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 • • • •

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.