Fernando Alcoforado*
This article aims to present the inventions that occurred with the means of air and space transport throughout history. Air transport means are those that move in the air (balloons, airships, planes, helicopters and drones) to transport people and cargo. Space transport means are those that move through outer space using rockets and/or spacecraft to transport astronauts, artificial satellites, space probes, robots, rovers or any other type of equipment for space exploration. The means of transport require appropriate infrastructure and vehicles. Airplanes require airport infrastructure to operate as well as passenger and cargo terminals. Rockets need launch centers to fire. It was only after the 1st Industrial Revolution (18th century) that the quantity and efficiency of means of transport expanded with the advancement of science and technology, based on which airships, airplanes, helicopters, drones were developed and the space rocket, among other means of transport.
The invention of the airship
The history of airships is intertwined with that of aviation. The first experiments to try to conquer the skies were with hot air balloons. One of the pioneers was Father Bartolomeu de Gusmão who performed the first demonstration in the city of Lisbon on August 5, 1709. The balloon caught fire without leaving the ground, but in a second demonstration, it rose to 95 meters high. French brothers Jacques and Joseph Montgolfier would be, 74 years later, the first to brave the skies with the first successful manned balloon in 1783. Some aviation pioneers sought to adapt steam engines in 1855 and battery-powered electric motors in 1884 to solve the steering problem. Such attempts proved fruitless, as the excessive weight of such engines made the devices impractical. Only the development of the internal combustion engine, at the end of the 19th century, made it possible to solve this problem [7]. It should be noted that, at the take-off location, the balloon is inflated with ambient air by a large gasoline-powered fan. Envelope is the name given to the fabric bag of the balloon that is made of nylon rip-stop (material that stops tears) and waterproofed with a fire-retardant resin. The blowtorch heats the air in the envelope, which expands and becomes less dense than the air outside the balloon. Take-off occurs when this air exceeds the external temperature by about 60ºC. The balloon’s altitude is controlled with a parachute-shaped lid that can be opened to release hot air. Cold air enters through the mouth of the balloon and increases the density of the air inside – causing the balloon to descend. To ascend, the pilot turns on the torch (heating up and decreasing the density of the internal air). The experiments continued throughout the 19th century.
In 1852, Jules Henri Giffard made the first flight of a dirigible balloon flying from Paris to Élancourt. One of the icons in aviation history was the airship LZ 127 Graf Zeppelin built in 1928, which was 213 m long and had five engines capable of carrying 20 to 24 passengers and about 36 crew. Modernly, the airship has internal balloons that are inflated with helium gas that allows controlling its altitude [7]. To ascend and stay suspended in the sky, the airship relies on helium gas, which is lighter than air; while moving forward, motorized propellers come into action. Less dense than air, helium tends to rise and pulls the airship up. The heavier the airship, the more gas it takes. This is basically how the airship, which appeared in France in the second half of the 19th century, flies. In the past, hydrogen was used to fill the balloon (or envelope) of airships, but this gas is flammable, which caused several accidents. The first long-haul airship flight took place in October 1928 between Frankfurt and New York. The LZ 127 Graf Zeppelin would have the primacy of being the first flying device to go around the world. The epic, in seven stages, was made in 1929 covering 33 thousand kilometers. The LZ 127 Graf Zeppelin was built by Ferdinand Von Zeppelin in 1928 and traveled over 500,000 kilometers carrying at least 17,000 people. The LZ 127 Graf Zeppelin was the pride of German aeronautical engineering. The Hindenburg airship was the largest flying device in history at 245 m long and 41.5 m in diameter. It flew at 135 km/h with an autonomy of 14 thousand kilometers and had the capacity to carry 50 passengers and 61 crew. This model that used hydrogen as a propellant exploded in New Jersey in the United States on May 6, 1937, killing 97 occupants and an American technician on the ground. This disaster spelled the end of the rigid airship era.
The invention of the airplane
The airplane was one of the greatest inventions of humanity in its history [16][17]. In 400 BC, Archytas of Tareto, philosopher, scientist, strategist, statesman, mathematician and astronomer, considered the most illustrious of the Pythagorean mathematicians, tried to build a flying machine and, sometime later, Leonardo da Vinci elaborated his projects, in the period between 1480 and 1505, when he carried out a large number of studies on flight, among them were studies on kites, gliders based on the skeletal structure of birds. Modern versions of these designs prove that most of them could effectively fly. One of the most recognizable of these da Vinci designs was the “flying machine”, a design of a pair of wings that resembled the wings of birds. Following the timeline, John Joseph Montgomery made the first flight with a glider in 1883. Although all the names mentioned above were essential parts for the invention of the airplane, it was Santos Dumont and the Wright brothers who brought aviation to another level higher [11].
Alberto Santos Dumont flew with an airship, the famous 14-bis, flying for 21 seconds in a distance of 200 meters and 6 meters high in this machine. Santos Dumont’s first public flight was made on October 23, 1906, aboard the 14-bis, when he flew over the Bagatelle field, in the French capital. Santos Dumont was essential in the history of the airplane for inventing an aircraft that did not need thrust to fly. She took off on her own. The feat was witnessed by more than a thousand people and filmed. In addition, it received recognition from the Aeroclube de Paris and was approved by the FAI (Federation Aéronautique International) for fulfilling requirements such as being documented and taking off by its own means – without a ramp or catapult. It should be noted that such a federation was only created in 1905 [16].
The Wright brothers created an aircraft in which the pilot could control and keep it stable. Despite the innovation, the Flyer, named after the Wright brothers’ aircraft, needed a little help to take off. However, if we consider flight only as stabilizing a motor-powered object in the air, we could place the Wright brothers’ experience as the first in history. The Americans Orville and Wilbur Wright, aboard the Flyer 3 model, flew about 39 kilometers in 1905 in 40 minutes. This could be considered the first flight in history, since to stay in the air for 40 minutes and travel such a great distance, it is necessary to have a well-developed system. The big problem is that this flight was recorded by images without the seal of official bodies at the time, which led to the questioning of the veracity of what happened as reported [16].
Regardless of who the real inventor of the airplane is, it can be said that both the brothers Orville and Wilbur Wright and Alberto Santos Dumont played a very important role in the development of aviation. The years between World War I and World War II were years in which aircraft technology in general developed greatly. In this period, rapid advances were made in aircraft design, and airlines began to operate. It was also the time when aviators began to impress the world with their accomplishments and skills. Airplanes stopped being made of wood, to be built with aluminum. Airplane engines have been greatly improved, with a notable increase in power. This great series of technological advances, as well as the growing social and economic impact that airplanes started to produce worldwide, makes this period the golden age of aviation.
A symbol of the golden age of aviation is the Douglas DC-3. This plane, equipped with a pair of thrusters, began its first flights in 1936. The DC-3 had a capacity for 21 passengers, and a cruising speed of 320 km/h. It quickly became the most used commercial aircraft at the time. This aircraft is also seen as one of the most important aircraft ever produced. It should be noted that the first planes used propellers. An aircraft propeller consists of two or more blades connected to the central hub to which these blades are attached. Each blade is essentially a rotary wing, each blade is an aerodynamic profile capable of generating lift. This lift force in the plane in which the blade moves is called traction or propulsion. The jet turbine began to be developed in Germany and England in the 1930s. The German Hans Von Ohain patented his version of the jet turbine in 1936, and began to develop a similar machine. Britain’s Frank Whittle patented a design for a jet turbine in 1930 and developed a turbine that could be used for practical purposes by the end of the decade. Neither of them knew of the work developed by the other, and for this, both are credited with the invention [17].
A turbojet engine is primarily used in aircraft propulsion. Air is introduced into the rotary compressor through the inlet and compressed to a higher pressure before entering the combustion chamber. The fuel is mixed with compressed air and ignited by a spark. This combustion process significantly increases the temperature of the gas. The hot products of combustion leaving the combustor expand through the turbine, where power is extracted to drive the compressor. The gas stream from the turbine expands to ambient pressure through the propulsion nozzle, producing a high-velocity jet at the engine exit. If the momentum of the outflow exceeds the momentum of the inflow, the thrust is positive, so there is a net forward thrust on the fuselage of the aircraft. First generation jet engines were pure turbojets with an axial compressor or a centrifugal. Modern jet engines are primarily turbofans, where a proportion of the air entering the engine bypasses the combustor.
At the end of the 2nd World War, Germany used the first jet planes and serially manufactured the Messerschimitt Me 262. In the late 1940s, engineers began to develop the turbines used in the jet fighters produced during the 2nd World War. In the beginning, the United States and the Soviet Union wanted high-performance jet engines to produce better and better bombers and jet fighters, and thus further improve their military arsenal. When the Korean War began in 1950, both the United States and the Soviet Union had high-performance military jet fighters, notably the American F-86 Saber and the Soviet MiG-15. The fact that planes were flying at higher and higher altitudes where turbulence and other undesirable weather factors are rarer created a problem because at higher altitudes, the air is less dense, and therefore has smaller amounts of oxygen for passengers, pilots and crew to breathe than at lower altitudes [18].
As planes flew higher and higher, pilots, crew and passengers found it increasingly difficult to breathe. To solve this problem, aeronautical engineers created the pressurized cabin, where the air is pressurized [18]. The first airplane with cabin pressurization was the Lockheed XC-35 which flew on May 9, 1937. Pressurized cabins became popular in the late 1940’s. Today, every cabin on commercial passenger planes is pressurized. After the end of World War II, commercial aviation began to develop into a branch apart from military aviation. The aeronautical industry started to produce planes specially designed for civil aviation and the airlines stopped using modified military planes for the transport of passengers. In a few years after the end of the 2nd World War, several airlines were established in the world. Of the various commercial aircraft that were developed during and after World War II, the four-engine Douglas DC-4 and the Lockheed Constellation stand out. These planes were widely used for domestic medium-haul passenger flights. Even so, they had to make stopovers for refueling on transoceanic routes.
Transatlantic flights would need more powerful thrusters. These already existed in 1945, in the form of jet turbines. But these still used so much fuel that a jet plane could travel only a short distance without needing to refuel. To temporarily solve this problem, two American factories created turboprops with propellers capable of generating more than three thousand horsepower. Such engines began to be used in the Douglas DC-7, Lockheed Super Constellation and the Boeing 377 Stratocruiser. The latter was the first double-decker aircraft in the history of aviation, and also the largest commercial aircraft until the arrival of the Boeing 707. Each of these aircraft could carry around 100 passengers, between New York and Paris nonstop, at a speed of cruise at 500 km/h. It was up to the British to produce the first commercial jet aircraft in the history of aviation, the De Havilland Comet. The Comet began to be used in passenger flights in 1952 that flew at approximately 850 km/h, whose cabin was pressurized and relatively silent. The Comet was initially a commercial success, and many airlines began ordering this aircraft. However, two accidents in 1954 caused both aircraft to explode on the high seas, creating great doubts about the safety of the aircraft [17].
Boeing launched the Boeing 707 in 1958 that was the first successful passenger jet aircraft [19]. The engineers involved in the creation of the Boeing 707 sought not to repeat the same mistakes made on De Havilland’s Comet. The Douglas DC-8 and Convair 880 jets were launched a few years later, although the commercial success achieved by both was much more modest than the success achieved by the Boeing 707. Boeing has since been the largest aircraft manufacturer in the world. The Boeing 727, 737 and 757 models are direct derivatives of the Boeing 707. The Boeing 737, whose production began in 1964, is the best-selling and most successful commercial airliner in aviation history. A total of five thousand Boeing 737s were produced, and the aircraft is still in production today. The gigantic Boeing 747, nicknamed the Jumbo, was capable of carrying more than 500 passengers on a single flight. Launched in 1968, the Boeing 747 was the world’s largest commercial airliner until 2005, when the Airbus A380 made its first flight.
The Boeing 767 revolutionized commercial aviation with its long range, low operating costs and reasonable passenger capacity (196) that allowed scheduled flights using the fewest number of planes possible on transatlantic routes and routes previously impractical because of high operating costs and low number of passengers. The Boeing 767 was responsible for popularizing transatlantic travel throughout the late 1980s and throughout the 1990s when more crossed the Atlantic Ocean daily than all other commercial airliners combined. Even today, the Boeing 767 remains the aircraft that crosses the Atlantic the most daily, despite increasing competition from more modern aircraft [17].
Until the end of the 2nd World War, the technology needed to carry out controlled supersonic flights was not yet available because until the 1940s they were not strong enough to be able to withstand the strong shock waves generated by supersonic speeds. At sea level, the speed of sound is approximately 1,225 km/h. At an altitude of 15,000 meters, the speed of sound is only 1,050 km/h. In World War II, many pilots crossed this barrier (through aerial dives, for example), however, with catastrophic results because the strong shock waves generated at supersonic speeds destroyed these aircraft, not designed for supersonic flights. Around 1943, American engineers began to work with small prototypes. The biggest concern of these aviation experts was that such planes would resist the shock waves created at supersonic speeds. American Charles Yeager became the first person to exceed the speed of sound, on October 14, 1947 in the Bell X-1 [17].
In 1962, the North American X-15 became the first aircraft to reach the thermosphere, which is the last layer of the atmosphere where the air is very thin [20]. The plane, piloted by the American Robert White, stayed at an altitude of 95,936 meters for about sixteen seconds, covering approximately 80 kilometers in this period. This was the first flight by a plane into the limits of outer space. Subsequently, the X-15 would reach an altitude of 107,960 meters. The X-15 was also the first hypersonic aircraft (5 times the speed of sound), breaking several speed records, exceeding Mach 6 (six times the speed of sound) in several flights. The first supersonic aircraft for civil use were created in the late 1960s. The world’s first commercial supersonic aircraft was the Soviet Tupolev Tu-144 which made its maiden flight on December 31, 1968 [22]. The Concorde, manufactured by a Franco-British commercial consortium, made its first flight two months later [21].
Concorde began its first commercial flights on January 21, 1976, serving transatlantic routes. The Concorde and Tu-144 are the only commercial supersonic aircraft developed to date. One of the Air France Concorde had an accident on July 25, 2000, when a tire burst and its remains were sucked into the turbine (which caused a fire), causing the plane to crash and crash into a hotel, shortly after its takeoff in Gonesse, France. Until then the plane was considered the safest commercial aircraft in the world. It underwent a modernization process until 2001, but because of low passenger numbers and high operating costs, it stopped being used on commercial flights on October 24, 2003. Currently, no supersonic aircraft operate on commercial flights in the world.
Since the beginning of the 21st century, subsonic aviation has focused its attention on trying to replace the pilot with remotely controlled aircraft or even computers. In April 2001, a Global Hawk, an unmanned aircraft, flew from Edwards AFB in the United States to Australia nonstop and without refueling. The flight took 23 hours and 23 minutes, and is the longest point-to-point flight ever performed by an unmanned vehicle. In October 2003, the first fully autonomous flight over the Atlantic Ocean by a computer-controlled aircraft was performed. In 2005, the Airbus A380 made its first flight, becoming the largest commercial passenger plane in the world, surpassing the Boeing 747, which had held the record for 35 years. The Soviet-built Antonov Na-225 has been the largest aircraft in the world since its first flight on December 21, 1988 [17].
Since the beginning of the 1990s, commercial aviation has developed technologies that have made the plane increasingly automated, thus gradually reducing the importance of the pilot in the operation of the aircraft, aiming to reduce air accidents caused by human error. Commercial aircraft manufacturers continue to research ways to improve planes, making them safer, more efficient and quieter. At the same time, pilots, airspace controllers and mechanics have become increasingly well trained, and aircraft are increasingly inspected to prevent accidents caused by human or mechanical failure. Despite the growing problems currently faced by aviation in general, it is believed that the 21st century will be a century of great advances for aviation. It is estimated that in the future the use of pilots will be reduced, being replaced by remote control with the use of computers [17].
The aeronautical industry works on the development of several aircraft projects that promise to revolutionize air transport in the coming years and decades. They are supersonic, electric, autonomous planes and even aircraft that look like a giant drone for transporting passengers in urban centers [15]. Airbus has developed three concepts for hydrogen-powered aircraft as part of an effort to build the first greenhouse gas-neutral commercial aircraft by 2035. Two of the aircraft are similar in design to the combustion engine planes, but one of the projects is more revolutionary and shows what the aircraft of the future can be. It is a ‘V’-shaped model, with wings integrated into the body of the plane. According to the company, the wide fuselage opens up several options for storage and distribution of hydrogen, as well as for the layout of the cabin [14]. Researchers at the Technical University of Delft in the Netherlands have managed for the first time to fly a prototype of the new Flying-V commercial aircraft, which is touted as a new aircraft that could change aviation in the future. The aircraft manufacturer Airbus is also a partner in the project. With a very different V-shape from traditional commercial aircraft, the Flying-V is designed to be more fuel efficient [13].
The search for more efficient ways to fly and transport passengers through the skies, emitting less polluting gases (or even zero) is the great challenge of the aeronautical industry for the coming years. This change will require a technological overhaul of aircraft and passenger habits. Finnair from Finland and Norway’s Widerøe, recently announced plans to introduce electric passenger planes to their fleets by 2026. In Canada, where the use of small commercial planes is also popular, Harbor Air is testing seaplanes adapted with electric propellers. In the not too distant past, the concept of the four-engine airplane was synonymous with safety and great capacity. Nowadays, machines, in the form of the giants Boeing 747 and Airbus A380, are falling into disuse in passenger transport. They are too expensive to operate, require more care to maintain and consume huge amounts of fuel. The alternative to these four-engine giants are the new, state-of-the-art twin-engine widebodies, such as the Airbus A350 and Boeing 787. Advances in engine technologies and new aerodynamic solutions have contributed to significantly reducing fuel consumption of commercial aircraft, opening up the possibility of increasingly longer routes. Taking advantage of this evolution, smaller planes, previously restricted to domestic flights, started to travel internationally between continents. Boeing’s 737 MAX series jets have good range figures. The use of smaller and less expensive planes compared to widebodies opens a new niche in the international travel market with the offer of cheaper tickets [12].
The invention of the helicopter
A helicopter is a type of diagonal-winged, heavier-than-air aircraft powered by one or more larger horizontal rotors (thrusters) that, when turned by the engine, create lift and propulsion necessary for flight. In contrast to fixed-wing aircraft (airplane), the helicopter can take off and land vertically, hover and go forward, backward and sideways. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft would not be able to land or take off [1].
The helicopter comes from the contribution of many people. The idea of a heavier-than-air object crossing the skies dates back many years. The first evidence of human attempts to fly was found in China, dating back to 400 BC. Of course it did not fly, but it’s still a prototype. After some time, Leonardo da Vinci appears on the scene, in 1483. The first impractical idea of a helicopter was conceived by Leonardo da Vinci in the 15th century. The famous gyroscope that he designed had a large rotating wing and was attached to a platform. The idea was that all machinery would fly thanks to the rapid movement of the wings. Who would make the rotation movement would be the person seated, but unfortunately this project failed, because it was not possible to generate enough energy to take off [1].
The first successful and recorded flight of a helicopter took place in 1907, carried out by the brothers Bréguet and Paul Cornu who gave their contribution and their prototype was presented to the French Academy of Sciences. It was a 20-second, unmanned flight, lifting the aircraft 50 centimeters off the ground. In the year 1908, Emil Berliner manages to create a rotary engine for the helicopter, which was used by other inventors. However, the first flight of a fully controllable helicopter was demonstrated by Hanna Reitsch in 1937 in Berlin, Germany. In 1938, German Anton Flettner created the first truly functional helicopter that kick-started everything we know today about helicopter flight. In 1942, Igor Sikorsky was behind the appearance of the Sikorsky R-4 which adapted floats on a Vought-Sikorsky VS-300 making it the world’s first practical helicopter. In 1946, production of the Bell 47B was launched which reached a speed of 140 km/h with two people on board [2].
Invention of the hybrid aircraft
A hybrid aircraft is one designed to take off and land vertically with tilt rotors. This type of aircraft is growing rapidly as designers and startups realize that this is the future of aircraft. VoltaAero, a French aviation startup, is developing a hybrid plane that could become a “Tesla” of the skies, popularizing the technology and putting it within reach of more people. The aircraft was designed to have a flight autonomy of up to 3.5 hours, with a range of 1,287 km, flying up to 8 times a day with a total flight time of 10 hours. Built with composite materials, the aircraft will be offered in three versions: the Cassio 330, with four seats and a hybrid propulsion system with a power of 330 kW, and the Cassio 480, with six seats and a hybrid propulsion system with 480 kW. The third model is the Cassio 600, with 10 seats and 600 kW hybrid propulsion. Its cruising speed is estimated at 370 km/h, and in all-electric mode the range is 200 km [3].
The aircraft will use two engines with continuous power of 45 kW. A third engine powered by biofuel and modified with the help of the Formula E Solution F team, drives the rear propeller and recharges the batteries of the electric motors. The hybrid electric propulsion system is reliable. The E-Fan project is the first fully electric twin-engine airplane to cross the English Channel, in 2015. In addition, he worked for 10 years in the development of fuel cells at General Motors. VoltaAero is expected to begin deliveries of its new aircraft in late 2022, initially in the four-seat Cassio 330 configuration [3].
The invention of the drone
The drone is an unmanned aerial vehicle that has controlled flight and can receive commands through radio frequency, infrared and even missions defined in advance by GNSS (Global Navigation Satellite System) coordinates. Its appearance is similar to that of mini helicopters with some models being replicas of jets, quadcopters (four propellers), in addition to models with eight propellers that use fuel for their flight. Drone has this name due to its hum when flying that ended up being popularly adopted to name the aircraft. Drones are designed and developed for military missions, fire rescue and non-military security. Drones have been one of the main instruments of US military strategy for several years. Drones are intended to allow monitoring or attacking a region. Nowadays, drones have enormous versatility when it comes to their use. Among its uses are monitoring and surveillance, photo and filming, military use, rescue and transport of goods [4].
In addition to military use, drones are being used by civilians, such as photographers and videographers at birthday parties, weddings or events in general. A drone can capture better angles for photos and footage, keeping the camera stable for longer, thus facilitating video production. These technical valences make them also used by TV stations. Drone technology can be used in rescues in hard-to-reach places, disaster areas (floods, landslides, fires, closed buildings, etc.), as such devices transmit images and video in real time, thus contributing to the success of the teams of rescue. Drones are also used to monitor people, as well as to prevent attacks or even vandalism. The use of drones for the delivery of goods and parcels is still being tested. One of the companies that is testing this possibility is Amazon. Another possible way of using drones is in agriculture to quickly identify pests and other problems that occur in crops. In addition, drones can be used for other functions, such as photographs [5].
The model we know today was developed by Israeli space engineer Abraham Karem. According to him, in 1977, when he arrived in the United States, 30 people were needed to control a drone. Faced with this situation, he founded the company Leading System and, using few technological resources, such as homemade fiberglass and wood scraps, he created the Albatross. With the improvements achieved with the new model in 56 hours of flight without recharging batteries and with three people operating, the engineer received funding from DARPA for the necessary improvements for the prototype and, with that, the new model called Amber [5] .
The invention of the space rocket
The first news of the use of the rocket is from the year 1232 in China, where gunpowder was invented, first used in fireworks as entertainment and, later, used for war purposes. Rockets were introduced to Europe by the Arabs, again being used in European conflicts shortly after the Hundred Years’ War (1337-1453). During the 15th and 16th centuries, it was used as an incendiary weapon. Later, with the improvement of artillery, the war rocket disappeared until the 19th century, coming to be used again during the Napoleonic Wars (1803-1815). In the late 19th and early 20th centuries, the first scientists appeared who saw the rocket as a system to propel manned aerospace vehicles. Among them, the Russian Konstantin Tsiolkovsky, the German Hermann Oberth, the North American Robert Goddard and, later, the Russians Sergei Karolev and Valentim Glushko and the German Wernher von Braun [6] stand out.
Goddard built the first liquid-fueled rocket in 1925. The rockets built by Goddard, although small, already had all the principles of modern rockets, such as gyroscope guidance, for example. The Germans, led by Wernher von Braun, developed, during World War II, the V-1 and V-2 rockets that served as the basis for research on rockets by the United States and the Soviet Union in the post-war period. Both of the Nazi rockets used to bomb London at the end of the war can be better defined as missiles because the V-1 and V-2 are not rockets flying missiles with jet aircraft propulsion. The space programs that the North Americans and the Russians put in motion were based on rockets designed with specific purposes for astronautics derived from these rockets for military use [6].
Particularly the rockets used in the Soviet space program were derived from the R.7 ballistic missile, which was eventually used to launch the Sputnik missions. In October 1957, the Soviet Union used a rocket to launch the first spacecraft, the Sputnik satellite. A space rocket is a machine that moves by expelling a stream of gas at high speed behind it. Its objective is to send objects (especially artificial satellites, space probes and rovers) and/or spacecraft and men into outer space at a speed greater than 40,320 km/h to overcome the gravitational pull of the Earth and reach altitudes greater than 100 km. above sea level [10]. A rocket consists of a structure, a reaction propulsion engine and a payload. The structure serves to house the fuel and oxidizer (oxidizer) tanks and the payload. These rockets also need to carry an oxidizer to react with the fuel. This mixture of superheated gases is then expanded in a diverging tube, the Laval Tube, also known as the Bell Tube, to direct the expanding gas backwards, thus propelling the rocket forward [10].
A new engine under development by two American engineers, however, proposes an alternative to optimize the amount of oxidants transported by rockets and reduce the cost of launches. This is the Fernis air aspiration propulsion system, a technology that combines characteristics of a conventional rocket engine and a jet engine [9] thermal nuclear weapons, which superheat a gas to high temperatures, using the heat generated by nuclear reactions, in particular through the process of nuclear fission, where the nuclear fuel is bombarded with neutrons, leading to the fission of the nuclei of atoms. This gas is then expanded in the Laval Tube as in chemical rockets. This type of rocket was developed and tested in the United States during the 1960s, but was never used. The gases expelled by this type of rocket can be radioactive, which is not recommended for use inside the Earth’s atmosphere, but they can be used outside it. This type of rocket has the advantage of allowing efficiencies much higher than those of conventional chemical rockets, since they allow the acceleration of exhaust gases to much higher speeds. Currently, it is Russia that stands out in the development of thermal nuclear engines [23].
Adoption of reusable vehicles such as NASA’s Space Shuttle is expected to expand. Space Shuttles take off like a conventional rocket, but land like airplanes. The Reusable Launch Vehicle (RLV)- Reusable Spacecraft is a space plane equipped with rockets, which would take off and land like planes, on long runways, which would be equipped with reusable rockets to reach space and orbit the Earth. These aircraft do not yet exist. However, it is thought that in the future, RLVs will be aircraft that can be used for low-cost, high-security space travel. A revolutionary engine, which can advance astronautic technology, is the Scramjet engine that is capable of reaching hypersonic speeds of up to 15 times the speed of sound. NASA successfully tested such an engine in 2004. Another possible advance in rocket engine technology is the use of nuclear propulsion, in which a nuclear reactor heats a gas, producing a jet that is used to produce thrust [23]. Another idea is to build a rocket in the form of a sail that would be accelerated by the solar wind that would allow greater speed and travel over greater distances [6]. The European Space Agency (ESA) has decided to bet on a technology that has been dreamed of since the beginning of space exploration. It is a spacecraft capable of taking off from an airport, like an ordinary plane, becoming a traditional rocket once it passes the limits of the densest atmosphere and enters orbit. The concept spacecraft was named Skylon, and the hybrid engine that will equip it is called Saber, which is an unprecedented hybrid engine capable of “breathing” air while in the atmosphere, like a jet engine, becoming a rocket when reaches space [9].
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* Fernando Alcoforado, 82, awarded the medal of Engineering Merit of the CONFEA / CREA System, member of the Bahia Academy of Education, engineer and doctor in Territorial Planning and Regional Development by the University of Barcelona, university professor and consultant in the areas of strategic planning, business planning, regional planning and planning of energy systems, is author of the books Globalização (Editora Nobel, São Paulo, 1997), De Collor a FHC- O Brasil e a Nova (Des)ordem Mundial (Editora Nobel, São Paulo, 1998), Um Projeto para o Brasil (Editora Nobel, São Paulo, 2000), Os condicionantes do desenvolvimento do Estado da Bahia (Tese de doutorado. Universidade de Barcelona,http://www.tesisenred.net/handle/10803/1944, 2003), Globalização e Desenvolvimento (Editora Nobel, São Paulo, 2006), Bahia- Desenvolvimento do Século XVI ao Século XX e Objetivos Estratégicos na Era Contemporânea (EGBA, Salvador, 2008), The Necessary Conditions of the Economic and Social Development- The Case of the State of Bahia (VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG, Saarbrücken, Germany, 2010), Aquecimento Global e Catástrofe Planetária (Viena- Editora e Gráfica, Santa Cruz do Rio Pardo, São Paulo, 2010), Amazônia Sustentável- Para o progresso do Brasil e combate ao aquecimento global (Viena- Editora e Gráfica, Santa Cruz do Rio Pardo, São Paulo, 2011), Os Fatores Condicionantes do Desenvolvimento Econômico e Social (Editora CRV, Curitiba, 2012), Energia no Mundo e no Brasil- Energia e Mudança Climática Catastrófica no Século XXI (Editora CRV, Curitiba, 2015), As Grandes Revoluções Científicas, Econômicas e Sociais que Mudaram o Mundo (Editora CRV, Curitiba, 2016), A Invenção de um novo Brasil (Editora CRV, Curitiba, 2017), Esquerda x Direita e a sua convergência (Associação Baiana de Imprensa, Salvador, 2018), Como inventar o futuro para mudar o mundo (Editora CRV, Curitiba, 2019) and A humanidade ameaçada e as estratégias para sua sobrevivência (Editora Dialética, São Paulo, 2021) .
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