At the universal level, the cosmic space is quite wide and the specific amount that there is in terms of space is not known. Satellites and of no type of celestial body. There may be many more natural satellites than astronomers imagine. In fact, even in the observable universe, the exact number of satellites is unknown. Observation alone is not sufficient; a true study of space bodies is essential. You can delve deeper into the topic of the universe and its observation.
Many satellites can be seen like any other kind of celestial body and at the same time, knowing that they are satellites in space. This is a type of universal satellite, it is the natural satellite that will be discussed in more detail later. On the other hand, artificial satellites They also have their own operation and here we will explain the importance of each one.
One: Natural satellites
The natural satellites They are celestial bodies that orbit around a planet. The satellite is usually smaller and accompanies the planet in its orbit around its parent star. The term natural satellite is opposed to that of artificial satellite, the latter being an object that revolves around the Earth, the Moon or some planets and that has been manufactured by man.
Our satellite is the Moon and it is the only one that accompanies planet Earth. This satellite has a mass approximately 1/81 of the mass of the Earth. On the other hand, there is the binary system of planets, which is carried out by a satellite and the planet it orbits; or of two planets orbiting together. In this regard, we refer to the case of Pluto and its satellite Charon.
In order to determine exactly what the binary system, two objects must have similar masses, rather than a parent object and a satellite. The usual criterion for considering an object as a satellite is that the center of mass of the system formed by the two objects is inside the primary object. The highest point in the satellite's orbit is known as the apoapsis.
To understand this point, it is necessary to conceptualize that specifically in the subject of astronomy and within the parameters that characterize an orbit, the apoapsis It is the point in a satellite's trajectory that is at its greatest distance from the star it orbits. This helps us learn a little more about satellites and their location. However, it's also essential to understand other fundamental aspects of them.
Natural satellites of the Solar System
In the Solar System, there is a total of 178 satellites that have been confirmed by NASA, both in the planets and in the dwarf planets. The planets Mercury and Venus do not have no natural satellite, as does the dwarf planet Ceres. Consecutive unmanned missions have periodically increased these figures by discovering new satellites, and they may still do so in the future. For more information on the characteristics of these satellites, visit information about Saturn.
Each satellite has a different size, within our Solar System. The seven largest natural satellites in the solar system (with more than 2500 km in diameter) are the four: Jovian Galileans—Ganymede, Callisto, Io, and Europa—, Saturn's satellite Titan, Earth's own Moon, and the satellite natural captured Neptune Triton.
For its part, the latter Triton, is the smallest of that group. This satellite has more mass than all the remaining smaller natural satellites combined. Similarly, in the next largest group of nine natural satellites, between 1000 and 1600 km in diameter—Titania, Oberon, Rhea, Iapetus, Charon, Ariel, Umbriel, Dione, and Tethys—the smallest, Tethys, has more mass than all the remaining minor satellites combined.
Apart from the natural satellites of the planets, there are also more than 80 known natural satellites Tiny planets, asteroids and other minor bodies of the Solar System. Some studies estimate that up to 15% of all trans-Neptunian objects could have satellites.
These transneptunian objects or trans-Neptunian, they are any object that is located within the Solar System. Its orbit is partially or totally located beyond the orbit of the planet Neptune. For this reason they are called trans-Neptunians. Some specific subdivisions of that space are called the Kuiper belt and the Oort cloud.
Satellite names
Within our system Sto smell, there are different satellites on the planets. Ours is only one: the Moon. The names of these satellites were chosen from the names of characters in mythology. Only the names of the satellites of the planet Uranus are excepted. These satellites bear the names of characters from different works by the literary author William Shakespeare.
Satellites of other planets are widely called moons. However Moon is the satellite of our planet Earth, in general they are satellites and not moons. An example of the best way to say it is when they mention: "the four satellites of Jupiter", but by extension, many people usually say: "the four moons of Jupiter". Although it is understood that they really refer to the satellites of that planet.
Another way in which a space star, is that any natural body that revolves around a celestial body is called a natural satellite or moon. This happens even if it is not a planet, as is the case of the asteroidal satellite Dactyl that revolves around the asteroid (243) Ida etc. These space bodies have other names and each one is included in the astronomical catalog. However, in some cases scientists are also wrong in the category in which they place them.
What is the orbit of these satellites?
Since the system of planets that can be investigated in greater detail is the Solar System, since it is ours, astronomers have made classifications in the solar system, with respect to the orbits of the satellites. These are the shepherd, trojan, coorbital and asteroidal satellites. Each of them is evaluated with respect to the planet they orbit. The classification of these satellites is as follows:
First: Shepherd satellites
Satellites are called that when they hold a ring of Jupiter, Saturn, Uranus or Neptune in place.
Second: Trojan satellites
It is when a planet and a major satellite have in the Lagrangian points L4 and L5 other satellites.
Third: Co-orbital satellites
It is when they rotate in the same orbit. The trojan satellites they are co-orbital, but so are the satellites of Saturn Janus and Epimetheus that are less distant in their orbits than their size and instead of colliding they exchange their orbits.
Fourth: Asteroid Satellites
At this point, it is important to note that some asteroids have satellites around them like Ida and its satellite Dactyl. On August 10, 2005, the discovery of an asteroid Silvia was announced, which has two satellites revolving around it. Romulus and Remus. Romulus, the first satellite, was discovered on February 18, 2001 at the WM Keck II 10-meter telescope on Mauna Kea.
This satellite, Romulus, is 18 km in diameter and its orbit. It is located at a distance of 1370 km from Silvia and takes 87,6 hours to complete. On the other hand, Remo is the second satellite. This satellite is much smaller than Romulus, as it is 7 km in diameter and rotates at a distance of 710 km. Also, it takes less time to complete. Taking a total of 33 hours to complete a orbit around Sylvia.
all natural satellites follow its orbit due to the force of gravity. This is the reason why the motion of the primary object is also affected by the satellite. This was the phenomenon that in some cases allowed the discovery of extrasolar planets.
satellites orbiting satellites
A phenomenon in the Universe that allows natural satellites to orbit around a natural satellite of another body has not yet been known. In most cases, the tidal effects of the primary would make such a system unstable. However, calculations performed after the most recent detection detected a possible Rhea ring system. It's about a natural satellite of saturn.
The researchers indicate that the satellites orbiting Rhea would have stable orbits. In addition, it is believed that the suspected rings would be narrow. Such a phenomenon is normally associated with shepherd satellites. On the other hand, the specific images taken by the Cassini spacecraft they did not detect any ring associated with Rhea. It has also been proposed that Iapetus, a satellite of Saturn, possessed a subsatellite in the past; this is one of several hypotheses that have been proposed to account for its equatorial ridge.
Two: Artificial satellites
Unlike natural satellites, artificial ones are a device, sent through a space launch. This satellite remains in orbit around bodies in space. The artificial satellites They also orbit natural satellites, asteroids, or planets. After their useful life, artificial satellites can remain in orbit as space debris, or they can disintegrate upon re-entering the atmosphere. This only occurs if their orbit is low. For more details on the history of satellites, see the history of spaceships.
Through a short story by Edward Everett Hale, The Brick Moon (the brick moon), which was serialized in the Atlantic Monthly in 1869, is the first known work of fiction describing how an artificial satellite is launched into orbit around the Earth. The same idea reappeared in The Begun's Five Hundred Million in 1879, a work written by Jules Verne.
Unlike the work The Brick Moon, the book entitled the five hundred million by author Jules Verne, describes the villain's unintended result. He does this by mentioning in his play that the villain decides to build a giant artillery piece to destroy his enemies. This gives the projectile a higher speed than intended, which leaves it in orbit like an artificial satellite.
The birth of the began during the Cold War between the United States and the Soviet Union. The aim of this war was to conquer space. In May 1946, RAND Project presented the Preliminary Design of an Experimental World-Circling Spaceship report. This is the preliminary design of an experimental spacecraft in orbit.
the space age
The preliminary design of an experimental spacecraft in orbit said that "A satellite vehicle with proper instrumentation it can be one of the most powerful scientific tools of the XNUMXth century. The realization of a satellite ship would produce a repercussion comparable to the explosion of the atomic bomb...».
However, the space age began in 1946, when scientists began using captured German V-2 rockets to make measurements of the atmosphere. Prior to that time, scientists used balloons reaching 30 km in altitude and radio waves to study the ionosphere. .
From 1946 to 1952, the V-2 and Aerobee rockets were used for research in the upper atmosphere. This is what allowed pressure measurements, density and temperature up to an altitude of 200 km. The United States had considered launching orbital satellites since 1945 under the Navy's Office of Aeronautics.
In addition to this, the RAND Project of the Air Force submitted its report but the satellite was not believed to be a potential military weapon. What happened was that rather a scientific, political and propaganda tool was created. In 1954, the Secretary of Defense stated, "I am not aware of any American satellite program."
Types of artificial satellites
Just as natural satellites have a typology and classification; also artificial satellites have their types. Each of them investigated and studied from history, to the present day. Artificial satellites can be classified into two big categories: Observation Satellites and Communications Satellites. Since those are the functions they have when they are sent into space.
The observation satellites, include all those that collect data and send that data back to Earth for use. A large number of satellites in this category take photographs of planet Earth itself. They also photograph the body they orbit, using different wavelengths. In addition to this, they include a wide variety of observation fields, such as photography or astronomical observation, space environment detectors (cosmic rays, solar wind, magnetism), and other fields. To better understand space phenomena, you can read about the sounds of the universe.
With respect to communication satellitesThese include those used to retransmit signals from one point on Earth to another. They are the satellites that facilitate communications and the dissemination of messages. This is the most commercial use of satellites and includes coverage for radio, television, internet, telephony and other uses.
They have also been key in understanding phenomena such as the sounds of the universe through precise measurements from space.
Classification of satellites by their specific purpose
Communications satellites, previously mentioned. These are the employees to carry out telecommunications (radio, television, telephony).
Meteorological satellites, are those that are used for the observation of the environment, meteorology, cartography without military purposes. Although they are mainly used to record the weather and climate of the Earth.
navigation satellites, are those that use signals to know the exact position of the receiver on earth, such as the GPS, GLONASS and Galileo systems.
reconnaissance satellites, are popularly known as spy satellites. They are observation or communications satellites, used by military or intelligence organizations. Most governments keep the information from their satellites secret.
astronomical satellites, are those satellites that are used for the observation of planets, galaxies and other astronomical objects.
solar powered satellites, they are a proposal for satellites in eccentric orbit that send collected solar energy to antennas on Earth as a power source.
space stations, these are structures that have been designed so that human beings can live in outer space. A space station is distinguished from other manned spacecraft in that it has no propulsion or landing capability, using other vehicles as transportation to and from the station.
Classification of satellites by the type of orbit they describe
Among the enormous diversity of possible orbits, the orbits of the artificial satellites of the Earth are generally classified by their height. Among them are described:
Low Earth Orbit (LEO): They are those satellites that have low orbit. They are located at a height of 700 to 1400 km and have an orbital period of 80 to 150 minutes.
Mean Earth Orbit (MEO): It is a medium orbit rotated from 9 to 000 km and has an orbital period of 20 to 000 hours. It is also known as intermediate circular orbit.
Geostationary orbit (GEO): It is the satellite that has an orbit at a height of 35 km above the terrestrial equator. It has an orbital period of 786 hours always remaining on the same place on earth.
Satellite orbit types
In addition to this, it is necessary to know the types of orbits around which satellites revolve in space. These orbits can be according to the altitude, to the star to which they orbit, to the eccentricity, to the inclination and to the synchrony. However, it is not ruled out that there are other types of orbits, for this reason they will also be mentioned below.
Satellite orbits by altitude
low earth orbit (LEO): a geocentric orbit at an altitude of 0 to 2000 km.
mean earth orbit (MEO): a geocentric orbit with an altitude between 2000 km and up to the geosynchronous orbit limit of 35 km. It is also known as intermediate circular orbit.
high earth orbit (HEO): a geocentric orbit above the 35 km geosynchronous orbit; also known as highly eccentric orbit or highly elliptical orbit.
Satellite orbits by the star they orbit
areocentric orbit: an orbit around Mars.
Molniya orbit: orbit used by the USSR and currently Russia to completely cover its territory far north of the planet.
geocentric orbit: an orbit around the Earth. There are approximately 2465 artificial satellites orbiting the Earth.
heliocentric orbit: an orbit around the Sun. In the Solar System, planets, comets, and asteroids follow that orbit. The artificial satellite Kepler follows a heliocentric orbit.
Satellite orbits by eccentricity
circular orbit: an orbit whose eccentricity is zero and its path is a circle.
Hohmann transfer orbit: An orbital maneuver that moves a ship from one circular orbit to another.
elliptical orbit: an orbit whose eccentricity is greater than zero but less than one and its path is ellipse-shaped.
Molniya orbit: a very eccentric orbit with an inclination of 63,4º and an orbital period equal to half a sidereal day (about twelve hours).
Geostationary Transfer Orbit: an elliptical orbit whose perigee is the altitude of a low Earth orbit and its apogee is that of a geostationary orbit.
Geosynchronous transfer orbit: an elliptical orbit whose perigee is the altitude of a low Earth orbit and its apogee is that of a geosynchronous orbit.
tundra orbit: a highly eccentric orbit with an inclination of 63,4º and an orbital period equal to one sidereal day (about 24 hours).
hyperbolic orbit: an orbit whose eccentricity is greater than one. In such orbits, the spacecraft escapes the gravitational pull and continues its flight indefinitely.
parabolic orbit: an orbit whose eccentricity is equal to one. In these orbits, the velocity is equal to the escape velocity.
capture orbit: a high-speed parabolic orbit where the object approaches the planet.
escape orbit: a high-speed parabolic orbit where the object is moving away from the planet.
Satellite orbits by inclination
inclined orbit: an orbit whose orbital inclination is not zero.
polar orbit: an orbit that passes above the poles of the planet. Therefore, it has an inclination of 90º or approximately.
Sun-synchronous polar orbit: A near-polar orbit that passes the Earth's equator at the same local time on each pass.
Synchronized satellite orbits
areostationary orbit: a circular areosynchronous orbit on the equatorial plane at about 17000 km altitude. Similar to geostationary orbit but on Mars.
Areosynchronous orbit: a synchronous orbit around the planet Mars with an orbital period equal to the sidereal day of Mars, 24,6229 hours.
geosynchronous orbit: an orbit at an altitude of 35 km. These satellites would trace an analemma in the sky.
graveyard orbit: an orbit a few hundred kilometers above the geosynchronous one where the satellites are moved when their useful life ends.
geostationary orbit: a geosynchronous orbit with zero inclination. To an observer on the ground, the satellite would appear to be a fixed point in the sky.
Sun-synchronous orbit: a heliocentric orbit about the Sun where the orbital period of the satellite is equal to the period of rotation of the Sun. It is located at approximately 0,1628 AU.
semi-synchronous orbit: an orbit at an altitude of approximately 12 km and an orbital period of about 544 hours.
synchronous orbit: an orbit where the satellite has an orbital period equal to the period of rotation of the main object and in the same direction. From the ground, a satellite would trace an analemma in the sky.
Satellite orbits other orbits
horseshoe orbit: an orbit in which an observer appears to see that it orbits a planet but actually co-orbits with the planet. An example is the asteroid (3753) Cruithne.
Lagrangian point: Satellites can also orbit over these positions.
Artificial satellites are launched by Russia and Ecuador
After three years of work, Russia and Ecuador finally decide to launch artificial satellites into space. In total, 72 satellites were launched, among which, at the Latin American level, the satellite that is called Ecuador UTE-UGUS. This is the first satellite built by an Ecuadorian university and launched in the middle of this current month (July 2017).
On the other hand, from the Baikonur space launch station, the Soyuz-2.1a rocket, which contains 72 satellites of different purposes, was launched into orbit. The Russian Federal Space Agency Roscosmos reported this Friday that from the Baikonur space launch station, the Soyuz-2.1a rocket, which contains 72 satellites of different purposes.
Returning to the most prominent satellite in Latin America, it is worth highlighting the Ecuador UTE-UGUS. This is a monitoring nanosatellite. It has a size of 100 millimeters in width, length and thickness. In addition, it weighs 1 kilogram and was developed jointly by the Equinoctial Technological University (UTE) of Quito and the Southwest State University (UESOR) of Russia.
The function of this nanosatellite is to study the influence of natural factors and humans to the structure and dynamics of the diversities produced in the ionosphere and the magnetosphere. The study carried out from this monitoring will help in the creation of climate forecast models and space telecommunications.
New Russian record
By placing in orbit 72 spacecraft at the same time, Russia breaks launch record. Among those satellites, we must mention one of those that attracts attention and is the "Mayak". This satellite has a pyramid-shaped solar reflector, which was designed to reflect sunlight towards planet Earth.
Among the objects that have been created by man, the mayak will be the brightest. In addition to being the fourth brightest object in space, including natural space bodies, after the Sun, the Moon and Venus.
The satellites that were launched, are the following: two state and two private satellites of Russian educational institutions and centers; an Ecuadorian satellite; two German satellites; a Japanese satellite; two joint satellites developed between Norway and Canada and 62 US satellites.
Importance of satellites
Importance of natural satellites
These elements that orbit around a celestial body, are of great importance for the human being. In the case of natural satellites, our great example is that of the moon and it has been of great importance for Earth studies and behaviors. This is because natural satellites influence some natural phenomena that occur on the planets they orbit. You can learn more about the origin of the Moon here.
On planet Earth, the Moon has an obvious relationship with the tides, according to what has been scientifically proven. These kinds of events have been known since ancient times. According to research, this phenomenon is due to the attraction that the Moon has on the surface of the water and that makes it cover larger or smaller portions of the coast depending on its position.
, the tides can affect fishing and, furthermore, the same tide can be used for processes to obtain energy, situations that account for its importance and the importance of our natural satellite.
Importance of artificial satellites
There is an infinity of satellites that were created since the middle of the XNUMXth century to carry out military tasks, communications, research, among other purposes. Certainly, in both natural and artificial satellites, there is a clear interest to man and this circumstance makes us value its importance.
Specifically, regarding the artificial satellites, they were developed in response to different problems that affect man. Their conception began to develop at the beginning of the XNUMXth century. Over time it deepened until it was possible, in the second half of the last century, to launch one. The first satellite put into orbit corresponded to a project of the Soviet Union.
Currently, these types of elements are used for a wide variety of functions, including those related to communication and earth observation for the creation of maps, geopositioning, among others; space research also makes use of them to more effectively observe other celestial bodies. If you are interested, you can find out about how the universe was discovered.
