Transcript Sikand_Satellites - Stevens Institute of Technology

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Satellite Motion
Monika V Sikand
Ph.d Student
Stevens Institute of Technology
Department of Physics.
Light and Life Laboratory. Hoboken.
OBJECTIVE
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Review laws of motion and gravitation
Satellite motion
Escape velocity
Geosynchronous
orbit(Telecommunication satellites)
Newton’s laws of motion
I. Law of Inertia
II. F=ma
III. Action-Reaction
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Isaac Newton
January 4, 1643 -March31,1727
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What is
Gravity?
Gravity is a pulling force
It pulls things down towards the earth
Things fall because of gravity
Things always fall down
Why do people not fall off the
earth?
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Newton’s Law of Gravitation
Gravity holds everything and
every one on the earth
In Space, Gravity keeps the
planets moving around the sun
Gravity on earth and moon
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So how can we understand orbital
motion?
Motion of the ball on earth
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Example
Earth’s curvature
Satellite
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Smaller body revolving
around a larger body
Natural satellites
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Moon, planets, comet
Artificial satellites
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Weather , spy , communication
Escape velocity
Artificial satellite in a circular
orbit
around
earth
first
achieving a speed of 7900m/s.
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If
speed
greater
than
7900m/s
satellite
has
a
elliptical orbit.
If velocity greater than 11km/s
then satellite leaves earth’s
orbit and has a escape orbit.
The escape orbit’s velocity is
called escape velocity.
Figure 7-22
Satellite orbits
Geostationary Earth Orbit
(GEO)
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Orbit is synchronous
with the earths
rotation.
From the ground the
satellite appears
fixed.
Altitude is about
22,300 miles or
36,000Km.
Coverage to 40% of
planet per satellite.
Conclusion
• Newton’s law of gravitation
F =Gm1m2/r2
• Satellites are revolving bodies around
earth.
• Escape velocity is the maximum velocity
required to escape the earth’s orbit.
• Geostationary orbits are synchronized with
earth’s rotation at 36000 km of height.