My Science School

          After the 1970s, the Moon was largely left unexplored till the 1990s. Moon exploration began again in the 1990s with the US sending three probes that took new pictures and explored the lunar surface with more scientifically advanced instruments.

          The orbiter Galileo passed by the Moon twice in 1990 and 1992, while taking a roundabout path to Jupiter. In 1994, Clementine orbited the Moon. Four years later, Lunar Prospector was placed in the orbit around the Moon. Both Clementine and Lunar Prospector returned with evidences of the presence of water on the lunar surface, something that scientists had long believed existed. However, when the Lunar Prospector crashed onto the surface of the Moon in 1999, it failed to detect the presence of water in the debris.

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          Apollo 17 was the last spacecraft of NASA’s Apollo mission. It was launched in December, 1972. Commanded by Eugene Cernan, the crew consisted of Ronald Evans and Harrison Schmitt.

          Apollo 17 also carried out biological experiments on five mice- Fe, Fi, Fo, Fum and Phooey. These five mice travelled from the Earth along with the astronauts and circled the Moon 75 times! Radiation monitors were implanted under their scalp to see whether they would suffer any damage from cosmic rays. One of the mice died while the other four were either killed or dissected for further studies upon their return.

          Cernan and Schmitt landed on the Moon, completed three moonwalks, and collected lunar samples that would give evidences of volcanic activity in lunar highlands.

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          Apollo 13 was the third mission aimed at landing on the Moon and was launched on April 11, 1970. Unfortunately, one of the oxygen tanks in the service module exploded. This happened because of the explosion of the fuel cell tank that resulted in the loss of power and oxygen. An insulation wire inside the tank was damaged which led to the explosion. Therefore, the crew had to cancel the plan to land on the Moon. However, they orbited around the Moon and returned safe on April 17, 1970.

          Apollo 13 was commanded by Jim Lovell and the crew included Jack Swigert and Fred Haise.

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          We know about the humans who landed on the Moon for the first time. But who was the first one to drive a lunar rover? David Scott and James Irwin, the crew of Apollo 15 are credited with this remarkable achievement.

          Apollo 15 was the fourth spacecraft to land on the Moon. It stayed on the Moon for a longer time than the other spacecraft and had a sharper scientific objective. David Scott and James Irwin landed near Hadley Rill. They travelled further from the lunar module with the help of a lunar rover and surveyed the local area. They spent eighteen and a half hours on the surface of the Moon, collecting almost 77 kilograms of surface material. While David and James explored the lunar surface, Alfred Worden, the Command Module Pilot orbited the Moon to collect data.

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          Neil Armstrong and Buzz Aldrin had to take the help of a lunar module, a special landing vehicle to descend to the Moon. This was because the mother ship, the main spacecraft travelled too fast. Once the mother ship entered the lunar orbit, the astronauts got into the lunar module and separated from the main craft. Their lunar module was named Eagle.

          Eagle had spidery legs; they cushioned the landing and could be folded while in flight. They also had footpads that prevented them from sinking into the lunar soil. The body of the Eagle was covered in golden foil. This was done in order to protect it from the Sun’s heat.

         Eagle comprised of two parts; the top, known as the ascent stage carried the astronauts while the descent stage at the bottom carried the scientific equipment. The ascent stage also had navigation control, communications, life support, environmental control, electric power and propulsion system. The additional electric power, water and oxygen for the ascent stage was stored in the descent stage.

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           Even after half a century, Apollo 11 is remembered with great pride not only by the Americans but the whole of humanity. Apollo 11 made it possible for America, to fulfil a dream that it had cherished for years, and a mission that no one had attempted before - to leave human footprints on the Moon.

          It was July 20, 1969. Apollo 11 travelled 3,84,400 kilometres in space carrying three astronauts and landed on the Moon. Neil Armstrong was the first to step on the Moon. He was followed by Buzz Aldrin while Michael Collins controlled the system. “That’s one small step for a man, one giant leap for mankind.” This was what Neil Armstrong said immediately after setting foot on the Moon.

          With Apollo 11, America succeeded in taking man to the Moon and back safely, thus accomplishing the national goal set by President John F Kennedy. It also conducted the scientific exploration of the lunar surface and deployed a camera to transmit signals to the Earth.

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          Apollo was a three-part spacecraft that consisted of a command module, service module and a lunar module. The command module or the CM contained the crew’s quarters and the flight control section.

          It contained all the necessary commands and instruments to operate the spacecraft and to return to the Earth. The CM was in fact the only part that returned to the Earth and the astronauts were provided with reclining couches, specially fitted for them.

          The Apollo spacecraft’s service module or the SM carried the rocket engine that could be started or stopped whenever needed. The SM held the spacecraft’s electrical power system. It also contained the fuel. The third part known as the lunar module, or the LM, took the crew to the surface of the Moon. This module also provided the astronauts with the necessary support on the Moon and returned them to the command module.

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          Launched in October 1968, Apollo 7 is credited with the first manned flight; it is the first mission in the Apollo programme to carry a crew into space.

          In fact, Apollo 1 was intended to take the first astronauts into space. Unfortunately, its cabin caught fire in one of the test flights, killing the crew. This happened in January 1967. NASA then banned all manned flights until the reason for the fire was found out. Safety measures were improved after the investigations and Apollo 7 was launched after that.

          Commanded by Walter M Schirra, Apollo 7 was a complete success which gave NASA enough confidence to launch Apollo 8.

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          The Apollo programme would not have been the same if not for Saturn V. It is the most powerful rocket ever built; Saturn V is a three-stage rocket that uses high performance liquid hydrogen fuel for propulsion. This launch vehicle was specially developed to support the Apollo programme.

          Saturn V is taller than a 36 storeyed building and holds a cluster of five engines in its first two stages. It was flight tested twice without a crew. In December 1968, the first manned Saturn V sent the Apollo 8 astronauts into the orbit around the Moon. A year later, Saturn V launched the first manned landing on the Moon. This legendary rocket was launched 13 times from the Kennedy Space Centre. It was also used to launch Skylab, America’s first space station.

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          We now know that reaching the Moon is not impossible. But it is not as easy as you may think. For a lunar probe to reach the Moon, it has to first escape Earth’s gravity. For this, the probe has to move at a great speed that can be achieved only by rockets.

         If the lunar probe is to land on the Moon safely, it has to slow down very much. Or else the probe will end up crash landing. In addition to that, returning to the Earth safely is another challenge. Rockets have to be used again to leave the Moon and the original spacecraft has to return to the atmosphere in such a way that it does not catch fire.

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          The Moon did not offer any favourable conditions for Man to stay there even for a minute. It did not have air to breathe or water to drink. Neither did it have an atmosphere to block the harmful radiations. Moreover, the Moon had extreme climatic conditions. Despite these adverse conditions, NASA aimed to send Man to the Moon.

          This project was named Apollo. Project Apollo was designed to land humans on the Moon and bring them back safely. They first had to aim for a precise point in space, or else the Moon would be missed altogether. The spacecraft had to travel 3,84,400 kilometres to reach the Moon.

          The Apollo programme consisted of a large number of unmanned test missions and eleven manned missions. Out of the manned missions, two were Earth orbiting missions. It had two lunar orbiting missions, one lunar swing-by and the others were moon landing missions.

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          For a long time, America had been dreaming about humans in space. Between 1958 and 1963, they carried out their first human spaceflight programme- Project Mercury. It aimed to put a man in the Earth’s orbit and bring him back safe. Project Mercury was taken over from the US Air Force and carried out by NASA.

          NASA conducted both developmental flights and flights by astronauts. Some of the flights made use of animals as well. Project Mercury managed to send six people to space.

          Project Mercury was followed by Project Gemini, NASA’s second spaceflight programme that began in 1961. This programme aimed at the development of the techniques of space travel that would come handy in the execution of the Apollo mission. The Gemini spacecraft had a two-astronaut crew. There were ten Gemini crews in total and all were successful.

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          In the late 1950s, the Soviet Union and the US were engaged in a war - not by the means of guns and bombs, but rather a war of science and technology. They competed with each other to see which was the more powerful and technologically advanced nation. The Space Race was a major event in this competition.

          Both the Soviet Union and the US competed to achieve several milestones in spaceflight capability. The space race led to many landmark achievements including the first space flight, the launch of artificial satellites and moon landing. The launch of Sputnik I by the Soviet Union in 1957 accelerated the Space Race. This was followed by unmanned satellites and later, the first dog into space.

          America went a step further by sending monkeys and bringing them back safe.

          The Soviet Union then sent the first man to space in 1961. His name was Yuri Gagarin. Eight years later, America sent the first man to the Moon.

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         NASA began the Surveyor program in 1966 to learn about the possibilities of soft landing on the surface of the Moon.

          In a span of less than two years, NASA sent seven robotic spacecraft to the Moon that carried cameras and a variety of instruments to determine surface physical properties for landings, and the physical and chemical analyses of lunar soils.

          The Surveyor program was carried out when the US was actively involved in the Space Race with the Soviet Union. Out of the seven, five achieved soft landing; these were the first American spacecraft to achieve soft landing on an extraterrestrial body. The Surveyor program was carried out by NASA’s Jet Propulsion Laboratory in preparation of the Apollo program. All the seven were designed to stay on the Moon; the mission did not envisage their return to Earth.

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          The Lunar Orbiter program was a series of five lunar orbiter missions that were launched by the US between 1966 and 1967. All the five were unmanned and were planned to select landing sites for the Apollo mission by mapping the Moon’s surface.

          They were designed to acquire high resolution images. All the five missions were successful and the orbiter images supplanted all previous lunar maps and photo atlases. The Lunar Orbiters managed to map almost 99 per cent of the surface of the Moon. They provided close-up views with 10 to 100 times higher resolution than the best telescopic images. These images were also used for detailed lunar geology investigations from the late 1960s.

          The first three missions photographed 20 potential Apollo landing sites while the Lunar Orbiters 4 and 5 were sent to the far side of the Moon.

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