Ryan Mayes Duarte Ho Jason Laing Bryan Giglio
Ryan Mayes Duarte Ho Jason Laing Bryan Giglio
Requirements � Overall: �Launch 10, 000 mt of cargo (including crew vehicle) per year �Work with a $5 M fixed cost for operations/flight � Launch Vehicle: �Minimize total program transport cost �Achieve a 500 km circular orbit � Crew Entry Vehicle: �Maximize operational flexibility (L/D) �Direct re-entry from 75, 000 km HEO �Capable of landing on ground ENAE 791: Launch and Entry Vehicle Design 2
Assumptions � Overall � 20 year program life �All costing estimates in 2012 dollars � Launch vehicle � 85% learning curve for vehicle costing �For initial design, 9. 2 km/s to LEO � Crew vehicle �Vehicle mass of 10, 000 kg �Quoted mass includes EDL systems ENAE 791: Launch and Entry Vehicle Design 3
LV: Costing Trade Study � Base/Expendable ΔV = 9, 200 m/s � Stage Safe life > 30 flights �+100 m/s ΔV per Stage � Reusable upper stage: +300 m/s ΔV � Resulting ΔV Maximums � 2 Stage = 9, 700 m/s � 3 Stage = 9, 800 m/s � All Costing and MER Analysis Completed in MS Excel 2007 ENAE 791: Launch and Entry Vehicle Design 4
LV: Costing Calculator (MS Excel) ENAE 791: Launch and Entry Vehicle Design 5
LV Trades: Fuel Types & Staging � Words, words, tables, words… � Add Cost totals, maybe a table or something ENAE 791: Launch and Entry Vehicle Design 6
LV Trades: Modularity Effects ENAE 791: Launch and Entry Vehicle Design 7
LV Trades: Safe Life Effects ENAE 791: Launch and Entry Vehicle Design 8
Launch Vehicle: Costing Conclusions 2 Stages, Both LH 2/LOX, Ballistic & Re-usable � Upper: TPS, Parachutes, Legs, +100 m/s ΔV for VL � Lower: Parachutes, Legs, +100 m/s ΔV for VL � Payload is 50, 000 kg to reasonably minimize cost � � ~ 200 launches per year � ~ 2 weeks between flights of the same vehicle � ~ 4 flights per week Trades suggest lower cost for payloads above 50 MT, but the greater required thrust negates any benefits and/or requires SRBs (3 rd Stage) � 641. 68 $/kg 2012$ � Total Lifetime Mission = $128. 3 Billion 2012$ � ENAE 791: Launch and Entry Vehicle Design 9
Engine Selection � Launch: � S 1 = 9 x Space Shuttle main engines (SSME/RS-25) � S 2 = 1 x J-2 X Re-entry: S 1: 20 x P&W CECE, S 2 = 1 x J-2 X � Number of engines on each stage was chosen to launch the maximum payload per launch in to orbit and maintain a mass margin of ~30% � en. wikipedia. org/wiki/Space_Shuttle_Main_Engine ENAE 791: Launch and Entry Vehicle Design 10
Launch Vehicle: Final Design � � � D 2 � L � Total ΔV = 9, 700 m/s Max. Payload = 50, 000 kg Diam. 1 (Stage 1) = 10. 2 m Diam. 2 (Stage 2) = 6 m Length = 80 m D 1 ENAE 791: Launch and Entry Vehicle Design 11
Launch Vehicle: ΔV – Stages Target ΔV = 9, 700 m/s � St 1: ΔV 1 = VE ln(m 0/mf, 1) � ΔV 1 = 5, 256 m/s St 2: ΔV 1 = VE ln(m 2/mf, 2) ΔV 2 = 4, 444 m/s Final Design Choice for Stage 2 ΔV ENAE 791: Launch and Entry Vehicle Design 12
Launch Vehicle: Overview 2 Stage � Uses LOX/LH 2 propellant systems � Total ΔV = 9, 700 m/s � Payload Stage 2 Propellant 2 � Stage 1 = 4, 444 m/s � Stage 2 = 5, 256 m/s � Engine 2 Total ΔV includes: � 9, 200 m/s to orbit � 300 m/s for reusables � 200 m/s for deceleration components Propellant 1 Stage 1 Engines 1 ENAE 791: Launch and Entry Vehicle Design 13
Launch Vehicle: Stage 1 � Total Propellant = 1, 031, 884 kg � Fuel (LH 2) / Oxidizer (LOX) ratio = 6 Number of Engines = 9 SSME, 20 P&W CECE � Inert Mass fraction � LOX � δ =. 0914 � Payload Mass fraction LH 2 � λ =. 1953 � Isp = 363 sec (SL) ENAE 791: Launch and Entry Vehicle Design 14
Launch Vehicle: Stage 2 � Total Propellant = 197, 193 kg � Fuel (LH 2) / Oxidizer (LOX) ratio = 5. 5 Number of Engines = 1 J-2 X � Inert Mass fraction � LOX � δ =. 1251 � Payload Mass fraction � λ =. 177 LH 2 � Isp = 448 sec (Vac) ENAE 791: Launch and Entry Vehicle Design 15
Launch Vehicle: Inert Mass Stage 1 Component Mass (kg) LOX Tank 9464 Re-entry Engines 3180 LOX Tank Ins 97 TPS System 0 LH 2 Tank 18869 Thrust Structure 4338 LH 2 Tank Ins 670 Gimbals 228 Payload Fairing 5099 Avionics 1675 Intertank Fairing 14104 Wiring 3234 Aft Fairing 1737 Landing Gear 3966 Launch Engines 31734 Parachutes 3305 Initial Estimate (Stage 1) = 132, 208 kg Final Inert Mass (Stage 1) = 101, 699 kg Final Design Margin = 30% ENAE 791: Launch and Entry Vehicle Design 16
Launch Vehicle: Inert Mass Stage 2 Component Mass (kg) LOX Tank 1785 TPS System 7070 LOX Tank Ins 25 Thrust Structure 494 LH 2 Tank 3883 Gimbals 93 LH 2 Tank Ins 235 Avionics 929 Payload Fairing 1178 Wiring 1399 Intertank Fairing 4099 Landing Gear 1060 Aft Fairing 1584 Parachutes 884 J-2 X Engine 2472 Initial Estimate (Stage 2) = 35, 349 kg Final Inert Mass (Stage 2) = 27, 191 kg Final Design Margin = 30. 0% ENAE 791: Launch and Entry Vehicle Design 17
Launch Vehicle: Analysis � Initial thrust/weight = 1. 2 � Stage 2 thrust/weight = 0. 7 � Assume constant mass flow rate (m_dot) based on number of engines and all thrusters at full throttle � Thrust / weight ratio is a function of time; increases as propellant is burned. � Assume: Gravity; no drag � Analysis performed in MATLAB using integrated equations of motion ENAE 791: Launch and Entry Vehicle Design 18
Launch Vehicle: Ascent First Pass Down Range vs. Time � Initial pitch angle: 89° (from horizontal) � Total Down Range after entire burn: 21 km � Down range distance of 2 km from the launch pad is achieved after 123 seconds ENAE 791: Launch and Entry Vehicle Design 19
Launch Vehicle: Ascent First Pass Altitude vs. Time � � � Tstage, 1: 215. 7 sec Tstage, 2: 49. 8 sec Total Burn: 265. 5 sec Final Height = 500 km This solution is not optimized because final velocity is not totally in the x-direction ENAE 791: Launch and Entry Vehicle Design 20
Launch Vehicle: Ascent TPBVP Matlab solver: Two Point Boundary Value Problem (function: bvp 4 c. m) � Initial conditions: � �x = y = Vx = Vy = 0 km � Final conditions: �y = 500 km �Vx = Orbital Vel. @500 km TPBVP solver in MATLAB creates the optimal trajectory to satisfy boundary conditions � Output: Min. flight time (saves cost) � ENAE 791: Launch and Entry Vehicle Design 21
Launch Vehicle: Ascent TPBVP Altitude vs. Time Stage 1 thrust scaled down to achieve an appropriate burn time � New Optimal Burn Time = 242. 5 sec � Indicates that another iteration required to optimize � � Final Velocity is fully in the xdirection for this optimal solution to the trajectory Velocity vs. Time ENAE 791: Launch and Entry Vehicle Design 22
TPBVP Burn Time = 242. 5 (cont. ) Total Velocity VFinal = 7. 612 km/s (@ 500 km) Downrange Distance Max ~ 500 km (X-dir) ENAE 791: Launch and Entry Vehicle Design 23
ENAE 791: Launch and Entry Vehicle Design 24
ENAE 791: Launch and Entry Vehicle Design 25
ENAE 791: Launch and Entry Vehicle Design 26
ENAE 791: Launch and Entry Vehicle Design 27
Crew Vehicle: Costing � Assuming: � Refurbishment rate of 3% � Nonrecurring cost for reusable vehicles doubled over expendable � 1 crew vehicle for the program Expendable vehicles cheaper up to 21 st flight � Reusable vehicles more cost efficient after 21 st � ENAE 791: Launch and Entry Vehicle Design 28
Crew Vehicle: Lift and Drag Wanted cross range of roughly 2, 000 km to span entire continental US � Drove selection for L/D = 1. 3 � Corresponds to angle of attack of 37. 57° � Newtonian Flow Estimations � � CD, Sphere = 1 � CD, Cone � = 2 sin 2(δ) Nominally chose CD = 1. 3 as a baseline � Based on Newtonian estimations and Soyuz figures � Sphere-cone with half angle δ = 54° ENAE 791: Launch and Entry Vehicle Design 29
Crew Vehicle: Ballistic Coefficient � � Using parachutes necessitates that vehicle be at M = 1 or lower at 3, 000 m β = 2000 kg/m 2, vehicle area of 3. 846 m 2, diameter of 2. 21 m ENAE 791: Launch and Entry Vehicle Design 30
Crew Vehicle: Nominal Entry Trajectory Beta = 2, 000 kg/m 3 � L/D = 1. 3 � FPA = -2° � Downrange Max 35 km � Peak velocity: 1. 296 m/s at 30. 3 km Peak deceleration: 5. 4483 g’s at 11. 9 km ENAE 791: Launch and Entry Vehicle Design 31
Crew Vehicle: Entry Heating � Heating rate approximation at stagnation point � � Leading edge radius r. LE = 3. 298 m Max heating rate = 18. 09 W/cm 2 Total heat load = 470. 94 J/cm 2 ENAE 791: Launch and Entry Vehicle Design 32
Crew Vehicle: TPS Mass Estimation � Ablative � Heuristic a function of total heat load � Q = 470. 94 J/cm 2 � TPS mass ○ 2. 18% of vehicle mass � Reusable (Shuttle tiles) � Small sample size, no heuristics � Mass was scaled based on shuttle � TPS mass o 8. 63% of vehicle mass ENAE 791: Launch and Entry Vehicle Design 33
Crew Vehicle: Landing Drogues upon entering atmosphere to stabilize, parachutes employed as final reentry phase � M = 1 achieved at roughly 3000 m as a result of β selection; allows for parachute deployment � Parachute radius of 10 m: terminal velocity of roughly 10 m/s � 3 Parachutes: Loss of 1 chute results in a 20% terminal velocity increase. � Chute Radius (m) 450 400 Radius(m) 350 300 250 200 Chute Radius (Three count) (m) 150 One Loss Velocity 100 50 0 0 5 10 Impact Velocity (m/s) ENAE 791: Launch and Entry Vehicle Design 15 34
Crew Vehicle: Landing ENAE 791: Launch and Entry Vehicle Design 35
Crew Vehicle: Landing ENAE 791: Launch and Entry Vehicle Design 36
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