry is regulated, and such minibuses must, by law, be fitted with seatbelts and speed governors. Present regulation may not be sufficient deterrent to prevent small infractions as even decoration may be prohibited. Kenya has one of the "most extensive regulatory controls to market entry", and a matatu worker can be pulled from the streets simply for sporting too loud a shirt.
As of 2008, Kampala, Uganda, has no independent transport authority, but transport is authorised by Kampala Capital city Authority (KCCA). In Kampala the informal vehicles are called taxis. 
Egyptian share cabs are generally known as micro-bus (mekrobass ميكروباص or mašrūʿ مشروع, "project"; plural mekrobassāt ميكروباصات or mašarīʿ مشاريع). The second name is used by Alexandrians.
Micro-buses are licensed by each governorate as taxicabs, and are generally operated privately by their drivers. Although each governorate attempts to maintain a consistent paint scheme for them, in practice the color of them varies wildly, as the "consistent" schemes have changed from time to time and many drivers have not bothered to repaint their cars.
Rates vary depending on distance traveled, although these rates are generally well known to those riding the micro-bus. The fares also depend on the city. Riders can typically hail micro-buses from any point along the route, often with well-established hand signals indicating the prospective rider's destination, although certain areas tend to be well-known micro-bus stops.
Like the Eastern European marshrutka, a typical micro-bus is a large van, most often a Toyota HiAce or its Jinbei equivalent, the Haise, and the latter is produced by the Bavarian Auto Manufacturing Group in 6th of October City in Egypt. Smaller vans and larger small buses are also used.
Sharing ajans in Tehran
In Iran a share taxi is usually called "taxi", while a non-share is called "ajans"/اژانس, pronounced [aʒans]. Four passengers share a taxi and sometimes there is no terminus and they wait in the street side and blare their destination to all taxies until one of them stops. These are regular taxies but if somebody wants to get a non-share taxi he can call for an ajans (taxi service) for himself or wait in the street side and say 'DARBAST' (which means non-share). It means he is not interested in sharing the taxi and is consequently willing to pay more for the privilege.
Minibuses, in the past years, with a capacity of 18 passengers, and nowadays van taxies, with a capacity of 10 passengers are other kinds of share transport in Iran.
Minibus taxis in Ethiopia are one of the most important modes of transport in big cities like Addis Ababa. They are preferred by the majority of the populace over public buses and more-traditional taxicabs because they are generally cheap, operate on diverse routes, and are available in abundance. All minibus taxis in Ethiopia have a standard blue-and-white coloring scheme, much like the yellow color of New York taxis except it isn't yellow. Minibus taxis are usually Toyota Hiaces, frequent the streets. They typically can carry 11 passengers, but will always have room for another until that is no longer the case. The minibus driver has a crew member called a weyala, and his job is to collect the fare from passengers.
In 2008, publicly operated public transport was available in Addis Ababa in addition to that provided by the minibuses. A fleet of 350 large buses may operate for this purpose, as such a number does exist. Also as of 2008, the city lacks an independent transport authority, but some regulation, such as that controlling market entry, does exist.
Route syndicates may be a presence but are described as "various".
Cape Town minibus taxi rank See also: Taxi wars in South Africa
Over 60% of South African commuters use shared minibus taxis (16 seater commuter buses).
Many of these vehicles are unsafe and not roadworthy, and often dangerously overloaded.
Prior to 1987, the taxi industry in South Africa was highly regulated and controlled. Black taxi operators were declined permits in the Apartheid era and all minibus taxi operations were, by their very nature, illegal.
Post 1987, the industry was rapidly deregulated, leading to an influx of new minibus taxi operators, keen to make money off the high demand for this service. Taxi operators banded together to form local and national associations. Because the industry was largely unregulated and the official regulating bodies corrupt, these associations soon engaged in anti-competitive price fixing and exhibited gangster tactics – including the hiring of hit-men and all-out gang warfare. During the height of the conflict, it was not uncommon for taxi drivers to carry shotguns and AK-47s to simply shoot rival taxi drivers and their passengers on sight.
Currently the South African Government is attempting to formalize and re-regulate the out-of-control minibus taxi industry. Along with new legislation, the government has instituted a 7-year recapitalization scheme to replace the old and unroadworthy vehicles with new 18- and 35-seater minibuses. These new minibus taxis carry the South African flag on the side and are notably more spacious and safe.
A public light bus (left) and a double-decker bus (right) in Hong Kong. Main article: Public light bus
Public light buses (Chinese: 公共小型巴士), also known as minibus or maxicab (Chinese: 小巴), run the length and breadth of Hong Kong, through areas which the standard bus lines cannot or do not reach as frequently, quickly or directly.
Typically offering a faster and more efficient transportation solution due to their small size, limited carrying capacity, frequency and diverse range of routes, although they are generally slightly more expensive than standard buses, minibuses carry a maximum of 16 seated passengers. Standing passengers are not allowed.
There are two types of public light minibus, green and red. Both types have a cream-coloured body, the distinguishing feature being the colour of the external roof, and the type of service that the colour denotes: green is like regular transit bus with fixed number, route, schedule and fare (but generally not fixed stops); red is a shared taxi, operating on semi-fixed route unregulated, with the driver waiting for enough passengers to justify leaving, as his income depends on the revenue.
In Guatemala, ruleteros, minibus share taxis, pick up and discharge passengers along major streets.
In New Zealand the first widespread motor vehicle services were shared taxi services termed service cars; a significant early provider was Aard, operating elongated Hudson Super-Six Coaches. By 1930 there were 597 service cars. Aard was taken over by New Zealand Railways Road Services in 1928. Shared taxis in New Zealand nowadays are referred to as Shuttles or Shuttle vans (see below).
In Cyprus, there are privately owned share taxis that travel to set destinations and board additional passengers en route called service taxis.
Shared taxis–and they are known by that exact name–have been operating in Mumbai, India, since the early 1970s. These are more like a point-to-point service that operates only during the peak hours than other share taxis. During off-peak hours, they ply just like the regular taxis; they can be hailed anywhere on the roads, and passengers are charged by the meter.
But during peak hours several of them will operate as shared taxis, taking a full cab load of passengers to a more or less common destination. The pick-up points for these taxis are fixed, and are marked by a sign saying "shared taxis" and the cabs will line up at this point during peak hours.
They display the general destination they are headed for on their windscreens, and passengers just get in and wait for the cab to fill up. As soon as this happens–which takes less than a few minutes–the cab moves off. Fares are a fixed amount and are far lower than the metered fare to the same destination but higher than a bus or train fare.
Share jeeps are a common form of transportation in the Himalayas, the North Eastern States and elsewhere.
Sherut (pl. moniot sherut) is a Hebrew word meaning "service". Also referring to vans that serve as share taxis in Israel, these can be picked up from sherut stations. They follow fixed routes (sometimes the same routes as public transport buses), leave when full, and will only disembark passengers along the route. Moniyot sherut operate both inter and intra-city. Payment is often done by passing money to the driver in a "human chain" formed by the passengers seated before. The change (and the receipt, when requested) are returned to the person who paid by the same means. In intra-city routes, where they compete with official buses, the drivers usually coordinate their travel by radio so that they can arrive at the bus station just before public transport buses and take the most passengers.
Called "ser-vees" (service taxi) by Palestinians, in the West Bank vans are replaced by minibuses, for a while "Ford Transit" model was predominant in the Palestinian occupied territories, hence the names "Ford" and "Fordat"(pl) are used to describe minibuses of various makes, which replaced aging Mercedes sedans previously used widely, etc.
A shuttle van
service to Dunedin International Airport picks up a passenger at Dunedin Railway Station in New Zealand
Shared buses or vans are available in many more developed countries connecting frequent destinations, charging a fixed fee per passenger. The most common case is a connection between an airport and central city locations. These services are often known as shuttles. Such services usually use smaller vehicles than normal buses, and often operate on demand. An air traveller can contact the shuttle company by telephone or Internet, not necessarily in advance; the company will ensure that a shuttle is provided without unreasonable delay. The shuttle will typically connect one airport with several large hotels, or addresses in a specified area of the city. The shuttle offers much of the convenience of a taxi, although taking longer, at a price which is significantly lower for one or two passengers. Scheduled services between an airport and a hotel, usually operated by the hotel, are also called shuttles.
In many cases the shuttle operator takes the risk of there not being enough passengers to make the trip profitable; in others there is a minimum charge when there are not enough passengers.
Usually there are regulations covering vehicles and drivers; for example in New Zealand under NZTA regulations, shuttles are only allowed to have up to eleven passenger seats, and the driver must have a passenger endorsement (P) on their drivers' licence.
Main article: Songthaew
Literally "two rows" a songthaew or song thaew (Thai สองแถว, Lao: ສອງແຖວ [sɔ̌ːŋtʰíw]) is a passenger vehicle in Thailand and Laos adapted from a pick-up or a larger truck and used as a share taxi. They are also known as baht buses.
In Mali, at least two words for share taxi may have common currency sotrama and dourouni.
As of 2008, Bamako, Mali, has no independent transport authority, but share taxi activity could fall under regulator Direction de la régulation et du contrôle du transport urbain (municipal) or DRCTU control.
a Haitian tap tap
Main article: Tap tap
Tap taps, gaily painted buses or pick-up trucks, and publiques, usually older saloon cars, serve as share taxis in Haiti.
Tap taps are privately owned and beautifully decorated. They follow fixed routes; won't leave until filled with passengers; and many feature wild colors, portraits of famous people, and intricate, hand-cut wooden window covers. Often they are painted with religious names or slogans.[Thompson 3] Riders can disembark at any point in the journey. Their name refers to "fast motion".[Thompson 4]
The publiques operate on fixed routes and pick up additional passengers all along the way.
While saying not to use any form of public transport in Haiti, the Foreign Affairs and International Trade Canada advises against tap tap travel especially. The US State Department also warns travelers not to use tap taps, "because they are often overloaded, mechanically unsound, and driven unsafely."
In Algeria, taxis collectifs ply fixed routes with their destination displayed. Rides are shared with others who are picked up along the way, and the taxi will leave only when it seats all the passengers it can. While stations, set locations to board and disembark, exist, prospective passengers flag down a taxis collectifs when they want a ride.
Operating inter and intra-city, taxis collectifs that travel between towns may be called interwilaya taxis.
Along with all forms of public transport in Algeria, the Foreign Affairs and International Trade Canada recommend against using these share taxis. The Irish Department of Foreign Affairs asks that you use taxis recommended by a hotel.
See also: Société de transport de Montréal and Réseau de transport de Longueuil § Shared taxi
In Quebec, share taxis or jitneys are called taxis collectifs (in English "collective taxis") or transport collectif par taxi (which may be translated in English as "taxibus") and are operated by subcontractors to the local transit authorities on fixed routes.
In the case of the Montréal the fare is the same as local bus fare, but no cash and transfers are issued or accepted; in case of the STL only bus passes. The Réseau de transport de Longueuil accepts regular RTL tickets and all RTL and some Réseau de transport métropolitain TRAM passes.
See also: Pesero and Combi Yellow Taxi Colectivo in Chile
Often share taxi routes in Mexico are ad hoc arrangements to fill in gaps in regular public transportation, and many operate inter-city as well as local routes. In many rural areas, they are the only public transportation.
In some cases truck/taxi combination vehicles have evolved to transport light goods as well as passengers. Heavily used share taxi routes often evolve into regulated microbus public transit routes, as has occurred in Mexico City and in Lima.
Taxis colectivos are also found in Perú, Chile, Guatemala, and Argentina, where they are most commonly referred to simply as colectivos, although in some places they have become essentially standard buses.
Besides the conventional deeltaxi, there are treintaxis in some Dutch towns. Operated on behalf of the Netherlands Railways, they run to and from railway stations and the ride is shared with additional passengers picked up along the way. Tickets can be purchased at railway ticket offices or from the cabdriver, but treintaxis must be ordered by phone unless boarding at a railway station.
In Ghana and neighboring countries, tro tro are privately owned minibus vehicles for hire that travel fixed routes leaving when filled to capacity. While there are tro tro stations, these share taxis can also be boarded anywhere along the route.
Operated by a driver and a conductor, who collects money, shouts out the destination, and is called a "mate", many are decorated with slogans and sayings, often religious, and few operate on Sundays.
As of 2008, there is no independent transport authority in Accra, Ghana, and the share taxi industry may be wholly unregulated.
Tro tro are used by 70% of Ghanaian commuters. This popularity may be because in cities such as Accra have no public transportation system save for these small minibuses.
Large buses also provide public transport in Accra, as of 2008.
An informal means of transportation, in Ghana they are licensed by the government, but the industry is self-regulated. In Accra, syndicates include GPRTU and PROTOA.
Share taxis do exist in Cameroon, but as of 2008 minibuses cannot be used for this purpose, by law. That same year, Douala, Cameroon, also was without an independent transport authority.
In Ouagadougou, capital of Burkina Faso, the share taxi role is not filled by the traditional African minibus.
In Athens, Greece most taxis were share taxis, but since the country joined the EU this tradition started to dissappear.
In Saint Lucia, waychehs are a name for minibus public transports using Toyota HiAce.
Modern Paratransit services, also known as demand responsive transport systems in the UK, can provide shared transport services in situations where scheduled services are not viable. Traditionally these services had to be booked a day in advance, but are becoming increasingly responsive using modern communications systems with a central booking system accessed by phone or internet and instant communications with GPS tracked vehicles. Unlike scheduled services the vehicles need not operate on fixed routes of timetables, although they do often have constrained routes.
Some newer taxi share systems now use internet and mobile phone communications for booking and scheduling purposes, with the actual service provided by normal hackney carriage or Private Hire vehicles. Prospective passengers make bookings and supply destination details using SMS to a central server which aggregates these travel requests and creates packages of trips which are then communicated to drivers.
There are many operators of airport shuttle services between Airports and Hotels around the world that operate on flexible routing and timing to offer a service that is both cheaper than a sole-occupancy taxi and also often more convenient that other forms of public transport. The requirement to carry luggage offers an added incentive to use such services over scheduled transport which will normally require a walk from the drop-off location to the final destination. Services from these operators are starting to spread from airports to railway stations and to other locations.
Main article: Demand responsive transport
Some operators and/or governments around the world are now offering demand-based shared transport to residents in community with low ridership numbers, which could help maintain the existence of public transport. Operations are predefined according to bookings.
- ^ a b Tap-tap, fula-fula, kia-kia: The Haitian bus in Atlantic perspective. Thompson, Robert Farris. African Arts. Los Angeles: Spring 1996. Vol. 29, Iss. 2; p. 41.
- ^ Thompson, p. 39.
- ^ Thompson, pp. 37, 38, 44, 45.
- ^ Thompson, p. 36.
The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U.S. National Aeronautics and Space Administration (NASA), as part of the Space Shuttle program. Its official program name was Space Transportation System (STS), 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 (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST); conducted science experiments in orbit; and participated in construction and servicing of the International Space Station. The Shuttle fleet's total mission time was 1322 days, 19 hours, 21 minutes and 23 seconds.
Shuttle components included the Orbiter Vehicle (OV) with three clustered Rocketdyne RS-25 main engines, a pair of recoverable solid rocket boosters (SRBs), and the expendable external tank (ET) 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, and the ET was jettisoned just before orbit insertion, which used the orbiter's two Orbital Maneuvering System (OMS) engines. At the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a runway landing, usually 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 version of the Boeing 747.
The first orbiter, Enterprise, was built in 1976, used in Approach and Landing Tests and had no orbital capability. Four fully operational orbiters were initially built: Columbia, Challenger, Discovery, 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 (and sixth in total) orbiter, Endeavour, 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 primarily on the Russian Soyuz spacecraft to transport supplies and astronauts to the International Space Station.
The Space Shuttle was a partially reusable human spaceflight vehicle capable of reaching low Earth orbit, commissioned and operated by the US National Aeronautics and Space Administration (NASA) from 1981 to 2011. It resulted from shuttle design studies conducted by NASA and the US Air Force in the 1960s and was first proposed for development as part of an ambitious second-generation Space Transportation System (STS) 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 expendable liquid hydrogen and liquid oxygen tanks, with reusable strap-on solid booster rockets. 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, and 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, and other equipment necessary for orbital flight was cancelled. A total of five operational orbiters were built, and of these, two were destroyed in accidents.
It was used for orbital space missions by NASA, the US Department of Defense, the European Space Agency, Japan, 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 partially funded by Japan.
STS-129 ready for launch Shuttle approach and landing test crews, 1976 Early concept for a space shuttle refueling a space tug, 1970
At launch, it consisted of the "stack", including the dark orange external tank (ET) (for the first two launches the tank was painted white); two white, slender solid rocket boosters (SRBs); and the Orbiter Vehicle, which contained the crew and payload. Some payloads were launched into higher orbits with either of two different upper stages developed for the STS (single-stage Payload Assist Module or two-stage Inertial Upper Stage). The Space Shuttle was stacked in the Vehicle Assembly Building, and 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 liftoff and first-stage flight. About two minutes after liftoff, frangible nuts were fired, releasing the SRBs, which then parachuted into the ocean, to be retrieved by NASA recovery ships for refurbishment and reuse. The orbiter and ET continued to ascend on an increasingly horizontal flight path under power from its main engines. Upon reaching 17,500 mph (7.8 km/s), necessary for low Earth orbit, the main engines were shut down. The ET, attached by two frangible nuts was then jettisoned to burn up in the atmosphere. After jettisoning the external tank, the orbital maneuvering system (OMS) engines were used to adjust the orbit. The orbiter carried astronauts and payloads such as satellites or space station parts into low Earth orbit, the Earth's upper atmosphere or thermosphere. Usually, five to seven crew members rode in the orbiter. Two crew members, the commander and pilot, were sufficient for a minimal flight, as in the first four "test" flights, STS-1 through STS-4. The typical payload capacity was about 50,045 pounds (22,700 kg) but could be increased depending on the choice of launch configuration. The orbiter carried its payload in a large cargo bay with doors that opened along the length of its top, a feature which made the Space Shuttle unique among spacecraft. This feature made possible the deployment of large satellites such as the Hubble Space Telescope and also the capture and return of large payloads back to Earth.
When the orbiter's space mission was complete, it fired its OMS thrusters to drop out of orbit and re-enter the lower atmosphere. During descent, the orbiter passed through different layers of the atmosphere and decelerated from hypersonic speed primarily by aerobraking. In the lower atmosphere and landing phase, it was more like a glider but with reaction control system (RCS) thrusters and fly-by-wire-controlled hydraulically actuated flight surfaces controlling its descent. It landed on a long runway as a conventional aircraft. The aerodynamic shape was a compromise between the demands of radically different speeds and air pressures during re-entry, hypersonic flight, and subsonic atmospheric flight. As a result, the orbiter had a relatively high sink rate at low altitudes, and it transitioned during re-entry from using RCS thrusters at very high altitudes to flight surfaces in the lower atmosphere.
President Nixon (right) with NASA Administrator Fletcher in January 1972, three months before Congress approved funding for the Shuttle program Vision for a Spacelab mission with various equipment in the Shuttle bay Vision for Space Station Freedom, with an STS orbiter docked
The formal design of what became the Space Shuttle began with the "Phase A" contract design studies issued in the late 1960s. Conceptualization had begun two decades earlier, before the Apollo program of the 1960s. One of the places the concept of a spacecraft returning from space to a horizontal landing originated was within NACA, in 1954, in the form of an aeronautics research experiment later named the X-15. The NACA proposal was submitted by Walter Dornberger.
In 1958, the X-15 concept further developed into a proposal to launch an X-15 into space, and another X-series spaceplane proposal, named X-20 Dyna-Soar, as well as variety of aerospace plane concepts and studies. Neil Armstrong was selected to pilot both the X-15 and the X-20. Though the X-20 was not built, another spaceplane similar to the X-20 was built several years later and delivered to NASA in January 1966 called the HL-10 ("HL" indicated "horizontal landing").
In the mid-1960s, the US Air Force conducted classified studies on next-generation space transportation systems and concluded that semi-reusable designs were the cheapest choice. It proposed a development program with an immediate start on a "Class I" vehicle with expendable boosters, followed by slower development of a "Class II" semi-reusable design and possible "Class III" fully reusable design later. In 1967, George Mueller held a one-day symposium at NASA headquarters to study the options. Eighty people attended and presented a wide variety of designs, including earlier US Air Force designs such as the X-20 Dyna-Soar.
In 1968, NASA officially began work on what was then known as the Integrated Launch and Re-entry Vehicle (ILRV). At the same time, NASA held a separate Space Shuttle Main Engine (SSME) competition. NASA offices in Houston and Huntsville jointly issued a Request for Proposal (RFP) for ILRV studies to design a spacecraft that could deliver a payload to orbit but also re-enter the atmosphere and fly back to Earth. For example, one of the responses was for a two-stage design, featuring a large booster and a small orbiter, called the DC-3, one of several Phase A Shuttle designs. After the aforementioned "Phase A" studies, B, C, and D phases progressively evaluated in-depth designs up to 1972. In the final design, the bottom stage consisted of recoverable solid rocket boosters, and the top stage used an expendable external tank.
In 1969, President Richard Nixon decided to support proceeding with Space Shuttle development. A series of development programs and analysis refined the basic design, prior to full development and testing. In August 1973, the X-24B proved that an unpowered spaceplane could re-enter Earth's atmosphere for a horizontal landing.
Across the Atlantic, European ministers met in Belgium in 1973 to authorize Western Europe's manned orbital project and its main contribution to Space Shuttle—the Spacelab program. Spacelab would provide a multidisciplinary orbital space laboratory and additional space equipment for the Shuttle.
STS-1 on the launch pad, December 1980
The Space Shuttle was the first operational orbital spacecraft designed for reuse. It carried different payloads to low Earth orbit, provided crew rotation and supplies for the International Space Station (ISS), and performed satellite servicing and repair. The orbiter could also recover satellites and other payloads from orbit and return them to Earth. Each Shuttle was designed for a projected lifespan of 100 launches or ten years of operational life, although this was later extended. The person in charge of designing the STS was Maxime Faget, who had also overseen the Mercury, Gemini, and Apollo spacecraft designs. The crucial factor in the size and shape of the Shuttle orbiter was the requirement that it be able to accommodate the largest planned commercial and military satellites, and have over 1,000 mile cross-range recovery range to meet the requirement for classified USAF missions for a once-around abort from a launch to a polar orbit. The militarily specified 1,085 nmi (2,009 km; 1,249 mi) cross range requirement was one of the primary reasons for the Shuttle's large wings, compared to modern commercial designs with very minimal control surfaces and glide capability. Factors involved in opting for solid rockets and an expendable fuel tank included the desire of the Pentagon to obtain a high-capacity payload vehicle for satellite deployment, and the desire of the Nixon administration to reduce the costs of space exploration by developing a spacecraft with reusable components.
Each Space Shuttle was a reusable launch system composed of three main assemblies: the reusable OV, the expendable ET, and the two reusable SRBs. Only the OV entered orbit shortly after the tank and boosters are jettisoned. The vehicle was launched vertically like a conventional rocket, and the orbiter glided to a horizontal landing like an airplane, after which it was refurbished for reuse. The SRBs parachuted to splashdown in the ocean where they were towed back to shore and refurbished for later Shuttle missions. Discovery
rockets into orbit, seen here just after solid rocket booster (SRB) separation Tail-end of an orbiter showing various nozzles during an orbital maneuver with ISS
Five operational OVs were built: Columbia (OV-102), Challenger (OV-099), Discovery (OV-103), Atlantis (OV-104), and Endeavour (OV-105). A mock-up, Inspiration, currently stands at the entrance to the Astronaut Hall of Fame. An additional craft, Enterprise (OV-101), was built for atmospheric testing gliding and landing; it was originally intended to be outfitted for orbital operations after the test program, but it was found more economical to upgrade the structural test article STA-099 into orbiter Challenger (OV-099). Challenger disintegrated 73 seconds after launch in 1986, and Endeavour was built as a replacement from structural spare components. Building Endeavour cost about US$1.7 billion. Columbia broke apart over Texas during re-entry in 2003. A Space Shuttle launch cost around $450 million.
Roger A. Pielke, Jr. has estimated that the Space Shuttle program cost about US$170 billion (2008 dollars) through early 2008; the average cost per flight was about US$1.5 billion. Two missions were paid for by Germany, Spacelab D1 and D2 (D for Deutschland) with a payload control center in Oberpfaffenhofen. D1 was the first time that control of a manned STS mission payload was not in U.S. hands.
At times, the orbiter itself was referred to as the Space Shuttle. This was not technically correct as the Space Shuttle was the combination of the orbiter, the external tank, and the two solid rocket boosters. These components, once assembled in the Vehicle Assembly Building originally built to assemble the Apollo Saturn V rocket, were commonly referred to as the "stack".
Responsibility for the Shuttle components was spread among multiple NASA field centers. The Kennedy Space Center was responsible for launch, landing and turnaround operations for equatorial orbits (the only orbit profile actually used in the program), the US Air Force at the Vandenberg Air Force Base was responsible for launch, landing and turnaround operations for polar orbits (though this was never used), the Johnson Space Center served as the central point for all Shuttle operations, the Marshall Space Flight Center was responsible for the main engines, external tank, and solid rocket boosters, the John C. Stennis Space Center handled main engine testing, and the Goddard Space Flight Center managed the global tracking network.
Main article: Space Shuttle orbiter Shuttle launch profiles. From left to right: Columbia
, and Endeavour
The orbiter resembled a conventional aircraft, with double-delta wings swept 81° at the inner leading edge and 45° at the outer leading edge. Its vertical stabilizer's leading edge was swept back at a 50° angle. The four elevons, mounted at the trailing edge of the wings, and the rudder/speed brake, attached at the trailing edge of the stabilizer, with the body flap, controlled the orbiter during descent and landing.
The orbiter's 60-foot (18 m)-long payload bay, comprising most of the fuselage, could accommodate cylindrical payloads up to 15 feet (4.6 m) in diameter. Information declassified in 2011 showed that these measurements were chosen specifically to accommodate the KH-9 HEXAGON spy satellite operated by the National Reconnaissance Office. Two mostly-symmetrical lengthwise payload bay doors hinged on either side of the bay comprised its entire top. Payloads were generally loaded horizontally into the bay while the orbiter was standing upright on the launch pad and unloaded vertically in the near-weightless orbital environment by the orbiter's robotic remote manipulator arm (under astronaut control), EVA astronauts, or under the payloads' own power (as for satellites attached to a rocket "upper stage" for deployment.)
Three Space Shuttle Main Engines (SSMEs) were mounted on the orbiter's aft fuselage in a triangular pattern. The engine nozzles could gimbal 10.5 degrees up and down, and 8.5 degrees from side to side during ascent to change the direction of their thrust to steer the Shuttle. The orbiter structure was made primarily from aluminum alloy, although the engine structure was made primarily from titanium alloy.
The operational orbiters built were OV-102 Columbia, OV-099 Challenger, OV-103 Discovery, OV-104 Atlantis, and OV-105 Endeavour.
Main article: Space Shuttle external tank An external tank floats away from the orbiter. Interior of an External Tank
The main function of the Space Shuttle external tank was to supply the liquid oxygen and hydrogen fuel to the main engines. It was also the backbone of the launch vehicle, providing attachment points for the two solid rocket boosters and the orbiter. The external tank was the only part of the Shuttle system that was not reused. Although the external tanks were always discarded, it would have been possible to take them into orbit and re-use them (such as a wet workshop for incorporation into a space station).
Main article: Space Shuttle Solid Rocket Booster
Two solid rocket boosters (SRBs) each provided 12,500 kN (2,800,000 lbf) of thrust at liftoff, which was 83% of the total thrust at liftoff. The SRBs were jettisoned two minutes after launch at a height of about 46 km (150,000 ft), and then deployed parachutes and landed in the ocean to be recovered. The SRB cases were made of steel about ½ inch (13 mm) thick. The solid rocket boosters were re-used many times; the casing used in Ares I engine testing in 2009 consisted of motor cases that had been flown, collectively, on 48 Shuttle missions, including STS-1.
Astronauts who have flown on multiple spacecraft report that Shuttle delivers a rougher ride than Apollo or Soyuz. The additional vibration is caused by the solid rocket boosters, as solid fuel does not burn as evenly as liquid fuel. The vibration dampens down after the solid rocket boosters have been jettisoned.
The orbiter could be used in conjunction with a variety of add-ons depending on the mission. This included orbital laboratories (Spacelab, Spacehab), boosters for launching payloads farther into space (Inertial Upper Stage, Payload Assist Module), and other functions, such as provided by Extended Duration Orbiter, Multi-Purpose Logistics Modules, or Canadarm (RMS). An upper stage called Transfer Orbit Stage (Orbital Science Corp. TOS-21) was also used once with the orbiter. Other types of systems and racks were part of the modular Spacelab system —pallets, igloo, IPS, etc., which also supported special missions such as SRTM.
Main article: Spacelab European astronauts prepare for their Spacelab mission, 1984 Interior of Spacelab LM2
A major component of the Space Shuttle Program was Spacelab, primarily contributed by a consortium of European countries, and operated in conjunction with the United States and international partners. Supported by a modular system of pressurized modules, pallets, and systems, Spacelab missions executed on multidisciplinary science, orbital logistics, and international cooperation. Over 29 missions flew on subjects ranging from astronomy, microgravity, radar, and life sciences, to name a few. Spacelab hardware also supported missions such as Hubble (HST) servicing and space station resupply. STS-2 and STS-3 provided testing, and the first full mission was Spacelab-1 (STS-9) launched on November 28, 1983.
Spacelab formally began in 1973, after a meeting in Brussels, Belgium, by European heads of state. Within the decade, Spacelab went into orbit and provided Europe and the United States with an orbital workshop and hardware system. International cooperation, science, and exploration were realized on Spacelab.
The Shuttle was one of the earliest craft to use a computerized fly-by-wire digital flight control system. This means no mechanical or hydraulic linkages connected the pilot's control stick to the control surfaces or reaction control system thrusters. The control algorithm, which used a classical Proportional Integral Derivative (PID) approach, was developed and maintained by Honeywell. The Shuttle's fly-by-wire digital flight control system was composed of 4 control systems each addressing a different mission phase: Ascent, Descent, On-Orbit and Aborts. Honeywell is also credited with the design and implementation of the Shuttle's Nose Wheel Steering Control Algorithm that allowed the Orbiter to safely land at Kennedy Space Center's Shuttle Runway.
A concern with using digital fly-by-wire systems on the Shuttle was reliability. Considerable research went into the Shuttle computer system. The Shuttle used five identical redundant IBM 32-bit general purpose computers (GPCs), model AP-101, constituting a type of embedded system. Four computers ran specialized software called the Primary Avionics Software System (PASS). A fifth backup computer ran separate software called the Backup Flight System (BFS). Collectively they were called the Data Processing System (DPS).
Simulation of SSLV at Mach 2.46 and 66,000 ft (20,000 m). The surface of the vehicle is colored by the pressure coefficient, and the gray contours represent the density of the surrounding air, as calculated using the OVERFLOW software package.
The design goal of the Shuttle's DPS was fail-operational/fail-safe reliability. After a single failure, the Shuttle could still continue the mission. After two failures, it could still land safely.
The four general-purpose computers operated essentially in lockstep, checking each other. If one computer provided a different result than the other three (i.e. the one computer failed), the three functioning computers "voted" it out of the system. This isolated it from vehicle control. If a second computer of the three remaining failed, the two functioning computers voted it out. A very unlikely failure mode would have been where two of the computers produced result A, and two produced result B (a two-two split). In this unlikely case, one group of two was to be picked at random.
The Backup Flight System (BFS) was separately developed software running on the fifth computer, used only if the entire four-computer primary system failed. The BFS was created because although the four primary computers were hardware redundant, they all ran the same software, so a generic software problem could crash all of them. Embedded system avionic software was developed under totally different conditions from public commercial software: the number of code lines was tiny compared to a public commercial software product, changes were only made infrequently and with extensive testing, and many programming and test personnel worked on the small amount of computer code. However, in theory it could have still failed, and the BFS existed for that contingency. While the BFS could run in parallel with PASS, the BFS never engaged to take over control from PASS during any Shuttle mission.
The software for the Shuttle computers was written in a high-level language called HAL/S, somewhat similar to PL/I. It is specifically designed for a real time embedded system environment.
The IBM AP-101 computers originally had about 424 kilobytes of magnetic core memory each. The CPU could process about 400,000 instructions per second. They had no hard disk drive, and loaded software from magnetic tape cartridges.
In 1990, the original computers were replaced with an upgraded model AP-101S, which had about 2.5 times the memory capacity (about 1 megabyte) and three times the processor speed (about 1.2 million instructions per second). The memory was changed from magnetic core to semiconductor with battery backup.
Early Shuttle missions, starting in November 1983, took along the Grid Compass, arguably one of the first laptop computers. The GRiD was given the name SPOC, for Shuttle Portable Onboard Computer. Use on the Shuttle required both hardware and software modifications which were incorporated into later versions of the commercial product. It was used to monitor and display the Shuttle's ground position, path of the next two orbits, show where the Shuttle had line of sight communications with ground stations, and determine points for location-specific observations of the Earth. The Compass sold poorly, as it cost at least US$8000, but it offered unmatched performance for its weight and size. NASA was one of its main customers.
During its service life, the Shuttle's Control System never experienced a failure. Many of the lessons learned have been used to design today's high speed control algorithms.
Payload specialist Millie Hughes-Fulford, who flew aboard Columbia
in 1991, displays the modernist Blackburn & Danne NASA logotype, known as "the worm".
The prototype orbiter Enterprise originally had a flag of the United States on the upper surface of the left wing and the letters "USA" in black on the right wing. The name "Enterprise" was painted in black on the payload bay doors just above the hinge and behind the crew module; on the aft end of the payload bay doors was the NASA "worm" logotype in gray. Underneath the rear of the payload bay doors on the side of the fuselage just above the wing is the text "United States" in black with a flag of the United States ahead of it.
The first operational orbiter, Columbia, originally had the same markings as Enterprise, although the letters "USA" on the right wing were slightly larger and spaced farther apart. Columbia also had black markings which Enterprise lacked on its forward RCS module, around the cockpit windows, and on its vertical stabilizer, and had distinctive black "chines" on the forward part of its upper wing surfaces, which none of the other orbiters had.
Challenger established a modified marking scheme for the shuttle fleet that was matched by Discovery, Atlantis and Endeavour. The letters "USA" in black above an American flag were displayed on the left wing, with the NASA "worm" logotype in gray centered above the name of the orbiter in black on the right wing. The name of the orbiter was inscribed not on the payload bay doors, but on the forward fuselage just below and behind the cockpit windows. This would make the name visible when the shuttle was photographed in orbit with the doors open.
In 1983, Enterprise had its wing markings changed to match Challenger, and the NASA "worm" logotype on the aft end of the payload bay doors was changed from gray to black. Some black markings were added to the nose, cockpit windows and vertical tail to more closely resemble the flight vehicles, but the name "Enterprise" remained on the payload bay doors as there was never any need to open them. Columbia had its name moved to the forward fuselage to match the other flight vehicles after STS-61-C, during the 1986–88 hiatus when the shuttle fleet was grounded following the loss of Challenger, but retained its original wing markings until its last overhaul (after STS-93), and its unique black wing "chines" for the remainder of its operational life.
Beginning in 1998, the flight vehicles' markings were modified to incorporate the NASA "meatball" insignia. The "worm" logotype, which the agency had phased out, was removed from the payload bay doors and the "meatball" insignia was added aft of the "United States" text on the lower aft fuselage. The "meatball" insignia was also displayed on the left wing, with the American flag above the orbiter's name, left-justified rather than centered, on the right wing. The three surviving flight vehicles, Discovery, Atlantis and Endeavour, still bear these markings as museum displays. Enterprise became the property of the Smithsonian Institution in 1985 and was no longer under NASA's control when these changes were made, hence the prototype orbiter still has its 1983 markings and still has its name on the payload bay doors. Atlantis
was the first Shuttle to fly with a glass cockpit, on STS-101. (composite image)
The Space Shuttle was initially developed in the 1970s, but received many upgrades and modifications afterward to improve performance, reliability and safety. Internally, the Shuttle remained largely similar to the original design, with the exception of the improved avionics computers. In addition to the computer upgrades, the original analog primary flight instruments were replaced with modern full-color, flat-panel display screens, called a glass cockpit, which is similar to those of contemporary airliners. To facilitate construction of ISS, the internal airlocks of each orbiter except Columbia were replaced with external docking systems to allow for a greater amount of cargo to be stored on the Shuttle's mid-deck during station resupply missions.
The Space Shuttle Main Engines (SSMEs) had several improvements to enhance reliability and power. This explains phrases such as "Main engines throttling up to 104 percent." This did not mean the engines were being run over a safe limit. The 100 percent figure was the original specified power level. During the lengthy development program, Rocketdyne determined the engine was capable of safe reliable operation at 104 percent of the originally specified thrust. NASA could have rescaled the output number, saying in essence 104 percent is now 100 percent. To clarify this would have required revising much previous documentation and software, so the 104 percent number was retained. SSME upgrades were denoted as "block numbers", such as block I, block II, and block IIA. The upgrades improved engine reliability, maintainability and performance. The 109% thrust level was finally reached in flight hardware with the Block II engines in 2001. The normal maximum throttle was 104 percent, with 106 percent or 109 percent used for mission aborts.
For the first two missions, STS-1 and STS-2, the external tank was painted white to protect the insulation that covers much of the tank, but improvements and testing showed that it was not required. The weight saved by not painting the tank resulted in an increase in payload capability to orbit. Additional weight was saved by removing some of the internal "stringers" in the hydrogen tank that proved unnecessary. The resulting "light-weight external tank" was first flown on STS-6  and used on the majority of Shuttle missions. STS-91 saw the first flight of the "super light-weight external tank". This version of the tank was made of the 2195 aluminum-lithium alloy. It weighed 3.4 metric tons (7,500 lb) less than the last run of lightweight tanks, allowing the Shuttle to deliver heavy elements to ISS's high inclination orbit. As the Shuttle was always operated with a crew, each of these improvements was first flown on operational mission flights.
The solid rocket boosters underwent improvements as well. Design engineers added a third O-ring seal to the joints between the segments after the 1986 Space Shuttle Challenger disaster.
The three nozzles of the Space Shuttle Main Engine with the two Orbital Maneuvering System (OMS) pods, and the vertical stabilizer above.
Several other SRB improvements were planned to improve performance and safety, but never came to be. These culminated in the considerably simpler, lower cost, probably safer and better-performing Advanced Solid Rocket Booster. These rockets entered production in the early to mid-1990s to support the Space Station, but were later canceled to save money after the expenditure of $2.2 billion. The loss of the ASRB program resulted in the development of the Super LightWeight external Tank (SLWT), which provided some of the increased payload capability, while not providing any of the safety improvements. In addition, the US Air Force developed their own much lighter single-piece SRB design using a filament-wound system, but this too was canceled.
STS-70 was delayed in 1995, when woodpeckers bored holes in the foam insulation of Discovery's external tank. Since then, NASA has installed commercial plastic owl decoys and inflatable owl balloons which had to be removed prior to launch. The delicate nature of the foam insulation had been the cause of damage to the Thermal Protection System, the tile heat shield and heat wrap of the orbiter. NASA remained confident that this damage, while it was the primary cause of the Space Shuttle Columbia disaster on February 1, 2003, would not jeopardize the completion of the International Space Station (ISS) in the projected time allotted.
A cargo-only, unmanned variant of the Shuttle was variously proposed and rejected since the 1980s. It was called the Shuttle-C, and would have traded re-usability for cargo capability, with large potential savings from reusing technology developed for the Space Shuttle. Another proposal was to convert the payload bay into a passenger area, with versions ranging from 30 to 74 seats, three days in orbit, and cost US$1.5 million per seat.
On the first four Shuttle missions, astronauts wore modified US Air Force high-altitude full-pressure suits, which included a full-pressure helmet during ascent and descent. From the fifth flight, STS-5, until the loss of Challenger, one-piece light blue nomex flight suits and partial-pressure helmets were worn. A less-bulky, partial-pressure version of the high-altitude pressure suits with a helmet was reinstated when Shuttle flights resumed in 1988. The Launch-Entry Suit ended its service life in late 1995, and was replaced by the full-pressure Advanced Crew Escape Suit (ACES), which resembled the Gemini space suit in design, but retained the orange color of the Launch-Entry Suit.
To extend the duration that orbiters could stay docked at the ISS, the Station-to-Shuttle Power Transfer System (SSPTS) was installed. The SSPTS allowed these orbiters to use power provided by the ISS to preserve their consumables. The SSPTS was first used successfully on STS-118.
Space Shuttle orbiter illustration Space Shuttle drawing Space Shuttle wing cutaway Space Shuttle Orbiter and Soyuz-TM (drawn to scale). Atlantis
on launch pads. This particular occasion is due to the final Hubble servicing mission, where the International Space Station is unreachable, which necessitates having a Shuttle on standby for a possible rescue mission.
Orbiter (for Endeavour, OV-105)
The earliest Shuttle flights had the minimum crew of two; many later missions a crew of five. By program end, typically seven people would fly: (commander, pilot, several mission specialists, one of whom (MS-2) acted as the flight engineer starting with STS-9 in 1983). On two occasions, eight astronauts have flown (STS-61-A, STS-71). Eleven people could be accommodated in an emergency mission (see STS-3xx).
External tank (for SLWT)
Solid Rocket Boosters
STS mission profile Shuttle launch of Atlantis
at sunset in 2001. The Sun is behind the camera, and the plume's shadow intersects the Moon across the sky. See also: Space shuttle launch countdown and Space shuttle launch commit criteria
All Space Shuttle missions were launched from Kennedy Space Center (KSC). The weather criteria used for launch included, but were not limited to: precipitation, temperatures, cloud cover, lightning forecast, wind, and humidity. The Shuttle was not launched under conditions where it could have been struck by lightning. Aircraft are often struck by lightning with no adverse effects because the electricity of the strike is dissipated through its conductive structure and the aircraft is not electrically grounded. Like most jet airliners, the Shuttle was mainly constructed of conductive aluminum, which would normally shield and protect the internal systems. However, upon liftoff the Shuttle sent out a long exhaust plume as it ascended, and this plume could have triggered lightning by providing a current path to ground. The NASA Anvil Rule for a Shuttle launch stated that an anvil cloud could not appear within a distance of 10 nautical miles. The Shuttle Launch Weather Officer monitored conditions until the final decision to scrub a launch was announced. In addition, the weather conditions had to be acceptable at one of the Transatlantic Abort Landing sites (one of several Space Shuttle abort modes) to launch as well as the solid rocket booster recovery area. While the Shuttle might have safely endured a lightning strike, a similar strike caused problems on Apollo 12, so for safety NASA chose not to launch the Shuttle if lightning was possible (NPR8715.5).
Historically, the Shuttle was not launched if its flight would run from December to January (a year-end rollover or YERO). Its flight software, designed in the 1970s, was not designed for this, and would require the orbiter's computers be reset through a change of year, which could cause a glitch while in orbit. In 2007, NASA engineers devised a solution so Shuttle flights could cross the year-end boundary.
After the final hold in the countdown at T-minus 9 minutes, the Shuttle went through its final preparations for launch, and the countdown was automatically controlled by the Ground Launch Sequencer (GLS), software at the Launch Control Center, which stopped the count if it sensed a critical problem with any of the Shuttle's onboard systems. The GLS handed off the count to the Shuttle's on-board computers at T minus 31 seconds, in a process called auto sequence start.
At T-minus 16 seconds, the massive sound suppression system (SPS) began to drench the Mobile Launcher Platform (MLP) and SRB trenches with 300,000 US gallons (1,100 m3) of water to protect the Orbiter from damage by acoustical energy and rocket exhaust reflected from the flame trench and MLP during lift off.
At T-minus 10 seconds, hydrogen igniters were activated under each engine bell to quell the stagnant gas inside the cones before ignition. Failure to burn these gases could trip the onboard sensors and create the possibility of an overpressure and explosion of the vehicle during the firing phase. The main engine turbopumps also began charging the combustion chambers with liquid hydrogen and liquid oxygen at this time. The computers reciprocated this action by allowing the redundant computer systems to begin the firing phase.
Space Shuttle Main Engine ignition
The three main engines (SSMEs) started at T-6.6 seconds. The main engines ignited sequentially via the Shuttle's general purpose computers (GPCs) at 120 millisecond intervals. All three SSMEs were required to reach 90% rated thrust within three seconds, otherwise the onboard computers would initiate an RSLS abort. If all three engines indicated nominal performance by T-3 seconds, they were commanded to gimbal to liftoff configuration and the command would be issued to arm the SRBs for ignition at T-0. Between T-6.6 seconds and T-3 seconds, while the SSMEs were firing but the SRBs were still bolted to the pad, the offset thrust caused the entire launch stack (boosters, tank and orbiter) to pitch down 650 mm (25.5 in) measured at the tip of the external tank. The three second delay after confirmation of SSME operation was to allow the stack to return to nearly vertical. At T-0 seconds, the 8 frangible nuts holding the SRBs to the pad were detonated, the SSMEs were commanded to 100% throttle, and the SRBs were ignited. By T+0.23 seconds, the SRBs built up enough thrust for liftoff to commence, and reached maximum chamber pressure by T+0.6 seconds. The Johnson Space Center's Mission Control Center assumed control of the flight once the SRBs had cleared the launch tower.
Shortly after liftoff, the Shuttle's main engines were throttled up to 104.5% and the vehicle began a combined roll, pitch and yaw maneuver that placed it onto the correct heading (azimuth) for the planned orbital inclination and in a heads down attitude with wings level. The Shuttle flew upside down during the ascent phase. This orientation allowed a trim angle of attack that was favorable for aerodynamic loads during the region of high dynamic pressure, resulting in a net positive load factor, as well as providing the flight crew with a view of the horizon as a visual reference. The vehicle climbed in a progressively flattening arc, accelerating as the mass of the SRBs and main tank decreased. To achieve low orbit requires much more horizontal than vertical acceleration. This was not visually obvious, since the vehicle rose vertically and was out of sight for most of the horizontal acceleration. The near circular orbital velocity at the 380 kilometers (236 mi) altitude of the International Space Station is 27,650 km/h (17,180 mph), roughly equivalent to Mach 23 at sea level. As the International Space Station orbits at an inclination of 51.6 degrees, missions going there must set orbital inclination to the same value in order to rendezvous with the station.
Around 30 seconds into ascent, the SSMEs were throttled down—usually to 72%, though this varied—to reduce the maximum aerodynamic forces acting on the Shuttle at a point called Max Q. Additionally, the propellant grain design of the SRBs caused their thrust to drop by about 30% by 50 seconds into ascent. Once the Orbiter's guidance verified that Max Q would be within Shuttle structural limits, the main engines were throttled back up to 104.5%; this throttling down and back up was called the "thrust bucket". To maximize performance, the throttle level and timing of the thrust bucket was shaped to bring the Shuttle as close to aerodynamic limits as possible.
Solid Rocket Booster (SRB) separation during STS-1. The white external tank pictured was used on STS-1 and STS-2.
At around T+126 seconds, pyrotechnic fasteners released the SRBs and small separation rockets pushed them laterally away from the vehicle. The SRBs parachuted back to the ocean to be reused. The Shuttle then began accelerating to orbit on the main engines. Acceleration at this point would typically fall to .9 g, and the vehicle would take on a somewhat nose-up angle to the horizon – it used the main engines to gain and then maintain altitude while it accelerated horizontally towards orbit. At about five and three-quarter minutes into ascent, the orbiter's direct communication links with the ground began to fade, at which point it rolled heads up to reroute its communication links to the Tracking and Data Relay Satellite system.
At about seven and a half minutes into ascent, the mass of the vehicle was low enough that the engines had to be throttled back to limit vehicle acceleration to 3 g (29.4 m/s² or 96.5 ft/s², equivalent to accelerating from zero to 105.9 km/h (65.8 mph) in a second). The Shuttle would maintain this acceleration for the next minute, and main engine cut-off (MECO) occurred at about eight and a half minutes after launch. The main engines were shut down before complete depletion of propellant, as running dry would have destroyed the engines. The oxygen supply was terminated before the hydrogen supply, as the SSMEs reacted unfavorably to other shutdown modes. (Liquid oxygen has a tendency to react violently, and supports combustion when it encounters hot engine metal.) A few seconds after MECO, the external tank was released by firing pyrotechnic fasteners.
At this point the Shuttle and external tank were on a slightly suborbital trajectory, coasting up towards apogee. Once at apogee, about half an hour after MECO, the Shuttle's Orbital Maneuvering System (OMS) engines were fired to raise its perigee and achieve orbit, while the external tank fell back into the atmosphere and burned up over the Indian Ocean or the Pacific Ocean depending on launch profile. The sealing action of the tank plumbing and lack of pressure relief systems on the external tank helped it break up in the lower atmosphere. After the foam burned away during re-entry, the heat caused a pressure buildup in the remaining liquid oxygen and hydrogen until the tank exploded. This ensured that any pieces that fell back to Earth were small.
Ascent tracking Contraves-Goerz Kineto Tracking Mount used to image the space Shuttle during launch ascent Multicolored afterglow of the STS-131 launch
The Shuttle was monitored throughout its ascent for short range tracking (10 seconds before liftoff through 57 seconds after), medium range (7 seconds before liftoff through 110 seconds after) and long range (7 seconds before liftoff through 165 seconds after). Short range cameras included 22 16mm cameras on the Mobile Launch Platform and 8 16mm on the Fixed Service Structure, 4 high speed fixed cameras located on the perimeter of the launch complex plus an additional 42 fixed cameras with 16mm motion picture film. Medium range cameras included remotely operated tracking cameras at the launch complex plus 6 sites along the immediate coast north and south of the launch pad, each with 800mm lens and high speed cameras running 100 frames per second. These cameras ran for only 4–10 seconds due to limitations in the amount of film available. Long range cameras included those mounted on the external tank, SRBs and orbiter itself which streamed live video back to the ground providing valuable information about any debris falling during ascent. Long range tracking cameras with 400-inch film and 200-inch video lenses were operated by a photographer at Playalinda Beach as well as 9 other sites from 38 miles north at the Ponce Inlet to 23 miles south to Patrick Air Force Base (PAFB) and additional mobile optical tracking camera was stationed on Merritt Island during launches. A total of 10 HD cameras were used both for ascent information for engineers and broadcast feeds to networks such as NASA TV and HDNet. The number of cameras significantly increased and numerous existing cameras were upgraded at the recommendation of the Columbia Accident Investigation Board to provide better information about the debris during launch. Debris was also tracked using a pair of Weibel Continuous Pulse Doppler X-band radars, one on board the SRB recovery ship MV Liberty Star positioned north east of the launch pad and on a ship positioned south of the launch pad. Additionally, during the first 2 flights following the loss of Columbia and her crew, a pair of NASA WB-57 reconnaissance aircraft equipped with HD Video and Infrared flew at 60,000 feet (18,000 m) to provide additional views of the launch ascent. Kennedy Space Center also invested nearly $3 million in improvements to the digital video analysis systems in support of debris tracking.
Once in orbit, the Shuttle usually flew at an altitude of 320 km (170 nmi) and occasionally as high as 650 km (350 nmi). In the 1980s and 1990s, many flights involved space science missions on the NASA/ESA Spacelab, or launching various types of satellites and science probes. By the 1990s and 2000s the focus shifted more to servicing the space station, with fewer satellite launches. Most missions involved staying in orbit several days to two weeks, although longer missions were possible with the Extended Duration Orbiter add-on or when attached to a space station.
Almost the entire Space Shuttle re-entry procedure, except for lowering the landing gear and deploying the air data probes, was normally performed under computer control. However, the re-entry could be flown entirely manually if an emergency arose. The approach and landing phase could be controlled by the autopilot, but was usually hand flown.
Glowing plasma trail from Space Shuttle Atlantis
re-entry as seen from the Space Station
The vehicle began re-entry by firing the Orbital maneuvering system engines, while flying upside down, backside first, in the opposite direction to orbital motion for approximately three minutes, which reduced the Shuttle's velocity by about 200 mph (322 km/h). The resultant slowing of the Shuttle lowered its orbital perigee down into the upper atmosphere. The Shuttle then flipped over, by pushing its nose down (which was actually "up" relative to the Earth, because it was flying upside down). This OMS firing was done roughly halfway around the globe from the landing site.
The vehicle started encountering more significant air density in the lower thermosphere at about 400,000 ft (120 km), at around Mach 25, 8,200 m/s (30,000 km/h; 18,000 mph). The vehicle was controlled by a combination of RCS thrusters and control surfaces, to fly at a 40-degree nose-up attitude, producing high drag, not only to slow it down to landing speed, but also to reduce reentry heating. As the vehicle encountered progressively denser air, it began a gradual transition from spacecraft to aircraft. In a straight line, its 40-degree nose-up attitude would cause the descent angle to flatten-out, or even rise. The vehicle therefore performed a series of four steep S-shaped banking turns, each lasting several minutes, at up to 70 degrees of bank, while still maintaining the 40-degree angle of attack. In this way it dissipated speed sideways rather than upwards. This occurred during the 'hottest' phase of re-entry, when the heat-shield glowed red and the G-forces were at their highest. By the end of the last turn, the transition to aircraft was almost complete. The vehicle leveled its wings, lowered its nose into a shallow dive and began its approach to the landing site.
The orbiter's maximum glide ratio/lift-to-drag ratio varies considerably with speed, ranging from 1:1 at hypersonic speeds, 2:1 at supersonic speeds and reaching 4.5:1 at subsonic speeds during approach and landing.
In the lower atmosphere, the orbiter flies much like a conventional glider, except for a much higher descent rate, over 50 m/s (180 km/h; 110 mph) or 9,800 fpm. At approximately Mach 3, two air data probes, located on the left and right sides of the orbiter's forward lower fuselage, are deployed to sense air pressure related to the vehicle's movement in the atmosphere.
Final approach and landing phase Play media
STS-127, Space Shuttle Endeavour
landing video, 2009
When the approach and landing phase began, the orbiter was at a 3,000 m (9,800 ft) altitude, 12 km (7.5 mi) from the runway. The pilots applied aerodynamic braking to help slow down the vehicle. The orbiter's speed was reduced from 682 to 346 km/h (424 to 215 mph), approximately, at touch-down (compared to 260 km/h or 160 mph for a jet airliner). The landing gear was deployed while the Orbiter was flying at 430 km/h (270 mph). To assist the speed brakes, a 12 m (39 ft) drag chute was deployed either after main gear or nose gear touchdown (depending on selected chute deploy mode) at about 343 km/h (213 mph). The chute was jettisoned once the orbiter slowed to 110 km/h (68.4 mph).
Media related to Landings of space Shuttles at Wikimedia Commons
Main article: Orbiter Processing Facility Discovery
after landing on Earth for crew disembarkment
After landing, the vehicle stayed on the runway for several hours for the orbiter to cool. Teams at the front and rear of the orbiter tested for presence of hydrogen, hydrazine, monomethylhydrazine, nitrogen tetroxide and ammonia (fuels and by-products of the reaction control system and the orbiter's three APUs). If hydrogen was detected, an emergency would be declared, the orbiter powered down and teams would evacuate the area. A convoy of 25 specially designed vehicles and 150 trained engineers and technicians approached the orbiter. Purge and vent lines were attached to remove toxic gases from fuel lines and the cargo bay about 45–60 minutes after landing. A flight surgeon boarded the orbiter for initial medical checks of the crew before disembarking. Once the crew left the orbiter, responsibility for the vehicle was handed from the Johnson Space Center back to the Kennedy Space Center.
If the mission ended at Edwards Air Force Base in California, White Sands Space Harbor in New Mexico, or any of the runways the orbiter might use in an emergency, the orbiter was loaded atop the Shuttle Carrier Aircraft, a modified 747, for transport back to the Kennedy Space Center, landing at the Shuttle Landing Facility. Once at the Shuttle Landing Facility, the orbiter was then towed 2 miles (3.2 km) along a tow-way and access roads normally used by tour buses and KSC employees to the Orbiter Processing Facility where it began a months-long preparation process for the next mission.
See also: List of space shuttle landing runways Atlantis
deploys the landing gear before landing.
NASA preferred Space Shuttle landings to be at Kennedy Space Center. If weather conditions made landing there unfavorable, the Shuttle could delay its landing until conditions are favorable, touch down at Edwards Air Force Base, California, or use one of the multiple alternate landing sites around the world. A landing at any site other than Kennedy Space Center meant that after touchdown the Shuttle must be mated to the Shuttle Carrier Aircraft and returned to Cape Canaveral. Space Shuttle Columbia (STS-3) once landed at the White Sands Space Harbor, New Mexico; this was viewed as a last resort as NASA scientists believed that the sand could potentially damage the Shuttle's exterior.
There were many alternative landing sites that were never used. Discovery
at ISS in 2011 (STS-133)
An example of technical risk analysis for a STS mission is SPRA iteration 3.1 top risk contributors for STS-133:
- Micro-Meteoroid Orbital Debris (MMOD) strikes
- Space Shuttle Main Engine (SSME)-induced or SSME catastrophic failure
- Ascent debris strikes to TPS leading to LOCV on orbit or entry
- Crew error during entry
- RSRM-induced RSRM catastrophic failure (RSRM are the rocket motors of the SRBs)
- COPV failure (COPV are tanks inside the orbiter that hold gas at high pressure)
An internal NASA risk assessment study (conducted by the Shuttle Program Safety and Mission Assurance Office at Johnson Space Center) released in late 2010 or early 2011 concluded that the agency had seriously underestimated the level of risk involved in operating the Shuttle. The report assessed that there was a 1 in 9 chance of a catastrophic disaster during the first nine flights of the Shuttle but that safety improvements had later improved the risk ratio to 1 in 90.
Main article: List of Space Shuttle missions
Below is a list of major events in the Space Shuttle orbiter fleet.
takes flight for the first time over Dryden Flight Research Facility, Edwards, California in 1977 as part of the Shuttle program's Approach and Landing Tests (ALT). Atlantis
lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida on the STS-132 mission to the International Space Station at 2:20 pm EDT on May 14, 2010. This was one of the last scheduled flights for Atlantis
before it was retired.
Sources: NASA launch manifest, NASA Space Shuttle archive
Main articles: Space Shuttle Challenger disaster and Space Shuttle Columbia disaster
On January 28, 1986, Challenger disintegrated 73 seconds after launch due to the failure of the right SRB, killing all seven astronauts on board. The disaster was caused by low-temperature impairment of an O-ring, a mission critical seal used between segments of the SRB casing. Failure of the O-ring allowed hot combustion gases to escape from between the booster sections and burn through the adjacent external tank, causing it to explode. Repeated warnings from design engineers voicing concerns about the lack of evidence of the O-rings' safety when the temperature was below 53 °F (12 °C) had been ignored by NASA managers.
On February 1, 2003, Columbia disintegrated during re-entry, killing its crew of seven, because of damage to the carbon-carbon leading edge of the wing caused during launch. Ground control engineers had made three separate requests for high-resolution images taken by the Department of Defense that would have provided an understanding of the extent of the damage, while NASA's chief thermal protection system (TPS) engineer requested that astronauts on board Columbia be allowed to leave the vehicle to inspect the damage. NASA managers intervened to stop the Department of Defense's assistance and refused the request for the spacewalk, and thus the feasibility of scenarios for astronaut repair or rescue by Atlantis were not considered by NASA management at the time.
Main article: Space Shuttle retirement Atlantis
orbiter's final welcome home, 2011
NASA retired the Space Shuttle in 2011, after 30 years of service. The Shuttle was originally conceived of and presented to the public as a "Space Truck", which would, among other things, be used to build a United States space station in low earth orbit in the early 1990s. When the US space station evolved into the International Space Station project, which suffered from long delays and design changes before it could be completed, the retirement of the Space Shuttle was delayed several times until 2011, serving at least 15 years longer than originally planned. Discovery was the first of NASA's three remaining operational Space Shuttles to be retired.
The final Space Shuttle mission was originally scheduled for late 2010, but the program was later extended to July 2011 when Michael Suffredini of the ISS program said that one additional trip was needed in 2011 to deliver parts to the International Space Station. The Shuttle's final mission consisted of just four astronauts—Christopher Ferguson (Commander), Douglas Hurley (Pilot), Sandra Magnus (Mission Specialist 1), and Rex Walheim (Mission Specialist 2); they conducted the 135th and last space Shuttle mission on board Atlantis, which launched on July 8, 2011, and landed safely at the Kennedy Space Center on July 21, 2011, at 5:57 AM EDT (09:57 UTC). The U.S. has since relied on the Russian Soyuz spacecraft to transport astronauts and supplies to the International Space Station.
Space Shuttle Program commemorative patch
NASA announced it would transfer orbiters to education institutions or museums at the conclusion of the Space Shuttle program. Each museum or institution is responsible for covering the US$28.8 million cost of preparing and transporting each vehicle for display. Twenty museums from across the country submitted proposals for receiving one of the retired orbiters. NASA also made Space Shuttle thermal protection system tiles available to schools and universities for less than US$25 each. About 7,000 tiles were available on a first-come, first-served basis, limited to one per institution.
On April 12, 2011, NASA announced selection of locations for the remaining Shuttle orbiters: Endeavour
at Los Angeles International Airport
In August 2011, the NASA Office of Inspector General (OIG) published a "Review of NASA's Selection of Display Locations for the Space Shuttle Orbiters"; the review had four main findings:
The NASA OIG had three recommendations, saying NASA should:
In September 2011, the CEO and two board members of Seattle's Museum of Flight met with NASA Administrator Charles Bolden, pointing out "significant errors in deciding where to put its four retiring Space Shuttles"; the errors alleged include inaccurate information on Museum of Flight's attendance and international visitor statistics, as well as the readiness of the Intrepid Sea-Air-Space Museum's exhibit site.
Flight and mid-deck training hardware will be taken from the Johnson Space Center and will go to the National Air and Space Museum and the National Museum of the U.S. Air Force. The full fuselage mockup, which includes the payload bay and aft section but no wings, is to go to the Museum of Flight in Seattle. Mission Simulation and Training Facility's fixed simulator will go to the Adler Planetarium in Chicago, and the motion simulator will go to the Texas A&M Aerospace Engineering Department in College Station, Texas. Other simulators used in Shuttle astronaut training will go to the Wings of Dreams Aviation Museum in Starke, Florida and the Virginia Air and Space Center in Hampton, Virginia.
Main article: Space Shuttle retirement STS conducted numerous experiments in space, such as this ionization experiment Sprint cameras, tested by the Shuttle, may be used on ISS and other missions
Until another US manned spacecraft is ready, crews will travel to and from the International Space Station (ISS) exclusively aboard the Russian Soyuz spacecraft.
A planned successor to STS was the "Shuttle II", during the 1980s and 1990s, and later the Constellation program during the 2004–2010 period. CSTS was a proposal to continue to operate STS commercially, after NASA. In September 2011, NASA announced the selection of the design for the new Space Launch System that is planned to launch the Orion spacecraft and other hardware to missions beyond low earth-orbit.
The Commercial Orbital Transportation Services program began in 2006 with the purpose of creating commercially operated unmanned cargo vehicles to service the ISS. The Commercial Crew Development (CCDev) program was started in 2010 to create commercially operated manned spacecraft capable of delivering at least four crew members to the ISS, to stay docked for 180 days, and then return them back to Earth. These spacecraft were to become operational in the 2010s.
Space Shuttles have been features of fiction and nonfiction, from children's movies to documentaries. Early examples include the 1979 James Bond film, Moonraker, the 1982 Activision videogame Space Shuttle: A Journey into Space (1982) and G. Harry Stine's 1981 novel Shuttle Down. In the 1986 film SpaceCamp, Atlantis accidentally launches into space with a group of U.S. Space Camp participants as its crew. A space shuttle named Intrepid is featured in the 1989 film Moontrap.
The 1998 film Armageddon portrays a combined crew of offshore oil rig workers and US military staff who pilot two modified Shuttles to avert the destruction of Earth by an asteroid. Retired American test pilots visit a Russian satellite in the 2000 Clint Eastwood adventure film Space Cowboys. In the 2003 film The Core, the Endeavour's landing is disrupted by the Earth's magnetic core, and its crew is selected to pilot a vehicle designed to restart the core. The 2004 Bollywood movie Swades, where a Space Shuttle is used to launch a special rainfall monitoring satellite, was filmed at Kennedy Space Center in the year after the Columbia disaster that had taken the life of Indian-American astronaut KC Chawla.
On television, the 1996 drama The Cape portrays the lives of a group of NASA astronauts as they prepare for and fly Shuttle missions. Odyssey 5 was a short-lived sci-fi series that features the crew of a Space Shuttle as the last survivors of a disaster that destroys Earth. The 1997–2007 sci-fi series Stargate SG-1 has a shuttle rescue written into an episode.
The 2013 film Gravity features the fictional Space Shuttle Explorer during STS-157, whose crew are killed or left stranded after it is destroyed by a shower of high speed orbital debris. The 2017 Lego film The Lego Batman Movie features a hybrid between the Batmobile and a Space Shuttle, named "the Bat Space Shuttle" by Dick Grayson. It's clearly based on the Lego City set 3367 ("Space Shuttle"), but is black and weapon-equipped.
A United States Space Shuttle stamp
The Space Shuttle has also been the subject of toys and models; for example, a large Lego Space Shuttle model was constructed by visitors at Kennedy Space Center, and smaller models have been sold commercially as a standard "LegoLand" set. A 1980 pinball machine Space Shuttle was produced by Zaccaria and a 1984 pinball machine Space Shuttle: Pinball Adventure was produced by Williams and features a plastic Space Shuttle model among other artwork of astronauts on the play field. The Space Shuttle also appears in a number of flight simulator and space flight simulator games such as Microsoft Space Simulator, Orbiter, FlightGear, X-Plane and Space Shuttle Mission 2007. Several Transformers toys were modeled after the Space Shuttle.
Main article: U.S. space exploration history on U.S. stamps § Space Shuttle Issues
The U.S. Postal Service has released several postage issues that depict the Space Shuttle. The first such stamps were issued in 1981, and are on display at the National Postal Museum.
Space Shuttle program insignia
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