Ryan Mayes Duarte Ho Jason Laing Bryan Giglio

Requirements  Overall: Launch 10,000 mt of cargo (including crew vehicle) per year Work with a $5M 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 Design2

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 Design3

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 Design4

LV: Costing Calculator (MS Excel) ENAE 791: Launch and Entry Vehicle Design5

LV Trades: Fuel Types & Staging  Words, words, tables, words…  Add Cost totals, maybe a table or something ENAE 791: Launch and Entry Vehicle Design6

LV Trades: Modularity Effects ENAE 791: Launch and Entry Vehicle Design7

8 LV Trades: Safe Life Effects

Launch Vehicle: Costing Conclusions  2 Stages, Both LH2/LOX, Ballistic & Re-usable  Upper: TPS, Parachutes, Legs, +100m/s Δ V for VL  Lower: Parachutes, Legs, +100m/s Δ V 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 50MT, but the greater required thrust negates any benefits and/or requires SRBs (3 rd Stage)  $/kg 2012$  Total Lifetime Mission = $128.3 Billion 2012$ ENAE 791: Launch and Entry Vehicle Design9

Engine Selection  Launch: S1 = 9 x Space Shuttle main engines (SSME/RS-25) S2 = 1 x J-2X  Re-entry: S1: 20 x P&W CECE, S2 = 1 x J-2X  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% ENAE 791: Launch and Entry Vehicle Design10 en.wikipedia.org/wiki/Space_Shuttle_Main_Engine

Launch Vehicle: Final Design  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 ENAE 791: Launch and Entry Vehicle Design11 D2 D1 L

Launch Vehicle: ΔV – Stages  Target ΔV = 9,700 m/s  St 1: ΔV 1 = V E ln(m 0 /m f,1 )St 2: ΔV 1 = V E ln(m 2 /m f,2 ) ΔV 1 = 5,256 m/sΔV 2 = 4,444 m/s ENAE 791: Launch and Entry Vehicle Design12 Final Design Choice for Stage 2 ΔV

Launch Vehicle: Overview  2 Stage  Uses LOX/LH2 propellant systems  Total ΔV = 9,700 m/s Stage 1 = 4,444 m/s Stage 2 = 5,256 m/s  Total ΔV includes: 9,200 m/s to orbit 300 m/s for reusables 200 m/s for deceleration components ENAE 791: Launch and Entry Vehicle Design13 Stage 1 Stage 2 Payload Propellant 2 Propellant 1 Engine 2 Engines 1

Launch Vehicle: Stage 1  Total Propellant = 1,031,884 kg Fuel (LH2) / Oxidizer (LOX) ratio = 6  Number of Engines = 9 SSME, 20 P&W CECE  Inert Mass fraction δ =.0914  Payload Mass fraction λ =.1953  I sp = 363 sec (SL) ENAE 791: Launch and Entry Vehicle Design14 LH2 LOX

Launch Vehicle: Stage 2  Total Propellant = 197,193 kg Fuel (LH2) / Oxidizer (LOX) ratio = 5.5  Number of Engines = 1 J-2X  Inert Mass fraction δ =.1251  Payload Mass fraction λ =.177  I sp = 448 sec (Vac) ENAE 791: Launch and Entry Vehicle Design15 LH2 LOX

Launch Vehicle: Inert Mass Stage 1 ComponentMass (kg) LOX Tank9464 LOX Tank Ins97 LH2 Tank18869 LH2 Tank Ins670 Payload Fairing5099 Intertank Fairing14104 Aft Fairing1737 Launch Engines31734 ENAE 791: Launch and Entry Vehicle Design16 ComponentMass (kg) Re-entry Engines3180 TPS System0 Thrust Structure4338 Gimbals228 Avionics1675 Wiring3234 Landing Gear3966 Parachutes3305 Initial Estimate (Stage 1) = 132,208 kg Final Inert Mass (Stage 1) = 101,699 kg Final Design Margin = 30%

Launch Vehicle: Inert Mass Stage 2 ComponentMass (kg) LOX Tank1785 LOX Tank Ins25 LH2 Tank3883 LH2 Tank Ins235 Payload Fairing1178 Intertank Fairing4099 Aft Fairing1584 J-2X Engine2472 ENAE 791: Launch and Entry Vehicle Design17 ComponentMass (kg) TPS System7070 Thrust Structure494 Gimbals93 Avionics929 Wiring1399 Landing Gear1060 Parachutes884 Initial Estimate (Stage 2) = 35,349 kg Final Inert Mass (Stage 2) = 27,191 kg Final Design Margin = 30.0%

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 Design18

Launch Vehicle: Ascent First Pass  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 Design19 Down Range vs. Time

Launch Vehicle: Ascent First Pass  T stage,1 : sec  T stage,2 : 49.8 sec  Total Burn: 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 Design20 Altitude vs. Time

Launch Vehicle: Ascent TPBVP  Matlab solver: Two Point Boundary Value Problem (function: bvp4c.m)  Initial conditions: x = y = V x = V y = 0 km  Final conditions: y = 500 km V x = Orbital 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 Design21

Launch Vehicle: Ascent TPBVP  Stage 1 thrust scaled down to achieve an appropriate burn time  New Optimal Burn Time = sec  Indicates that another iteration required to optimize ENAE 791: Launch and Entry Vehicle Design22 Altitude vs. Time  Final Velocity is fully in the x- direction for this optimal solution to the trajectory Velocity vs. Time

TPBVP Burn Time = (cont.) Total Velocity V Final = km/s 500 km) Downrange Distance Max ~ 500 km (X-dir) ENAE 791: Launch and Entry Vehicle Design23

ENAE 791: Launch and Entry Vehicle Design24

ENAE 791: Launch and Entry Vehicle Design25

ENAE 791: Launch and Entry Vehicle Design26

ENAE 791: Launch and Entry Vehicle Design27

Crew Vehicle: Costing  Assuming: Refurbishment rate of 3% Nonrecurring cost for reusable vehicles doubled over expendable 1 crew vehicle for the program ENAE 791: Launch and Entry Vehicle Design28  Expendable vehicles cheaper up to 21st flight  Reusable vehicles more cost efficient after 21st

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 C D,Sphere = 1 C D,Cone = 2sin 2 (δ)  Nominally chose C D = 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 Design29

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 m 2, diameter of 2.21 m ENAE 791: Launch and Entry Vehicle Design30

Crew Vehicle: Nominal Entry Trajectory  Beta = 2,000 kg/m 3  L/D = 1.3  FPA = -2°  Downrange Max 35 km ENAE 791: Launch and Entry Vehicle Design31 Peak velocity: m/s at 30.3 km Peak deceleration: g’s at 11.9 km

Crew Vehicle: Entry Heating  Heating rate approximation at stagnation point  Leading edge radius r LE = m  Max heating rate = W/cm 2  Total heat load = J/cm 2 ENAE 791: Launch and Entry Vehicle Design32

Crew Vehicle: TPS Mass Estimation ENAE 791: Launch and Entry Vehicle Design33  Ablative Heuristic a function of total heat load Q = 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

Crew Vehicle: Landing  Drogues upon entering atmosphere to stabilize, parachutes employed as final reentry phase  M = 1 achieved at roughly 3000m as a result of β selection; allows for parachute deployment  Parachute radius of 10m: terminal velocity of roughly 10 m/s  3 Parachutes: Loss of 1 chute results in a 20% terminal velocity increase. ENAE 791: Launch and Entry Vehicle Design34

Crew Vehicle: Landing ENAE 791: Launch and Entry Vehicle Design35

Crew Vehicle: Landing ENAE 791: Launch and Entry Vehicle Design36