cricos no. 00213j a university for the world real r enb443: launcher systems image credit: esa...
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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.
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
Launcher Systems: Summary
• Introduction and Overview• Examples of Launcher Systems and Rockets• Launch Sites• Launch Environment• Orbits Issues
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
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
CRICOS No. 00213Ja university for the worldrealR
Overview: Basic Orbit Injection
Image Credit:braeunig
CRICOS No. 00213Ja university for the worldrealR
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
CRICOS No. 00213Ja university for the worldrealR
Overview: Launch Losses
Image Credit:SMAD, p. 722
The actual losses experienced are system dependent.
CRICOS No. 00213Ja university for the worldrealR
Overview: Launch Reliability
Image Credit:SMAD, p. 727
• Has slowly increased from 0.85 to 0.95 in the last 30 years.
CRICOS No. 00213Ja university for the worldrealR
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).
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
Launcher Systems: Overview
Image Credit:N. A. Bletsos
Orbit insertion Burn: Upper stage?
Launcherstage burns
CRICOS No. 00213Ja university for the worldrealR
Launcher Systems: Summary
• 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.
CRICOS No. 00213Ja university for the worldrealR
GTO: Transfer orbit?
Image Credit:Braeunig
Or Holmann transfer orbit
Apogee burn required at GEO.
Typ. Low earth orbit
GEO
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
ESA Launcher System: Current
• An Ariane 5G rocket engine
Image Credit:ESA
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
RS-68
• The Delta IV RS-68 main engine is the world's most powerful hydrogen/oxygen engine.
• Bi-propellant
Image Credit:NASA
CRICOS No. 00213Ja university for the worldrealR
Atlas V solid rocket motor
Image Credit:International Launch Services
CRICOS No. 00213Ja university for the worldrealR
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
CRICOS No. 00213Ja university for the worldrealR
Upperstages
Image Credit:SMAD, p. 730
CRICOS No. 00213Ja university for the worldrealR
Launcher Systems: Summary
• Introduction and Overview• Examples of Launcher Systems and Rockets• Launch Sites
– Sites– Direction– Launch Related Orbit Issues
• Launch Environment• Orbits Issues
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
Launch Sites
Image Credit:SMAD, p. 733
CRICOS No. 00213Ja university for the worldrealR
Launch Directions
Image Credit:SMAD, p. 734
Western RangeEastern Range
Why not out here?
Retrograde launch
CRICOS No. 00213Ja university for the worldrealR
Launch Performance
Image Credit:SMAD, p. 729
Mini-Quiz: Which systemto put 10,000kg in LEO?
Answer: Assume LEOis 300km, then red boxsuggests: Proton, Titan IV or Zenit.
CRICOS No. 00213Ja university for the worldrealR
Polar Launch performance
Image Credit:SMAD, p. 729
CRICOS No. 00213Ja university for the worldrealR
Launcher Systems: Summary
• 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
CRICOS No. 00213Ja university for the worldrealR
Launch Acceleration loads.
Image Credit:SMAD, p. 740
During several important events.
CRICOS No. 00213Ja university for the worldrealR
Fundamental Frequencies.
Image Credit:SMAD, p. 741
Payload/boost-adaptor stiffness should be above these.
CRICOS No. 00213Ja university for the worldrealR
Vibration loads
Image Credit:SMAD, p. 740
But payload/adaptor stiffness should avoid these.That is, dampen vibration energy at these frequencies.
CRICOS No. 00213Ja university for the worldrealR
Shock Environment.
Image Credit:SMAD, p. 741
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
CRICOS No. 00213Ja university for the worldrealR
Launch Differential Pressures
Image Credit:SMAD, p. 739
CRICOS No. 00213Ja university for the worldrealR
Launcher Systems: Summary
• Introduction and Overview• Examples of Launcher Systems and Rockets• Launch Sites• Launch Environment• Orbits Issues
– Accuracy– Ground tracks– Orbital Transfers
CRICOS No. 00213Ja university for the worldrealR
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.
CRICOS No. 00213Ja university for the worldrealR
Ground Tracks
Image Credit:SMAD, p. 138
L =change in longitude
CRICOS No. 00213Ja university for the worldrealR
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).
CRICOS No. 00213Ja university for the worldrealR
Least Energy Transfer
Image Credit:Braeunig
CRICOS No. 00213Ja university for the worldrealR
Fastest Transfer
Image Credit:Braeunig
These are larger
CRICOS No. 00213Ja university for the worldrealR
Transfer Orbits
• Often, satellite is initially placed in low-earth orbit.
• Must transition to operational orbit.
Image Credit:SMAD, p. 185
Remember their lowthrust profile
CRICOS No. 00213Ja university for the worldrealR
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.