BIT MESRA

1. DESIGN OF SUN-
SYNCHRONOUS AND
GEOSYNCHRONOUS ORBIT
Submitted by-
MD SHAHID IQNAL ANSARI
Roll No. MT/RS/10008/15

2. INTRODUCT
ION
What is an Orbit?
An orbit is a regular, repeating path that one object in space takes
around another one. An object in an orbit is called a satellite. A
satellite can be natural, like Earth or the moon. Many planets have
moons that orbit them.

3. DEFINITION OF
SYNCHRONOUS ORBIT
A synchronous orbit is an orbit where the orbital
period equals the rotation rate of the orbited body.
That is, an orbiting body (usually a satellite) has a
period equal to the average rotational period of the
body being orbited (usually a planet), and in the
same direction of rotation as that body.
So, the synchronous orbit is where the satellite has
a period equal to the average rotational period of
the planet.

4. ORBIT TYPES
Synchronous types are :
 Sun-synchronous orbit : An orbit which combines altitude
and inclination(angle between reference place and orbital
plane) in such a way that the satellite passes over any
given point of the earth surface at the same local solar
time.
It orbits at 700-800km altitude over the Earth surface and
always same orientation
 Geostationary orbit : An orbit around the Earth with an
orbital period matching the Earth’s sidereal rotation
period . It lies in the equatorial plane around earth. A
satellite in such an orbit is at an altitude of approximately
35,786 km .

5. SUN SYNCHRONOUS ORBIT
 Rate is equal to average rate of Earth’s
rotation around the sun
 Position of Sun relative to orbital plane
remains relatively constant
 Sun Synchronous orbits can be achieved
around other central bodies
 Usually near 90º inclinations

6. Sun-Synchronous:
The satellite is always in the
same relative position between
the Earth and Sun.
Equatorial-Crossing Time:
The local apparent solar time
when the satellite crosses the
equator.
Example: Terra has an
equatorial crossing time of
10:30 am, and is called an
“AM” or morning satellite.
Ascending Orbit:
The satellite is moving South
to North when that portion of
the orbit track crosses the
equator.
Descending Orbit:
The satellite is moving North
to South when that portion of
the orbit track crosses the
equator.
Period:
A typical polar, Sun-
synchronous LEO satellite
takes about 90 minutes to
completely circle the Earth.
This gives it about 16 orbits
per day.
Low Earth Orbit:
Orbiting at an altitude
of 600-1,000 km.
6

7. A geosynchronous orbit is an orbit around the Earth with an orbital
period of one sidereal day, intentionally matching the Earth's sidereal
rotation period approximately 23 hours 56 minutes and 4.9 seconds.
The synchronization of rotation and orbital period means that, for an
observer on the surface of the Earth, an object in geosynchronous
orbit returns to exactly the same position in the sky after a period of
one sidereal day.
GEO-SYNCHRONOUS ORBIT

8. ORBIT DESIGN PROCESS
 Step 1: Establish Orbit Types
 Earth referenced orbits
 GEO, LEO
 Space referenced orbits
 Lagrange points, planetary
 Transfer orbit
 GTO, Interplanetary
 Parking orbit
 Temporary orbit for satellite operational checks,
EOL

9. OUTLINE
 Orbit Design
 Orbit Selection
 Orbit Design Process
 ΔV Budget
 Launch
 Earth Coverage
 Constellation Design
 Basic Formation
 Stationkeeping
 Collision Avoidance

10. ORBIT DESIGN PROCESS
Establish Orbit-Related Mission Requirements
 Altitude
 Resolution  Lower altitude is better
 Swath width  Higher altitude is better
 Inclination
 Ground station coverage
 Lifetime
 Survivability (ambient environment)
 Must be able to survive the entire orbital profile (e.g. transit
through Van Allen Radiation Belts)

11. EARTH COVERAGE

12. THANK YOU