The Space Shuttle, officially called the Space Transportation System (STS), is a currently used manned spacecraft purposely created to transport astronauts and space components into space. It consists of two white Solid Rocket Boosters (SRBs), a rust colored external tank (ET), and the Orbiter Vehicle (OV). These major components in a space shuttle each have their roles and technological benefits for a successful shuttle launch and allow astronauts to return to Earth safely. The Space Shuttle is the first orbital spacecraft that has reusable components. For example, the shuttle´s Solid Rocket Boosters (SRBs) reinforce the thrust into the atmosphere but eventually both SRBs parachute into the ocean where it can be reused. Another reusable component is the orbiter where after each mission, the orbiter carries its astronauts back to Earth and lands on an airstrip safely. Before the creation of space shuttles, the government realized that they were spending too much money on rockets that were not reusable. As a result, Maxime Faget designed the Space Transportation System where it consisted of reusable solid rocket boosters and orbiters which decreased the financial expenses on space exploration as requested by the Nixon administration. The creation of space shuttles was a major achievement in space exploration because of its unique reusable system which caused lower costs for space exploration in contrast of the rocket systems that were not reusable which caused a large financial expense to the government.

The “Stack” in the space shuttle consists of the Orbiter Vehicle (OV), the two white Solid Rocket Boosters (SRBs), and the external tank (ET). Each of these major components in the space shuttle carries a role during a mission. The orbiter, a white winged space plane, carries astronauts and loads such as satellites and space station parts into low orbit located in the thermosphere. The crew in an orbiter is usually five to seven astronauts each contributing different roles in the STS´s specific launch. Usually, the crew is made up of a commander, pilot, several mission specialists, and rarely, a flight engineer. In some occasions, there are some exceptions such as an extra astronaut or in an emergency mission where eleven astronauts are fit in. The orbiter´s wings contain four elevons located at the edge of the wings that helps the orbiter´s pitch and roll stabilization. It also possesses a rudder brake and a body flap that controls the orbiter during the descending and landing process. Most of the orbiter´s body is the cargo bay measuring 15 by 60 feet.  There are three Space Shuttle Main Engines (SSMEs) in the OV located on the fuselage. The engines allow the orbiter to thrust itself through the atmosphere and use a bit of its thrust during the descending process to change direction and for steering to be possible. Aluminum alloy is the material used in the OV´s structure but exceptionally, titanium alloy is used for the engine´s thrust structure. The Solid Rocket Boosters (SRBs) are rocket boosters located at the sides of the external tank. The SRB´s role in a launch is to thrust the shuttle enough for it to escape the gravitational pull from Earth and also give enough thrust to have sufficient speed to break through the atmosphere very quickly. The SRBs help the shuttle for the initial two minutes and afterwards separates itself from the external tank, and dropping into the Atlantic Ocean with parachute. They are picked up by ships and brought back to the space centers to be reused. The solid rocket motor in the SRBs is the largest solid propellant motor ever developed for space flight. It consists of a solid motor case loaded with solid propellants, an ignition system, a movable nozzle, and instrumentation and integration hardware. Each of the SRBs contains 1,000,000 lbs of propellant which requires special mixing in special plants located in Utah. The propellant is actually powdered aluminum similar to the aluminum foil wraps at home but mixed with oxygen provided by a chemical called ammonium perchlorate. In total, each SRB weighs 1,300,00 lbs including the propellant which weighs about 1,107,00 lbs. The external tank (ET) is the major backbone of the space shuttle. Without it, the shuttle´s structural design would be different. The ET is the component that puts the OV and SRBs together. The SRBs are stuck together onto the ET and the ET disconnects them after the initial two minutes of launch. Before the shuttle reaches the boundaries of Earth, the ET disconnects from the OV(orbiter) and falls to the Atlantic Ocean. In contrast of the OV and SRBs, the ET is not reusable and is design to break up before impact into the oceans. STS-1 and 2´s ET have been painted white in order for all the three major components to look alike. However, scientists noticed that the white paint gave a huge amount of additional weight onto the shuttle which meant one worrying thought to the government, money loss. The extra paint caused the scientists to use more propellant in order for the shuttle to carry the weight into space. As a result, from STS-3 and on, the ET remained rust colored. This caused less propellant to be applied during shuttle missions. The ET´s major role in a shuttle launch is to hold the main components together and contribute its propellant in order for the shuttle to escape the gravitational pull and reach the boundaries of the Earth. After the ET releases itself from the OV, the OV uses its thrusters to adjust itself in low orbit.

The creation of Space Shuttles allowed a variety of options for the government to use in space exploration and knowledge. Satellites were transported by the STS missions and satellite repairing was possible due to manned STS missions. Also, one of a minor purpose the space shuttle was created was the government´s desire for its people to get excited about space exploration. Although the creation of space shuttles was not as exciting as the space race and the landing of the moon. However, the space shuttle reduced expenses for the government and lots of new knowledge can be revealed through the research in space stations located in Earth´s orbit. The space shuttle´s job in the conquest of space knowledge is to be a STS, a Space Transportation System. However, many people believe that the space shuttles do more than transport astronauts and components to space, but also, an icon of hope for future space knowledge seekers.

Information thanks to http://en.wikipedia.org/wiki/Space_Shuttle_program, www.nasa.gov, http://en.wikipedia.org/wiki/Space_Shuttle, http://en.wikipedia.org/wiki/External_tank. Shuttle cargo bay opened. SRBs being carried back. SRB releasing process

Since the birth of the Soviet Union’s Salyut and Mir space stations, the United States began developing a counterpart space station. However, it was cancelled due to the end of the Soviet Union and the beginning of the Cold War. After the space race, the U.S. began negotiating with international partners from Europe, Russia, Japan, and Canada in the 1990’s to develop a huge international space station. As the project continued till now, 16 nations, Canada, Japan, Russia, 11 countries from the European Space Agency, and Brazil, began contributing technological and scientific resources. The International Space Station (ISS) is a research facility where it gives scientists the opportunity to experiment using zero gravity. The size of the ISS is equivalent to a football field and therefore, is currently being assembled in orbit. The ISS is split into many different parts where different research modules are owned by different countries. For example, Japan owns the Kibo Japanese Experiment Module but American or Russian space shuttles will transport it to the space station. Currently, the ISS is 70% complete and an estimated time for ISS´s finished construction is in 2010. The U.S. again estimates that the ISS will be used till 2017. Till then, many people contributing to the program believes it is a research benefit to the developing space exploration program.

The ISS uses the sun to power electricity with its numerous solar panels. The solar panels are programmed to adjust its angle towards the sun’s rays to maximize its power supply. However, some countries such as Russia, needs to depend on American solar panels for energy. The Environmental Control and Life Support System aboard the ISS provides and controls the atmospheric pressure, oxygen, water, and among others. It can store water and waste used by the resident crew and can even recycle urine and water used by the showers. This system is used to achieve more time a crew will be able to operate since waste is a big problem in long-termed orbits. However, this system can also remove human sweat from the air which will prevent it from neutralizing or disturbing technological equipment. Another important system in the ISS is the altitude control. As many people know, we still have gravitational pull outside our atmosphere and it is how space stations can become orbited. When a satellite is launched into orbit, gravity slowly pulls it closer to the Earth’s atmosphere and as a result, the satellite burns in the atmosphere. Its remains will be scattered somewhere in the oceans since engineers calculate the designated re-entry area. Contrasting from ordinary satellites, the ISS will have an altitude control where it is thrust several kilometers higher. This process must be done several times each year since the ISS is very close to the atmosphere (ISS can be visible with the naked eye) which results in a stronger gravitational pull. Every month, the ISS is pulled 2.5 kilometers.

The purpose of the construction of the International Space Station is to research many different things that cannot be done without the support of zero-gravity. One of the things that scientists want to research aboard the ISS is to invent a new combustion form. They believe that combustion is a major part in human’s way of life but it increases pollution and global warming. Because of their observations of combustion in daily life, they want to try and develop a new form of combustion in zero-gravity. Another very unique research the scientists want to perform is the development of protein crystals. According to astronaut Dan Bursch, “The National Institute of Health has said that protein crystal growth is the number one research tool that we’ll be using in the next century…” These protein crystals are imperfect during its creation in a gravity environment. However, in zero-gravity, the protein crystals have a perfect form and content. These crystals can be useful in food and medicine. Although the ISS is not fully constructed, it is still habitable. Dennis Tito, an American billionaire, paid 20 million dollars for a trip to the ISS and became the first space tourist ever. As shown in the example, the ISS is a very expensive tourist site where beforehand, must pass G-force tests and must be able to perform various tests in order to support the launch and 0-gravity. Many people believe that “floating in space” is very cool and want to try it. I, personally, wouldn’t go to space even if I had the chance. Zero-gravity is equivalent to the highest freefall rollercoaster in the world and the feeling you acquire from it, multiply it by four. When in orbit, you are basically “falling” to Earth because of the fact that gravity is pulling you except in a long distance. For example, when you jump inside our atmosphere, we fall very quickly since the Earth is really close to us. However, in orbit, gravity is pulling you with less force therefore, you fall very slowly. As you are falling, you will feel the same feeling as if you jumped from the highest building in the world and had that feeling for your duration of the trip. Because of this problem, space tourists such as Dennis Tito, must be able to cope with the feeling and must take tests if he is able to resist zero-gravity in space.

The ISS project will cost about 157 billion dollars. However, many different space agencies and organizations will all contribute money in order to receive the 157 billion. NASA will contribute 100 billion dollars since they will construct most of the key components of the station. Also, the space shuttle launches to transport components of the station will be paid by NASA. The European Space Agency (ESA) will contribute 9 billion euros since they are in charge of the Columbus Control Center and the Ariane 5 launches. The Japanese Aerospace Exploration Agency (JAXA) will contribute over 10 billion dollars to ISS program. Their main contribution is the Japanese Experiment Module which will cost them about 2.8 billion dollars. The Russian Space Agency has contributed many different key components of the space station, however, since the exchange rate of the ruble and US dollars are not accurate, people currently does not know how much Russia is contributing in dollars. Canada is contributing 1.4 billion dollars to the program and is currently developing the Special Purpose Dexterous Manipulator, a very unique and important component of the ISS. All of these nations are contributing billions of dollars for the development of the International Space Station. As you can see, lots of NASA´s funds are going into the ISS program. However, many people criticize that the money used towards the ISS program could be used for robotic space exploration. Others argue that the program produces very little research that does not help space exploration. Many others argue about the excess use of maintenance and risky space shuttle docking procedures where more than once, docking problems occurred that could have caused the destruction of the ISS. Others with their opinions against the ISS have not been revealed however, the final performance from the ISS will determine the amount of benefit from NASA´s spent money.Because of the ISS´s size and reflections from the gigantic numerous solar panels, a human’s naked eye will be able to see the ISS. NASA provides the public with a schedule where it tracks the ISS´s location. http://spaceflight.nasa.gov/realdata/sightings/index.html(For Costa Rican residents, every Tuesday at 3:50 AM [unfortunately], the ISS will approach from the north)The ISS is a currently under construction space station that will be achieved with the cooperation from 16 different nations, each contributing money and technological resources. Since a large amount of money is taken out from NASA´s funds, many people argue over the excess use of money towards a single project. However, if NASA wants to prove that their decision to participate in the ISS program was beneficial, the completion of the ISS and further research benefits will altogether prove its effectiveness.Information from www.wikipedia.org and http://spaceflight.nasa.gov/station/benefits/index.html

 Construction of International Space Station