This document discusses different types of satellite orbits. It defines an orbit as two bodies orbiting a common center of mass. It describes Kepler's laws of planetary motion. It then defines and compares different orbit classifications including altitude classifications like geostationary and low Earth orbits, inclination classifications, eccentricity classifications, and others. It provides details on important orbit types like geostationary, low Earth, and medium Earth orbits.

1. Satellite Orbits
GOM 221
IFFAT ARA
DEPT. OF GEOMATICS

2. What is an Orbit?
Two bodies with a difference in
mass orbiting a common
barycenter external to both bodies,
as in the Pluto–Charon system

3. What is an Orbit?
Two bodies with the same
mass orbiting a common
barycenter (similar to the
90 Antiope system)

4. What is an Orbit?
Two bodies with a major
difference in mass orbiting a
common barycenter internal
to one body (similar to the
Earth–Moon system)

5. What is an Orbit?
Two bodies with an extreme
difference in mass orbiting a
common barycenter internal to
one body (similar to the Sun–
Earth system)

6. What is an Orbit?
Two bodies with the same mass orbiting a common barycenter, external to both bodies,
with eccentric elliptic orbits (a common situation for binary stars)

7. What is an Orbit?

8. Keplar’s Law

9. Keplar’s Law
1. The Law of Orbits: All planets move in elliptical orbits, with the sun at one focus.
2. The Law of Areas: A line that connects a planet to the sun sweeps out equal areas in
equal times.
3. The Law of Periods: The square of the period of any planet is proportional to the
cube of the semimajor axis of its orbit.
Johannes Kepler developed three laws which described the motion of the planets
across the sky.

10. The Law of Orbits

11. The Law of Areas
A line that connects a planet to the sun sweeps out equal areas in equal times.

12. Angular Momentum of a Particle

13. Law of Period

14. Law of Period

15. Let’s Flow!

16. Orbital Classification

17. Orbital Classification
• Centric classifications
• Altitude classifications for geocentric orbits
• Inclination classifications
• Eccentricity classifications
• Synchronicity classifications
• Orbits in galaxies or galaxy models
• Special classifications
• Pseudo-orbit classifications

18. Centric Classification
1. Galactocentric
2. Heliocentric
3. Geocentric
4. Areocentric
5. Lunar
6. Hermocentric
7. Aphrodiocentric
8. Jovicentric
9. Kronocentric
10.Oranocentric
11.Poseidocentric

19. Altitude classifications

20. Altitude classifications

21. Orbital Shape & Size Parameter

22. Orbital Shape & Size Parameter
• Semi major Axis: Half the distance between the two points in the orbit
that are farthest apart
• Apogee/Perigee Radius: Measured from the center of the Earth to the
points of maximum and minimum radius in the orbit
• Apogee/Perigee Altitude: Measured from the "surface" of the Earth (a
theoretical sphere with a radius equal to the equatorial radius of the Earth)
to the points of maximum and minimum radius in the orbit
• Period: The duration of one orbit, based on assumed two-body motion
• Mean Motion: is the angular speed required for a body to complete one
orbit. Counted as per solar day (86,400 sec/24 hour), based on assumed
two-body motion
• Eccentricity: The shape of the ellipse comprising the orbit, ranging
between a perfect circle (eccentricity = 0) and a parabola (eccentricity = 1)

23. Geostationary Earth Orbit (GEO)

24. Geostationary Earth Orbit (GEO)
• These satellites are in orbit 35,863 km above the
earth’s surface along the equator.
• Objects in Geostationary orbit revolve around the
earth at the same speed as the earth rotates. This
means GEO satellites remain in the same position
relative to the surface of earth.

25. GEO (cont.)
• Advantages
 A GEO satellite’s distance from earth gives it a large
coverage area, almost a fourth of the earth’s surface.
 GEO satellites have a 24 hour view of a particular area.
 These factors make it ideal for satellite broadcast and
other multipoint applications.

26. GEO (cont.)
• Disadvantages
A GEO satellite’s distance also cause it to have
both a comparatively weak signal and a time delay
in the signal, which is bad for point to point
communication.
GEO satellites, centered above the equator, have
difficulty broadcasting signals to near polar
regions

27. Low Earth Orbit (LEO)
• LEO satellites are much closer to the earth than
GEO satellites, ranging from 500 to 1,500 km above
the surface.
• LEO satellites don’t stay in fixed position relative to
the surface, and are only visible for 15 to 20
minutes each pass.
• A network of LEO satellites is necessary for LEO
satellites to be useful

28. Low Earth Orbit (LEO)

29. LEO (cont.)
• Advantages
A LEO satellite’s proximity to earth compared to a
GEO satellite gives it a better signal strength and
less of a time delay, which makes it better for point
to point communication.
A LEO satellite’s smaller area of coverage is less of a
waste of bandwidth.

30. LEO (cont.)
• Disadvantages
 A network of LEO satellites is needed, which can be
costly
 LEO satellites have to compensate for Doppler shifts
cause by their relative movement.
 Atmospheric drag effects LEO satellites, causing gradual
orbital deterioration.

31. MEO (cont.)

32. Medium Earth Orbit (MEO)
• A MEO satellite is in orbit somewhere between 8,000
km and 18,000 km above the earth’s surface.
• MEO satellites are similar to LEO satellites in
functionality.
• MEO satellites are visible for much longer periods of
time than LEO satellites, usually between 2 to 8
hours.
• MEO satellites have a larger coverage area than LEO
satellites.

33. MEO (cont.)
• Advantage
 A MEO satellite’s longer duration of visibility and wider
footprint means fewer satellites are needed in a MEO
network than a LEO network.
• Disadvantage
 A MEO satellite’s distance gives it a longer time delay and
weaker signal than a LEO satellite, though not as bad as a
GEO satellite.

34. Orbital Zones

35. Other Orbits
• Molniya Orbit Satellites
 Used by Russia for decades.
 Molniya Orbit is an elliptical orbit. The satellite remains in a nearly fixed
position relative to earth for eight hours.
 A series of three Molniya satellites can act like a GEO satellite.
 Useful in near polar regions.

36. Other Orbits (cont.)
• High Altitude Platform (HAP)
 One of the newest ideas in satellite communication.
 A blimp or plane around 20 km above the earth’s surface is
used as a satellite.
 HAPs would have very small coverage area, but would have
a comparatively strong signal.
 Cheaper to put in position, but would require a lot of them
in a network.

37. Inclinational Orbit
• Inclined orbit: An orbit whose inclination in reference to the
equatorial plane is not 0.
• Polar orbit: An orbit that passes above or nearly above both
poles of the planet on each revolution. Therefore, it has an
inclination of (or very close to) 90 degrees.
• Polar Sun-synchronous orbit (SSO): A nearly polar orbit that
passes the equator at the same local solar time on every pass.
Useful for image-taking satellites because shadows will be the
same on every pass.

38. Inclinational Orbit
• Non-inclined orbit: An orbit whose inclination is equal to zero with
respect to some plane of reference.
• Ecliptic orbit: A non-inclined orbit with respect to the ecliptic.
• Equatorial orbit: A non-inclined orbit with respect to the
equator.
• Near equatorial orbit: An orbit whose inclination with respect to
the equatorial plane is nearly zero. This orbit allows for rapid
revisit times (for a single orbiting spacecraft) of near equatorial
ground sites

39. Eccentricity Classification
• Circular orbit
• Elliptic orbit
• Geostationary or geosynchronous transfer orbit
• Hohmann transfer orbit
• Ballistic capture orbit
• Coelliptic orbit
• Parabolic orbit
• Escape orbit
• Capture orbit
• Hyperbolic orbit
• Radial orbit
• Radial elliptic orbit
• Radial parabolic orbit
• Radial hyperbolic orbit
• Decaying orbit