Satellite Motion Flashcards
State the condition needed for a satellite to be in stable motion Describe what happens to the speed of satellite if it moves closer to the Earth Discuss why a geostationary satellite must be in an orbit above the Equator
Why must a geostationary satellite have an equatorial orbit?
To have a fixed position relative to the earth’s surface
To synchronise with the earth’s rotation
Define a synchronous orbit
When an orbiting body has a time period equal to that of the body being orbited and is in the same direction of rotation as that body
Define a geosynchronous orbit
An orbit directly above a planet’s equator
State the characteristics of a geostationary orbit
- remains directly above the equator
- orbits at the same point above the earth’s surface
- Moves from west to east
- Has an orbital time period of 24 hours
What are geostationary satellites used for?
Telecommunication transmissions
- radio broadcast
- television broadcast
Why must satellite receiver dishes point to above the equator?
Because geostationary satellites are at a fixed point above the equator, the dish must point towards the same point to receive a strong signal
What is meant by a low orbit?
A satellite orbit with altitude closer to the earth’s surface
What is a polar orbit?
Where a satellite orbits around the North and South Pole of the earth
Why is it more efficient for a geostationary satellite to have an equatorial orbit?
So that only the gravitational force is required to keep the satellite in orbit
- At other latitudes additional forces are needed to keep the satellite in orbit which is less efficient
State Kepler’s 3rd Law
r3/T2 = GM/4pi2
State the condition required for a satellite to be in stable orbit
The centripetal force must equal the gravitational force
What happens to the speed of a satellite as it moves closer to Earth?
Its speed increases
State the total energy of a satellite
-GMm/2r
Derive an equation for the total energy of a satellite
Check notes
