Narayana Murthy

Narayana Murthy,  (b. Aug. 20, 1946, Kolar, Karnataka state, India), Indian software entrepreneur who cofounded Infosys Technologies Ltd., the first Indian company to be listed on an American stock exchange.
Murthy earned a bachelor’s degree in electrical engineering from the University of Mysore in 1967 and a master’s degree in technology from the Indian Institute of Technology, Kanpur, in 1969. During the 1970s he worked in Paris, where, among other projects, he helped design an operating system for handling air cargo at Charles de Gaulle Airport. Returning to India, he accepted a position with a computer systems company in Pune, but eventually he decided to launch his own company. He cofounded Infosys with six fellow computer professionals in 1981.

The company grew slowly until the early 1990s, when the Indian government’s decisive move toward economic liberalization and deregulation contributed to dramatic growth in the country’s high-technology and computer sectors. Murthy aggressively expanded his company’s services and client base, negotiating deals with many overseas businesses to provide them with consulting, systems integration, software development, and product engineering services. By 1999 Infosys had joined NASDAQ, becoming the first Indian company to be listed on an American stock exchange. The following year Asiaweek included Murthy in its Power 50, the magazine’s annual list of the most powerful people in the region. In addition, BusinessWeek named him one of its “Stars of Asia” for three consecutive years (1998–2000), and he was Fortune magazine’s 2003 Asian Businessman of the Year.

In April 2004 Murthy announced that the Bangalore-based Infosys had posted $1.06 billion in total annual revenues an astonishing 33 percent increase in revenues over the previous fiscal year. The company’s growth was all the more remarkable because it came in the midst of a global downturn in the information technology industry. Such phenomenal success was not without controversy, however. A political debate erupted in the United States over job losses caused by offshoring, the outsourcing of work overseas. This was of serious concern to Infosys, which derived more than two-thirds of its revenue from American corporations. Murthy responded that it was “normal” that concerns over job losses would be voiced, and while he indicated that he thought outsourcing was “here to stay,” he made efforts to assuage some of the anger by announcing that Infosys would establish a consulting unit in the United States that would employ 500 workers. In the end the controversy appeared not to have significantly dented Infosys’s business. When Murthy retired in 2006, he left behind a company with some 70,000 employees and $3 billion a year in revenues. He was awarded the Legion of Honour in 2008.

Big Science

Big Science, style of scientific research developed during and after World War II that defined the organization and character of much research in physics and astronomy and later in the biological sciences. Big Science is characterized by large-scale instruments and facilities, supported by funding from government or international agencies, in which research is conducted by teams or groups of scientists and technicians. Some of the best-known Big Science projects include the high-energy physics facility CERN, the Hubble Space Telescope, and the Apollo program.

The term Big Science first appeared in a 1961 article in Science magazine, titled “Impact of Large-Scale Science on the United States,” by physicist and Oak Ridge National Laboratory director Alvin Weinberg. The article described Big Science as part of the new political economy of science produced by World War II, during which the U.S. government sponsored gigantic research efforts such as the Manhattan Project, the American atomic bomb program, and the Radiation Laboratory, a centre for radar research at the Massachusetts Institute of Technology (MIT). Weinberg was not only describing a new form of scientific research; his concept was an expression of nostalgia for “Little Science,” a world of independent, individual researchers free to work alone or with graduate students on problems of their own choosing. Whether or not the world of Little Science as imagined by Weinberg ever existed became irrelevant; high-technology warfare had turned support of scientific research into a national security priority and promised to turn scientists and engineers into beneficiaries of Cold War largesse.

Big Science shared many characteristics of other industrial and government enterprises. Large scale, expensive, and heavily bureaucratic, Big Science’s most ambitious projects satellites and space probes, particle accelerators, and telescopes rivaled those of military and industrial institutions in their size and complexity. Weinberg argued that they were the contemporary equivalents of Egyptian pyramids or Gothic cathedrals. Indeed, some countries founded entire cities such as the United States’ Oak Ridge, Japan’s Tsukuba Academic City, and the Soviet Union’s Akademgorodok to support scientific research. For researchers, the advent of Big Science signaled a transformation of the scientist from an independent researcher into a member of a hierarchically organized group. Scientists at facilities such as CERN found themselves working on projects that brought together hundreds of scientists, engineers, technicians, and administrators. This bureaucratic culture in turn reshaped scientific careers by making it possible to succeed through administrative skill, fund-raising ability, and managerial talent, as well as scientific brilliance. It also joined the trend in higher education to emphasize research over teaching for scientists at research universities. The high cost of scientific instruments, facilities, and payrolls made Big Science affordable only to government agencies or international consortia, drawing influence away from the universities, societies, and philanthropies that had been the main supporters of scientific research before World War II.

The products of Big Science also differed from those of preceding forms of scientific research. The literary results of Big Science were articles “written” by dozens or even hundreds of coauthors, rather than individuals or a few collaborators. As important as the published reports are the machine-readable archives of data generated by projects, which can be used by researchers long after the instruments that produced them are rendered obsolete.

With the end of the Cold War, the fortunes and complexion of Big Science began to change. The phenomenon had never been without its critics: its impact on science education was mixed, and during the 1960s American students at a number of campuses protested military-sponsored research conducted at Big Science facilities such as Charles Stark Draper’s Instrumentation Laboratory at MIT. The withdrawal of funding for the Superconducting Super Collider in 1993 marked the U.S. government’s retreat from its formerly lavish sponsorship of high-energy physics. The development at the National Aeronautics and Space Administration (NASA) of smaller, lower-cost satellites in the 1990s was likewise motivated by demands to conduct research on a more economical scale. At the same time, Big Science began to spread to the biomedical disciplines via the Human Genome Project. However, in that project, work was decentralized among a number of research sites, rather than concentrated in a single large facility. Further, its goal was not a set of research papers but the production of an archive, the sequence of the human genome. Finally, the project was supported in part by private firms hoping to use the archive in their own efforts to develop new pharmaceuticals and other medical products.

TRON Gadgets

TRON: Legacy Playstation 3 (PS3) Wired USB Controller By PDP Review

What's In The Box

• Collector's box with magnetic flap
• Instruction booklet
• 1 of 20,000 limited edition TRON Collector's Edition Playstation 3 Controller (ours is 03984/20,000)
  

Pros:

• Tight and compact.
• Rubber handle grips.
  
• Illuminated front is bright and vibrant.
  
• Looks like a Recognizer.
  
• L2 & R2 buttons flare outwards for better finger grip.
  
• Cable length is approx 10 feet.
  

Cons:

• Square, Triangle, Circle, and X buttons have curved tops instead of the flat tops of the original controller.
  
• There are only 20,000 of these.
  
• D-Pad is one single rocker piece instead of individual buttons.
  
• Wired. It's wired. Not wireless, wired. Really? Yes.
  

Conclusion

We're not sure why PDP decided to take the wired approach to the PS3 and Xbox 360 TRON: Legacy Collector's Edition controllers - perhaps there's some technical limitation with drawing power from the internal lithium ion battery? Regardless, this special edition TRON PS3 controller is recommended for collectors and those who don't mind wired controllers, but sadly just isn't as cool as his TRON Wii remote counterpart. TRON Wired Controller for PS3 Collector's Edition

Human Genome Project

Human Genome Project, an international collaboration that successfully determined, stored, and rendered publicly available the sequences of almost all the genetic content of the chromosomes of the human organism, otherwise known as the human genome.
The Human Genome Project (HGP), which operated from 1990 to 2003, provided researchers with basic information about the sequences of the three billion chemical base pairs (i.e., adenine [A], thymine [T], guanine [G], and cytosine [C]) that make up human genomic DNA (deoxyribonucleic acid). The Human Genome Project was further intended to improve the technologies needed to interpret and analyze genomic sequences, to identify all the approximately 25,000 genes encoded in human DNA, and to address the ethical, legal, and social implications that might arise from defining the entire human genomic sequence.

Timeline of the Human Genome Project

Prior to the Human Genome Project, the base sequences of numerous human genes had been determined through contributions made by many individual scientists. However, the vast majority of the human genome remained unexplored, and researchers, having recognized the necessity and value of having at hand the basic information of the human genomic sequence, were beginning to search for ways to uncover this information more quickly. Because the Human Genome Project required billions of dollars that would inevitably be taken away from traditional biomedical research, many scientists, politicians, and ethicists became involved in vigorous debates over the merits, risks, and relative costs of sequencing the entire human genome in one concerted undertaking. Despite the controversy, the Human Genome Project was initiated in 1990 under the leadership of American geneticist Francis Collins, with support from the U.S. Department of Energy and the National Institutes of Health (NIH). The effort was soon joined by scientists from around the world. Moreover, a series of technical advances in the sequencing process itself and in the computer hardware and software used to track and analyze the resulting data enabled rapid progress of the project.

Technological advance, however, was only one of the forces driving the pace of discovery of the Human Genome Project. In 1998 a private-sector enterprise, Celera Genomics, headed by American biochemist and former NIH scientist J. Craig Venter, began to compete with and potentially undermine the publicly funded Human Genome Project. At the heart of the competition was the prospect of gaining control over potential patents on the genome sequence, which was considered a pharmaceutical treasure trove. Although the legal and financial reasons remain unclear, the rivalry between Celera and the NIH ended when they joined forces, thus speeding completion of the rough draft sequence of the human genome. The completion of the rough draft was announced in June 2000 by Collins and Venter. For the next three years, the rough draft sequence was refined, extended, and further analyzed, and in April 2003, coinciding with the 50th anniversary of the publication that described the double-helical structure of DNA, written by British biophysicist Francis Crick and American geneticist and biophysicist James D. Watson, the Human Genome Project was declared complete.

Science behind the Human Genome Project

To appreciate the magnitude, challenge, and implications of the Human Genome Project, it is important first to consider the foundation of science upon which it was based the fields of classical, molecular, and human genetics. Classical genetics is considered to have begun in the mid-1800s with the work of Austrian botanist, teacher, and Augustinian prelate Gregor Mendel, who defined the basic laws of genetics in his studies of the garden pea (Pisum sativum). Mendel succeeded in explaining that, for any given gene, offspring inherit from each parent one form, or allele, of a gene. In addition, the allele that an offspring inherits from a parent for one gene is independent of the allele inherited from that parent for another gene.

Mendel’s basic laws of genetics were expanded upon in the early 20th century when molecular geneticists began conducting research using model organisms such as Drosophila melanogaster (also called the vinegar fly or fruit fly) that provided a more comprehensive view of the complexities of genetic transmission. For example, molecular genetics studies demonstrated that two alleles can be codominant (characteristics of both alleles of a gene are expressed) and that not all traits are defined by single genes; in fact, many traits reflect the combined influences of numerous genes. The field of molecular genetics emerged from the realization that DNA and RNA (ribonucleic acid) constitute the genetic material in all living things. In physical terms, a gene is a discrete stretch of nucleotides within a DNA molecule, with each nucleotide containing an A, G, T, or C base unit. It is the specific sequence of these bases that encodes the information contained in the gene and that is ultimately translated into a final product, a molecule of protein or in some cases a molecule of RNA. The protein or RNA product may have a structural role or a regulatory role, or it may serve as an enzyme to promote the formation or metabolism of other molecules, including carbohydrates and lipids. All these molecules work in concert to maintain the processes required for life.

Studies in molecular genetics led to studies in human genetics and the consideration of the ways in which traits in humans are inherited. For example, most traits in humans and other species result from a combination of genetic and environmental influences. In addition, some genes, such as those encoded at neighbouring spots on a single chromosome, tend to be inherited together, rather than independently, whereas other genes, namely those encoded on the mitochondrial genome, are inherited only from the mother, and yet other genes, encoded on the Y chromosome, are passed only from fathers to sons.

Advances based on the Human Genome Project

Advances in genetics and genomics continue to emerge. Two important advances include the International HapMap Project and the initiation of large-scale comparative genomics studies, both of which have been made possible by the availability of databases of genomic sequences of humans, as well as the availability of databases of genomic sequences of a multitude of other species.

The International HapMap Project is a collaborative effort between Japan, the United Kingdom, Canada, China, Nigeria, and the United States in which the goal is to identify and catalog genetic similarities and differences between individuals representing four major human populations derived from the continents of Africa, Europe, and Asia. The identification of genetic variations called polymorphisms that exist in DNA sequences among populations allows researchers to define haplotypes, markers that distinguish specific regions of DNA in the human genome. Association studies of the prevalence of these haplotypes in control and patient populations can be used to help identify potentially functional genetic differences that predispose an individual toward disease or, alternatively, that may protect an individual from disease. Similarly, linkage studies of the inheritance of these haplotypes in families affected by a known genetic trait can also help to pinpoint the specific gene or genes that underlie or modify that trait. Association and linkage studies have enabled the identification of numerous disease genes and their modifiers.

In contrast to the International HapMap Project, which compares genomic sequences within one species, comparative genomics is the study of similarities and differences between different species. In recent years a staggering number of full or almost full genome sequences from different species have been determined and deposited in public databases such as NIH’s Entrez Genome database. By comparing these sequences, often using a software tool called BLAST (Basic Local Alignment Search Tool), researchers are able to identify degrees of similarity and divergence between the genes and genomes of related or disparate species. The results of these studies have illuminated the evolution of species and of genomes. Such studies have also helped to draw attention to highly conserved regions of noncoding sequences of DNA that were originally thought to be nonfunctional because they do not contain base sequences that are translated into protein. However, some noncoding regions of DNA have been highly conserved and may play key roles in human evolution.

Impacts of the Human Genome Project

Impact on medicine

The public availability of a complete human genome sequence represented a defining moment for both the biomedical community and for society. In the years since completion of the Human Genome Project, the human genome database, together with other publicly available resources such as the HapMap database, has enabled the identification of a variety of genes that are associated with disease. This, in turn, has enabled more objective and accurate diagnoses, in some cases even before the onset of overt clinical symptoms. Association and linkage studies have identified additional genetic influences that modify the development or outcome for both rare and common diseases. The recognition that human genomes may influence everything from disease risk to physiological response to medications has led to the emergence of the concept of personalized medicine—the idea that knowledge of a patient’s entire genome sequence will give health care providers the ability to deliver the most appropriate and effective care for that patient. Indeed, continuing advances in DNA sequencing technology promise to lower the cost of sequencing an individual’s entire genome to that of other, relatively inexpensive, diagnostic tests.

Impact on law and the social sciences

The Human Genome Project affects fields beyond biomedical science in ways that are both tangible and profound. For example, human genomic sequence information, analyzed through a system called CODIS (Combined DNA Index System), has revolutionized the field of forensics, enabling positive identification of individuals from extremely tiny samples of biological substances, such as saliva on the seal of an envelope, a few hairs, or a spot of dried blood or semen. Indeed, spurred by high rates of recidivism (the tendency of a previously convicted criminal to return to prior criminal behaviour despite punishment or imprisonment), some governments have even instituted the policy of banking DNA samples from all convicted criminals in order to facilitate the identification of perpetrators of future crimes. While politically controversial, this policy has proved highly effective. By the same token, innocent men and women have been exonerated on the basis of DNA evidence, sometimes decades after wrongful convictions for crimes they did not commit.
Comparative DNA sequence analyses of samples representing distinct modern populations of humans have revolutionized the field of anthropology. For example, by following DNA sequence variations present on mitochondrial DNA, which is maternally inherited, and on the Y chromosome, which is paternally inherited, molecular anthropologists have confirmed Africa as the cradle of the modern human species, Homo sapiens, and have identified the waves of human migration that emerged from Africa over the last 60,000 years to populate the other continents of the world. Databases that map DNA sequence variations that are common in some populations but rare in others have enabled so-called molecular genealogists to trace the continent or even subcontinent of origin of given families or individuals. Perhaps more important than helping to trace the roots of humans and to see the differences between populations of humans, DNA sequence information has enabled recognition of how closely related one population of humans is to another and how closely related humans are to the multitude of other species that inhabit the Earth.

Management Science

Management science, any application of science to the study of management. Originally a synonym for operations research, the term management science (often used in the plural) now designates a distinct field. Whereas operations research affords analytical data, statistics, and methods to increase the efficiency of management systems, management science applies these tools in such fields as data mining, engineering, economic forecasting, and logistics.

Management science initially included any application of science to management problems or to the process of management itself; it thus encompassed operations research, systems analysis, and the study of management-information systems. This broad understanding of the scope of the field was reflected in the constitution of the Institute of Management Sciences (TIMS), founded in 1953 as an outgrowth of the Operations Research Society of America (ORSA). It stated that “the objects of the Institute shall be to identify, extend, and unify scientific knowledge that contributes to the understanding and practice of management.” In 1995 ORSA and TIMS merged to form the Institute for Operations Research and the Management Sciences (INFORMS).

Although management science could include the study of all activities of groups that entail a managerial function, it generally entails the following: (1) discovering, developing, defining, and evaluating the goals of the organization and the alternative policies that will lead toward the goals, (2) getting the organization to adopt the policies, (3) scrutinizing the effectiveness of the policies that are adopted, and (4) initiating steps to change policies that are ineffective or inadequately effective. Management science often has drawn its concepts and methods from the older disciplines of economics, business administration, psychology, sociology, and mathematics.

Bird Flu

bird flu, also called avian influenza, a viral respiratory disease mainly of poultry and certain other bird species, including migratory waterbirds, some imported pet birds, and ostriches, that can be transmitted directly to humans. The first known cases in humans were reported in 1997, when an outbreak in poultry in Hong Kong led to severe illness in 18 people, a third of whom died. Symptoms of bird flu in humans resemble those of the human variety of influenza and include fever, sore throat, cough, headache, and muscle aches, which appear following an incubation period of several days. Severe infection can result in conjunctivitis or such life-threatening complications as bacterial or viral pneumonia and acute respiratory illness. Between 2003 and late 2005, outbreaks of the most deadly variety of bird flu occurred among poultry in Cambodia, China, Indonesia, Japan, Kazakhstan, Laos, Malaysia, Romania, Russia, South Korea, Thailand, Turkey, and Vietnam. Hundreds of millions of birds in those countries died from the disease or were killed in attempts to control the epidemics. From 2003 through November 2010, some 508 people were reported to have been infected with bird flu, and about 60 percent of them died. The majority of human infections and deaths occurred in China, Egypt, Indonesia, Thailand, and Vietnam. Poultry-associated human infection with a less severe form of the disease was reported in the Netherlands.

Bird flu in avian species occurs in two forms, one mild and the other highly virulent and contagious; the latter form has been termed fowl plague. Mutation of the virus causing the mild form is believed to have given rise to the virus causing the severe form. The infectious agents of bird flu are any of several subtypes of type A orthomyxovirus. Other subtypes of this virus are responsible for most cases of human influenza and for the great influenza pandemics of the past (see influenza epidemic of 1918–19). Genetic analysis suggests that the influenza A subtypes that afflict mainly nonavian animals, including humans, pigs, whales, and horses, derive at least partially from bird flu subtypes. All the subtypes are distinguished on the basis of variations in two proteins found on the surface of the viral particle hemagglutinin (H) and neuraminidase (N). The 1997 bird flu outbreak in Hong Kong was found to be caused by H5N1. This subtype, first identified in terns in South Africa in 1961, has been responsible for nearly all laboratory-confirmed bird flu infections in humans and for the most devastating outbreaks in poultry. Other bird flu subtypes recognized to cause disease in birds and humans are H7N2, H7N3, H7N7, and H9N2.
Waterfowl such as wild ducks are thought to be primary hosts for all bird flu subtypes. Though normally resistant to the viruses, the birds carry them in their intestines and distribute them through feces into the environment, where they infect susceptible domestic birds. Sick birds pass the viruses to healthy birds through saliva, nasal secretions, and feces. Within a single region, bird flu is transmitted readily from farm to farm by airborne, feces-contaminated dust and soil, by contaminated clothing, feed, and equipment, or by wild animals carrying the virus on their bodies. The disease is spread from region to region by migratory birds and through international trade in live poultry. Humans who are in close contact with sick birds for example, poultry farmers and slaughterhouse workers are at the greatest risk of becoming infected. Virus-contaminated surfaces and intermediate hosts such as pigs can also be sources of infection for humans. Although isolated instances of person-to-person transmission appear to have occurred since 1997, sustained transmission has not been observed. However, through a rapid evolutionary process called antigenic shift, two viral subtypes e.g., one a bird flu virus such as H5N1 and the other a human influenza virus can combine parts of their genetic makeup to produce a previously unknown viral subtype. If the new subtype causes severe disease in humans, spreads easily between people, and has a combination of surface proteins to which few people have immunity, the stage will be set for a new influenza pandemic to occur.

Early detection of avian influenza is important in preventing and controlling outbreaks. One way the virus can be detected is by polymerase chain reaction (PCR), in which nucleic acids from blood or tissue samples are analyzed for the presence of molecules specific to bird flu. Other methods include viral antigen detection, which detects the reaction of antibodies to viral antigens in samples of skin cells or mucus, and viral culture, which is used to confirm the identity of specific subtypes of influenza based on the results of PCR or antigen detection and requires growth of the virus in cells in a laboratory. Tests based on lab-on-a-chip technology that take less than an hour to complete and can accurately identify specific subtypes of bird flu are being developed. This technology consists of a small device (the “chip”) that contains on its surface a series of scaled-down laboratory analyses requiring only a tiny volume of sample (e.g., picolitres of saliva). These chip-based tests, which are portable and cost-effective, can be used to detect different subtypes of influenza in both poultry and humans.

Because of the many immunologically distinct viral subtypes that cause influenza in animals and the ability of the virus to rapidly evolve new strains, preparation of effective vaccines is complicated. The most effective control of outbreaks in poultry remains rapid culling of infected farm populations and decontamination of farms and equipment. This measure also serves to reduce the chances for human exposure to the virus. In 2007 the U.S. Food and Drug Administration approved a vaccine to protect humans against one subtype of the H5N1 virus. It was the first vaccine approved for use against bird flu in humans. Drug manufacturers and policy makers in developed and developing countries are working toward establishing a stockpile of the vaccine to provide some measure of protection against a future outbreak of bird flu. In addition, scientists are developing a vaccine that is effective against another subtype of H5N1, as well as a vaccine that might protect against all subtypes of H5N1. Studies suggest that antiviral drugs developed for human flu viruses would work against bird flu infection in humans. The H5N1 virus, however, appears resistant to at least two of the drugs, amantadine and rimantadine. (See also respiratory disease: Viral infections.)

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Launch Vehicle

 Rocket system that boosts a spacecraft into Earth orbit or beyond Earth’s gravitational pull.
A wide variety of launch vehicles have been used to lift payloads ranging from satellites weighing a few pounds (or kilograms) to large modular components of space stations. Most launch vehicles are expendable (one-use) systems; many early ones were derived from intercontinental ballistic missiles (see ICBM). The Saturn V, which launched the spacecraft that carried humans to the Moon (see Apollo), had three stages (see staged rocket). The U.S. space shuttle system (from 1981) represents a significant departure from expendable launch vehicles in that it is partially reusable its manned orbiting component is designed for numerous flights, and its solid rocket boosters can be recovered and refurbished.

launch vehicle, in spaceflight, a rocket-powered vehicle used to transport a spacecraft beyond Earth’s atmosphere, either into orbit around Earth or to some other destination in outer space. Practical launch vehicles have been used to send manned spacecraft, unmanned space probes, and satellites into space since the 1950s. They include the Soyuz and Proton launchers of Russia, the Ariane series of Europe, and the space shuttle and Atlas, Delta, and Titan families of vehicles of the United States.

In order to reach Earth orbit, a launch vehicle must accelerate its spacecraft payload to a minimum velocity of 28,000 km (17,500 miles) per hour, which is roughly 25 times the speed of sound. To overcome Earth’s gravity for travel to a destination such as the Moon or Mars, the spacecraft must be accelerated to a velocity of approximately 40,000 km (25,000 miles) per hour. The initial acceleration must also be provided very rapidly in order to minimize both the time that a launch vehicle takes to transit the stressful environment of the atmosphere and the time during which the vehicle’s rocket engines and other systems must operate near their performance limits; a launch from Earth’s surface or atmosphere usually attains orbital velocity within 8–12 minutes. Such rapid acceleration requires one or more rocket engines burning large quantities of propellant at a high rate, while at the same time the vehicle is controlled so that it follows its planned trajectory. To maximize the mass of the spacecraft that a particular launch vehicle can carry, the vehicle’s structural weight is kept as low as possible. Most of the weight of the launch vehicle is actually its propellants i.e., fuel and the oxidizer needed to burn the fuel. Designing reliable launch vehicles is challenging. The launchers with the best recent records have a reliability rate between 95 and 99 percent.

With the exception of the partially reusable U.S. space shuttle and the Soviet Buran vehicle (which was flown only once), all launch vehicles to date have been designed for only a single use; they are thus called expendable launch vehicles. With costs ranging from more than 10 million dollars each for the smaller launch vehicles used to put lighter payloads into orbit to hundreds of millions of dollars for the launchers needed for the heaviest payloads, access to space is very expensive, on the order of many thousands of dollars per kilogram taken to orbit. The complexity of the space shuttle has also made it extremely expensive to operate, even though portions of the shuttle system are reusable. Attempts to develop a fully reusable launch vehicle in order to reduce the cost of access to space have so far not been successful, primarily because the propulsion system and materials needed for successful development of such a vehicle have not been available.
Having both its own launch vehicles and a place to launch them are prerequisites if a particular country or group of countries wants to carry out an independent space program. To date, only eight entities Russia, the United States, Japan, China, certain European countries through the European Space Agency, Israel, India, and Iran have successfully developed and currently maintain their own space launch capability. Other countries aspiring to such capability include Brazil, North Korea, South Korea, and Pakistan. Historically, many launch vehicles have been derived from ballistic missiles, and the link between new countries developing space launch capability and obtaining long-range military missiles is a continuing security concern.
Most launch vehicles have been developed through government funding, although some of those launch vehicles have been turned over to the private sector as a means of providing commercial space transportation services. Particularly in the United States, there have also been a number of entrepreneurial attempts to develop a privately funded launch vehicle. Although none of these attempts has yet been successful, several appear to be potentially viable.

Origins

Most space launch vehicles trace their heritage to ballistic missiles developed for military use during the 1950s and early ’60s. Those missiles in turn were based on the ideas first developed by Konstantin Tsiolkovsky in Russia, Robert Goddard in the United States, and Hermann Oberth in Germany. Each of these pioneers of space exploration recognized the centrality of developing successful launch vehicles if humanity were to gain access to outer space.

Tsiolkovsky late in the 19th century was the first to recognize the need for rockets to be constructed with separate stages if they were to achieve orbital velocity. Oberth’s classic 1923 book, Die Rakete zu den Planetenräumen (“The Rocket into Interplanetary Space”), explained the mathematical theory of rocketry and applied the theory to rocket design. Oberth’s works also led to the creation of a number of rocket clubs in Germany, as enthusiasts tried to turn Oberth’s ideas into practical devices. Goddard was the first to build experimental liquid-fueled rockets; his first rocket, launched in Auburn, Mass., on March 16, 1926, rose 12.5 metres (41 feet) and traveled 56 metres (184 feet) from its launching place.

V-2

While Goddard spent 1930–41 in New Mexico working in isolation on increasingly sophisticated rocket experiments, a second generation of German, Soviet, and American rocket pioneers emerged during the 1930s. In particular, a team led by Wernher von Braun, working for the German army during the Nazi era, began development of what eventually became known as the V-2 rocket. Although built as a weapon of war, the V-2 later served as the predecessor of some of the launch vehicles used in the early space programs of the United States and, to a lesser extent, the Soviet Union.

Early U.S. launch vehicles

With the end of World War II and the beginning of the Cold War, rocket research in the United States and the Soviet Union focused on the development of missiles for military use, including intermediate-range ballistic missiles (IRBMs) capable of carrying nuclear warheads over distances of approximately 2,400 km (1,500 miles) and intercontinental ballistic missiles (ICBMs) with transoceanic range. Braun and his team had been transported to the United States after the war, together with a number of captured V-2 rockets. These rockets were launched under army auspices to gain operational and technological experience. Braun’s team during the 1950s developed the Jupiter IRBM, which was in many ways a derivative of the V-2 rocket. A version of the Jupiter was the launch vehicle for the first U.S. artificial satellite, Explorer 1, launched on Jan. 31, 1958. Another V-2 derivative, called Redstone, was used to launch the first U.S. astronaut, Alan Shepard, on his May 5, 1961, suborbital flight.

Another line of development within the U.S. industry led in the early 1950s to the Navaho cruise missile. (A cruise missile flies like an unpiloted airplane to its target, rather than following the ballistic trajectory of an IRBM.) This program was short-lived, but the rocket engine developed for Navaho, which itself was derived from the V-2 engine, was in turn adapted for use in a number of first-generation ballistic missiles, including Thor, another IRBM, and Atlas and Titan, the first two U.S. ICBMs. A version of Atlas was used to launch John Glenn on the first U.S. orbital flight on Feb. 20, 1962, and Titan was adapted to be the launch vehicle for the two-person Gemini program in the mid-1960s.
After Pres. John F. Kennedy’s announcement in 1961 that sending Americans to the Moon would be a national goal, Braun and others in and outside of the National Aeronautics and Space Administration (NASA) set about developing a launch vehicle that would enable a lunar mission based on rendezvous either in Earth or Moon orbit. The Braun team already had a less powerful rocket called Saturn I in development; their advanced design, intended for lunar missions, was configured to use five F-1 engines and on that basis was named Saturn V.

The Saturn V with the Apollo spacecraft on top stood 110.6 metres (363 feet) tall; its weight at the time of liftoff was over 3,000,000 kg (6,600,000 pounds). Its first stage provided 33,000 kilonewtons (7,500,000 pounds) of lifting power at takeoff. The second stage accelerated the rocket to 24,600 km (15,300 miles) per hour, or nearly orbital velocity. The third stage accelerated the spacecraft to a velocity of 39,400 km (24,500 miles) per hour, or over 10 km (6 miles) per second, sending the three Apollo crewmen toward the Moon. The Saturn V was used from 1968 to 1972 during the Apollo program and launched the Skylab space station in 1973.

The Saturn family of launch vehicles, which also included the Saturn IB, was the first American launch vehicle family developed specifically for space use. The less powerful Saturn IB was used to launch Apollo spacecraft on Earth-orbiting missions and during the U.S.-Soviet Apollo-Soyuz Test Project in 1975. After Apollo-Soyuz, the Saturn family was retired from service as the United States decided to use the space shuttle as the sole launch vehicle for future government payloads.

Early Soviet launch vehicles

A similar pattern was followed in the Soviet Union. Under the direction of the rocket pioneer Sergey Korolyov, the Soviet Union during the 1950s developed an ICBM that was capable of delivering a heavy nuclear warhead to American targets. That ICBM, called the R-7 or Semyorka (“Number 7”), was first successfully tested on Aug. 21, 1957. Because Soviet nuclear warheads were based on a heavy design, the R-7 had significantly greater weight-lifting capability than did initial U.S. ICBMs. When used as a space launch vehicle, this gave the Soviet Union a significant early advantage in the weight that could be placed in orbit or sent to the Moon or nearby planets. There have been a number of variants of the R-7 with an upper stage, each with a different name, usually matching that of the payload, and each optimized to carry out specific missions. An unmodified R-7 was used to launch the first Soviet satellite, Sputnik 1, on Oct. 4, 1957, and an R-7 variant, the Vostok, launched the first Soviet cosmonauts, among them Yury Gagarin, who on April 12, 1961, became the first human to orbit Earth. Other variants include the Voshkod, used to launch reconnaissance satellites, and the Molniya, used to launch communication satellites. A multipurpose variant, the Soyuz, was first used in 1966 and, with many subsequent variants and improvements, is still in service. This family of launch vehicles has carried out more space launches than the rest of the world’s launch vehicles combined.

In the early 1960s, Soviet designers began work on the N1, which was originally designed to undertake journeys that would require true heavy-lift capability (that is, the ability to lift more than 80,000 kg [176,000 pounds] to low Earth orbit). When the Soviet Union in 1964 decided to race the United States to a first lunar landing, that became the sole mission for the N1. The N1 was a five-stage vehicle. The N1 vehicle and the L3 lunar landing spacecraft mounted atop it stood 105 metres (344 feet) tall and weighed 2,735,000 kg (6,000,000 pounds) fully fueled. To provide the 44,000 kilonewtons (10,000,000 pounds) of thrust needed to lift the vehicle off of its launchpad, 30 small rocket engines, firing in unison, were required.
There were four N1 launch attempts between February 1969 and November 1972. All failed, and on the second test launch, on July 3, 1969, the vehicle exploded on the launchpad, destroying it and causing a two-year delay in the program. In 1974 the N1 program was canceled.

In 1976 approval was given for development of the Energia heavy-lift launch vehicle (named for the design bureau that developed it) and its primary mission, the space shuttle Buran. Energia could lift 100,000 kg (220,000 pounds) to low Earth orbit, slightly more than the Saturn V. Takeoff thrust was 29,000 kilonewtons (6,600,000 pounds). The Energia was 60 metres (197 feet) high. Its spacecraft payload was attached to the side of its core stage, not placed on top as with almost all other launch vehicles.Energia’s first launch was in 1987 and had Polyus, an experimental military space platform, as its payload. In 1988 its second and final launch carried Buran to orbit on its only mission, without a crew aboard. Energia was deemed too expensive for the Soviet Union to continue to operate, and no other uses for the vehicle emerged.

Sounding rockets

Another contributor to the development of space launch capability in the post-World War II period was work on sounding rockets, which are used to carry scientific instruments and other devices to heights above those that can be reached by high-altitude balloons but which do not have the power to accelerate their payloads to orbital velocities. Rather, sounding rockets provide several minutes of data-gathering time above the atmosphere for the instruments they carry; those instruments then fall back to Earth. Most countries that have developed space launch capability have first developed sounding rockets as, among other factors, a way of gaining experience with the technologies needed for launch vehicle development. Sounding rockets remain in use for some areas of scientific investigations that do not require the more expensive and technically demanding access to Earth orbit.

Launch vehicles of the world

There are many different expendable launch vehicles in use around the world today. As the two countries most active in space, the United States and Russia have developed a variety of launch vehicles, with each vehicle being best suited to a particular use. The ESA, China, India, and Japan have fewer types of launch vehicles; Israel and Iran have only one type. See the table of major launch vehicles of the world.

Launch vehicles
country	name	weight (kg)	height (m)	stages	payload (kg)	dates in service
China	CZ-1	79,400– 81,310	28.2–29.4	3	250–740	1969–2002
	CZ-2	190,000– 464,000	32–40.4	2 or 3	1,400–9,200	1974–
	CZ-3	204,000– 425,800	43.3–54.8	3	1,400–11,200	1984–
	CZ-4	249,000	41.9–45.8	3	1,100–4,680	1988–
European Space Agency	Ariane 1	207,200	50	4	1,850	1979–86
	Ariane 4	240,000– 470,000	58.4	3 or 4	2,175–9,100	1988–2003
	Ariane 5	777,000	59	2	10,500–16,000	2002–
	Vega	137,000	30	3	1,500	not launched
Japan	Lambda-4S	9,400	16.5	5	26	1966–74
	M-5	137,500	30.8	3 or 4	1,300–1,800	1997–
	N-I	131,330	34	4	360–1,200	1975–82
	N-II	132,690	35	3 or 4	730–2,000	1981–87
	H-I	142,260	42	3 or 4	1,100–3,200	1986–92
	H-II	260,000	49	3	3,930–10,060	1994–99
	H-IIA	285,000– 289,000	49	3	5,000–11,730	2001–
India	SLV-3	17,610	24	4	42	1979–83
	PSLV	294,000	44.4	5	800–3,700	1993–
	GSLV	402,000	49	3	2,500–5,000	2001–
Israel	Shavit	23,260–30,000	18	3	160–225	1988–
United States	Jupiter C	29,060	21.2	3 or 4	11	1958
	Redstone (Mercury)	28,400	20	1	1,290	1961
	Atlas (Mercury)	116,100	25	2	1,355	1960–63
	Titan II	150,530	32.8	2	3,600	1962–2003
	Titan IV	868,000– 943,050	44–63	4	5,760–21,680	1989–2005
	Delta II	231,870	38.3	2	900–5,000	1989–
	Delta IV	249,500– 733,400	63–70.7	2	4,300–23,000	2002–
	Atlas V	337,000– 541,200	58.3	2	1,500–20,050	2002–
	Pegasus	23,130	16.9	3	450	1990–
	Taurus	73,000	27.9	4	430–1,360	1989–
	Falcon	27,200	21.3	2	430–670	2006–
	Saturn V	3,038,500	102	3	47,000–118,000	1967–73
	Saturn I	509,660	55	3	2,200–9,000	1961–65
	Saturn IB	589,790	51	3	18,600	1966–75
	space shuttle	2,030,000	56	3	12,500–24,400	1981–
U.S.S.R./Russia	R-7	267,000– 269,000	30	2	84–1,327	1957–61
	Vostok	275,000– 282,300	31	3	3,800–4,700	1960–91
	Voshkod	298,400	31	2	5,900	1963–76
	Soyuz	298,000– 310,000	43–51	2	5,500–7,800	1966–
	Molniya	303,500– 305,640	40	4	900–1,800	1960–
	Kosmos	48,110– 109,000	26–32	2	300–1,500	1966–
	Proton	595,490– 712,800	46–59	2 to 4	1,880–21,000	1965–
	Start	49,200– 60,000	23–29	4 or 5	500–645	1995–
	Rokot	107,000	29	3	1,000–1,800	1990–
	Shtil	40,000	15	3	350–430	1998–
	N1	2,735,000	105	5	70,000	1969–72
	Energia	2,524,600	97	2	22,000–88,000	1987–88
Ukraine	Tsyklon	182,000–189,000	40	2 or 3	2,820–4,100	1967–
	Zenit	459,000– 471,000	57–60	2 or 3	5,000–13,740	1985–

United States

Most U.S. launch vehicles in use since the late 1950s have been based on the Thor IRBM (Thor became known as Thor-Delta and then simply Delta) or the Atlas and Titan ICBMs. The last launch of a vehicle based on the Titan ICBM was on Oct. 19, 2005. The two other families of launch vehicles, Delta and Atlas, have undergone a series of modifications and improvements since they were developed in the 1950s. The Delta II is used to launch small to medium payloads; its lifting power can be adjusted by varying the number of solid rocket motors attached as “strap-ons” to its first stage. The Delta IV and Atlas V vehicles, which both entered service in 2002, have little in common with the original ballistic missiles or early space launchers of the same names. The Delta IV uses the first new rocket engine developed in the United States since the 1970s space shuttle main engine; that engine, the RS-68, burns cryogenic propellant (liquefied gas kept at very low temperatures). The Delta IV has several configurations, depending on the weight and type of payload to be launched. Several configurations use solid rocket motors attached to the vehicle’s core first stage; the Delta IV model used to launch heavy spacecraft consists of three core stages strapped together. The Atlas V uses in its first stage a Russian-produced rocket engine, the RD-180, the design of which is based on the RD-170 developed for the Soviet Energia and Zenit launch vehicles. Like the Delta IV, the Atlas V offers several configurations. These two so-called evolved expendable launch vehicles are intended to be the workhorses for U.S. government launches for years to come.

The launch vehicles described above are used to carry medium-weight spacecraft into orbit or beyond. The Delta IV Heavy vehicle can launch payloads weighing from 6,275 kg (13,805 pounds) to geostationary orbit and can lift more than 23,000 kg (50,600 pounds) to low Earth orbit. Atlas V vehicles can launch payloads weighing up to 20,500 kg (45,100 pounds) to low Earth orbit and up to 3,750 kg (8,250 pounds) to geostationary orbit; a heavier lift version of the Atlas V is also possible. In addition, a number of smaller launch vehicles have been developed to launch lighter spacecraft at a lower overall cost (although not necessarily a lower cost per kilogram), though they have not found a wide market for their use. These include the solid-fueled Pegasus launch vehicle, which had its first flight in 1990 and is launched from under the fuselage of a carrier aircraft. First launched in 1994, a version of Pegasus known as Taurus lifts off from the ground, using a converted ICBM as a first stage and Pegasus as a second stage. A new small launch vehicle called Falcon was first tested in 2006. It was developed on the basis of private investment rather than being funded by government contracts and is intended to be the first in a new, lower-cost family of liquid-fueled expendable launch vehicles.

The U.S. space shuttle is unique in that it combines the functions of launch vehicle and spacecraft. The first partially reusable launch vehicle, it is one of the most complex machines ever developed, with more than 2.5 million parts. Its main elements are an orbiter, which houses a cockpit, a crew compartment, and a large payload bay and has three high-performance reusable rocket engines; a large external tank that contains the cryogenic liquid hydrogen fuel and the liquid oxygen oxidizer for those engines; and two large solid rocket motors, called boosters, attached to the external tank. These solid rocket motors provide 85 percent of the thrust needed for liftoff.

With the promise of partial reusability and routine operation, the shuttle was promoted when it was approved for development in 1972 as a means of providing regular access to space at a much lower cost than was possible with the use of expendable launch vehicles. The intent was to use the space shuttle as the only launch vehicle for all U.S. government spacecraft and to attract commercial spacecraft launch business in competition with other countries’ launchers. The promise of low cost and routine operations has not been realized; preparing the shuttle for each launch has proven to be an intensive and expensive process, and many of the shuttle orbiter’s elements have had to be replaced or refurbished more often than anticipated. Each shuttle launch has cost hundreds of millions of dollars.

The three space shuttle main engines and the two solid rocket motors are ignited at the time of liftoff; combined, they provide 31,000 kilonewtons (7,000,000 pounds) of thrust. The solid rocket motors burn for just over two minutes. They are then detached from the external tank and parachuted into the ocean, where their now empty casings are recovered for reuse. The three space shuttle main engines continue to fire for an additional six and a half minutes, at which point they shut down and the external tank is detached, falling into the atmosphere and disintegrating over the Indian Ocean. A final small firing of the space shuttle’s Orbital Maneuvering System engines, which use hypergolic propellant (fuel that ignites when it comes into contact with its oxidizer), places the orbiter into the desired orbit.

The height of the shuttle stack on the launchpad is 56.1 metres (184.2 feet), and the shuttle orbiter itself is 37.2 metres (122.2 feet) long. The shuttle’s fueled weight at liftoff is 2,000,000 kg (4,500,000 pounds). Unlike other launch vehicles that detach themselves from their spacecraft payload when orbital speed is achieved, the shuttle orbiter, which weighs approximately 104,000 kg (229,000 pounds) when empty, is carried into orbit along with whatever payload it is carrying, two to seven crew members and their supplies, and fuel for orbital maneuvering and reentry. It is thus the heaviest spacecraft ever launched. Maximum weight for cargo in the shuttle’s payload bay was planned to be 28,803 kg (63,367 pounds), but the vehicle has never carried such heavy payloads. The heaviest payload carried into space by the space shuttle was the Chandra X-ray Observatory and its upper stage, which weighed 22,753 kg (50,162 pounds) when the satellite was launched on the STS-93 mission on July 23, 1999.

A new privately developed family is Falcon, which consists of two launch vehicles, Falcon 1 and Falcon 9, built by the U.S. corporation SpaceX with funding from South African-born American entrepreneur Elon Musk. Falcon 1 was designed to place a 420-kg (925-pound) payload into orbit at a lower cost than that of other launch vehicles, in part by using a recoverable first stage. Falcon 9 was designed to compete with the Delta family of launchers in that it was planned to lift payloads of 4,640 kg (10,200 pounds) to geostationary orbit. One of the payloads it will launch to low Earth orbit is Dragon, a spacecraft designed to carry crew and cargo to the International Space Station. A heavy-lift version of the Falcon 9 was designed to carry payloads of 15,000 kg (33,000 pounds) to geostationary orbit.

The first test flight of the Falcon 1 took place on March 24, 2006, on Kwajalein Atoll in the Pacific Ocean; it failed just 25 seconds after liftoff. Corrosion between a nut and a fuel line had allowed the line to leak, which caused an engine fire. Later in 2006 SpaceX won a $278 million contract from NASA for three demonstration launches of the company’s Dragon spacecraft and Falcon 9 launcher in 2009–10. Two subsequent tests of Falcon 1 ended in failure, but on Sept. 28, 2008, Falcon 1 successfully entered Earth orbit.

Russia and Ukraine

Russia has the most diverse set of launch vehicles of any spacefaring country. Most were developed under the Soviet Union, which included both Russia and Ukraine, and both countries continue to produce launch vehicles. Like the United States, the Soviet Union used various ballistic missiles as the basis for several of its space launch vehicles. The approach taken was to use a version of the ballistic missile as a first stage and then add a variety of upper stages to modify the vehicle for different missions. The most famous of these ballistic missiles was the aforementioned R-7, developed in the 1950s under the direction of Sergey Korolyov. Other Soviet launchers based on ICBM first stages include the Kosmos and Tsyklon (which is built in Ukraine).

The Proton and Zenit launch vehicles were not derived from operational ICBMs, although the Proton was first conceived as a large ICBM and then was developed from the start for space use. Introduced in 1965, Proton was the first dedicated Soviet space launch vehicle and still remains in service as the largest Russian launch vehicle. It was never used as an ICBM. Its first stage, unique among Russian launch vehicles, uses hypergolic propellants. With various upper stages, the Proton has been used to launch spacecraft to geostationary orbit (an orbit with a 24-hour period that keeps a satellite above a specific point on Earth) and to destinations beyond Earth orbit and to launch elements of the Salyut and Mir space stations and of the International Space Station.

First launched in 1985, the Zenit launch vehicle was developed in Ukraine. The Zenit uses an RD-170 first-stage engine, considered to be one of the most efficient and reliable rocket engines ever made. It was used by the Soviet Union and is now used by Russia to launch both military payloads to low Earth orbit and communication satellites to geostationary orbit. It was also used as a strap-on booster for the two flights of the heavy-lift Energia launcher.Several other Russian launch vehicles are derived from decommissioned ballistic missiles. These include Start, Rokot, Dnepr, and the submarine-launched Shtil.

Europe

Several European countries, with France playing a leading role, decided in 1973 that it was essential for Europe to have its own access to space, independent of the United States and the Soviet Union. To develop a new launcher, these countries formed a new space organization, the European Space Agency (ESA), which in turn delegated lead responsibility of what was named the Ariane launch vehicle to the French space agency. The first Ariane was launched in December 1979. There were four generations of this initial booster design, Ariane 1–4. The Ariane family of launch vehicles does not draw directly on ballistic missile technology. The evolution of the family came through modifications or additions of the core stages and addition of strap-on solid rocket motors to increase lifting capacity. Ariane 4 proved a very reliable launcher before it was retired from service in 2003; while it launched differing spacecraft to a variety of orbits, its main mission was placing communications satellites into geostationary orbit.

Europe began developing the Ariane 5 launch vehicle in 1985. Its initial primary mission was to launch a crew-carrying space glider called Hermes; to do this, Ariane 5 had to be more powerful than its predecessors. Unlike Ariane 1–4, which used first-stage engines fueled by kerosene and liquid oxygen, Ariane 5 has a single engine fueled by liquid hydrogen, with two large strap-on solid rocket motors. The first launch of Ariane 5, in 1996, was a failure. For its first six years in operation, there was a mixed history of mainly successes but also several failures. Since 2003 Ariane 5 has not had any failures. Ariane 5 has been upgraded to increase its lifting capacity and reliability, and the intent of the ESA is to use Ariane 5 well into the future as its principal launch vehicle. A commercially oriented company, Arianespace, was created in 1980 to manage Ariane marketing, production, and launch operations.In order to complement Ariane 5, the ESA in 2000 decided to develop a small launch vehicle called Vega. The first launch for this vehicle eventually was set for late 2009. In 2003 the ESA also decided to build a launch facility for the Russian Soyuz launcher at the European launch site in French Guiana. This would give Europe a medium-lift launch vehicle capability and could also provide Europe with the capability to launch humans into space, since that is one of the roles that the Soyuz launcher plays for Russia.

China

Like the United States and the Soviet Union, China’s first launch vehicles were also based on ballistic missiles. The Chang Zheng 1 (CZ-1, or Long March 1) vehicle, which put China’s first satellite into orbit in 1970, was based on the Dong Feng 3 IRBM, and the Chang Zheng 2 family of launch vehicles, which has been used for roughly half of Chinese launches, was based on the Dong Feng 5 ICBM. There are several models of the CZ-2 vehicle, with different first stages and solid strap-ons; a CZ-2F vehicle was used to launch the first Chinese astronaut into space in October 2003. There are also CZ-3 and CZ-4 launchers. The CZ-3 is optimized for launches to geostationary orbits, and the CZ-4, first launched in 1988, uses hypergolic propellants rather than the conventional kerosene–liquid oxygen combination used in previous Chang Zheng variants. China has begun development of a second-generation family of launchers, identified as CZ-5, or Long March 5, that are not based on an ICBM design; these vehicles can launch payloads to geostationary orbit that are more than five times heavier than those carried by the CZ-4.

Japan

Until 2003 Japan had three separate space agencies, two of which developed their own line of launch vehicles. Japan did not have a previous ballistic missile program.
Japan’s Institute of Space and Astronautical Sciences based its launch vehicles on the use of solid propellants. Its Lambda L-4S vehicle sent the first Japanese satellite, Osumi, into orbit in 1970. Each subsequent launcher in the Mu series gave the institute greater lifting power for its scientific satellites, with the M-5 vehicle, first launched in 1997, capable of sending spacecraft beyond Earth orbit.During the 1970s the National Space Development Agency developed the N-I and N-II launchers based on licensed U.S. Delta technology. As an interim step to its own launch vehicle, in the 1980s the agency next developed the H-I, which had a Delta-derived first stage but a Japanese-designed cryogenically fueled upper stage. In 1984 Japan decided to develop an all-Japanese launch vehicle, the H-II, using cryogenic propellants in both stages and a very advanced first-stage rocket engine. The H-II was first launched in 1994; it proved a very expensive vehicle because of its total dependence on Japanese-manufactured components. Thus, Japan decided in 1996 to develop an H-IIA vehicle that would use some foreign components and simplified manufacturing techniques to reduce the vehicle’s costs. There are several models of the H-IIA, with both solid rocket motors and liquid-fueled strap-ons possible. The first H-IIA launch took place in August 2001.

India

India launched its first satellite in 1980 using the four-stage solid-fueled Satellite Launch Vehicle 3 (SLV-3), which was developed from the U.S. Scout launch vehicle first used in the 1960s. India did not have a prior ballistic missile program, but parts of the SLV-3 were later incorporated into India’s first IRBM, Agni. The four-stage Polar Satellite Launch Vehicle (PSLV) was then developed; it used a mixture of solid- and liquid-fueled stages. The first PSLV launch took place in 1993. During the 1990s India developed the liquid-fueled Geostationary Space Launch Vehicle (GSLV), which used cryogenic fuel in its upper stage. The GSLV was first launched in 2001. Both the PSLV and GSLV remain in service.

Israel

Israel’s Shavit launch vehicle is a small three-stage solid-fueled vehicle, first launched in 1988. It was based on the Jericho 2 ballistic missile. Because of its geographic location and hostile relations with surrounding countries, Israel must launch its vehicles to the west, over the Mediterranean Sea, in order to avoid flying over those countries. This necessity imposes a penalty of 30 percent on the Shavit’s lifting capability, since the Shavit is unable to take advantage of the velocity imparted by Earth’s rotation.

Iran

Iran’s launch vehicle is the Safīr (Farsi for “messenger”). It has two liquid-fueled stages and is based on the North Korean Taepodong-1 missile. It is 22 metres (72 feet) long and 1.4 metres (4.6 feet) across. Its estimated payload is less than 100 kg (220 pounds). On Feb. 2, 2009, a Safīr rocket launched Omīd, the first satellite put into orbit by Iran.

How a launch vehicle works

A launch vehicle is a good illustration of Newton’s third law of motion, “For every action, there is an equal and opposite reaction.” (For a detailed explanation, see rocket.) In the case of a launch vehicle, the “action” is the flow out the rear of the vehicle of exhaust gases produced by the combustion of the vehicle’s fuel in its rocket engine, and the “reaction” is the pressure, called thrust, applied to the internal structure of the launch vehicle that pushes it in the direction opposite to the exhaust flow. Unlike jet engines, which operate on the same action-reaction principle but obtain the oxygen needed for burning their fuel from the atmosphere, rockets carry with them their own oxidizing agent. In that way, they can operate in the vacuum beyond the atmosphere.

The primary goal of launch vehicle designers is to maximize the vehicle’s weight-lifting capability while at the same time providing an adequate level of reliability at an acceptable cost. Achieving a balance among these three factors is challenging. In order for the launch vehicle to lift off of Earth, its upward thrust must be greater than the combined weight of its spacecraft payload, the vehicle’s propellants, and its structure. This puts a premium on making the vehicle’s mechanical structure, fuel tanks, and rocket engines as light as possible but strong enough to withstand the forces and stresses associated with rapid acceleration through a resistant atmosphere. Most often, propellant makes up 80 percent or more of the total weight of a launch vehicle–spacecraft combination prior to launch.

Stages

A basic approach to launch vehicle design, first suggested by Konstantin Tsiolkovsky, is to divide the vehicle into “stages.” The first stage is the heaviest part of the vehicle and has the largest rocket engines, the largest fuel and oxidizer tanks, and the highest thrust; its task is to impart the initial thrust needed to overcome Earth’s gravity and thus to lift the total weight of the vehicle and its payload off of Earth. When the first-stage propellants are used up, that stage is detached from the remaining parts of the launch vehicle and falls back to Earth, either into the ocean or onto sparsely populated territory. With the weight of the first stage gone, a second stage, with its own rocket engines and propellants, continues to accelerate the vehicle. Most expendable launch vehicles in use today have only two or three stages, but in the past up to five stages, each lighter than its predecessor, were needed to attain orbital velocity. When an upper stage has completed its mission, it either falls back to Earth’s surface, enters orbit itself, or, most frequently, disintegrates and evaporates as it encounters atmospheric heating on its fall back toward Earth.

A particular launch vehicle can be configured in several different ways, depending on its mission and the weight of the spacecraft to be launched. This reconfiguration can be done by adding a varying number of strap-on boosters, usually solid rocket motors, to the vehicle’s first stage or by using different upper stages.
In principle, a space launcher could reach Earth orbit using only one stage, and in fact there have been several attempts to develop a reusable “single stage to orbit” vehicle. All attempts have failed, however; the propulsion and materials technologies needed to make a single-stage vehicle light and powerful enough to achieve orbital velocity while carrying a meaningful payload have not been developed.

Upper stages

All launch vehicles employ more than one stage to accelerate spacecraft to orbital velocity. Since the first orbital launch (Sputnik), in 1957, there have been many different upper stages. Most are used as part of only one type of launch vehicle. The evolution of these upper stages is driven by a desire to introduce more modern technology that will increase the overall lift capability of the launch vehicle, lower its costs, and increase its reliability or a combination of these factors. Small improvements in upper stages can produce significant gains in launch vehicle performance, since these stages operate only after the first stage has accelerated the vehicle to a high speed through the thickest parts of the atmosphere.

Several upper stages have been used with more than one family of launch vehicle. For example, the Agena upper stage was first developed in the United States as part of its initial reconnaissance satellite program. The Agena upper stage of a Thor-Agena launch vehicle propelled the Corona spacecraft into orbit, stayed attached to it, and provided power and pointing for the spacecraft’s operation. Agena used hypergolic propellant; it was also combined with the Atlas and Titan first stages on a number of subsequent missions. Later versions of Agena were able to restart their engine in orbit, carried other national security payloads, sent Ranger and Lunar Orbiter spacecraft to the Moon and Mariner spacecraft to Venus and Mars, and served as the target vehicle for rendezvous by the Gemini two-man spacecraft. Use of the Agena upper stage extended through the mid-1980s.

Another U.S. upper stage, used with the Atlas and Titan launch vehicles, is Centaur. This was the first U.S. rocket stage to employ cryogenic propellant. The first use of the Atlas-Centaur launch vehicle was to send Surveyor spacecraft to the Moon in 1966 and 1967; it flew many subsequent missions atop an Atlas first stage. When combined with powerful versions of the Titan launch vehicle, Centaur also has been used to send various spacecraft to Mars and the outer planets and to launch various heavy national security payloads.
Various upper stages using solid propellants were used to carry payloads from the space shuttle’s low Earth orbit to higher orbits. There were plans to carry the liquid-fueled Centaur on the shuttle to launch planetary spacecraft, but those plans were canceled after the 1986 Challenger accident because of safety concerns. Solid-propellant upper stages have also been used with the Delta and Titan launch vehicles.

Soviet and Russian launch vehicles have used a variety of upper stages; most have used conventional kerosene as fuel. More recently two upper stages, the Block DM using cryogenic propellant and the more popular Briz M using hypergolic propellant, have been developed for the Proton launcher. There has been a constant evolution of upper stages used with the Soyuz launcher; in 1999 upper stages with restartable rocket engines entered service.The ESA used a cryogenic upper stage for its Ariane 1–4 launchers. Initial versions of the Ariane 5 used hypergolic propellant in its upper stage, though a new cryogenic upper stage was introduced in 2006. Japan and India use cryogenic propellants in the upper stages of their most powerful launch vehicles, the H-IIA and the GSLV, respectively.

Fuel

The fuel used to power rockets can be divided into two broad categories: liquid and solid. Liquid fuels can range from a widely available substance such as ordinary kerosene, which can be used at ground temperature, to liquid hydrogen, which must be maintained at the extremely low temperature of 20 °K (−253 °C, or −423 °F). Liquid hydrogen is called a cryogenic fuel. Another type of liquid fuel, called hypergolic, ignites spontaneously on contact with an oxidizer; such fuels are usually some form of hydrazine. Hypergolic fuels are extremely toxic and thus difficult to handle. However, because of their reliable ignition and their ability to be restarted, they are used in the first or second stages of some rockets and in other applications such as orbital maneuvering motors. During the Apollo program they were used to lift the crew compartment of the lunar module off of the Moon’s surface.

In order to burn, liquid rocket fuel must be mixed in the combustion chamber of a rocket engine with an oxygen-rich substance, called an oxidizer. The oxidizer usually used with both kerosene and liquid hydrogen is liquid oxygen. Oxygen must be kept at a temperature less than −183 °C (−298 °F) in order to remain in a liquid state. The oxidizer used with hypergolic fuel is usually nitrogen tetroxide or nitric acid. Like hypergolic fuel, the oxidizers are extremely toxic substances and so are difficult to handle.

Liquid-fuel rocket engines are complex machines. In order to reach maximum efficiency, both fuel and oxidizer must be pumped into the engine’s combustion chamber at high rates, under high pressure, and in suitable mixtures. The fuel pumps are driven by a turbine powered by the burning of a small proportion of the fuel. There are various approaches to powering the turbomachinery of a rocket engine, but all require high-performance mechanisms and are one of the major potential sources of launch vehicle failure. After combustion, the resulting exhaust gas exits through a nozzle with a shape that accelerates it to a high velocity.

Solid-propellant rocket motors are simple in design, in many ways resembling large fireworks. They consist of a casing filled with a rubbery mixture of solid compounds (both fuel and oxidizer) that burn at a rapid rate after ignition. The fuel is usually some organic material or powdered aluminum; the oxidizer is most often ammonium perchlorate. These are mixed together and are cured with a binder to form the rocket propellant. Solid rocket motors are most often used as strap-ons to the liquid-fueled first stage of a launch vehicle to provide additional thrust during liftoff and the first few minutes of flight. (However, the United States has begun development of a new launch vehicle named Ares-1 that will use a large solid rocket motor as its first stage.) Unlike some rocket engines using liquid fuels, which can be turned off after ignition, solid rocket motors once ignited burn their fuel until it is exhausted. The exhaust from the burning of the fuel emerges through a nozzle at the bottom of the rocket casing, and that nozzle shapes and accelerates the exhaust to provide the reactive forward thrust.

Payload protection

The spacecraft that a launch vehicle carries into space is almost always attached to the top of the vehicle. During the transit of the atmosphere, the payload is protected by some sort of fairing, often made of lightweight composite material. Once the launch vehicle is beyond the densest part of the atmosphere, this fairing is shed. After the spacecraft reaches initial orbital velocity, it may be detached from the launch vehicle’s final upper stage to begin its mission. Alternatively, if the spacecraft is intended to be placed in other than a low Earth orbit, the upper-stage rocket engine may be shut down for a period of time as the spacecraft payload coasts in orbit. Then the engine is restarted to impart the additional velocity needed to move the payload to a higher Earth orbit or to inject it into a trajectory that will carry it deeper into space.

Navigation, guidance, and control

In order for a launch vehicle to place a spacecraft in the intended orbit, it must have navigation, guidance, and control capabilities. Navigation is needed to determine the vehicle’s position, velocity, and orientation at any point in its trajectory. As these variables are measured, the vehicle’s guidance system determines what course corrections are needed to steer the vehicle to its desired target. Control systems are used to implement the guidance commands through movements of the vehicle’s rocket engines or changes in the direction of the vehicle’s thrust. Navigation, guidance, and control for most launch vehicles are achieved by a combination of complex software, computers, and other hardware devices.

Reliability

A launch vehicle thus comprises one or more rocket engines; fuel for those engines carried in fuel tanks; guidance, navigation, and control systems; a payload; and a structure housing all of these elements, to which extra engines may be attached for added lift. There are also various attachments between the launch vehicle and its launchpad and associated structures. An expendable launch vehicle has only one opportunity to perform its mission successfully, so all of its elements must be designed and manufactured precisely and for very high operational reliability. Also, as noted above, launch vehicles are designed to be as light as possible, in order to maximize their payload lifting capability. As a result, every part in a launch vehicle operates close to its breaking point during a launch, as the vehicle undergoes the stresses associated with accelerating past the speed of sound and transiting the atmosphere and as its rocket engines operate under extremes of pressure, temperature, shock, and vibration.

The end result is that launching a spacecraft into outer space remains an extremely difficult undertaking and that launch failures are a fact of life for those seeking access to space. Many space launches, particularly those carrying commercial spacecraft, are insured against failure, since they often represent an investment of more than a hundred million dollars.Launch vehicles that carry people into space are “human rated.” This means that they use components of the highest possible reliability, have redundancy in critical systems, undergo more testing prior to launch than does a launch vehicle carrying an automated spacecraft, and contain systems that warn of impending problems so that a crew might be able to escape an accident. There has been only one failure of a launch vehicle at liftoff that resulted in crew fatalities; this was the explosion of the Challenger, on Jan. 28, 1986, which killed all seven astronauts aboard.

Launching into outer space

Although they differ in many details for various vehicles and at different launch bases, the steps needed to prepare a launch vehicle and its spacecraft payload for launch are, in general, similar.
Most often, the different stages and other elements of a launch vehicle are manufactured separately and transported to the launch base for assembly. That assembly can take place either in a facility away from the launchpad or on the launchpad itself. The advantage of a separate assembly building is that many of the steps needed to prepare the vehicle for launch, including assembly and then checkout of the integrated vehicle, can be performed in a closed environment. This also means that the launchpad is available for other uses during the assembly and checkout period.

Launch vehicle assembly and checkout are carried out either vertically or horizontally. Vertical assembly requires a facility tall enough to shelter the whole vehicle and spacecraft. The various components are “stacked,” starting with the first stage and often ending with the attachment of the spacecraft to the launch vehicle. (Sometimes the spacecraft and the launch vehicle are mated only at the launchpad.) Strap-on solid rocket engines, if they are to be used, are attached to the core first stage. Horizontal assembly is carried out on an end-to-end basis and does not require a high building with vehicle access at multiple levels. After assembly, as much testing as possible is conducted on the integrated vehicle to check its readiness for launch before it is transported to the launchpad.
Once it reaches the launchpad, the vehicle is attached to a launch tower, which contains the various umbilical connections and access points needed to complete the checkout process and to monitor the vehicle’s final readiness for launch. If the vehicle has been assembled horizontally, it must be raised into a vertical position as it reaches the launchpad. Often the launchpad includes some sort of shelter to protect the launch vehicle and spacecraft from the elements until close to the time for launch and to allow technicians to continue the checkout process. The launch vehicle is held on the pad by some form of attachment device.
If the launch vehicle is assembled on the launchpad, all of the above steps are conducted there. Assembly and checkout can take several months, and during this period the launchpad cannot be used for other purposes.
As the time for launch approaches, a countdown is initiated. Countdown time can range from hours to days. During the countdown, various final steps are carried out at specific times to make the vehicle ready for launch. If the vehicle uses liquid propellants, they are loaded in the hours before launch, after being stored in tanks near the launchpad. Cryogenic propellants are difficult to maintain in a liquid state; they tend to become gaseous and “boil off” of the vehicle. Therefore, they are loaded into the vehicle’s fuel tanks as close to the time of launch as possible and must be constantly topped off to ensure that the fuel and oxidizer tanks are full. Some hours before a scheduled launch, the structure that has been protecting the vehicle is rotated away from it and the launch tower.

Launch bases must have access to up-to-date weather information. There are usually preset rules with respect to what weather conditions are acceptable for a space launch, including winds at the launch site and aloft, visibility (for monitoring the vehicle during the first few minutes of flight), and temperature. These conditions vary among launch sites and for different launch vehicles. For example, manned spacecraft are launched from Russian sites during much more severe weather conditions than those deemed acceptable for the launch of a U.S. space shuttle from its Florida launch base.

In the last few minutes of the countdown, a final check is made to ensure that the vehicle and spacecraft are ready for launch and that all other conditions are in a “go” status. All umbilical connections between the launch tower and the vehicle are detached. Liquid-fueled rocket engines are usually allowed to fire for a few seconds before the vehicle is committed to launch; a rapid computer check is performed, and the engines can be shut down if there are any indications of a problem. Once solid rocket engines are ignited, the vehicle is committed to launch. When the moment of launch arrives, the devices holding the vehicle to the launchpad are explosively detached, and the vehicle begins its liftoff.Launchpads have trenches for channeling exhaust flames away from the vehicle, and frequently large volumes of water are injected into the flames. This is done to minimize damage to vehicle and launchpad from the heat and sonic vibrations associated with liftoff.
Associated with each launch base is a launch range with facilities for tracking and closely monitoring the launch vehicle through all stages of its mission. A range safety officer makes sure that no aspects of the vehicle’s performance could pose a threat to public safety or destroy property. If such a condition arose, the officer would be able to command the launch vehicle to destroy itself.

Launch bases

Most launch vehicles take off from sites on land, although a few are air- or sea-launched. To function as a launch base, a particular location has to have facilities for assembling the launch vehicle, handling its fuel, preparing a spacecraft for launch, mating the spacecraft and launch vehicle, and checking them out for launch readiness. In addition, it must have launchpads and the capability to monitor the launch after liftoff and ensure safety in the launch range. This usually requires a significant amount of land located away from heavily populated areas but with good air, sea, rail, or land access for transport of various components. Other desirable characteristics include a location that allows the early stages of launch, when first stages are separated and most launch accidents happen, to take place over water or sparsely populated land areas.

Another desirable characteristic is a location as near as possible to the Equator. Many launches take place in an eastward direction to take advantage of the velocity imparted by the rotation of Earth in that direction. This velocity is greatest at the Equator and decreases with increased latitude. For example, the additional velocity provided by Earth’s rotation is 463 metres per second (1,037 miles per hour) at the European launch base in French Guiana, which is located very close to the Equator at latitude 5.2° N. It is 410 metres per second (918 miles per hour) at the U.S. launch site at Cape Canaveral, Fla., located at latitude 28° N, and it is only 328 metres per second (735 miles per hour) at the Russian Baikonur Cosmodrome in Kazakhstan, which is located at latitude 46° N. Earth’s naturally imparted velocity, though small in comparison with the velocity provided by the rocket engines, lessens the demands on the launch vehicle.

Many satellites are intended to be placed in a geostationary orbit. Geostationary orbit is located 35,785 km (22,236 miles) above the Equator. Spacecraft launched from a base near the Equator require less maneuvering, and therefore use less fuel, to reach this orbit than do spacecraft launched from higher latitudes. Fuel saving translates into either a lighter spacecraft or additional fuel that can be used to extend the operating life of the satellite.The benefits of an equatorial location do not apply to launches into a polar or near-polar orbit, since there is no added velocity from Earth’s rotation for launches in a northward or southward direction. Launch bases used for polar orbits do need to have a clear path over water or empty land for the early stages of a launch.

Space launches have taken place at more than 25 different land-based locations around the globe, though not all of these bases are in operation at any one time. Most are government-operated facilities. There have been a number of proposals to build commercially operated launch bases at various locations around the globe, and several such bases in the United States have begun operation.Not all space launches lift off from land. In particular, the U.S.-Russian-Norwegian-Ukrainian commercial launch firm Sea Launch uses the innovative approach of a mobile launch platform, based on a converted offshore oil-drilling rig, which is towed by a command ship from its home base in Long Beach, Calif., to a near-equatorial location in the Pacific Ocean. Once the platform reaches the desired location, the firm’s Ukrainian Zenit launch vehicle is transferred along with its communications satellite payload from the command ship to the launch platform, checked out, and launched to geostationary orbit. This approach gives Sea Launch the advantages associated with an equatorial launch site without the need for a permanent installation in an equatorial country.

Other spacecraft have been launched with the Shtil launch vehicle from a converted Russian submarine and with Pegasus from under the wings of an airplane owned by the U.S. firm Orbital Sciences Corporation. Only relatively small launch vehicles carrying light spacecraft can be launched in this manner. The advantages of an air-based launch are the flexibility in the launch location and the use of a carrier aircraft to lift the launch vehicle the first 12,000 metres (40,000 feet) above Earth, thus reducing the propulsion requirements needed to reach orbit.

Commercial launch industry

Until the early 1980s, all launches into space were carried out under government auspices, even those launches intended to place commercially owned and operated communications satellites into geostationary orbit. With the growth of the commercial communications satellite industry around the world, there was a market opportunity to provide launch services on a commercial basis, since those wanting to launch communications satellites were willing to pay many millions of dollars to do so.First to take advantage of this opportunity was Europe, which formed the Arianespace Corporation to market Ariane launches to commercial customers. Arianespace was a mixed public-private corporation with close ties to the French government; the French space agency was a major shareholder.

Once the space shuttle had been declared operational in 1982 after its first four flights, the United States pursued a contradictory policy. The U.S. government offered to turn over ownership and operation of existing expendable launch vehicles such as Delta, Atlas, and Titan to the private sector for commercial use; at the same time, it pursued an aggressive policy of marketing the space shuttle as a commercial launcher. The private sector could not compete with this government activity. After the 1986 Challenger accident, the space shuttle was prohibited from launching commercial spacecraft. This provided a renewed opportunity for the manufacturers of the Delta, Atlas, and Titan vehicles to seek commercial customers in competition with Arianespace, and they took advantage of that opportunity. After a few years, the Titan was removed from this competition because it had failed to attract many commercial users. Evolved versions of Atlas and Delta continue in commercial service.

In 1983 the Soviet Union began to seek commercial customers through a marketing organization called Glavkosmos. China followed in 1985; its Chang Zheng family of launchers was marketed by the China Great Wall Industry Corporation. Soviet and Chinese entry into the commercial launch market was slowed by quotas imposed by the United States, which argued that Russian and Chinese launchers had an unfair price advantage because of the nonmarket nature of their countries’ economies. Japan also planned to market its H-II launch vehicle on a commercial basis but was hindered by the H-II being much more expensive than competing launch vehicles. However, the H-IIA was more successful and less expensive, and Japan has marketed it as a commercial launcher. India had its first commercial launch in April 2007.

In addition to commercial launch services marketed by entities in a particular country, several transnational launch service providers have emerged. International Launch Services is jointly owned by the British Virgin Islands firm Space Transport, the Russian Khrunichev State Research and Production Space Centre, and the Russian firm RSC Energia and markets both the Atlas and Proton launch vehicles. Starsem is a joint venture of European and Russian companies and the Russian Federal Space Agency to market the Soyuz launcher. Sea Launch is an alliance of U.S., Ukrainian, and Russian aerospace companies and a Norwegian offshore oil drilling and shipbuilding company to market the Zenit launch vehicle.

In the mid-1990s the rapid growth in the geostationary communications satellite industry and plans to launch several multisatellite constellations in low Earth orbit created a sense of optimism that the commercial space launch market would grow rapidly. However, none of the satellite constellations was an economic success, and the demand for communications via satellite leveled off by the turn of the century. This led to an oversupply of launch services. In 1997 there were 23 commercial launches worldwide, but by 2003 the number of launches had declined to 12. That same year the commercial space launch industry had the capacity to carry out almost 60 launches. Though the launch industry rebounded somewhat afterward (in 2006 there were 21 commercial launches), demand still lags behind supply.

The quest for reusability

An important limiting factor in the use of space is the high cost of launching spacecraft. In particular, using an expendable launch vehicle involves the single use of a vehicle that costs approximately as much as a jet transport. Since the start of spaceflight, there has been a hope that it might be possible to avoid such high costs by making space launch vehicles reusable for multiple launches. The original plans for the space shuttle called for it to be a two-stage, fully reusable vehicle. Unfortunately, both technological barriers and financial constraints made it impossible to pursue those plans, and the space shuttle is in fact only partially reusable. Indeed, a space shuttle launch is even more expensive than the launch of an expendable vehicle. The United States has made several subsequent attempts to develop a fully reusable single-stage-to-orbit launch vehicle (that is, one that can fly directly to orbit without shedding any of its parts). Among these attempts were the National Aerospace Plane project (1986–93) and the X-33 project (1995–2001). Both programs were canceled before any flights were attempted. In both cases, neither the materials needed to construct the vehicle nor a rocket engine to propel it proved to be at a stage of adequate technological maturity.
In the United States a number of entrepreneurial firms have also investigated various approaches to lower the cost of space access, with an emphasis on reusability. These approaches have included using a variation of the rocket engine used on the Soviet N1 lunar launch vehicle and parachuting spent rocket stages and their engines back to Earth for reuse and using technologically advanced rocket engines and materials to construct a totally new vehicle design. None of these efforts have been technically successful, and all have struggled to attract the investments needed for them to proceed. In 2002 the American firm Space Exploration Technologies began efforts to develop a low-cost expendable launch vehicle, Falcon, using primarily proven technology.

Beyond rockets

It is difficult to find alternatives to chemically fueled rocket propulsion for lifting mass out of Earth’s gravity well. One concept, originally advanced by Konstantin Tsiolkovsky in 1895, is a “space elevator” an extremely strong cable extending from Earth’s surface to the height of geostationary orbit or beyond. The competing forces of gravity at the lower end and outward centripetal acceleration at the farther end would keep the cable under tension and stationary over a single position on Earth. It would then be possible to attach a payload to this cable on Earth and lift it by mechanical means to an orbital height. When released at that point, it would have the velocity to remain in orbit or to use an additional in-space propulsion system to send it to deep-space destinations. This concept, far-fetched as it may seem, has been the subject of serious preliminary research.

Another Earth-to-space transportation concept is called a mass driver. A mass driver is an electromagnetic accelerator, probably miles in length, that would use pulsed magnetic fields to accelerate payloads to orbital or near-orbital velocity. The advantage of a mass driver is that the accelerating device and its source of energy remain on Earth for reuse, rather than accompanying a spacecraft into space. The mass driver concept was given the most attention during the 1970s and ’80s by American physicist Gerard O’Neill and his colleagues as part of his proposal to build large orbital space colonies. Mass drivers have also been considered as a means of launching material from the lunar surface.