AEROSPACE ENGINEERING AE449 Senior Design Project I!1 Auburn University, Alabama FINAL STUDY REPORT FOR THE SPACE SHUTTLE II ADVANCED SPACE TRANSPORTATION SYSTEM Volume I: Executive Summary Submitted to: Dr. James O. Nichols Submitted by: James N. Adinaro Philip A. Benefield Shelby D. Johnson Lisa K. Knight Date Submitted: April 27, 1989 Table of Contents t . 1.0 ProjectSummary 1 2.0 Review 2 3.0 Proposed System Configuration 3 3.1 Changes in Preliminary Configuration 3 3.2 Wing 3 3.3 VerticalTail 4 3.4 Forward Fuselage 6 3.5 Mid Fuselage 6 3.6Aft Fuselage 8 3.7 Fuel and OxidizerTanks 8 3.8 Payload Bay and Payload Bay Doors 9 3.9Thrust Structure 12 3.10 Ascent Propulsion 12 3.11 Fuel/OxidizerFeed System 12 3.12 OrbitalManeuvering System/Reaction Control System 14 3.13 Landing Structures 14 • '" 4.0 Performance/Mission Analysis 15 4.1 Launch Event Schedule 15 4.2 Booster Launch/Landing Event Schedule 16 4.3 Orbital Event Schedule 17 4.4 Orbiter Landing Event Schedule 17 5.0 Stability and Control 19 6.0 Interface With Other Systems 21 7.0 Safety Analysis 22 7.1 Ascent Propulsion Failure Modes 24 7.2 Structural Failure Modes 24 7.3 Electronic Controls Failure Modes 25 8.0 Bibliography 27 9.0 Miscellaneous Figures 29 1.0 Project Summary This reportsummarizes an investigationintothe feasibilityof establishinga second generationspace transportationsystem. Incorporatingsuccessfulsystems from the Space Shuttle and technologicaladvances made sinceitsconception,the second generation shuttle presentedhere was designed tobe a lower-cost,more reliablesystem which would guarantee accessto space well intothe next century.A fullyreusable,all-liquidpropellant booster/orbitercombination using parallelburn was selectedas the base configuration. Vehicle characteristicswere determined from NASA ground rules and optimization evaluations.The launch profilewas constructedfrom particularsof the vehicledesign and known orbitalrequirements.A stabilityand controlanalysiswas performed for the landing phase of the orbiter'sflight.Finally,a preliminary safetyanalysiswas performed to indicatepossiblefailuremodes and consequences. k x_ , ''4 2.0 Review The Advanced Space Transportation System (ASTS) is a program designed to initially supplement and later replace the current Space Transportation System (STS). Problems characteristic of the current system include a 1970's base technology level, high operational cost per launch, excessive turn-around time, and a low level of reliability. An Advanced Space TransportationSystem, designed to enter serviceat the beginning of the twenty-firstcentury,isthe next logicalstepin the evolutionofthe space transportation program. DeSigned as a high-technologyreplacementto theSTS, the ShuttleIIoffersthe promise of lower operationalcostsand greaterefficiencyin both manned missions and cargo deployment. Itsdesign willtake advantage of industrialadvances made sincethe originaldesignof the currentSpace Shuttle.These advantages include,but are not limited to,composite materials,automated controlsystems,propulsionsystems,hypersonic aerodynamics, and the experiencegained from the present STS. A number of factorsdeemed criticalto itsoperationalsuccessand technicalfeasibility influencedthe design ofthe ShuttleII.Among thesewere: decreasedturnaround time,a lower cost per launch, emphasis on reliabilityover performance, maintaining a reusable system, low costengines,pre-processedpayloads,STS-developed technology,the presence of a permanently-manned space station,development of a Heavy LiftLaunch Vehicle (HLLV) to off-loadpayload requirements,and compatibilityof cargo/passengertransport with systems already operational. To selectthe most practicaland efficientconfiguration,a number of design classification parameters were examined. These includedreusabilityof the system, the possibilityof a manned boostersystem,the number ofvehiclestages,the type of propellantused,and the type of burn staging.These fiveconsiderationswere variedto determine allpotential designs.These configurationswere then subjectedto primary evaluationcriteriato select the optimum design. These criteria included the overall safety of the system, the performance of the system, the expense involved for the total ASTS program (including the cost per flight), and the operation and support of the system, including turnaround time, overhauls, and reliability. The finaldesign was required to meet National Aeronautics and Space Administration (NASA) ground rulesforthe ASPS. The proposed configurationwas evaluated on its abilityto deliverpayload intothe two standard orbitscurrentlyemployed by NASA: a due- eastlaunch from Kennedy Space Center intoa 270 nauticalmile orbitwith an inclination of 28.5 degrees,and a launch from Vandenberg Air Force Base intoa 150 nauticalmile orbitwith an inclinationof98 degrees.The proposed design was based on an anticipated 1992 technologylevel.Other ground rulesincludedthe abilitytobe transportedby airfrom the landingsitetothe launch site,the abilityto abortto orbitifan engine islostduring flight(engine-outcapability),and an initial(sealevel)thrust-to-weightratioof 1.3. After subjecting the potential configurations to the weighted criteria, the optimum ASTS design was determined to be a fully reusable system with an unmanned fly-back booster and a two-stage parallel burn of all-liquid propellants. i' 2 If ' 3.0 Proposed System Configuration Description From the preliminary design studies,a fully-reusablesystem employing parallelburn from a manned orbiterand an unmanned flybackboosterwas determined to be the most efficientand economicallyfeasiblearrangement for extended life-cycles.It was further decidedthat the orbiterand boosterwould be designedto be as similaras possibletoreduce development and productioncosts.The ultimateresultofthese decisionsis the configurationpresented here (See Figures 3.0.1and 3.0.2). The booster and orbiterwillhave a common fuselage,wing, verticaltail,and avionicsand controlsystems.They willdifferin the sizeand number of fueland oxidizertanks, number and arrangement of engines,payload,and passenger compartment. Design and constructioncostswillbe minimized by having a common structurein which components can fitforeitherthe boosterorthe orbiter. 3. I Changes In Preliminary'Configuration The most dramatic change in the system conceptinvolvedthe ascent propulsionsystem. Propulsion was originallydividedequallybetween booster and orbitervehicles. Subsequently,however, one of theSTMEs from the orbiterwas shiftedto the booster,leaving the orbiterwith a totaloffour enginesand the boosterwith a totalofsixengines.This change was made forthree principalreasons: • to reducethe dry weight ofthe orbiter;, / • to givethe boostera largerthrust/weightratio,thus making itmore suitableas a generalpurpose boosterthatisnot necessarilyrestrictedtothe ShuttleII system; • to allowthe boosterto carrymore propellant,loweringthe grosslift-offweight ofthe orbiterand givingthe boostera longerburn duration. The fuselagewas expanded by increasingthe radius of curvature of the fuselageceiling. This alterationallowed oxygen tanks on both vehiclesto be increasedfrom 26 feetto28 feet in diameter.The hydrogen tank on the booster,which is similarin design to itsoxygen tank,was alsoenlargedto 28 feetin diameter. The crew compartment, originallyenvisionedas being two-storied(asin the present Shuttle Orbiter),was changed to a single-levelfacilityto provide room forhydrogen tanks underneath the flightdeck and forward ofthe cargobay.The cargo bay was expanded, from the 60 feetx 15 feetsizeemployed on thepresent shuttle,to encompassing allavailable volume (an irregularly-shapedsectionhaving 165% of the volume ofthe 60 feetx 15 feet section)in the sixtyfeetunder the cargobay doors. Sincethe boosterdoes not requirea crew compartment and support facilities,cargo bay doors,itsdry weight is some 20,000 pounds lessthan that ofthe orbiter.This figureincludes the additionalweight incurredby two extraengines and correspondingpumping facilities. 3.2 Wing A deltawing configurationwas chosen foritssignificantadvantages over conventional constant-taperwings in terms of both heat shieldingduring re-entryand staticstability. 3 The horizontaltailm_, be eliminatedby using a deltawing which isbeth swept and twisted.Furthermore, flightexperiencegained from the STS can be incorporatedinto anticipatedShuttle II wing performance. The wings on beth theorbiterand boosterare similartothat used on the currentSTS, but largerto accommodate the greaterweight and fuselagelengthof the ASTS. The wing- loading does not significantlydifferfrom that of the ShuttleOrbiter. The followingtableliststhe wing data used in aerodynamic analysis. Table 3.2.1: Delta Wing Physical Characteristics Root Chord 87.00feet Tip Chord 18.00feet Mean Aerodynamic Chord 51.12feet Aspect Ratio 2.8OO Taper Ratio 0.246 Leading Edge Sweep 47° Quarter Chord Sweep 42° TrailingEdge Sweep 13° Planform Area 5818 feet2 Wetted Area 9738 feet2 Body Width at Wing 30.0feet Body Height at Wing 28.0feet / 41 • The wing mass isestimated as that of an aluminum wing sizedto the same wing loading. The wing mass includesthe box body sectionand main gear installationprovisions.A constantthickness/chordratioof 6% was assumed. Also,the wing willincorporatea controlsurfaceon each half-wingforlateralcontrolof the orbitervehicle. 3.3 Vertical Tail A simpleconstant-taperverticaltailwas chosen forboth the orbiterand the booster.The only controlsurfaceincorporatedintothe tailisa combination rudder and speed brake. This design reduces both complexityand