The elliptical orbit indicates the movement of the planets around the Sun.
An elliptical orbit is the ellipse-shaped path that an object follows around a central point due to the influence of gravity , as happens with the planets around the Sun. In this type of orbit, the distance between the object and the center Attraction varies, being lowest at perihelion (closest point) and highest at aphelion (farthest point). Elliptical orbits are common in planetary and satellite systems.
Theoretical foundations of the elliptical orbit
An elliptical orbit is the result of the gravitational interaction between two bodies, as described by Isaac Newton's law of universal gravitation . According to Kepler's laws (Johannes Kepler), planets and other celestial objects follow elliptical orbits, with a focus of an ellipse coinciding with the center of mass of the system, generally occupied by the most massive object (such as the Sun in the case of the Solar system).
Orbital eccentricity is a measure of how elongated the orbit is and is expressed as a value between 0 and 1, where 0 represents a perfectly circular orbit and values close to 1 indicate a very elongated or eccentric orbit. Eccentricity is key to determining the shape of the orbit and the variations in the speed of the object along its path.
The elements of an elliptical orbit include:
- semimajor axis : half the length of the greatest distance between the ends of the ellipse;
- semi-minor axis : half the length of the shortest distance between the ends of the ellipse;
- focus of an ellipse : two points inside the ellipse, one of which is occupied by the central body;
- Periapsis and apoapsis : Periapsis is the point of an elliptical orbit at which the orbiting object is closest to the central body. Apoapsis is the point in the orbit at which the object is furthest from the central body.
The circular orbit above the Earth's equator is called geostationary .
Types of elliptical orbits
In the context of space exploration and satellite technology, elliptical orbits play a crucial role, allowing satellites and spacecraft to perform various functions. These orbits vary in altitude and orientation, each with specific characteristics adapted to their missions. They offer practical solutions to various space missions, optimizing resources and maximizing efficiency in satellite coverage and performance.
Geostationary orbit
This is a circular orbit approximately 35,786 km above the Earth's equator, where a satellite moves at the same angular speed as the Earth's rotation. This allows it to stay over a fixed point, which is ideal for communications and weather observation.
Geosynchronous orbit
It is similar to the geostationary orbit, but may be inclined with respect to the equator. A satellite in this orbit returns to the same point on Earth within a 24-hour period, which is useful for certain communication and monitoring applications.
Low Earth Orbit (LEO)
It is located at an altitude between 160 and 2000 km above Earth. It is used by observation satellites, the International Space Station and short-range telecommunications satellites, due to its proximity to the Earth's surface and lower launch cost.
Medium Earth Orbit (MEO)
This orbit is between 2000 and 35,786 km altitude, and is where the global positioning system (GPS) satellites and some telecommunications satellites are located. Offers a balance between coverage and signal delay time.
High Earth Orbit (HEO)
Orbits with an altitude greater than 35,786 km are considered high altitude. They are mainly used for satellites that need wide coverage or long-distance observation missions, including astronomical studies.
Sun-synchronous orbit
A satellite in this orbit passes over the same point on Earth at the same local solar time in each revolution. This is essential for Earth observation missions that require constant solar illumination.
polar orbit
A satellite in polar orbit passes over the Earth's poles, allowing it to cover almost the entire surface of the Earth over the course of multiple orbits. It is key for scientific and global climate observation missions.
Hohmann transfer orbit
This elliptical orbit is used to move an object from one circular orbit to another with the least possible fuel expenditure. It is common in interplanetary and satellite transfer missions at different altitudes.
Elliptical orbits are essential for the initial phases of flight.
Applications and advances in space exploration
The elliptical orbit is fundamental for a wide range of activities related to the exploration and use of space, allowing everything from the placement of satellites to the sending of interplanetary missions. Its use has been key to achieving great advances in the knowledge of space and in the development of technologies and missions that bring us ever closer to the goal of exploring and, eventually, colonizing other planets.
The following concepts show how this orbital path is key to the technologies and missions that have expanded our reach into the cosmos.
space rocket
Rockets are the vehicles responsible for placing satellites, probes and spacecraft in elliptical orbits. They take advantage of fuel efficiency to reach precise altitudes and execute maneuvers that allow objects to be positioned on their intended trajectories .
Space flight
It involves the movement of manned or unmanned spacecraft through space. Elliptical orbits are essential for the initial phases of flight, where trajectories are adjusted according to mission objectives.
space mission
Space missions, both manned and robotic, depend on elliptical orbits to optimize their energy efficiency and meet their objectives, whether it is the exploration of planets or the collection of data from deep space.
space probe
These unmanned spacecraft are designed to explore distant celestial bodies. They use elliptical orbits for flyby maneuvers and to save fuel on long journeys, as seen on the New Horizons mission to Pluto .
space telescope
Space telescopes like Hubble operate in elliptical orbits that allow them to observe the cosmos without interference from Earth's atmosphere, providing images and data fundamental to astronomy .
spaceship
Manned spacecraft use elliptical orbits for both the initial launch phases and reentry trajectories. The orbits allow the safe return of crews to Earth and also the arrival at destinations such as the International Space Station .
Space colonization
Although still in a theoretical phase, plans for the colonization of other planets, such as Mars , require precise planning of elliptical orbits for sending colonizers and resources on long-duration missions.
Space tourism
With the advances of private companies, space tourism is in its early stages. Elliptical orbits are used for suborbital journeys and for low orbits on tourist flights, such as those of the SpaceX company.
Kepler Mission
A space telescope designed to search for exoplanets, it used an elliptical orbit around the Sun. Its orbit allowed for prolonged observations without terrestrial interference, resulting in the detection of thousands of planets in other solar systems.