Geostationary satellites how many

Meteosat Second Generation has a geostationary orbit A stationary satellite provides the advantage for remote sensing that it always views the Earth from the same perspective, which means that it can record the same image at brief intervals. Meteosat and other satellites in geostationary orbit There are a number of weather satellites evenly distributed in geostationary orbit all around the world to provide a global view.

Like Thank you for liking You have already liked this page, you can only like it once! Focus on. Since the Sun and Earth are in a single line, satellites at this location only need one heat shield to block heat and light from the Sun and Earth. The third Lagrange point is opposite the Earth on the other side of the Sun so that the Sun is always between it and Earth.

A satellite in this position would not be able to communicate with Earth. Closer to the Earth, satellites in a medium Earth orbit move more quickly. Two medium Earth orbits are notable: the semi-synchronous orbit and the Molniya orbit. The semi-synchronous orbit is a near-circular orbit low eccentricity 26, kilometers from the center of the Earth about 20, kilometers above the surface.

A satellite at this height takes 12 hours to complete an orbit. As the satellite moves, the Earth rotates underneath it. In hours, the satellite crosses over the same two spots on the equator every day. This orbit is consistent and highly predictable. The second common medium Earth orbit is the Molniya orbit.

Invented by the Russians, the Molniya orbit works well for observing high latitudes. The Molniya orbit offers a useful alternative. The Molniya orbit is highly eccentric: the satellite moves in an extreme ellipse with the Earth close to one edge. As it moves away, its speed slows, so it spends more time at the top of its orbit farthest from the Earth. A satellite in a Molniya orbit takes 12 hours to complete its orbit, but it spends about two-thirds of that time over one hemisphere.

Like a semi-synchronous orbit, a satellite in the Molniya orbit passes over the same path every 24 hours. This type of orbit is useful for communications in the far north or south. Most scientific satellites and many weather satellites are in a nearly circular, low Earth orbit. Therefore, it has a relatively low inclination 35 degrees , staying near the equator. In this highly inclined orbit, the satellite moves around the Earth from pole to pole, taking about 99 minutes to complete an orbit.

During one half of the orbit, the satellite views the daytime side of the Earth. At the pole, satellite crosses over to the nighttime side of Earth. As the satellites orbit, the Earth turns underneath. The drawback is the satellite is limited to a small parcel of ground; if a natural disaster happens elsewhere, for example, the satellite won't be able to move there due to fuel requirements.

This is a large benefit for the military. If, for example, the United States is concerned about activities in a certain region of the world — or it wants to see how its troops are doing — a geosynchronous orbit allows constant pictures and other surveillance of one particular region.

Joining a "constellation" of four other WGS satellites, it extends the military's communications system to provide blanket coverage over virtually the entire planet. The network serves troops, ships, drones and civilian leaders and is supposed to provide communications for ground personnel. Communications for civilians also benefit from geosynchronous orbit. There are numerous companies that provide telephone, Internet, television and other services from satellites in that orbital slot.

Because the satellite is constantly hovering over one spot on the ground, communications from that location are reliable as long as the satellite is well connected to the location you want to communicate with. According to Satellite Signals , there are satellites in geosynchronous orbit. However, there are obvious space and technological limitations. The International Telecommunication Union assigns slots for geosynchronous orbit and settles disputes between countries about slots.