PPt shows the movement of satellites around the earth. Escape Velocity. Apogee and Perigee. GPS.

1. COMSAT
INSAT
TV TOWER MOSCOW
OSTANKINO
577 m

2. ORBITAl ELEMENTS

3. 1. Planets move in elliptical orbits with the
sun as one focus
Johannes Kepler (1571 – 1630)
German mathematician, astronomer
and astrologer

4. a
b
e=0
0<e<1
e=1
e>1

5. 2. the radius vector from the sun to the planet sweeps
out equals areas in equal times
3. T2 : r3 ratio is constant for all planets, where T is
orbital period and r is semi-major axis of the orbit
T2 = (4π2/μ).r3
μ=3.986004418 .10 14 m3/s2= Kepler constant=Gme

6. Geometry in Orbit Plane
Semi-major Axis a
Eccentricity e

7. Geometry of Orbit in Space
INCLINATION (i) 0o ≤ I ≤ 180o
Equatorial orbit i= 0o or i=180o
Polar orbit i= 90o
Prograde orbit 0o ≤ I ≤ 90o orbiting Eastward
around Earth
Retrograde orbit 90o ≤ I ≤ 180o orbiting Westward
around Earth

8. Right Ascension of Ascending Node (Ω) 0o ≤ I ≤ 360o
( Celestial Longitude)
Argument of Perigee (ω) 0o ≤ I ≤ 360o
True Anomaly (ν) 0o ≤ I ≤ 360o

10. Six Orbital Elements

11. Impact of each of the elements on Orbit

12. Impact of each of the elements on Orbit

14. Newton discovered the laws of gravitation and explained planetary
and satellite orbits in terms of the balance of forces:
1. Centripetal acceleration
2. Centrifugal force
Isaac Newton (1643 - 1727)
English physicist, mathematician, astronomer, theologian)
2
r
m
FIN


r
v
mFOUT
2


15. Sources of Perturbations
Earth Gravitational Field
Air Drag
Solar Radiation
Sun/Moon Influence
Thruster Activity
Others (e.g. planets, albedo)

16. Earth's gravity
measured by
NASA's GRACE
mission,
showing
deviations from
the theoretical
gravity of an
idealized
smooth Earth,
the so called
earth ellipsoid.
Red shows the areas where gravity is stronger than the smooth,
standard value, and blue reveals areas where gravity is weaker.
Non –uniorm Gravitation of the Earth

17. . Orbit Perturbations
Air Drag
• Generally decrease of semi-major
axis
• For elliptical orbits decrease of
apogee height
• For circular orbits decrease of orbital
height
• Decrease of orbital period (increase
of satellite velocity)
• Depending on Solar activity (Solar
Flux)

20. Azimuth by definition
North is 0 deg, East is 90 deg, South is 180 deg and west is 270
deg. North can also be called 360 deg.
e
e
e

22. Look Angles Chart for
Geostationary satellite

30. After Deployment
26 m
Stowed ( Before Launch):
3.8 m

31. A GSLV in the VAB before
launch
ISRO
Size
Height 49 metres (161 ft)
Diameter 2.8 metres
Mass 402,000 kilograms
Stages
Capacity
Payload to
LEO 5000 kg

34. Space Shuttle : Reusable

35. Frequency (GHz)

37. en.wikipedia.org/wiki/Geosynchronous_satellite