History of Human Space Exploration
Within each human cell lies the blueprint for the human body and mind. Genes control how we look, sound and even think. Hence the key to the future of humanity lies within each cell. DRD4-7R is not just another gene among thousands. It regulates dopamine and is associated with risk-taking behaviour in modern humans. When this gene was present in more than 50% of our ancestors, they tended to be more explorative. Hence this gene is rightly called the 'Explorer' gene. Human migration across continents from Africa can be associated with the presence of this gene in the ancestral population. Humans are hence unique in this curiosity to explore the Earth. The exploration of space can be seen as an extension of this effect.
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Robert Goddard with a liquid oxygen-gasoline cylinder credits: Esther C. Goddard, Public domain, via Wikimedia Commons |
Space has always enticed humans. We began by naming and identifying the stars and planets spread across the night sky. Though rockets were first developed and used in weaponry, William Leitch first proposed the concept of using rockets to enable human spaceflight only in 1861. It took another 60 years for Professor Robert Goddard of Clark University to publish proposed improvements to rocket technology for propelling humans to space in A Method of Reaching Extreme Altitudes. Then in 1926, Goddard attached a supersonic nozzle to a high-pressure combustion chamber. These nozzles turn the hot gas from the combustion chamber into a cooler, hypersonic, highly directed jet of gas, more than doubling the thrust and raising the engine efficiency from 2% to 64%. His use of liquid propellants instead of gunpowder considerably lowered the weight and increased the effectiveness of rockets. Their use in World War II artillery developed the technology further and opened up the possibility of human spaceflight after 1945. Germany was also making improvements in rocket technology parallelly. They produced V-2 rockets and guided missiles and mainly relied on liquid propellants. Wernher von Braun, who was spearheading the German space program, was captured in 1945 and brought to the US as a part of Operation Paperclip. He gave a further boost to the American space program. During this time, the Russian space program was under the leadership of chief designer Sergei Korolev. But living animals were still not sent to space.
Animals in Space
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| Laika the dog credits: The NewYorker |
Cold War was upon the world, and the competition for space supremacy was on. Significant improvements were made in rockets, which led to the first animals being sent into space. Fruit flies were sent aboard a U.S.-launched V-2 rocket from White Sands Missile Range, New Mexico, on February 20 1947. The first mammal sent to space was a rhesus monkey named Albert II, launched on June 14 1949, in a U.S.-launched V-2. He was also the first monkey and first primate in space. While these developments were from the US side, the Soviets did not back down. On July 22 1951, the Soviet Union launched the R-1 IIIA-1 flight, carrying the dogs Tsygan and Dezik into space. On November 3 1957, the second-ever orbiting spacecraft took the first animal into orbit, the dog Laika, aboard Sputnik 2 spacecraft. Several other animals were also put in orbit after Laika to study the impact of space on the animals and thereby understand the effect space would have on humans. All this led to the first human-crewed space flight.
Humans in Space
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| Graph showing the yearly budget of NASA Credits: Benjamin Heasly |
The competition between the US and the Soviet Union was at its peak. For every space mission sent by the US, the Soviets sent another one. As part of the Vostok program, Yuri Gagarin, a Soviet cosmonaut, became the first human in space on April 12 1961. Less than a month later, on May 5, 1961, Alan Shepard piloted the Mercury-Redstone 3 mission and became the second person and the first American to travel into space. The graph above shows NASA's yearly budget from 1955 to 2015. We can clearly see that NASA's funding was at its peak from 1960 to 1970. This was a significant factor that led to NASA putting the first men on the Moon.
From Space to the Moon
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| The crew from Apollo 11 credits: NASA |
But the race was not over yet. The next target was the Moon. In 1961, the US set the goal of landing a man on the Moon and returning him safely to Earth by the 1970s. The US began the Apollo program to launch three-man capsules atop the Saturn family of launch vehicles to accomplish moon landings. They also started Project Gemini intending to be a support to Apollo by developing American orbital spaceflight techniques to be used during the Moon mission.
Meanwhile, the USSR proceeded to stretch the limits of their Vostok capsule by adapting it to the Voskhod capsule to compete with Gemini. They launched two orbital flights and achieved the first spacewalk, performed by Alexei Leonov on March 8 1965. The US succeeded in developing the Saturn V rocket necessary to send the Apollo spacecraft to the Moon. They sent Frank Borman, James Lovell, and William Anders into 10 orbits around the Moon on Apollo 8 in December 1968. Neil Armstrong and Buzz Aldrin landed on the Moon on July 21 and returned safely on July 24, along with Command Module pilot Michael Collins in Apollo 11. This was a significant breakthrough. Humans went from space to the Moon in a matter of years.
By 1972, six Apollo missions landed 12 men to walk on the Moon, half of which drove electric-powered vehicles on the surface. Meanwhile, the USSR pursued crewed lunar orbiting and landing programs. They developed the three-person Soyuz spacecraft for use in the lunar programs but failed to create the rocket necessary for a human landing and discontinued their lunar programs in 1974. Upon losing the Moon race, they concentrated on developing space stations.
Beyond Apollo and Today
After the Apollo missions, the major developments in space technology were focused on space shuttles. The idea was to reuse the transportation system used to take the astronauts to space. It was expected that this, along with some other changes in the fuels, would propel humans to Mars by 2000. The Space Shuttle started flying in 1981 with a fleet of four: Columbia, Challenger, Discovery and Atlantis.
The end of the Cold War in 1991 opened the door to genuine cooperation between the US and Russia. The Soviet Soyuz and Mir programs were taken over by the Russian Federal Space Agency. The Shuttle-Mir Program included American Space Shuttles visiting the Mir space station, Russian cosmonauts flying on the Shuttle, and an American astronaut flying aboard a Soyuz spacecraft for long-duration expeditions aboard Mir.
In 1993, the US secured Russia's cooperation in converting the planned Space Station Freedom into the International Space Station (ISS). Construction of the station began in 1998. The station orbits at an altitude of 409 kilometres and an orbital inclination of 51.65°. Several of the Space Shuttle's orbital flights were to help assemble, supply, and crew the ISS. Russia has built half of the ISS and has continued its cooperation with the US.
China became the third nation in the world after USSR and USA sent humans to space by putting Yang Liwei in orbit for 21 hours on October 15 2003. Zhai Zhigang and Liu Boming completed China's first extravehicular activity on September 25 2008. On November 3 2011, China conducted its first automatic rendezvous and docking. On June 16 2012, Liu became the first Chinese woman in space.
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| credits: SpaceX |
Humanity has also entered the age of private commercial spaceflight. With increasing economic impetus from private organizations and people, the fear of danger associated with space travel has been alleviated. Organizations like SpaceX, Virgin Galactic and Blue Origin plan to fly commercial passengers in the emerging space tourism market. SpaceX has already launched humans to orbit.
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