Rocket Types

EGR 4347 Analysis and Design of Propulsion Systems

Rocket Propulsion

Ideal Rocket Thrust

Specific Impulse

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Rocket Propulsion

Rocket Propulsion Elements – Sutton and Biblarz

Rocket Propulsion

Rocket Propulsion Elements – Sutton and Biblarz

Rocket Propulsion

Chemical Rockets

Liquid – typical O2 and H2

Solid

Scientific American – March 2000

Liquid Rockets

Scientific American – March 2000

Solid Rockets

Scientific American – March 2000

Solid Rockets

Rocket Performance – Mars Mission

Thrust – force 1 N ¼ lbf

Exhaust Speed – Measure of fuel efficiency Sample Burn Time – How long the rocket must fire to

accelerate a 25-ton payload from low earth orbit to escape velocity. The time is inversely related to the thrust.

Sample fuel ratio – fraction of the total spacecraft mass taken up by propellant. The amount of fuel is exponentially related to the exhaust speed.

Scientific American – March 2000

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110K 4.5 21 min 55

Nuclear Rockets

Tested in 1960s Hydrogen heated to

2,500 deg C

Reactors can generate electricity

Public opposition

Scientific American – March 2000

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110,000 4.5 21 min 55

Nuclear 67,000 9.0 27 min 32

ION

1950s Electrical fields

accelerate particles

Scientific American – March 2000

Fuel – cesium or xenon Cathode dumps

electrons into flow at exit Grids get in the way

ION

Rocket Propulsion Elements – Sutton and Biblarz

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110,000 4.5 21 min 55

Nuclear 67,000 9 27 min 32

Ion 30 30 79 days 22

Hall Effect

1970s Russia Radial Magnetic Field

Xenon No grids

Scientific American – March 2000

Hall Effect

Rocket Propulsion Elements – Sutton and Biblarz

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110,000 4.5 21 min 55

Nuclear 67,000 9 27 min 32

Ion 30 30 79 days 22

Hall Effect 30 15 90 days 38

Magnetoplasmadynamic (MPD)

Scientific American – March 2000

Magnetic acceleration Magnetic field electrically generated

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110,000 4.5 21 min 55

Nuclear 67,000 9 27 min 32

Ion 30 30 79 days 22

Hall Effect 30 15 90 days 38

MPD 100 20 - 100 21-25 days

6.7 - 31

Pulsed Inductive Thruster (PIT)

Argon Fuel Radial Magnetic Field

200 times a second No electrodes

Scientific American – March 2000

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110,000 4.5 21 min 55

Nuclear 67,000 9 27 min 32

Ion 30 30 79 days 22

Hall Effect 30 15 90 days 38

MPD 100 20 - 100 21-25 days

6.7 - 31

PIT 20 50 110 days 14

VASIMR

Variable Specific Impulse Magnetoplasma Rocket

Radio waves heat fuel

Ionized propellant (Hydrogen)

Magnetic fields

Scientific American – March 2000

VASIMR

Rocket Performance

Type Thrust (N) Exhaust Speed (km/s)

Burn Time Fuel ratio (%)

Chemical 110,000 4.5 21 min 55

Nuclear 67,000 9 27 min 32

Ion 30 30 79 days 22

Hall Effect 30 15 90 days 38

MPD 100 20 - 100 21-25 days 6.7 - 31

PIT 20 50 110 days 14

VASIMR H 40 300 53 days 2.4

VASIMR L 1,200 10 2.1 days 46

Solar Sails

Scientific American – March 2000

9 N per square km Large fragile structure NASA working on Magnetic “sail” to catch sun

particles