Where is low earth orbit

It is similar to LEO in that it also does not need to take specific paths around Earth, and it is used by a variety of satellites with many different applications. It is very commonly used by navigation satellites, like the European Galileo system pictured. Galileo powers navigation communications across Europe, and is used for many types of navigation, from tracking large jumbo jets to getting directions to your smartphone.

Galileo uses a constellation of multiple satellites to provide coverage across large parts of the world all at once. Satellites in polar orbits usually travel past Earth from north to south rather than from west to east, passing roughly over Earth's poles.

Satellites in a polar orbit do not have to pass the North and South Pole precisely; even a deviation within 20 to 30 degrees is still classed as a polar orbit. Polar orbits are a type of low Earth orbit, as they are at low altitudes between to km. Sun-synchronous orbit SSO is a particular kind of polar orbit.

Satellites in SSO, travelling over the polar regions, are synchronous with the Sun. This means that the satellite always visits the same spot at the same local time — for example, passing the city of Paris every day at noon exactly.

This means that the satellite will always observe a point on the Earth as if constantly at the same time of the day, which serves a number of applications; for example, it means that scientists and those who use the satellite images can compare how somewhere changes over time. This is because, if you want to monitor an area by taking a series of images of a certain place across many days, weeks, months, or even years, then it would not be very helpful to compare somewhere at midnight and then at midday — you need to take each picture as similarly as the previous picture as possible.

Therefore, scientists use image series like these to investigate how weather patterns emerge, to help predict weather or storms; when monitoring emergencies like forest fires or flooding; or to accumulate data on long-term problems like deforestation or rising sea levels. Often, satellites in SSO are synchronised so that they are in constant dawn or dusk — this is because by constantly riding a sunset or sunrise, they will never have the Sun at an angle where the Earth shadows them.

A satellite in a Sun-synchronous orbit would usually be at an altitude of between to km. At km, it will be travelling at a speed of approximately 7. Transfer orbits are a special kind of orbit used to get from one orbit to another. When satellites are launched from Earth and carried to space with launch vehicles such as Ariane 5, the satellites are not always placed directly on their final orbit. Often, the satellites are instead placed on a transfer orbit: an orbit where, by using relatively little energy from built-in motors, the satellite or spacecraft can move from one orbit to another.

This allows a satellite to reach, for example, a high-altitude orbit like GEO without actually needing the launch vehicle to go all the way to this altitude, which would require more effort — this is like taking a shortcut. Reaching GEO in this way is an example of one of the most common transfer orbits, called the geostationary transfer orbit GTO. Orbits have different eccentricities — a measure of how circular round or elliptical squashed an orbit is. In transfer orbits, the payload uses engines to go from an orbit of one eccentricity to another, which puts it on track to higher or lower orbits.

After liftoff, a launch vehicle makes its way to space following a path shown by the yellow line, in the figure. At the target destination, the rocket releases the payload which sets it off on an elliptical orbit, following the blue line which sends the payload farther away from Earth. The point farthest away from the Earth on the blue elliptical orbit is called the apogee and the point closest is called the perigee. When the payload reaches the apogee at the GEO altitude of 35 km, it fires its engines in such a way that it enters onto the circular GEO orbit and stays there, shown by the red line in the diagram.

So, specifically, the GTO is the blue path from the yellow orbit to the red orbit. For many spacecraft being put in orbit, being too close to Earth can be disruptive to their mission — even at more distant orbits such as GEO. Bliley now offers high-performance timing and communications technology specifically for LEO and space applications. Learn how we can take your space application further! Inside Frequency Control.

In this post, we're going to answer: What exactly is the purpose of these large LEO constellations? Why are so many satellites needed? How are LEO satellites different from traditional satellites? Which frequency bands will these constellations operate on? Who are the current major players in this space? So, hold on tight! What is the purpose of large LEO Satellite constellations? Source: www. Luckily, with the new developments in LEO satellite constellations, this is about to change.

This leads us to… Q2. Why are so many satellites Low Earth Orbit satellites used? How are these LEO satellites different from traditional satellites? Some of the main limitations of GEO satellites as opposed to LEO SATs include: The entire frequency spectrum is shared across the entire coverage area Many users on one single satellite coverage area There is no coverage around the polar caps There are limitations and challenges for mobile antennas on the ground with respect to pointing to a GEO satellite as as the mobile antenna moves further away in longitude from the orbital slot location effectively called the skew angle to the spacecraft in GEO orbit Q4.

Which frequency bands will LEO satellite constellations operate on? Did we answer all your questions? Search for a Topic Search. See What's Popular. Disclosure: This blog contains product affiliate links to help support the blog. We only link trusted, well-rated products. Epic Content. Blog Resources Privacy Policy. Satellites in this orbit travel at a speed of around 7.

However, individual LEO satellites are less useful for tasks such as telecommunication, because they move so fast across the sky and therefore require a lot of effort to track from ground stations.

Instead, communications satellites in LEO often work as part of a large combination or constellation, of multiple satellites to give constant coverage. This lets them cover large areas of Earth simultaneously by working together.