
Space travel is a form of travel in which passengers enter space, the vast region outside the protective envelope of the Earth’s atmosphere. Space starts 6.2 mile (100 kilometers) above the Earth’s crust at a point called the Karman line, and it continues for a distance which appears to be infinite, interrupted periodically by celestial bodies such as stars, planets and so forth. Humans have long had romantic associations with space travel with people considering space “the final frontier” as they famously say on star Trek.
Humans have been intrigued by the night sky for centuries, tracking the movement of stars, planet comets and other features in the sky and pondering the mysteries of the heavens. In the 20th century, the fascination with space took on a whole new level of excitement when humans successfully launched manned spaceflight out of the Earth’s atmosphere, putting astronauts in space and on the moon.
With the proof that manned spacecraft was possible the concept of space travel began to seem less like a pipe dream and more like a reality, and private companies began to enter the field, developing space planes and offering commercial flights in the 20th century, space travel was restricted astronauts who worked for various governments, and it was primarily performed for research purposes. Space travel allowed people to collect sample from the moon, maintain space telescope such as Hubble. Telescope and eventually to perform research on the international space station, a structure which orbits the Earth and houses astronaut from several nations at any given time.
While space travel for research is certainly admirable and important, many people are more interested in the potential for space travel as a form of recreation, tourism or exploration. Civilian began purchasing tickets for tourist flight into space in the early 2000s, sometimes going on brief suborbital flights in which the barely entered space and sometimes spending several days in space, exploring the international space station and enjoying the experience of being in space. The potential for space travel is infinite just like the universe, bounded only by human technology. Many people hope that the dreams of science fiction, such as massive ships which can travel between galaxies will someday be realized. Space travel could be used to explore the rest of the solar system and galaxy learning more about the nature of the universe and potentially leading to a discovery of the life beyond the boundaries of Earth.
Satellite and its Uses in the Society
A satellite can be defined as any object either man made or naturally occurring that orbits around something else. For example, the moon orbits, around Earth and is thus a satellite. The Earth orbits around the sun and is a satellite of the sun. Other examples of naturally occurring satellites include comets, stars, asteroid and other planets.
Orbits is determined by the gravitational pull of the object around which the satellite circles. A satellite circles around a body called the primary object. However, primary objects are also affected by their satellites, and feel some of their gravitational pull. Most are more familiar with the terms satellite in relationship to the many satellites that circulate the earth.
Sputnik was the first artificial satellite launched in 1957 by the Soviet Union. The launching of sputnik is almost analogous for the beginning of the space race that followed between the US and the USSR. In today’s climate, however, many countries have found that a cooperative effort is more successful in space exploration and studies. The international space station a satellite that orbits earth, is currently the largest man made satellite in space, and it represent the cooperative effort of numerous countries.
Man-made satellites are classified by types. Some of the main types of satellite used today include astronomical satellite, communication satellites, earth observation satellite, weather satellites and space stations. Other types of satellite include those used to monitor earth from military standpoint, and biosatellite which may carry animals or other life forms for the purpose of research on earth life forms in space.
Navigational satellites are now popular and form a vital part of the Global Positioning System (GPS) now available in many cars. A satellite can also be classified by the height at which the orbit earth or another body. A low earth orbit circles the earth at a height of 0.12 (1995.59km). High earth orbits can be as far away as 22.240 miles (35,791.81km).
Medium earth orbit represent the distance between high and low earth orbits. Satellite can also be classified by their function since they are launched into space to do a specific job. The type of satellite that is launched to monitor cloud pattern for a weather station will be different than a satellite launched to send television signals across different places.
The satellite must be designed specifically to fulfill it role;
Different types of Satellite and its Uses
- Milstar: A communication satellite ie Anti-satellite weapons/killer satellites are satellites that designed to destroy enemy war head, satellites or other space assets.
- Astronomical satellite: are satellites used for observation of distant planets, galaxies and other outer space objects.
- Communication satellite: are satellite stationed in space for the purpose of telecommunication.
- Biosatellite: are satellite designed for carrying living organism, generally for scientific experimentation.
- Navigational satellite: are satellites which use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time.
- Reconnaissance satellites: are earth’s observation or communication satellites developed for military or intelligence application. Very little is known about the full power of these satellites as government who operate them usually keep information pertaining to their reconnaissance satellite classified.
Earth observation satellite are satellite intended for non-military use such as environmental monitoring meteorology, map-making etc.
- Space stations: are man-made structures that are designed for human being to live on in outer space. A space station is distinguished from other manned spacecraft by its lack of major propulsion or landing facilities – instead, other vehicles are used to transport to and from the station. Space stations are designed for medium-term living in orbit, for periods of weeks months or even years.
- Tether satellite: are satellites which are connected to another satellite by a thin cable called tether.
- Weather satellite: are primarily used to monitor Earth’s weather and climate.