Download - Launch System
Booster Design
• German V-2
– Fins for stability and steering
– Exterior skin with Propellant tanks within
– Single stage
• U.S. Launch Vehicles
– Engine gimbals
– Wall of tank and skin of vehicle one and the same
– Multiple Stages
Launch VehiclesExpendable
Air Force and commercial US systems
Divided into small, medium, and heavy classes
Next generation of expendable vehicles in development
MannedSpace Shuttle
ReusableTest vehicles only
Launch Ranges
Launch ranges provide tracking, telemetry, communications, command & control, and other support necessary for safe and successful space lift operations, and aeronautical and ballistic missile tests.
Launch FundamentalsLaunch Events
ShroudProtects the spacecraft
Main vehiclePrimary liquid or solid
rocket propellant tanks
Engine / nozzlesMechanism for
combining propellants and focusing thrust
Booster packsSolid strap-ons for some
rockets to increase initial thrust
Step 2: Booster cut-off and separation
Step 3: Main engine cut-off and separation
Step 4: Shroud opening
Step 5: Orbit insertion
Step 6: Satellite initial checkout
Step 7: Mechanical deployments
Upper stageOrbit insertion rocket
engines and propellant tanks
Step 1: Ignition and launch
Usual Launch Sequence
Launch into parking orbit(With orbit insertion burn)
North Pole
V
Step 1
Orbit plane transfer(With vector thrust burn)
VStep 3
Minimum energy transferBurn 1 to change pathBurn 2 to change to higher orbit
N
V1
V2
Step 2
Launch Ranges
Ranges usually located to minimize overflight of populated areas and reduce
potential debris hazards
Launch site latitude limits the inclination of the satellite’s orbit The minimum inclination of the orbit is equal to the
latitude of the launch site
To get to a lower inclination, satellites need to go through an orbit plane transfer
DOD LAUNCH LOCATIONS
201 DEG
158 DEG
37 DEG
112 DEG
VANDENBURG AFB(WESTERN SPACE LAUNCH RANGE)
• TITAN IV• TITAN II• ALTAS• DELTA
VANDENBURG AFB(WESTERN SPACE LAUNCH RANGE)
• TITAN IV• TITAN II• ALTAS• DELTA
CAPE CANAVERAL AFS / KENNEDY SPACE CENTER(EASTERN SPACE LAUNCH RANGE)
• SHUTTLE• TITAN IV• TITAN II• ALTAS• DELTA
CAPE CANAVERAL AFS / KENNEDY SPACE CENTER(EASTERN SPACE LAUNCH RANGE)
• SHUTTLE• TITAN IV• TITAN II• ALTAS• DELTA
30 DEGREES LATITUDESPACE LAUNCH AZIMUTH
SPA
CE
LA
UN
CH
A
ZIM
UT
H
Launch Window
The “launch window” is the period of time during which the launch must occur to achieve a desired orbit
Duration of window is determined by desired orbit, launch location, weather, and launch vehicle performance
Examples of issues: Vehicle may require specific orbit for rendezvous
Vehicle may require orientation to get correct solar array exposure before reaching final orbit
Launch FundamentalsScience
force = (mass) x (acceleration)f = (m)(a)
The thrust of a launch vehicle must oppose gravity and
atmospheric drag
To get into orbit, a vehicle must achieve a velocity of
mach 24 (24 times the speed of sound)
Thrust = Pounds or Kg Impulse = Pounds per sec Specific Impulse (Isp)= Newtons per sec Isp = Thrust (lb)
fuel weight (lb) burned in 1 sec
FORCE FORCE & TIME FORCE & TIME & FUEL
Mass Ratio of a Vehicle
Mass Ratio (MR) is the ratio between the booster mass before the rocket engine burn (mf ) divided by the booster mass after rocket engine burn (m0 ).
MR = mf /m0
PROPULSION: GETTING INTO AND AROUND IN ORBIT
NORTH POLE
NORTH POLE
NORTH POLE
LAUNCH INTO PARKING ORBIT(WITH ORBIT INSERTION BURN)
ORBIT PLANE TRANSFER(WITH VECTOR THRUST BURN)
HOHMANN (MINIMUM ENERGY) TRANSFER(BURN 1 TO CHANGE TO ELLIPTICAL ORBIT AND BURN 2 TO CHANGE TO HIGHER ALTITUDE CIRCULAR ORBIT)
FAST TRANSFER(BURN 1 TO CHANGE TO LARGE ELLIPSE AND BURN 2 TO FORCE INTO NEW ORBIT)
V
V
V2
V1V1
V2
Launch from Vandenberg
• Launch site latitude 37 deg N latitude
• Desired Orbits – Inclination 80 degrees 104 degrees– Apogee 250 NM 250 NM– Perigee 100 NM 100 NM
• What is the launch azimuth for each orbit?
• What velocity (V) must the payload have in each desired orbit at perigee and apogee?
Launch Azimuth
* cos Inclination = cos Latitude x sin Azimuth
sin Azimuth = cos Inclination/cos Latitude
Posigrade Orbit, i.e., with Earth’s rotationsin Az = cos 80/cos 37 = sin 12.56 degreesLaunch Azimuth = 167.44 degrees
Retrograde Orbit, i.e., against Earth’s rotationsin Az = cos 104/cos 37 = sin -17.63 degreesLaunch Azimuth = 197.63 degrees
* Formula from page 81 Space Handbook, Analysts Guide.
North
167
198