This document discusses electric propulsion technologies for rockets. It describes three main types of electric propulsion: electrothermal, electrostatic, and electromagnetic. Electrothermal propulsion heats propellant electrically, including resistojets which heat propellant on a solid surface and arcjets which use an electric arc. Ion engines and Hall thrusters are examples of electrostatic propulsion which accelerate ions with electric and magnetic fields. Electric propulsion provides much higher specific impulse than chemical rockets, allowing for higher exhaust velocities and lower fuel usage. While slower, electric propulsion can reduce launch costs for missions where time is not critical.

1. Electric Propulsion

2. Most commonly used Rocket
Engines!!!
Chemical Rocket Engines

3. Criteria for rating Rocket performance
• Specific Impulse
• Weight of the Engine

4. What is Electric Propulsion (EP)??
The acceleration of gases for the purpose
of producing propulsive thrust by electric
heating, electric body forces, and/or
electric and magnetic body forces.

5. Specific Impulses of Various
Propulsions
 Solid & Liquid Propellants (In use)
250 s
 Best Liquid Propellants
350s
 Nuclear Rockets
1200 s
 Ion Engine
20,000 s

6. Electric Propulsion
1)
• Electrothermal Propulsion
• Propellant is electrically heated in some chamber and then
expanded through a suitable nozzle to obtain thrust.
2)
• Electrostatic Propulsion
• Propellant is accelerated by direct application of electrostatic
forces to ionized particles.
3)
• Electromagnetic Propulsion
• Propellant is accelerated under the combined action of
electric and magnetic fields.

7. Electrothermal Propulsion
 Three Subclasses of this family:(Propellant
heating)
 A)Resistojets : Heat is transferred to the
propellant from some solid surface, such as
the chamber wall or a heater coil.
 B) Arcjets : Propellant is heated by an electric
arc driven through it
 C)Radiatively Heated Devices: Highfrequency radiation heats the flow

8. Resistojets
 Chamber Temperature : 3000K , thus limiting the exhaust velocity
not exceeding more than 10km/sec. (~3500m/s)
 Propellant : Catalytically decomposed hydrazine
 Advantages : Low operational Voltage
Avoids complex power processing
 In Use : INTEL SAT V series - 1980
 Recent application : Attitude control, Orbit insertion and
deorbit of LEO satellites, including 72 satellites in the
Iridium Constellation.

10. Arcjets
 Temperature range should be of 10,000 K to reach exhaust
speeds greater than 10,000m/s.
 Effective means : Passing an electric arc directly through
the chamber.
 3 segments
Cathode Fall Region
Arc Column
Anode Fall Region

11. 
Telstar-4 series of GEO communication satellites – 1993
Limitations:
1)Difficulty of providing high power in space.
2)Lifetime limiting problems of electrode erosion.
3) Whiskering.

12. Ion Engine
• Scheme of a gridded ion engine with neutralization

13. Ion Engine
NASA’s Deep Space One Ion Engine

14. Ion Engine
NASA’s Evolutionary Xenon Thruster (NEXT) at NASA’s JPL

15. Hall Thruster
The Hall effect

17. Electric Propulsion Applications
1. ISS
2. Interplanetary Missions
3. Commercial/Defense

18. Conclusion



Electric thrusters in general are about 1.5 times as
efficient as a good chemical propulsion system
A parameter called an specific impulse comes
into play here. (~20,000 s)
So why use an electric thruster? If the mission is
not time sensitive an electric propulsion system
will use less fuel, and therefore cost less to launch
into space. On average it currently costs about
$10,000 for every kilogram launched into low
Earth orbit. Therefore if time is not a crucial issue
the delay can be worth the money saved at
launch.

19. THANK YOU!!
 Presented By :
V SHYAM PRASADA RAO
shyamforever@live.com