Understanding Geosynchronous Orbits for Communication Satellites

  • Thread starter jaypee
  • Start date
  • Tags
    Orbit
In summary, communication satellites must be in geosynchronous orbits, meaning they remain above a fixed point on Earth's surface for sending and receiving antennas to aim at. The orbital period for a communication satellite can be infinite relative to Earth, 24 hours relative to the Sun, and 23 hours 56 minutes 4.09 seconds relative to the cosmic background. While it is not necessary for all systems to be in geosynchronous orbit, TV satellites typically use this orbit due to the cost of launching multiple satellites and the difficulty of actively tracking them.
  • #1
jaypee
Communications satellites must be in geosynchronous orbits. That is, they must remain above a fixed point on Earth’s surface, enabling sending and receiving antennas to be aimed at a fixed point overhead. What, then, must be a communication satellite’s orbital period (the time for one complete orbit around Earth)?
 
Physics news on Phys.org
  • #2
Sounds like a textbook problem. My guess is that, relative to the Earth, the orbital period is infinite, relative to the Sun, 24 hours, and relative to the cosmic background, 23 hours 56 minutes 4.09 seconds.
 
  • #3
Booda is correct and that should be self evident. Clarification though - comms satellites do NOT necessarily need to be in geo orbit. If you have enough of them you can ensure one is overhead at all times.
 
  • #4
Yes, communication satelites can broadcast over wide areas, so not all systems need to be in a geo-sync orbit, the main systems that use geo-sync are TV, because they can't afford 20 satellites to cover all the Earth at once, that is why you always point your dish towards the equator.
 
  • #5
the main systems that use geo-sync are TV, because they can't afford 20 satellites to cover all the Earth at once, that is why you always point your dish towards the equator.
Actually given the expense of launching a satellite into geo orbit, I believe the reason they do it with tv satellites is the difficulty in having every dish actively track satellites.
 

1. What is a geosynchronous orbit?

A geosynchronous orbit is an orbit around Earth where a satellite's orbital period matches Earth's rotational period, resulting in the satellite appearing to stay in a fixed position in the sky above a specific location on Earth. This is achieved by placing the satellite in an orbit 35,786 kilometers above the equator.

2. How do communication satellites use geosynchronous orbits?

Communication satellites use geosynchronous orbits because it allows them to remain in a fixed position relative to Earth, making it easier for ground stations to communicate with them. This also allows for continuous coverage over a specific region on Earth.

3. What are the advantages of using geosynchronous orbits for communication satellites?

The main advantage of using geosynchronous orbits for communication satellites is the ability to provide continuous coverage over a specific region on Earth. This is especially important for services such as television broadcasting, where uninterrupted communication is necessary.

4. What are the challenges of maintaining a geosynchronous orbit for communication satellites?

One challenge is the limited number of orbital slots available in the geosynchronous orbit. As more and more satellites are launched, it becomes increasingly difficult to find a spot to place a new satellite. Another challenge is maintaining the satellite's position in the orbit, as small changes in the satellite's speed or direction can cause it to drift away from its designated orbital slot.

5. Can geosynchronous orbits be used for other purposes besides communication satellites?

Yes, geosynchronous orbits can be used for other purposes such as weather monitoring, navigation systems, and military surveillance. However, since these orbits are limited and highly sought after, alternative orbits such as geostationary orbits (where the satellite appears to stay in a fixed position above the equator) are often used for these purposes.

Similar threads

  • Special and General Relativity
Replies
5
Views
1K
  • Electrical Engineering
Replies
5
Views
804
  • Special and General Relativity
Replies
20
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
1K
Replies
3
Views
1K
Replies
4
Views
721
  • Other Physics Topics
Replies
2
Views
1K
Replies
1
Views
950
  • Electrical Engineering
Replies
2
Views
3K
  • Special and General Relativity
Replies
26
Views
2K
Back
Top