Rocket Design Prelims

pro (means before or forward)

pellere (to drive)

propulsion is derived from two Latin words:

propulsion

the act of changing the motion of a body with respect to an inertial reference time

propulsion

means to push forward or drive an object forward

Newton's Third Law of Motion

propulsion of all rockets, jet engines, deflating balloons, and even squids and octopuses is explained by the same physical principle

jet propulsion

a type of motion whereby a reaction force is imparted to a vehicle by the momentum of ejected matter (gas or liquid) at high speeds

Air-breathing engines

Non-air breathing engines

Two general types of jet propulsion

Air-breathing engines

use oxygen from the atmosphere in the combustion of fuel

include the turbojet, turboprop, ramjet, and pulse-jet

jet

this term is generally used only in reference to air-breathing engines

Non-air breathing engines

carry an oxygen supply

can be used both in the atmosphere and in outer space

are of two kinds- liquid propellant and solid-propellant

rockets

non-air breathing engines are commonly called _____

Air-breathing propulsion systems

also known as "duct jet propulsion" compromises devices which entrain and energize airflow inside a duct

Air-breathing propulsion systems

they use oxygen to burn fuel stored in the flight vehicle

includes turbojets, turboprop, turbofans, ramjets, and pulsejets

turbojet engines

most widely used air-breathing propulsion system

combustion chamber

it is where the air/gas is burned with fuel to increase its temperature

turbine

a wheel-like device where the hot, high-pressure gas expands where it produces power

turboprop engines

a conventional aircraft propeller is usually mounted in front of the jet engine and in one type of engine is driven by a second, or free, turbine. This is located behind the turbine that is driving the compressor

turboprops

advantageous for small and medium-sized planes and at air speeds from 300 to 400 miles (480 to 640 km) per hour

cannot compete with turbojets for very large planes or at higher speeds

turbofan engines

combine the best of both worlds between turbojets and turboprops as it employs a duct fan located at its inlet

turbofan engines

the duct fan in front creates additional thrust, helps cool the engine, and lowers the noise output of the engine

by pass air

one stream that flows around the engine

duct fan

one of the few cons a turbofan has is that because of the introduction of the ____, these types of engines are heavier than turbojets and offers a larger area than turbojets

turboshaft engines

a type of gas turbine engine specifically designed to produce rotational shaft power rather than jet thrust

highly efficient, lightweight engines widely used where high power-to-weight ratios necessary, most notably in helicopters, ships, and industrial applications

ramjet engine

a variant of an air breathing jet engine that does not include a rotary compressor; rather, it uses the engine's forward motion to compress the incoming air

ram effect

the air into which an engine rushes at high flight speeds is partially compressed by the so called ______. If the speed is high enough, this compression can be sufficient to be called ______

flying stovepipe

a ramjet has been called ____ because it is open at both ends and has only fuel nozzles in the middle

ramjet

cannot function at zero airspeed and therefore cannot be used to power an aircraft

a ramjet equipped aircraft

requires another type of propulsion to accelerate it to a speed at which the ramjet is capable of producing thrust

subsonic

the combustion that produces thrust in the ramjet occurs at a _____ speed in the combustor

mach 5 ; scramjet

above _______ , ramjet propulsion becomes performance losses for the propulsion system. The new supersonic combustion ramjet or ____ solves this problem by performing the combustion supersonically in the burner

scramjet engine

supersonic combustion ramjet

an air-breathing engine designed for hypersonic flight (typically Mach 5+)

scramjet engine

unlike turbojets, it lacks moving parts, relying on high forward speed to compress incoming air through its inlet

burns fuel in a supersonic airstream, allowing for efficient, sufficient high-speed travel

pulse-jet engine

is similar to a ramjet, however, the combustion is intermittent or pulsing rather than continuous as in a ramjet

Non Air-Breathing Propulsion System

also called rocket propulsion

a class of jet propulsion that produces thrust by ejecting matter

working fluid or propellant

the ejecting matter stored entirely in the flying vehicle, fluid or propellant, stored entirely in the flying vehicle

chemical combustion

the energy source most commonly used in rocket propulsion

solar radiation

nuclear reactor

energy can be also supplied by these

chemical propulsion

nuclear propulsion

solar propulsion

the various propulsion devices in use can be divided into these

rocket propulsion systems

may be classified in a number ways, for example, according to energy source type or by their basic function or by the type of vehicle they propel or by their size, type of propellant, type of they propel or by their size, type of propellant, type of construction, and/or by the number of rocket propulsion units used in a given vehicle

solid-propellant rocket

the combustion chamber carries the fuel and oxidizer mixed together in a solid state

liquid-propellant rocket

the pump forces fuel and oxidizer from their tanks into the combustion chamber

chemical rocket propulsion

also known as chemical combustion

propulsion in which the thrust is provided by the product of a chemical reaction usually burning (or oxidizing) a fuel

chemical reacton

combines two or more kinds of chemicals and makes a different chemical as a product

whether they burn propellants as solid or as liquid

chemical rocket propulsion systems are classified into two general types according to _______

solid systems

usually called motors

liquid systems

referred to as engines

LIQUID PROPELLANT. rocket engines

use propellants stored as liquids that are fed under pressure from tanks into a thrust chamber

bipropellant

monopropellant

sub-classifications of liquid stored propellants

bipropellant

common liquid rocket

uses two separate propellants, a liquid fuel and liquid oxidizer. these are contained in separate tanks and are mixed only upon injection into the combustion chamber

monopropellants

certain liquid chemicals can be made to form hot gas for thrust production by decomposition in a rocket chamber such as ______

hydrogen peroxide

most common monopropellant

gas pressure feed systems

used mostly on low thrust, low-total-energy propulsion systems, such as those used for attitude control of flying vehicles

pump-fed liquid rocket systems

most common in applications needing larger amounts of propellant and higher thrust, such as those in space launch vehicles

SOLID PROPELLANT rocket motors

the ingredients to be burned are already stored within combustion chamber or a case

grain

in the solid-chemical rocket, the fuel and oxidizer are intimately mixed together and cast inro a solid mass, called a _______

perforation

a hole that may be shaped in various ways, as star, gear or other more unusual outlines

perforation shape and dimension

affects the burning rate or number of pounds of gas generated per second and thereby the thrust of the engine

GASEOUS PROPELLANT rocket engine

use a stored high-pressure gas, such as air, nitrogen, or helium as working fluid

HYBRID PROPELLANT rocket propulsion systems

employ both liquid and solid propellant storage

most frequent for such combination is to have the oxidizer in a liquid state and the fuel in solid state

Classic hybrid propellant mixture: liquid oxidizer- solid fuel

Inverse hybrid propellant mixture: solid oxidizer- liquid fuel

Quasi-hybrid propellant mixture: liquid oxidizer- fuel rich solid propellant

Inverse hybrid propellant mixture: oxygen rich solid propellant- liquid fuel

Types of Hybrid Propellant Combinations

NUCLEAR ROCKET ENGINES

type of liquid propellant rocket engine where the power input comes from a single nuclear reactor and not from any chemical combustion

1960s

during this, an experimental rocket engine with a nuclear fission graphite reactor was built and ground tested with liquid hydrogen as the propellant (specific impulse of 848 sec, thrust over 40,000 lbf)

fission reactor

radioactive isotope decay source

fusion reactor

Types of Nuclear Rocket Engines

NUCLEAR FISSION REACTOR rocket

heat can be generated by the fission of uranium in the solid reactor material and subsequently transferred to the working fluid

nuclear fission rocket

primarily a high-thrust engine (above 40,000 N) with specific impulse values up to 900 sec

ISTOPE DECAY engine

in this, a radioactive material gives off radiation, which is readily converted into hear

isotope decay sources

have been used successfully for generating electrical power in space vehicles and some have been flown as a power supply for satellites and deep space probes

provides usually a lower thrust and lower temperature than the other types of nuclear rocket

fusion

the third nuclear method of creating nuclear energy than can heat a working fluid

electric rocket propulsion

a class of propulsion which makes use of electrical power to accelerate a propellant by different possible electrical and/or magnetic means

separate

in all electric propulsion the source of the electric power is physically _____ from the mechanism that produces the thrust

electrostatic engine

ion propulsion

electromagnetic engine

magneto-plasma

ion rocket ; xenon

in an _______, a working fluid, typically _____, is ionized (by stripping off electrons) and then the electrically charged heavy ions are accelerated to very high velocities ( 2000 - 60000 m/s) by mean of electrostatic fields

electrical plasm

an energized hot gas containing ions, electrons and neutral particles

magneto-plasma

in this rocket, as electrical plasma is accelerated by the interaction between electric currents and magnetic fields and ejected at very high velocity (1000 - 50000 m/s)

solar cell

also called photovoltaic cell

any device that directly converts the energy of light device directly converts the energy of light intro electrical energy through photovoltaic effect

silicon

the overwhelming majority of solar cells are fabricated from this

solar cells

unlike batteries or fuel cells, these do not utilize chemical reactions or require fuel to produce electric power, and electric generators, they do not have any moving parts

well developed and have been successful for several decades

most electric propulsion systems have used these for their power supply

solar thermal rockets

an attractive concept that were first proposed in 1954 as a way to provide greater specific impulse than chemical rockets

these devices use the sun's energy to heat a propellant (typically hydrogen) to extremely high temperatures and then expel the hot gas through a nozzle to provide thrust

solar thermal rockets

have been of either a "direct gain" design in which the propellant is heated directly by very large solar collectors during a long continuous burn or of a "thermal energy storage"

thermal energy storage

a design which collects and stores energy from smaller collectors for use in short pulse burns

solar sail

basically a big photon reflector surface

power source is the sun and it is external to the vehicle

Nanosail-D

a nanosatellite that deployed NASA's first-ever solar sail in low-earth orbit

completed its earth orbiting mission after spending more than 240 days "sailing" around the earth

Nanosail-D

launched to space Nov 19, 2010 as a payload on NASA's FASTAT sail deployed on Jan 20

Solar Sail Demonstration (Sunjammer)

a Technology Demonstration Mission in 2011

intended to prove the viability and value of using a huge, ultra thin sail unfurling in space and using the pressure of sunlight itself to provide propellant-free transport, hovering and exploration capabilities

2015

it is when NASA has abandoned plans to fly a solar-sail mission after investing four years and more than $21 million on the project

space launch vehicles (space boosters)

can be classified broadly as expendable or recoverable/reusable

earth orbit or a moon landing

each space launch vehicle has a specific space flight objective such as ______

two and five stages

earth orbit or a moon landing uses between _____ stages, each with its own propulsion system and each is usually fired sequentially after the lower stage is expended

specific space trajectory

the number and types of maneuvers

the energy content of a unit mass of the propellant

the number of rocket stages depends on:

rocket staging

the combination of several rocket sections, or stages, that fire in a specific order and then detach, so a ship can penetrate Earth's atmosphere and reach space

about five miles per second

orbital speed that must be maintained by a rocket to stay in orbit around eath

jettisons

when the fuel/oxygen for each stage of a rocket is used up, the ship ____ that stage and it falls back to earth

rocket's mass fraction

the portion of a rocket fully fueled pre-launch mass that does reach orbit

drag

a force that pushes against the propelled object that must be opposed by a rocket

decreases

as the spaceship moves away from earth and further in atmosphere, air density ______

zero ; drag

out in the vacuum of space, the density is essentially ____, so there is virtually no _____

available power ; drag

the difference in rocket engine types not only create a disparity in _____ but also on the _____ produced by each rocket

stacked or parallel

common rocket stages are typically this

two-stage rocket

common but space programs have successfully launched rockets with as many as five separate stages

serial staging

in this staging, there is a small, second stage rocket that is placed on top of a larger first stage rocket

was used on the Saturn v moon rockets