Aerospace Technology

Many people in their childhoods have seen a space shuttle in a picture book or image. However, the early stages of a child causes them to assume from the picture that the shuttle is another big rocket flying into space without any thought of the space shuttle´s true purpose or technology behind it. As children grow into teenagers and then reach adulthood, education reveals the true purpose of space shuttles, the history, and its technological benefits to human society. Many people don´t realize but space shuttles have been a major role in space transportation that allowed space stations to be created and even allowed astronauts to return to damaged satellites and repair them. Without space shuttles, the Hubble Space Telescope could not have existed in space which then, the incredible images taken from the telescope would have not existed. In my opinion, space shuttles have a great part in human technology and advancement in knowledge.

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