Propulsion Systems Design ENAE 483/788D

Propulsion Systems Design • Power/Propulsion/Thermal Systems Project • Rocket engine basics • Survey of the technologies • Propellant feed systems • Propulsion systems design

© 2013 David L. Akin - All rights reserved http://spacecraft.ssl.umd.edu U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 1 PPT Systems Project • Due Thursday 10/18 • Submit electronic files to Dropbox on Blackboard site • Please submit PDF and editable slides (Powerpoint or Keynote) in two separate files

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 2 PPT Design Problem – Overview • Design the power system, orbital maneuvering system, reaction control system, and perform the thermal equilibrium calculations for the human habitat from the Crew Systems project • Select one of your designs from one of the solutions of the crew systems project (state clearly which was selected and why) • As before, submission will be in the form of presentation slides with high information bandwidth

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 3 PPT Design Problem – Power • Design power system(s) to provide electrical power to the spacecraft throughout the mission (with duration margin from last time) • Must design to support all mission phases and potential destinations – LEO checkout – Cis-lunar space – Low lunar orbit – Lunar surface operations • Decide whether one power system will work for all cases, or if lunar surface requires unique power system design U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 4 PPT Design Problem - OMS Propulsion • Design an orbital maneuvering system capable of providing propulsion to move the habitat between LLO, EM-L1, and EM-L2 locations. • System must be capable of at least five years endurance in orbit • System must be capable of refueling and in-orbit maintenance

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 5 PPT Design Problem – RCS Propulsion • Design a reaction control system for the habitat chosen • Must be capable of independent and uncoupled control of three rotational degrees of freedom – Attitude hold in dead band for six months – Able to overcome environmental torques (e.g., gravity gradients, atmospheric moments) – Capable of extended operations in inertial or LVLH mode in LEO and LLO

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 6 PPT Design Problem – Thermal • Design thermal control system (with radiator temperatures, sizes, and design locations on vehicle) to maintain cabin temperatures in following cases – Full sun (translunar) – Eclipse (Earth/Moon orbit) – Lunar surface dawn/dusk/polar – Lunar surface 45° sun angle (high latitudes/ midmorning or midafternoon) – Lunar surface noon equatorial • Can use supplemental radiators if necessary U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 7 Design Problem Submissions • Create “Preliminary Design Review” slide package for your design • Follow guidelines from Engineering Graphics lecture, especially in maximizing information transfer • Grade will reflect both content from PPT Systems lectures and quality of presentation created

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 8 PPT Project Teams Team C1: Team C4: Team C7: Team C10: Levine, Edward Gregorich, Donald Adamson, Colin Brassard, Brianna Pashai, Pegah Klein, Douglas King, Jennifer Cloutier, Kyle Phillips, Brandyn Kunnath, Sahin Muller, Brooks Downes, Alexander Shallcross, Michael Ouyang, William Toothaker, Cody Garay, Samuel Wallace, Mazi Ortiz, Oliver

Team C2: Team C5: Team C8: Garcia, Irving Kittur, Chandan Moran, Ryan Kantzer, Michael Kumar, Rubbel Patel, Mihir Raghu, Nitin Kunnath, Sarin Schneider, Mark Zittle, Kyle Mellman, Benjamin Todaro, Daniel Team C11(G): Carlsen, Chris Rodriguez, Jon Team C3: Team C6: Team C9: Borillo Llorca, Irene Adams, Matthew Chattopadhyay, Rajarshi Ferguson, Kevin Bhattarai, Ashok Du Toit, Charl Horowitz, Matthew Feeney, Matthew Gonter, Kurt Mittra, Atin Weber, Kristy Schaffer, Michael U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 9 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Chemical Non-Chemical

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Chemical Non-Chemical

Monopropellants Bipropellants

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Chemical Non-Chemical

Monopropellants Bipropellants

Solids Hybrids Liquids Air-Breathing

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Chemical Non-Chemical

Monopropellants Bipropellants

Solids Hybrids Liquids Air-Breathing

Pressure-Fed Pump-Fed U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Chemical Non-Chemical

Nuclear Monopropellants Bipropellants Beamed Electrical Cold Gas Solar

Solids Hybrids Liquids Air-Breathing

Pressure-Fed Pump-Fed U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Ion Chemical Non-Chemical

MPD Nuclear Monopropellants Bipropellants Beamed Electrical Cold Gas Solar

Solids Hybrids Liquids Air-Breathing

Pressure-Fed Pump-Fed U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Ion Chemical Non-Chemical Solar Sail

MPD Laser Sail Nuclear Monopropellants Bipropellants Beamed Electrical Microwave Sail Cold Gas Solar MagnetoPlasma

Solids Hybrids Liquids Air-Breathing ED Tether

Pressure-Fed Pump-Fed U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 Thermal Rocket Exhaust Velocity • Exhaust velocity is + γ −1. 2γ ℜT - % p ( γ 0 0 ' e * Ve = -1 −' * 0 γ −1 M - & p ) 0 , 0 / where

M ≡ average molecular weight of exhaust Joules ℜ ≡ universal gas const.= 8314.3 mole°K γ ≡ ratio of specific heats ≈1.2

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 11

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€ € Ideal Thermal Rocket Exhaust Velocity • Ideal exhaust velocity is 2γ ℜT V = 0 e γ −1 M • This corresponds to an ideally expanded nozzle • All thermal energy converted to kinetic energy of exhaust • Only a function of temperature and molecular weight!

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 12

€ Thermal Rocket Performance • Thrust is

T = m˙ Ve + ( pe − pamb)Ae • Effective exhaust velocity A " c % ˙ e $ ' T = m c ⇒ c = Ve + ( pe − pamb) $ Isp = ' m˙ # g0 & • Expansion ratio

1 1 * γ −1- γ −1# & γ # & γ At # γ +1& pe γ +1, pe / = % ( % ( ,1 −% ( / A $ 2 ' $ p ' γ −1, $ p ' / e 0 + 0 .

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 13

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€ A Word About Specific Impulse • Defined as “thrust/propellant used” – English units: lbs thrust/(lbs prop/sec)=sec – Metric units: N thrust/(kg prop/sec)=m/sec • Two ways to regard discrepancy - – “lbs” is not mass in English units - should be slugs – Isp = “thrust/weight flow rate of propellant” • If the real intent of specific impulse is

T I = and T = mV˙ then I = V !!! sp m˙ e sp e

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 14 Nozzle Design

• Pressure ratio p0/pe=100 (1470 psi-->14.7 psi) Ae/At=11.9

• Pressure ratio p0/pe=1000 (1470 psi-->1.47 psi) Ae/At=71.6

• Difference between sea level and ideal vacuum Ve γ −1 # & γ Ve pe = 1−% ( Ve,ideal $ p0 '

• Isp,vacuum=455 sec --> Isp,sl=333 sec

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 15

€ Solid Rocket Motor

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 16 Solid Propellant Combustion Characteristics

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 17 Solid Grain Configurations

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 19 Advanced Grain Configurations

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 20 Liquid Rocket Engine

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 21 Liquid Propellant Feed Systems

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 22 Space Shuttle OMS Engine

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 2001 U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 23 Turbopump Fed Liquid Rocket Engine

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 27 SSME Engine Cycle

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 30 Injector Concepts

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 32 Solid Rocket Nozzle (Heat-Sink)

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 34 Active Chamber Cooling Schematic

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 37 Hybrid Rocket Combustion

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 39 Reaction Control Systems • Thruster control of vehicle attitude and translation • “Bang-bang” control algorithms • Design goals: – Minimize coupling (pure forces for translation; pure moments for rotation)except for pure entry vehicles – Minimize duty cycle (use propellant as sparingly as possible) – Meet requirements for maximum rotational and linear accelerations

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 40 Single-Axis Equations of Motion ⌧ = I✓¨ ⌧ t = ✓˙ + C I 1 ⌧ at t = 0, ✓˙ = ✓˙ = t = ✓˙ ✓˙ o ) I o 1 ⌧ t2 + ✓˙ t = ✓ + C 2 I o 2 1 ⌧ at t = 0, ✓ = ✓ = t2 + ✓˙ t = ✓ ✓ o ) 2 I o o 1 2 ⌧ ✓˙2 ✓˙ = (✓ ✓ ) 2 o I o U N I V E R S I T Y O⇣ F ⌘ Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 41 Attitude Trajectories in the Phase Plane

3.00%

2.00%

1.00%

0.00% !20.00% !10.00% 0.00% 10.00% 20.00% 30.00% 40.00%

!1.00% tau/I=0% !0.001% !0.002% !2.00% !0.003% !0.004%

!3.00% U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 42 Gemini Entry Reaction Control System

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 43 Apollo Reaction Control System

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 44 Apollo CSM RCS Assembly

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 45 Lunar Module Reaction Control System

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 46 LM RCS Quad

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 47 Viking Aeroshell RCS Thruster

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 48 Space Shuttle Primary RCS Engine

1 2 T p V = < 0 1 e e v ¯ u 1 M " po # u ✓ ◆ t M¯ = 28 p0 = 300 psi

T0 = 300 K pe =2psi = 8314.3 =1.4 < 1.4 1 2(1.4) 8314.3(300) 2 1.4 m V = 1 = 689 e v u1.4 1 28 " 300 # sec u ✓ ◆ t U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 51 Cold-gas Propellant Performance

From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 52 Total Impulse

• Total impulse It is the total thrust-time product for the propulsion system, with units

It = Tt =˙mvet ⇢V t = m˙

It = ⇢Vve • To assess cold-gas systems, we can examine total impulse per unit volume of propellant storage I t = ⇢v V e U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 53 Performance of Cold-Gas Systems

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 54 Self-Pressurizing Propellants (CO2)

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 55 Self-Pressurizing Propellants (N2O)

Density 625 kg/m3 Density 1300 kg/m3

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 56 N2O Performance Augmentation • Nominal cold-gas exhaust velocity ~600 m/sec

• N2O dissociates in the presence of a heated catalyst 2N2O 2N2 + O2 engine temperature ~1300°C! exhaust velocity ~1800 m/sec • NOFB (Nitrous Oxide Fuel Blend) - store premixed N2O/hydrocarbon mixture exhaust velocity >3000 m/sec

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 57 Pressurization System Analysis Adiabatic Expansion of Pressurizing Gas γ γ γ pg,0Vg = pg, f Vg + pl Vl Pg0, Vg Pgf, Vg Known quantities:

Pg,0=Initial gas pressure

P , V P , V L L L L Pg,f=Final gas pressure

PL=Operating pressure of propellant Initial Final tank(s)

VL=Volume of propellant tank(s)

Solve for gas volume Vg U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 58

€ Boost Module Propellant Tanks • Gross mass 23,000 kg – Inert mass 2300 kg – Propellant mass 20,700 kg – Mixture ratio N2O4/A50 = 1.8 (by mass) • N2O4 tank – Mass = 13,310 kg – Density = 1450 kg/m3 3 – Volume = 9.177 m --> rsphere=1.299 m • Aerozine 50 tank – Mass = 7390 kg – Density = 900 kg/m3 3 – Volume = 8.214 m --> rsphere=1.252 m

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 59 Boost Module Main Propulsion 3 • Total propellant volume VL = 17.39 m • Assume engine pressure p0 = 250 psi • Tank pressure pL = 1.25*p0 = 312 psi • Final GHe pressure pg,f = 75 psi + pL = 388 psi • Initial GHe pressure pg,0 = 4500 psi • Conversion factor 1 psi = 6892 Pa • Ratio of specific heats for He = 1.67 1.67 1.67 3 1.67 (4500 psi)Vg = (388 psi)Vg + (312 psi)(17.39 m ) 3 • Vg = 3.713 m pg,0M • Ideal gas: T=300°K --> ρHe = 3 ℜT0 ρ=49.7 kg/m (4500 psi = 31.04 MPa) MHe=185.1 kg U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 60

€ € Nuclear Thermal Rockets • Heat propellants by passing through nuclear reactor • Isp limited by temperature limits on reactor elements (~900 sec for H2 propellant) • Mass impacts of reactor, shielding • High thrust system

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 61 VASIMR Engine Concept

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 62 VASIMR Engine Concept

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 62 Ion Propulsion

• Uses electrostatic forces to accelerate ions • Injects electrons to keep beam neutral • High Isp (~3000 sec) at low thrust (~10 N) • Substantial mass penalty for electrical power generation

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 63 Solar Sails

• Sunlight reflecting off sail produces momentum transfer T = 2m˙ V = 2m˙ c E E 1 P E = mc 2 ⇒ m = ⇒ m˙ = = c 2 t c2 c 2 • At 1 AU, P=1394 W/m2 • c=3x108 m/sec • T=9x10-6 N/m2

U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 64

€

€ Propulsion Taxonomy

Mass Expulsion Non-Mass Expulsion

Thermal Non-Thermal

Ion Chemical Non-Chemical Solar Sail

MPD Laser Sail Nuclear Monopropellants Bipropellants Beamed Electrical Microwave Sail Cold Gas Solar MagnetoPlasma

Solids Hybrids Liquids Air-Breathing ED Tether

Pressure-Fed Pump-Fed U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 65