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Orbital mechanics, otherwise known as astrodynamics, focuses on the motion of spacecraft, such as rockets or satellites, in space. This is an extremely important concept to understand for space missions both in the design of the spacecraft as well as how they are controlled on these missions. In this article, we will be focusing solely on the various types of orbits but before jumping in, it is important to first review the history of orbital mechanics and how space travel even came about. It all started in the late 1950’s when the Soviet Union achieved a major advancement in space dynamics with the first successful satellite launch of Sputnik, and shortly after, successfully sending the first human to space. This was very concerning to the United States since lagging behind other countries could potentially put America at a technological, economic, and even military disadvantage. Because of this, the United States government created a new federal agency called NASA, National Aeronautics and Space Administration, just a year after the Soviet Union launched Sputnik. The creation of NASA began the start of the U.S.-Soviet space race where the United States would eventually “win” by successfully putting a man on the moon in 1969. Since then, NASA as well as newer companies, one in particular being SpaceX founded by Elon Musk, have continued to advance in space exploration. For both of these organizations, it is essential for the engineers designing these rockets and other spacecraft, as well the mission control team to understand astrodynamics for the safety of the team as a whole. There are a couple “rules of thumb” we can abide by to understand how orbital mechanics works in simpler terms. First, Johannes Kepler proposed three laws of planetary motion, also known as Kepler’s laws of planetary motion. These laws state that the path of the planets around the sun is elliptical with the sun obviously being in the center, they help determine the speed at which a given planet is moving while orbiting the sun, and also help to compare the orbital period and radius of orbit of a given planet to other planets. In addition, the laws of astrodynamics are imperative to understand since they are based upon the basic ideas of Newton’s law of universal gravitation and Newton’s laws of motion. These laws can be understood very simply by saying that a rocket will stay still until a force acts on the rocket to move it, and once it is in motion, it will continue to be in motion until a force acts on it to stop it. In addition, the heavier the rocket weighs, the more force is needed to move it and make it stop moving. Newton’s Third Law is demonstrated when the rocket is pushed upward by the fire that the rocket releases from the back when it is taking off. Finally, escape velocity is another concept that is imperative to be able to be calculated in order to determine the minimum velocity it would take in order for the rocket, or any object for that matter, to be able to escape the gravitational attraction of the planet. Understanding these important concepts is just the start of understanding orbital mechanics. One other very important aspect to focus on is the different shape orbits spacecraft can take and how that affects the orbital velocity of the spacecraft. There are numerous different types of orbits, each of which have their own unique advantages. A few of the most common types of orbits are listed below. Geosynchronous Orbits: According to “Satellite Signals” there are 402 satellites rotating in geosynchronous orbit. Each orbit rotates at a height of 22,236 miles above Earth’s equator, and it’s orbital period matches that of the Earth’s. Throughout the 24 hour orbital period a geosynchronous orbit does not experience much movement. The lack of movement in a geosynchronous orbit is most commonly referred to as a geostationary orbit. When a satellite is in geostationary orbit, it appears to remain in one spot for quite some time, the orbit may be slightly altered, just as much as an incline or tilt, however the longitude of the orbit remains constant. The minimal movement of the geosynchronous orbits make them ideally suited for communication via satellite. Television/cable, internet, and phone companies all utilize satellites in the geosynchronous orbit simply because the stillness of the orbit allows the connection to be a lot more reliable. Low Earth Orbits: While Geosynchronous orbits are located very high above the Earth’s equator, Lower Earth orbits are not. Low Earth Orbits are usually located somewhere between 160 km to 1000 km above the Earth’s equator. These orbits also do not follow a specific path of rotation, meaning that their plane can be tilted. This type of orbit is used quite often because of its short distance and flexibility in routes. Low earth orbits are closer to Earth, making their satellites better for things like image resolution. These types of orbits are also commonly used by the International Space station; traveling to the lower Earth orbits is easier because they are relatively close to the earth in comparison to other orbits. Medium Earth Orbits: The medium Earth orbit is the area of outer space between the Geosynchronous orbit and the low earth orbit. Spacecraft in this orbit may travel at a constant altitude or speed. Many times, this region of orbit can be used quite often, like in our navigation systems. Coverage is brought to your phone, cars, and other electronic devices, by a spacecraft in the medium Earth orbit. Transfer Orbits: Lastly, we have transfer orbits. Many aircrafts that are projected into orbit are transported there by a launch vehicle. These launch vehicles can require a lot of energy, just to get the spacecraft into the low Earth orbits. The purpose of a transfer orbit is to reduce the need for copious amounts of energy when transferring between the orbits. Using transfer orbits, a satellite can easily be transferred from one orbit to another, with the use of a launch vehicle. Now that we understand the various types of atmospheric orbits and their history, we get a better idea of how space mechanics are applied in our everyday lives. Great scientists such as Newton and Kepler used ideas from this topic to apply towards greater discoveries in the scientific world. Their discoveries were then later studied by scientists for generations thereafter, who applied the idea of space mechanics to our everyday lives. Satellites and other aircraft are launched into space to help us perform tasks, on a daily basis. As we previously mentioned, one can thank orbital mechanics for a functioning television, GPS, telephone, airplane and so much more. Space mechanics is such a crucial topic, when looking back into the history of our science. Without space mechanics there are a plethora of things that we still would not be able to do today.