1 Part 5 Rockets Chap. 21- Rocket Fundamentals Chap. 22- Chemical PropulsionChap. 23- Orbits & Trajectories
2 21 Rocket Fundamentals History of Rocketry Rocketry is based on propelling a vehicle by a reactive force.Chinese developed rockets in 1220; first to use in war.German engineer Konrad Kyeser von Eichstadt devised a rocket propelled by gunpowderBritain’s William Congreve developed flight-stabilizing guide sticks and built first viable launching pad.William Hale (English) developed spin stabilization with angled exhaust tubes.WW I - rockets used as signal flares and to carry messages, not used as primary weapon.Dr. Robert H. Goddard - Developed and launched first liquid propelled rocket. Recognized as the “Father of Modern Rocketry”.Germany developed liquid rocket as weapon in WW II know as the V-2.
3 21 Rocket Fundamentals Fundamental Physics Rocket Systems Gravitation-Force of attraction between all matter within the universeGravity- Gravitation force with a body (mass) on or near Earth (Galileo)Newton’s Law of Universal Gravitation:Newton’s Three Law’s of Motion:1) Inertia2) F=ma3) Action=ReactionGm1m2d2F =Momentum = m x VAcceleration = rate of change of velocityRocket SystemsSpecific Impulse (Isp) = lbs of thrust delivered by consuming 1 lb of propellant in 1 secondAirframe-StructurePropulsionEngines - Liquid PropellantMotors- Solid PropellantGuidance Systems - “Brain”, inertial platform, star trackingControl Systems - “Steering”, thrust vector control, reaction control
4 22 Chemical Propulsion Oxidizers & Reducers Oxidation - combination of oxygen with another substance. Time it takes for this process determines if substance rusts, corrodes, burns, or explodesCombustion - Rapid oxidationOxidizer - Chemical element of Oxygen used to facilitate oxidationReducers - Fuel used to combine with Oxygen to produce combustion.Propellant - Common reference to both oxidizer and fuelBipropellant - Propellant with separate storage of oxidizer and fuel.Monopropellant - Oxidizer and fuel stored in same container.
5 22 Chemical PropulsionSolid Motors-Oxidizer and fuel are mixed together in solid stateStorableNo thrust controlCannot stop or throttleLiquid PropellantHard to store/handleCan stop or throttleHybrid PropellantCombination of solid and liquid propellant.Can stop or throttle.Easier to store/handle.
6 23 Orbits & Trajectories X Orbit - Path described by one body in its revolution about another body.XSatelliteEarthFocal AApogeePerigeeFocal BCircular Orbit - Constant altitude above Earth’s surfaceElliptical Orbit - Not circularEquatorial - West to East over EquatorGeostationary Orbit - Equatorial orbit of period of 24 hoursPolar Orbit - Crosses North and South polesSunsynchronous Orbit - Constant exposure to sunlightSounding Rocket - Straight up trajectory, never reaches orbit
7 23 Orbits & Trajectories Velocity Requirements Burnout - Moment a rocket engine ceases to produce thrust.Satellite in circular Earth orbit - 17,856 MPH (Moon requires 2300 MPH)Minimum velocity to Moon - 24,409 MPHEscape velocity of Earth - 25,560 MPH (Moon requires 5300 MPH)Escape velocity of Solar System - 36,000 MPHLaunch VehiclesRocket - Power plant used to propel a payload.Missile - Rocket propelled vehicle used to deliver a weapon.Launch Vehicle - Rocket propelled vehicle use to deliver payload other than a weapon.Expendable - Vehicles used only once and do not return to Earth.Reusable - Space Shuttle is only reusable launch vehicle. Plans are in work for a replacement in 2015 to 2020.