Launch vehicles use multi-stage configurations and rocket propulsion to inject payloads into specific orbital trajectories based on velocity and altitude, with chemical propulsion being the most common but ion engines providing higher exhaust velocities. Satellites are launched on expendable or reusable vehicles depending on their design from sites around the world, with factors like Earth's rotation sometimes providing an assist through sling effect to reduce launch costs. Over 2500 satellites currently orbit Earth for purposes including communication, and careful orbital placement prevents collisions despite increasing congestion.

1. SATELLITE COMMUNICATION
(Unit-1 Satellite Orbits)
LAUNCH VEHICLES AND PROPULSION
Prepared by
L.K.Balaji Vignesh,
Assistant Professor/ECE

2. CONTENT:
• WHAT IS LAUNCH VEHICLES AND PROPULSION
• TYPES OF LAUNCH VEHICLE
• CONCEPTS IN LAUNCHING A SATELLITE
• SOME INTERESTING FACTS ABOUT SATELLITE
COMMUNCATION

3. LAUNCHES
A satellite cannot be placed at a stable
orbit unless two parameters are uniquely
coupled together. Those parameters are,
• The velocity vector
• The orbital height

4. Launching Stages
(Proton Launch)

6. LAUNCH VEHICLES
• In space flight, a launch vehicle or carrier
rocket a is a rocket used to carry a payload
from Earth’s surface into outer space.
• A launch system includes the launch pad and
other infrastructure.
• Each orbital launch vehicles typically have
atleast two stages, often three or sometimes
four or five

7. Types of launch vehicles
• Expendable launch vehicles – Designed for
one time use.
• Reusable launch vehicles – Designed to be
recovered impact and launched again.
• We can classified the launch vehicle by,
- Amount of mass they can carry into
orbit.

8. staging
Series staging Parallel staging

9. Propulsion
• A force that pushes something forward.
• Spacecraft propulsion is any method used to
accelerate spacecraft and artificial satellites.
• Rocket engine used in spacecraft propulsion.

10. How does a rocket related to Newton’s
Third Law of motion?
• Newton’s Third Law states that “every action
has an equal and opposite reaction”.
• This law explains the generation of thrust by a
rocket engine.
• In a rocket, burning fuel creates a push on the
front of the rocket pushing it forward.
• This creates an equal and opposite push on
the exhaust gas backward.

11. 1.PRINCIPLES OF ROCKET EQUATION:

14. 2.Thrust
• Thrust is the force which moves the
rocket through the air, and through
space.
• Thrust is generated by the propulsion
system of the rocked through the
application of Newton’s Third Law of
motion.

16. 3.SPECIFIC IMPULSE
• The characteristic that is most
often used to describe the
propellant performance is called
specific impulse (Isp).

17. 4.Chemical propulsion
• Nozzle
thermodynamics:

18. 5.Solid propellants

19. 6.Ion Engines
• To achieve high
exhaust
velocities is
through the
use of engines.

20. 7.Powered Flight
• The launch vehicle
acceleration depends
on the thrust of engine.
• The thrust F increases
as the atmospheric
pressure decreases.

21. 8.Earth’s Rotation
• If correct direction can
be considered as free to
launch vehicle then it is
sometimes called sling
effect.

22. 9. Injection into the final orbit
• Parking orbit
• Transfer orbit (or) Hohmann
transfer orbit.

24. Polar satellite launch vehicle(PSLV)
• It is an Expendable launch system developed and
operated by the Indian Space Research
Organization (ISRO).
• C38-PSLV-XL
23 June 2017- 9:29AM
• 29 Nano satellite from 14 countries…
• Total weight 955kg.
• 37 crore($5.7million)

27. Some interesting facts about satellite
communication:
• There are over 2500 satellites in orbit round
the earth.
• Geostationary satellite orbit the equator at
the speed of the Earth’s rotation so seem not
to move.
• In 2009 two communications satellites, from
the US and Russia, collided. This is the only
time two man-made satellites have collided by
accident.

28. Why don’t satellite crash into each
other?

29. Youtube Videos:
https://www.youtube.com/watch?v=JyaYF9tpEQw
https://www.youtube.com/watch?v=Tk338VXcb24