1. 1 Rocket Science

2. 2 ??: woman convinces man to make fire (or maybe it was man convinces woman…) 2800 BC: Construction begins on Stonehenge 1000 BC: Mayan’s build Caracol Temple as a calendar 350 BC: Aristotle uses a lunar eclipse to prove that Earth is round 200 BC: Eratosthenes calculates Earth’s circumference is 24855 miles 682: 1 st Record of rockets used in China 1510: Copernicus proves Earth orbits the Sun 1896: Tsiolkovsky describes rockets for space exploration 1957: Sputnik circles Earth every 96.2 minutes 1963: Discoverer 13 returns first payload from space 1966: Venera 3 reaches surface of Venus 1969: Neil Armstrong takes first step on Moon 2007: 1 st robotic repair and refueling 2011: Voyager 1 spacecraft reaches edge of solar system History of Spaceflight

3. 3 Basic Rocket Theory How does one propel an object without application of external force? Thrust, F = (dm/dt) V e + A e (P e - P o ) dm/dt= mass flow rate V e = nozzle exhaust velocity A e = nozzle exit area P e = exit pressure of gases P o = ambient pressure –Throw material (gases) out the back –Thrust force comes from Newton’s 2nd & 3rd Laws Law II: Law III: “Actioni contrariam semper et æqualem esse reactionem”

4. 4 ImpulseI =  F(t)dt = F  t Specific Impulse (Isp) = impulse per unit mass of propellant Mixture Ratio (MR) = ratio of oxidizer to fuel flow rate Rocket Equation (derived from F = ma) Minimum velocity to be added for: –Sustained Earth orbit = 7.8 km/s –Earth escape = 11 km/s

5. 5 How a Rocket Engine Works Chamber/pumps add potential energy –Via pressurization (pumps or pneumatics) –Or by combustion –Or by ionization Nozzle converts potential energy to kinetic energy –For chemical rockets: Converging section accelerates flow to speed of sound Diverging section creates supersonic flow Nozzle shapes flow to maximize thrust –For electrical rockets Electric/magnetic field accelerates ions Magnetic “nozzle” shapes flow to maximize thrust Engine: a machine that converts energy into motion

6. 6 Chemical –Solid -- Chinese flaming arrows circa 682 –Bipropellant -- 1 st flight by Goddard, 1926 –Monopropellant (exothermic decomposition) – V1 bombs, 1944 Cold gas Nuclear -- experiments only, 1966 Electric/Magnetic -- 1 st flight 1970 Non-impulsive (not really rockets) –Planetary fly-by -- Mariner 10, 1974 –Tethers – 1 st propulsive use 1993 –Space/time warping?? Types of Rocket Engines (in order of invention) ChemistryPressurizationCooling Earth storablePressure fedFilm/Regenerative CryogenicPump fedAblation HypergolicAutogenousRadative

7. 7 Recipe for 1 Working Liquid Rocket Engine 3. Push propellant to engine 2. Add a converging/ diverging nozzle 4. Meter flow to taste Pressure drives flow Valve Controls Performance Nozzle transforms potential energy into kinetic energy 6. Light the flame 5. Inject propellant 1. Build one can Chamber contains the pressure & heat Combustion adds energy

8. 8 Add a converging/ diverging nozzle Pour and mold propellant Build one can Mix propellant Recipe for 1 Working Solid Rocket Engine Light the flame

9. 9 Examples of Pump Fed Rocket Engines F-1: Five were required to lift the Saturn V rocket to the moon RS-68: Powers the Delta-IV launch vehicles Turbopump Nozzle Injector Turbine exhaust Chamber (hidden)

10. 10 Example: Pressure Fed Rocket Engine for Spacecraft LOx/Methane engine under development for Constellation Radiatively cooled chamber Note, no pumps, turbines, or cooling loops

11. 11 Example: Electromagnetic “Rocket” Engines Ionization “chamber” Cathodes Electron path Ion exhaust plume Cluster of 4 Hall Effect Thrusters in test at AFRL

12. 12 How can any of that be so hard?

13. 13 The Challenges of Rockets A chemical rocket engine is essentially a device for turning an explosion into useable momentum –High temperatures and pressures A rocket engine the size of a small car produces more power than the largest nuclear reactor Requires high quality material, precision parts, carefully controlled operating conditions, and numerous fail safes Development of a rocket engine requires the marriage of numerous high-technology fields –Thermodynamics, chemistry, fluid dynamics, structural design, metallurgy, mechanical design, control theory, and experimental design Nuclear and electromagnetic rockets are equally complex –Plasma or nuclear physics replaces chemistry as a critical field …and the engine is just one part of the rocket!

14. 14 Performance Comparison NERVA (5 GW) F1 (33GW) BPT-4000 (4.5kW) 1 MW = 1 Bugatti Veyron (a limited edition 260 mph-capable sport car selling for $2.6M) Image from carnest.com

15. 15 Building the Rocket Engine Is Just One Step Design the rocket Build the parts Test the parts Assemble the engine Build the test rig Test the engine Clean/decontaminate Analyze the system Integrate engine onto rocket Ship to launch base Load the propellant (if liquid) Light the match Typical Rocket Engine Test Stand

16. 16 Success Comes from Failure

17. 17 Notable Launch Vehicle Failures Failure of Vanguard Titan 34D Explosion Indian Launch Failure