Satellite Orbits: Meteostat Geostationary Orbit Explained

In summary, the periodic time of the Meteostat satellite in the geostationary orbit is not exactly equal to 24 hours when viewed from the equator due to mean motion measuring revolutions per sidereal day instead of per solar day. This is because a sidereal day measures the time for the Earth to rotate 360 degrees while a solar day measures the time from the Sun being directly overhead to the next time it is directly overhead. Additionally, orbital perturbations from various sources can also affect the satellite's orbit and cause it to drift, requiring adjustments from the operators. The inclination of the orbit does not affect the period, but it can affect the shape of the satellite's ground track.
  • #1
Jack16
13
0
Hi People ,Could You Please help me with this question...

There's a satellite called Meteostat which in the geostationary orbit.Could you explain me why its periodic time is not exactly equal to 24 when it is viewed by an observer positioned at a point on the equator...
 
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  • #2
Where are you getting the idea that it doesn't take 24 hours to reach the same same point above the Earth? If you're looking at mean motion in two line element sets (about 1.0027), it's because mean motion is measuring revolutions per sidereal day, not per solar day.

A sidereal day is measuring the amount of time for the Earth to rotate 360 degrees and a solar day is measuring the amount of time from the Sun being directly overhead to the next time the Sun is directly overhead.
 
  • #3
A sidereal day being 23 hours, 56 mins and 4 seconds.
 
  • #4
It may be that Meteostat is either slightly above or below the required altitude for a 24 hour orbit; or its inclination may not be exactly 0 degrees.
 
  • #5
If you're getting extremely precise, it's almost never exactly at a geosynchronous altitude. Orbital perturbations from the Earth's triaxiality, the Sun, the Moon, and (to a much lesser extent) the planets pull it out of its desired orbit. The rate a geosynchronous satellite drifts depends upon the longitude it's stationed over. Normally, the only significant difference you'll notice is right after the operators maneuver the satellite to compensate for how much it has drifted during the last few months.

Inclination won't affect the period. It'll just affect how big of a 'figure-8' the satellite's ground track makes each orbit.
 
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1. What is a geostationary orbit?

A geostationary orbit is a circular orbit around the Earth at an altitude of approximately 35,786 kilometers (22,236 miles) above the equator. It is called "geostationary" because the satellite appears to remain stationary in the sky when viewed from a fixed location on Earth.

2. How does a satellite maintain a geostationary orbit?

To maintain a geostationary orbit, a satellite must have a specific velocity and altitude. Its velocity must match the rotation of the Earth, and its altitude must be high enough to counteract the Earth's gravitational pull. Additionally, small adjustments are made using thrusters to correct any deviations from the desired orbit.

3. What is the purpose of a meteorological satellite in a geostationary orbit?

Meteorological satellites in geostationary orbits are used to provide real-time imagery and data of the Earth's weather and climate. They are able to continuously monitor a specific area on the Earth's surface, providing valuable information for weather forecasting and disaster management.

4. How long does it take for a satellite in a geostationary orbit to complete one orbit around the Earth?

A satellite in a geostationary orbit takes approximately 24 hours to complete one orbit around the Earth. This is the same amount of time it takes for the Earth to complete one rotation on its axis, which is why the satellite appears to remain stationary from the perspective of an observer on Earth.

5. Are all satellites in geostationary orbits?

No, not all satellites are in geostationary orbits. Satellites in low Earth orbits (LEO) are much closer to the Earth and complete one orbit in a much shorter amount of time. Additionally, some satellites are placed in highly elliptical orbits, which causes them to have a longer orbital period and appear to move across the sky at a slower pace compared to geostationary satellites.

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