CRICOS No. 00213J a university for the world real R ENB443: Launcher Systems Image Credit: ESA Caption: The generic Ariane-5 (Ariane Flight 162) lifting

CRICOS No. 00213Ja university for the worldrealR

ENB443: Launcher Systems

Image Credit:ESA

Caption:The generic Ariane-5 (Ariane Flight 162) lifting off from the Guiana Space Centre, Europe’s spaceport at Kourou, French Guiana.


Today’s Key Learning Objectives

Today’s Key Content:• Examples of Launcher Systems and Rockets• Launch Sites• Launch Environment• Orbits Issues

Learning Objectives:

1. Motivation: Why rockets important.


Launcher Systems: Summary

• Introduction and Overview• Examples of Launcher Systems and Rockets• Launch Sites• Launch Environment• Orbits Issues


Introduction

• Roles/attributes of Launch System:– Places S/c in orbit.– Protects S/c during launch.– Create a severe environment.– Delta-Velocity is fundamental measure of

performance.

• A “launcher system” involves:– One of more rocket stages.– Ground station + launch infrastructure.


Introduction (cont.)

• Launcher system typically designed in different organisation than satellite.– Launch payload = whole s/c to be put in orbit.

Everything above the “boost adaptor”.

• Yet, launch process can constrain S/C design:– Lift capacity (mass and dimensions).– Severe environment during launch:

• Force/shock/vibrations/pressure, etc.


Overview: Basic Orbit Injection

Three distinct phases:

1. Vertical launch, followed by turn manoeuvre.

2. Elliptical ballistic trajectory

3. Orbit insertion burn at orbit apogee.

Apogee burn

Image Credit:NASA


Overview: Basic Orbit Injection

Image Credit:braeunig


Overview: Basic Launch Equation

• Basic performance characterised by velocity.• We can estimated the velocity required from the launch

vehicle as:

where

draggravityburnoutdesign VVVV velocityrequired is designV

orbit desiredreach to velocity is burnoutV

losseslocity gravity ve is gravityV

losses velocity drag is dragV


Overview: Launch Losses

Image Credit:SMAD, p. 722

The actual losses experienced are system dependent.


Overview: Launch Reliability


• Has slowly increased from 0.85 to 0.95 in the last 30 years.


Overview: Basic S/C Deployment Options

• 3 main deployment options:1. Direct injection by launch system.

2. Using various vehicle/stage configurations.

3. Injection using integral propulsion system (kick stage).

• Small payloads typically use option 1.• GEO satellites typically need to augment launch

vehicles with upper stage.• Third option allows us to both orbit injection and

maintain orbit/attitude (if engine restart possible).


Overview: Option 2 - Upper Stage

• An extra stage added to launch system– Not part of satellite.– Different from integral propulsion system (or “Kick”

motor).– Discarded during transfer orbit or once final orbit

reached.• Once discarded, designed to avoid other GEO satellites.


Launcher Systems: Overview

Image Credit:N. A. Bletsos

Orbit insertion Burn: Upper stage?

Launcherstage burns



• Introduction and Overview• Examples of Launcher Systems and Rockets

– Shuttle/ESA– Rocket stages– Upper Stages.

• Launch Sites• Launch Environment• Orbits Issues

CRICOS No. 00213Ja university for the worldrealR Image Credit:

SMAD, p. 728

Notes:- Both mass and dimensional constraints.- Mass constraints dependon desired orbit.

Ariane 5 ECA is a higher capacity Ariane 5 Generic launcher. Designed to place up to9 tonne in GTO (geosynchronous transfer orbit).

GTO means mass placed on Holmann Transfer orbit to GEO.Apogee burn required at GEO.

A bit dated.. Up to Delta IV andAtlas V.


GTO: Transfer orbit?

Image Credit:Braeunig

Or Holmann transfer orbit

Apogee burn required at GEO.

Typ. Low earth orbit

GEO


Space Shuttle: From Nixon (1972) to 2010An expressive commercialoption.. Real cost > 6 timesAtlas-Centaur or Ariane cost.

By 2010 phase-out131 successful missionsover a 30 year life.In 1973, was “sold” as 580 missions over 12 years.


ESA Launcher System: Current

• An Ariane 5G rocket engine

Image Credit:ESA


Rocket Engines Stages

Some pictures of:• Liquid

– RL10– RS-68

• Solid– Atlas V solid rocket motor (booster stage)

• Note: Atlas V has liquid stages, and various configurations.


RS-68

• The Delta IV RS-68 main engine is the world's most powerful hydrogen/oxygen engine.

• Bi-propellant

Image Credit:NASA


Atlas V solid rocket motor

Image Credit:International Launch Services


RL10

• The RL10 engine propels the Delta IV and Atlas V upper stages to their final orbit for payload delivery.

• Initial version used in the Surveyor program (Late 1960s). Upgrade version, still used today… 45 years..

Image Credit:US Air Force


Upperstages




• Introduction and Overview• Examples of Launcher Systems and Rockets• Launch Sites

– Sites– Direction– Launch Related Orbit Issues

• Launch Environment• Orbits Issues


Launch Sites

• Launch from near the equator is preferred:– To take maximum advantage of easterly rotation of

the Earth.

• Launch from higher latitudes cannot easily access orbit inclination below their latitude.– 1 degree of inclination change ~ 210m/s delta-v in

LEO.– The Delta-V cost of inclination changes decreases

with altitude. Hence ??? • are typically done towards the end of the transfer orbit.


Launch Sites



Launch Directions


Western RangeEastern Range

Why not out here?

Retrograde launch


Launch Performance


Mini-Quiz: Which systemto put 10,000kg in LEO?

Answer: Assume LEOis 300km, then red boxsuggests: Proton, Titan IV or Zenit.


Polar Launch performance




• Introduction and Overview• Examples of Launcher systems and Rockets• Launch Sites• Launch Environment

– Accelerations and Shocks– Vibration and Fundamental Frequencies– Pressure

• Orbits Issues

Sort of numbers might be requiredin structure sub-systemdesign


Launch Acceleration loads.


During several important events.


Fundamental Frequencies.


Payload/boost-adaptor stiffness should be above these.


Vibration loads


But payload/adaptor stiffness should avoid these.That is, dampen vibration energy at these frequencies.


Shock Environment.


Often payload separation by pyrotechnic device. Causes a shock load. For example:

CRICOS No. 00213Ja university for the worldrealR Image Credit:

SMAD, p. 737

Must withstand and ventpressure differentials

Fairing and PressureLowpressure

Highpressure


Launch Differential Pressures




• Introduction and Overview• Examples of Launcher Systems and Rockets• Launch Sites• Launch Environment• Orbits Issues

– Accuracy– Ground tracks– Orbital Transfers


Injection Accuracy

• Important because injection errors typically need to be corrected:– Often the job of the last stage of launcher.– Might require some of the mission delta-v budget.


Ground Tracks


L =change in longitude


Points from Figure

• E is geosynchronous.– Question: Period of E is ? – Answer: 1436 mins (matching Earth rotation).

• An orbit’s inclination can be determined by the ground tracks maximum latitude. (SMAD p. 138).– Question: Geostationary has a maximum latitude of?– Answer=0 degrees (ie. at/above the equator).

• Retrograde orbit track ground tracking in an westerly direction. (Direct orbits shown in the figure).


Least Energy Transfer



Fastest Transfer


These are larger


Transfer Orbits

• Often, satellite is initially placed in low-earth orbit.

• Must transition to operational orbit.


Remember their lowthrust profile


Today’s Key Learning Objectives

Today’s Key Content:• Examples of Launcher Systems and Rockets• Launch Sites• Launch Environment• Orbits Issues

Learning Objectives:

1. Motivation: Why rockets important.

Documents

CRICOS No. 00213J a university for the world real R ENB443: Launcher Systems Image Credit: ESA Caption: The generic Ariane-5 (Ariane Flight 162) lifting