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International Space Station, the “star” that orbits around the Earth

publicado a la‎(s)‎ 3 ene 2020, 3:32 por Plataforma Sites Dgac   [ actualizado el 8 oct 2020, 10:24 ]
The dead of night. Suddenly, when we look up at the sky or while watching the stars, we detect a point of light moving in a straight path through the celestial vault, with constant speed, until it is out of sight.
A NASA image of the International Space Station orbiting around Earth.

Former astronauts and twin brothers Mark and Scott Kelly, in an image by Derek Storm (www.derekstorm.com)
Sometimes, those who observe the phenomenon are left with the impression of having spotted an unidentified flying object (UFO), but in reality they have witnessed the passage of the International Space Station (ISS).

The station will be visible from the central zone of Chile, from the Southwest, on January 3 between 22:38 and 22:42; Saturday, January 4, between 9:50 p.m. and 9:56 p.m., also from the Southwest; Sunday, January 5, between 10:40 PM and 10:43 PM, from the West; and Monday, January 6, between 9:51 p.m. and 9:57 p.m., from the West-Southwest. 

The ISS is a habitable artificial satellite that moves around the Earth in a low orbit (on average, at about 410 kilometers above the surface of the planet) and that serves for astronauts of different nationalities to carry out scientific experiments on biology, meteorology, physics, astronomy and other disciplines in a microgravity habitat.

One of its main objectives, apart from contributing to the development and well-being of Humanity, is to add experience and knowledge for the next leap: the trip to Mars and beyond. 

Into orbit 

The first component of the International Space Station was launched in 1998 and its first long-term residents, astronauts Sergei Krikalev (Russia), William Sheperd (United States) and Yuri Pavlovich (Russia), arrived on November 2, 2000, and remained there for 136 days, until March 18, 2001. 

The ISS is the largest structure that Humanity has put in space and, due to its size, it had to be sent in parts and then built or assembled in orbit. Its cost is also estimated to be astronomical, at about 100 billion dollars. 

It is the ninth space station inhabited by crews. Previously, there were smaller space stations, such as the Russian Salyut, Almaz and Mir, and the American Skylab. 

The station is supplied by several visiting spacecraft, such as the Russian Soyuz and Progress, the American Crew Dragon and Cygnus and the Japanese H-II Transfer Vehicle. The Crew Dragon spacecraft allows the return of pressurized cargo to Earth, which is used, for example, to repatriate scientific experiments for further analysis.

The program for the ISS is a joint project between NASA, the Russian space agency Roscosmos, Japan's JAXA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

The station has been continuously manned for 19 years and has been visited by astronauts, cosmonauts and space tourists from 19 different countries, including Italy, France, Germany, South Africa, Denmark, Brazil, Spain and the United Arab Emirates, to name a few.

It is divided into two sections, the Russian Orbital Segment (ROS), operated by Russia, and the United States Orbital Segment (USOS, which is shared by several countries.

Twin experiments 

At the ISS, dozens of experiments are carried out simultaneously to better understand different phenomena and mechanisms, from Parkinson’s disease to combustion, which helps life on Earth and prepares the ground for future missions to the Moon and Mars. 

In one of the most interesting studies, 10 teams from different parts of the United States observed the changes that occurred in a person subjected to the rigors of space travel and microgravity. 

The so-called “Study of the Twins,” published in an article in Science magazine in April 2019, compared various samples and measurements made on retired astronaut Scott Kelly, to his twin brother's, former astronaut Mark Kelly, who remained on Earth. 

The idea was to determine what physiological, molecular and cognitive changes could occur to people over long periods in space. According to NASA, it was the first study of its kind that compared molecular profiles of identical twin astronauts. 

Because they share the same genetic makeup, twin studies give scientists the ability to explore how health is influenced by the environment, regardless of the physical variations that naturally occur between individuals. 

One of the results included the observation of the lengthening of Scott Kelly’s telomeres, which are formations at the tips of each DNA strand that usually shrink with age. 

Another study found that artificial light affects the behavior of urban wildlife, in which animals were examined in the laboratory and in the field.