Simulating Ground Support Capability for NASA’s Reusable Launch Vehicle Program

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Simulating Ground Support Capability for NASA’s Reusable Launch Vehicle Program Kathryn E. Caggiano Peter L. Jackson John A. Muckstadt Cornell University Operations Research and Industrial Engineering. NASA Goals. Reusable Launch Vehicle Program. Today: Space Shuttle 1st Generation RLV - PowerPoint PPT Presentation

Transcript of Simulating Ground Support Capability for NASA’s Reusable Launch Vehicle Program

  • Simulating Ground Support Capability for NASAs Reusable Launch Vehicle Program

    Kathryn E. Caggiano Peter L. Jackson John A. Muckstadt

    Cornell UniversityOperations Research and Industrial Engineering

  • NASA Goals

  • Reusable Launch Vehicle ProgramToday: Space Shuttle1st Generation RLVOrbital Scientific PlatformSatellite Retrieval and RepairSatellite Deployment2010: 2nd Generation RLVSpace TransportationRendezvous, Docking, Crew TransferOther on-orbit operationsISS Orbital Scientific Platform10x Cheaper100x Safer2025: 3rd Generation RLVNew Markets EnabledMultiple Platforms / Destinations100x Cheaper10,000x Safer2040: 4th Generation RLVRoutine Passenger Space Travel1,000x Cheaper20,000x Safer

  • Systems Approach: Safety, Reliability, and CostOperatingMarginRobustDesignIVHMRedundancyInherentReliabilityToxic FluidInterfacesAccessibilityRangeOperationsOperations100x Cheaper10,000x SaferMoveOperatingRange/De-rateAdd MaterialCapability/WeightRequires Increased MarginRequires Increased TestingReduceVariabilityWeight Margin

  • Marshall Space Flight Center: NASA Flight Projects DirectorateProject ManagementSystems Engineering & IntegrationPayload Operations Engineering & IntegrationMission Preparation & ExecutionMission Training Requirements & ProcessesGround System Design, Development, and TestFacility Operations

  • Cornell Project GoalsDevelop analysis tools for determining and evaluating spare parts stocking policies for avionics components of Reusable Launch Vehicles

  • Project ObjectivesConstruct a methodology that:Evaluates the effectiveness of a proposed logistics support strategy

    Determines stock levels for recoverable items needed to operate the system effectively

  • System FrameworkRLV Ground Maintenance Process

    Line Replaceable Unit (LRU) Repair Process

    Shop Replaceable Unit (SRU) Repair Process

  • RLV Mission Cycle

  • RLV Maintenance Cycles

  • One Maintenance CycleFailed LRUs must be replaced by the scheduled end date in order to avoid a delay.

  • RLV Ground MaintenanceTest LRUsRemoveand Replace Failed LRUs

  • LRU Repair Process

  • SRU Repair Process

  • System FrameworkRepairSRUSRUInventoryTest LRURepairLRURemoveand ReplaceFailed SRUsLRUInventoryRemoveand Replace Failed LRUDiagnoseLRUFailure

  • Failed LRU removed from RLVLRU Repair Cycle Time

  • Simulation Model FeaturesCaptures many aspects of integrated systemOutsourcing and condemnationLimited capacity for in-house diagnosis and repairProbabilistic transport and service timesLimited inventories of LRUs and SRUsDynamic prioritiesImplemented in MS Excel with VBA

  • A Model of RLV RepairsIdentify EventsModel Delays Between EventsManage PrioritiesTrack InventoriesSelect InputsCapture Outputs

  • Identify Events

  • Model Delay Between Events

  • Manage Priorities

  • Track Inventories

  • Select Inputs

  • Capture Outputs

  • Sample Cases

    Case 1: Ample Capacity Case 2: Sufficient InventoriesCase 3: Effective Service PrioritiesThree Cases using SimulatorRLV arrivalsevery 50 daysRLV ground time20 daysLRU work stations5SRU work stations5Service times75 - 100 daysRepair priority rulesimple Baseline:

  • Sample CasesCase 1: Ample Capacity Baseline Case Results Percent of RLVs Delayed: 60 46Average Delay Time: 41 26Case 2: Sufficient LRU InventoriesPercent of RLVs Delayed: 60 27Average Delay Time: 41 39Case 3: Effective Repair PrioritiesPercent of RLVs Delayed: 60 39Average Delay Time: 41 25Simulation Results

  • Sample Cases1. Sufficient service capacity significantly improves on-time performance.2. Appropriate LRU and SRU inventory levels improve performance considerably.3. Effective repair priorities increase utilization, reduce costs, and improve on-time performance.4. System utilization rates, inventory levels, and on-time service targets cannot be selected independently.Four General Lessons