How Space is Explored

How Space is Explored

Space was explored as early as the fourth century BCE, through ancient astronomy. It was only in the twentieth-century that man sent out probes and himself to explore space. Space exploration, then, can be broken into three conclusive categories: astronomy, unmanned probes, and manned probes. The sub-page branches listed below represent these three fields of space exploration. Although seemingly contrary to the divisions just drawn, man is the explorer in all of these sub-pages; it is man's dream, technology, and understanding of science that forms the basis of all forms of space exploration. The exploration of space is value based, that is, man has "reason" to send men to the moon and to study distant galaxies, just to name a couples such values. (For a more complete exploration of man's "reason," see Issues on Space Exploration: Why we explore space.) From ancient times, to well into to the twentieth-century, the only technologically feasible method to explore space was astronomy--the studying of the millions of stars and neighboring planets, which invade night sky, as they have done for billions of years. The mysterious movements of the planets and the ebbing of stars across the sky had originally found explanations in religion, but as man's understanding of the science of astronomy increased natural laws, and not dogma, took form. And, as a solid foundation was laid with ground-based astronomy, man walked resolutely into the Space Age, upon the advent of the modern rocket. Given this stepping stone of the liquid fueled rocket, man was able to enter the cosmic "ocean." Public support for the space program, during the Cold War era, allocated millions of dollars to the exploration of space, but this trend has ceased in the later part of the twentieth-century. The peak of space exploration, as a function of government and public support, apexes in the 1970's, with the Apollo program. The public has generally been more supportive of the manned exploration program, but the costs and the values at risk are malignant to the support of space exploration as a whole. Today, economic resources for space exploration are scarce and public, and thus government support is relatively low. The glorious Apollo missions are impossible to reconstruct, and instead there has been a steady trend towards unmanned space exploration. What the future of space exploration will hold is highly dependant on the rising generation, and the values they hold towards space exploration.

Man, the Traditional Explorer

Man, the Traditional Explorer
The exploration of space has always been filled with danger and peril but man and his tools have learned how to overcome and explore "the last, the
greatest, and the most dangerous frontier of all" (-National Geographic).

The story of the American manned space exploration starts with the Mercury rocket program. The rockets used were nothing more than ready-to-fly,
modified military missiles that had capsules instead of warheads. This method of early non-reusable rockets was costly and impractical, but it placed us
into the space race by putting astronaut Alan B. Shepard into space. The second leg of the manned space program was the Gemini rocket program. Its
purpose was to tackle the difficulties that a moon mission would start to supply such as docking in space and maneuvering a craft in zero gravity. The
other thing that they had to improve was the life support systems. All of the new developments on the capsule added weight and the old launch rockets
(mercury missiles) wouldn't do so they had to use a new intercontinental ballistic missile (ICBM). With the new launch vehicle, Titan, the Gemini program
was a success and making it possible to go to the moon.

The third stage of manned flight was the Apollo program. This program was the first and only program of the 20th century to bring men to the moon.
This time the rocket wasn't just a modified missile It was the "big daddy" of all missiles, it was the Saturn V rocket, larger than any functional rocket on the
face of the planet--standing 363 feet tall. When the time came, with Apollo 11, to take Neil Armstrong, Edwin "Buzz" Aldrin and Michael Collins to the
moon the world was ready. On July 16, 1969 the count down ended and the F-1 engines of the Saturn V rocket took to life guzzling 15 Tons of fuel each
second the first moon mission was under way. Four days later, a man was walking on the moon. Several other men went on the three moon missions
before the program was abandoned.

The fourth of the manned space programs started in April 1981 with the Space Shuttle. The Space shuttle is the answer to congress's demands for a less expensive alternative to the Saturn V rocket, to explore space with. What they got was just that the shuttle has three of the most efficient engines of there kind on its tail end and two of the largest reusable solid rocket boosters in the world. The shuttle carries 49 engines, 23 antennas, 5 computers up to 5 satellites and 2-7 people. There was only one major disaster for the space shuttle and that was the most famous of all the shuttle flights and that the Challenger mission. Seven astronauts were killed as a result of two faulty O-rings which had allowed the gasses in the main tank to catch fire, leading to a tragic explosion that shocked the world; an episode which set the manned space program back several years.
Today, next phase of the manned space program is being entered with the development of VentureStar. This replacement for the Space Shuttle will reduce the price to one-tenth of today's current levels, by the use of a single-stage-to-orbit (SSTO) launch vehicle. The VentureStar requires no additional booster rockets an external fuel tanks, and launches simply by accelerating off a runway. Some of its advanced features include: linear aerospike engines for all altitude efficiency (see How Rockets Work), a lifting body design to aid in launching and re-entry, advanced composite materials for lighter structure and propellant tanks, an advanced thermal protection system. The X-33 will prelude the VentureStar as prototype employing the same (but downscaled) design and features.
Man experienced his greatest glory of exploration in the twentieth century with the Apollo missions. What will be his next great endeavor into the twenty-first century? Missions to Mars are proposed but what next? The cold war competition with the former Soviet Union fueled nationalism and thwarted resources (money) into space program. What will fuel the next great stride, the mission to Mars suggests the question: "are we alone" (see Issues on Space Exploration). There is little doubt that man will begin to explore the interstellar universe in the distant future, but the rate at which we approach this is dependant on today when the fuels to manifest the "dream" to explore are smothered by an increasing conservative society.
During the 1960's there was a race to beat the Russians to the moon. In the United States Americans were fueled in this space race by nationalism and eight million pound thrust rockets as we ushered into a new ear, the Space Age. America, so engulfed in cold war tensions and competition with the former Soviet Union, allowed for such great (and expensive) steps to taken early on.
Man's conquering of the moon was a major triumph of technology and perseverance. After all, it required the largest, most expensive, and most powerful rocket ever to have left the planet earth. The Saturn V rocket, resulting from the impedus of millions of dollars and thousands of scientists, represents not only a means to propel three men to the moon, but it is the product of an age when man donned the crown of exploration.
The Saturn V rocket begins its construction in the Vehicle Assembly Building (VAB), at the Kennedy Space Center. This building is 526 feet ( 160 meters ) tall and was designed to hold and assemble four Saturn V rockets at a time. This building is where all the components came together to form the finished rocket. All of the sections are stacked upon the Crawler, which is the worlds largest land vehicle. Once fully assembled, the doors are opened and the Saturn V heads towards its destiny. At a slow rate of 5mph, the Saturn V rolls towards its launch pad. There, after final checks and fueling, it awaits the count down. For when the clock strikes zero, 7.5 million pounds ( 3.5 million kg) of thrust is mustered to propel the rocket from its 365 foot tall launching structure. Twelve minutes later, after the first three stages have done their work, having lifted the final stages of this great giant into a three hour temporary orbit around earth. Then, after proper alignment, the 3rd engine roars to life accelerating the final two stages from 17,500 mph to 24,400 mph. Once this is completed the third stage is shut down and the capsule filled with the three astronauts inside continues its long journey towards the moon. Two days later, due to the force of gravity, the capsule slows to 2,300 mph deaccelerating at a rate of 460 miles per hour squared. Next, the ship enters the moons field of gravity and starts to accelerate again. The next day in the trip, the will pass behind the moon and start their burn to initiate moon orbit. This is a very scary and dangerous time because they are out of communication with earth (due to their location behind the moon). After successfully gaining moon orbit, they would launch the lunar lander. The lander is a small transport vehicle that ferried the astronauts and their equipment to the lunar surface and back to the moon orbiting return capsule (where one astronaut remained). The lander, after serving its purpose, was then discarded and left as space debris. The lander would spend several days on the surface of the moon while the crew collected samples and left experiments such as the reflectors that tell us accurately how far away the moon is and how fast it is moving away from the earth. When the lander then returns to the ship the crew will start there voyage home. After a long time in space the crew is quite tired and stressed due to the extreme isolation. This next step is the most dangerous due to the condition of the astronauts and the complexity of the maneuver. The ship will enter earth's the atmosphere at almost 25,000 mph (mach 35). The ship has its center of gravity offset so that they can adjust their angle of attack (entry). The ship skips in and out of the atmosphere twice before releasing its parachutes at 10,000 ft and splashing down into the ocean at a gentle 35 mph.
Some of the most famous astronauts in this program are Neil Armstrong, Buzz Aldrin and Michael Collins just to name some of the 10 or so men who have walked upon the surface of the moon.

About Rockets

The evolution of the rocket has made it an indispensable tool in the exploration of space. For centuries, rockets have provided ceremonial and warfare uses for the ancient Chinese, the first to create rockets. The history of the rocket is extensive and the three sub-pages below explore different aspects of rockets and rocketry. The field of rocket science is expansive, but one does not need to be a rocket scientist to garner the understanding of rockets, provided on these sub-pages. Exploration of space is performed in other ways (observatories, and radio satellite dishes), but for today, and perhaps many more years, rockets will remain king of "this new ocean" of space. Rockets, by breaking new frontiers in this cosmic ocean, have allowed the "dream," that carried such great explorers as Columbus and Magellan, to materialize in a world absent of uncharted seas. Science is exploration of the "truth," and by coupling it with rockets' exploration of space, we receive a product that not only charts the foreign sea of space, but improves our sense of placement in the universe. Man was "the measure of all things," but he has stepped out of this cave of complacency, searching for an understanding. In 1969, with modern rockets, man made another step, as Neil Armstrong placed his foot on the moon--breaking the limits of earth--transcending man to a greater state of being, where he is no longer one with just the earth, but one with cosmos. The rocket, as evolved through science, has given us an invaluable understanding of ourselves, as well as the "ocean" that envelopes us. Where rockets will take us tomorrow is unfathomable, as their development in dependant on the random discoveries of science. And to this one might step so far as to say that "rockets are the measure of all things"--but we will have to wait for time to unfold to ascertain this.

Mercury

Mercury

Mercury remains the least explored of the inner planets. As of January 2008, the Mariner 10 and MESSENGER missions have been the only missions that have made close observations of Mercury. MESSENGER made a fly-by of Mercury on 14 January 2008, to further investigate the observations made by Mariner 10 in 1975 (Munsell, 2006b). A third mission to Mercury, scheduled to arrive in 2020, BepiColombo is to include two probes. BepiColombo is a joint mission between Japan and the European Space Agency. MESSENGER and BepiColombo are intended to gather complementary data to help scientists understand many of the mysteries discovered by Mariner 10's flybys.

Flights to other planets within the Solar System are accomplished at a cost in energy, which is described by the net change in velocity of the spacecraft, or delta-v. Due to the relatively high delta-v to reach Mercury and its proximity to the Sun, it is difficult to explore and orbits around it are rather unstable.

Targets of exploration

The Sun

While the Sun will probably not be physically explored in the close future, one of the reasons for going into space includes knowing more about the Sun. Once above the atmosphere in particular and the Earth's magnetic field, this gives access to the Solar wind and infrared and ultraviolet radiations that cannot reach the surface of the Earth. The Sun generates most space weather, which can affect power generation and transmission systems on Earth and interfere with, and even damage, satellites and space probes.

Space explorationv

Space exploration is the use of astronomy and space technology to explore outer space.^[1] Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft. While the observation of objects in space, known as astronomy, predates reliable recorded history, it was the development of large liquid-fueled rocket engines during the early 20th century that allowed physical space exploration to become a reality. Common rationales for exploring space include advancing scientific research, uniting different nations, ensuring the future survival of humanity and developing military and strategic advantages against other countries. Various criticisms of space exploration are sometimes made, generally on cost or safety grounds.

Outer Space:Intergalactic

Intergalactic space is the physical space between galaxies. Generally free of dust and debris, intergalactic space is very close to a total vacuum. Certainly, the space between galaxy clusters, called the voids, is nearly empty. Some theories put the average density of the universe as the equivalent of one hydrogen atom per cubic meter.^[15][16] The density of the universe, however, is clearly not uniform; it ranges from relatively high density in galaxies (including very high density in structures within galaxies, such as planets, stars, and black holes) to conditions in vast voids that have much lower density than the universe's average.

Surrounding and stretching between galaxies, there is a rarefied plasma^[17][18] that is thought to possess a cosmic filamentary structure^[19] and that is slightly denser than the average density in the universe. This material is called the intergalactic medium (IGM) and is mostly ionized hydrogen, i.e. a plasma consisting of equal numbers of electrons and protons. The IGM is thought to exist at a density of 10 to 100 times the average density of the universe (10 to 100 hydrogen atoms per cubic meter). It reaches densities as high as 1000 times the average density of the universe in rich clusters of galaxies.

The reason the IGM is thought to be mostly ionized gas is that its temperature is thought to be quite high by terrestrial standards (though some parts of it are only "warm" by astrophysical standards). As gas falls into the Intergalactic Medium from the voids, it heats up to temperatures of 10⁵ K to 10⁷ K, which is high enough for the bound electrons to escape from the hydrogen nuclei upon collisions. At these temperatures, it is called the Warm-Hot Intergalactic Medium (WHIM). Computer simulations indicate that on the order of half the atomic matter in the universe might exist in this warm-hot, rarefied state. When gas falls from the filamentary structures of the WHIM into the galaxy clusters at the intersections of the cosmic filaments, it can heat up even more, reaching temperatures of 10⁸ K and above.