Integration of Reusable Launch Vehicles (RLV) into the Air Traffic Management System J.K. Kuchar, K.A. Khan, J. Falkner Department of Aeronautics and Astronautics Massachusetts Institute of Technology A.A. Trani, H.D. Sherali J.C. Smith, S. Sale, Q. Chuanwen Department of Civil Engineering Department of Industrial Engineering Virginia Tech Sponsor: FAA Office of Commercial Space Kelvin Coleman NEXTOR - National Center of Excellence for Aviation Operations Research 1 of 24
Motivation Current mode of airspace utilization for space operations Activate Special Use Airspace (SUA), reroute air traffic Large spatial and temporal safety buffers Limited flexibility Disparity between air and space user costs Improvements in sensors & datalink capabilities Potential to reduce uncertainty of some vehicle trajectories More efficient information flow between ATC - space operator Example: launch delay of STS-87 (with John Glenn) due to intruding GA aircraft Advanced ATM models could streamline the integration of RLVs with ATC NEXTOR - National Center of Excellence for Aviation Operations Research 2 of 24
Opportunities and K ey Issues Some vehicle types / missions might be integrated with air traffic Reusable Launch Vehicles with conventional phases of flight Key Research Issues 1) What is required for integrated operations to occur? Equipage, communications, surveillance requirements 2) How should those operations be carried out? Flow management procedures 3) What are the user & service provider cost / benefit trade-offs? NEXTOR - National Center of Excellence for Aviation Operations Research 3 of 24
Scope of Work Investigate current and future methods of RLV-aircraft separation in use at the Special Use Airspace (SUA) areas around the US Launch Ranges (Cape Canaveral, Vandenberg AFB, and Wallops AFB) Identify mission profiles of the proposed RLVs and characteristics of the respective phases of flight Develop a generalized model of airspace / air traffic / RLV operations to provide a consistent framework to describe and evaluate options Define potential modes of operation / airspace utilization for RLV operations by understanding current requirements and procedures, and explore possible alternatives Develop a methodology to estimate RLV operation impacts NEXTOR - National Center of Excellence for Aviation Operations Research 4 of 24
Summary of Pr evious Acti vities Collected data on proposed RLVs Surveyed typical phases of flight / mission profiles Identified 8 potential modes of operation Continue use of SUA (strategic segregation) Activate new SUA Mission-specific SUA Controlled Space Activity Zone (c.f. Class B airspace) RLV corridor RLV as high-priority vehicle (vectors) RLV as nominal-priority vehicle Self-separation NEXTOR - National Center of Excellence for Aviation Operations Research 5 of 24
Phase II Acti vities Investigate trade-offs in tactical modes of operation Appropriate safety buffer size and duration Equipage and procedural requirements Explore limits of tactical ATC vectors (heading / altitude / speed) Ability to manage high speeds / vertical rates Display / procedure / control issues Preliminary model development Describe when SUA vs. Tactical operation can/should be used Impact of state uncertainties, vehicle profile & performance Airspace conflict and sector analysis models Airspace planning model development and validation NEXTOR - National Center of Excellence for Aviation Operations Research 6 of 24
RLV Airspace Usage Implications VPI Air traffic flow VPI Safety Airspace Usage MIT Vehicle equipment requirements MIT RLV operations MIT Operator workload VPI MIT Ground equipment requirements VPI NEXTOR - National Center of Excellence for Aviation Operations Research 7 of 24
RLV Operation Modes Current Operational Mode a) Strategic b) Large SUA c) Indirect integration Airline Operations Center (AOC) Air Traffic Control RLV Operations Center (ROC) Future Operational Modes a) Tactical b) Smaller SUA c) Direct integration Airline Operations Center (AOC) Air Traffic Control RLV Operations Center (ROC) NEXTOR - National Center of Excellence for Aviation Operations Research 8 of 24
Framew ork to Model RL Modes of Operation Analysis Flight Plans/Tracks Trajectory Descriptor V Impacts AOM 1, AEM 2 Models ATC Scenario Restriction Database Simulation Model RAMS and SIMMOD Optimization Model 3 Airspace Scenario Generation Cost Benefit Analysis Non-airspace User Cost 1 AOM = Airspace Occupancy Model 2 AEM = Aircraft Encounter Model 3 Airspace Planning Model NEXTOR - National Center of Excellence for Aviation Operations Research 9 of 24
NEXT OR/MITRE Relationship MITRE (Looking at current operational practices) Quantified operational cost for two launches from CCAS using actual traffic data and perceived delays Same approach to evaluate Kodiak Island operations NEXTOR (Studying future operational practices) Identified possible tactical separation envelopes and SUA regions Modeling generic size spaceports (Phase III) using simulation tools Quantifying costs for future Free Flight conditions Minimizing detour impacts (optimization model) NEXTOR - National Center of Excellence for Aviation Operations Research 10 of 24
Confl ict Detection and Resolution Protected Zone: safety buffer around each vehicle Aircraft: 5 nmi, ± 1000 or 2000 ft. Alert Zone: Space in which action must be taken to prevent PZ violation Alert Zone Protected Zone Protected Zone As Alert Zone size increases, SUA becomes more attractive NEXTOR - National Center of Excellence for Aviation Operations Research 11 of 24
Tactical/Strategic Confl Velocity ict Ev aluation Traffic density Geometry Current State Uncertainties Projected Trajectory Uncertainties Maneuverability Delays Conflict Model Tactical Alert Zone size Airspace Model Alert rates Spatial extent of alerts Comparison aids in Cost / Benefit studies Strategic SUA Mode of Operation Reroute rates Spatial extent of rerouting Traffic density NEXTOR - National Center of Excellence for Aviation Operations Research 12 of 24
Simplifi ed Tactical Alert Zone Model Intruder A Intruder B Left turn swept area Right turn swept area Alert Zone Ownship Enables first-order tradeoff analysis (uncertainty vs. AZ) NEXTOR - National Center of Excellence for Aviation Operations Research 13 of 24
45 Example Pr eliminary Trade Studies Effect of Maximum Turning Angle 35 Effect of Turn Rate 0.4 /s 40 35 15 30 25 0.8 /s 1.4 /s 30 30 20 Instantaneous 25 45 20 60 15 15 10 10 5 5 0 0-10 -5 0 5 10 NM -10-5 0 5 10 NEXTOR - National Center of Excellence for Aviation Operations Research 14 of 24
Alert Zone Gr owth Due to Trajectory Uncertainty 200 Apex Distance, NM 150 100 50 5 2 1 V I / V O = 0.5 0 0 30 60 90 Uncertainty, ± Tactical conflict resolution untenable at large trajectory uncertainties & velocities Tactical conflict resolution untenable at large trajectory uncertainties & velocities NEXTOR - National Center of Excellence for Aviation Operations Research 15 of 24
Netw ork Flo w Modeling and Optimization Traffic flow model analysis tools SIMMOD - predicts delays and changes in travel times for current scenario conditions) RAMS - predicts delays, travel times and sector workload for current and anticipated 2005 conditions (i.e., Free Flight) Development of an optimization model to reduce the impacts of RLV operations around sites Dynamically schedules flights affected by RLV operations to minimize a performance index (cost and workload) Model development tools: Matlab 1 and CPLEX 2 1.Matlab is a trademark of the Mathworks Inc. 2.CPLEX is a trademark of ILOG International NEXTOR - National Center of Excellence for Aviation Operations Research 16 of 24
Sample Sector Occupancies 30 Latitude (deg) 29 28 27 26 25-88 -86-84 -82-80 -78-76 -74-72 Longitude (deg) 15 STS SUA Activation Traffic (acft) 10 5 0 400 600 800 1000 1200 1400 1600 Zulu Time (min) NEXTOR - National Center of Excellence for Aviation Operations Research 17 of 24
Optimization Model to Integrate RL V with Minimum Cost to F AA and Airspace Users Attempts to mimic and advanced ATM system of the future (i.e., 2005, 2010) A mature form of Collaborative Decision Making is in place (i.e., airlines and FAA share information about flight schedules and possible delays associated with each flight) Free Flight operations will be routine across NAS for all enroute sectors and flight levels Considers FAA resources (i.e., a function of traffic density), sector and airline equity constraints Serves as a policy tool to evaluate operations around spaceports NEXTOR - National Center of Excellence for Aviation Operations Research 18 of 24
Optimization Model Rationale KSC-CCAS War ning Ar eas Several flight plan detour strategies can be studied. The best strategy should be a system optimal alternative with minimum effects on users and service providers NEXTOR - National Center of Excellence for Aviation Operations Research 19 of 24
Airspace Planning Model Optimization Model Objective function Min i M p P i C ip x ip n s e e e + µ sn y sn + µ e ( x u x l ) + µ u x u s S n = 1 Cost of adopting flight plan (i,p) Penalty associated with sector load Penalty to maintain equity among airlines Assignment Constraint (a single flight plan is selected) Sector Load Constraint (restricts the number of flights to sector ) Airline Equity Constraint (penalizes equally all airlines flying) n s NEXTOR - National Center of Excellence for Aviation Operations Research 20 of 24
Application of the Optimization Model The optimization model selects among surrogate flight plans to minimize the cost to users and service providers 34 33 32 31 30 29 28 27 26 Jacksonville Enroute Center 23 24 61 40 62 84 87 77 86 89 75 93-88 -86-84 -82-80 -78-76 113 115 51 49 143 55 Longitude (deg.) 91 131 119 126 SUA 129 121 Surrogate FP Original FP NEXTOR - National Center of Excellence for Aviation Operations Research 21 of 24
Integration with Existing N ARIM Tools Currently generation of surrogate flight plans is done using a simple globe circle flight planning module Future will use proven tools such as OPGEN 1 OPGEN output data structure is already integrated in AOM/AEM OPGEN AOM ATM Strategy Demand Func. AEM APM 1.A single flight optimization program developed by CSSI for FAA NEXTOR - National Center of Excellence for Aviation Operations Research 22 of 24
Implementation of Optimization Model The current optimization model is implemented in CPLEX a standard mixed-integer programming solver From, AOM AEM Model Extract Flight Proximity Information a) Time adjacency b) Spatial adjacency c) Sector adjacency Proximal Flight Conflict Generation Based on time, space and proximal sector adjacency Conflict Analysis Statistics Compiles C.A. statistics and estimates conflict metrics Flight Path Conflict Analysis Analytical model to find conflict times and acft. conflict geometries Translate Conflict and Workload Constraints CPLEX Solver Routines Optimal Cost ATM Flow Strategy NEXTOR - National Center of Excellence for Aviation Operations Research 23 of 24
Possible ATM Extensions of the Optimization Model Analysis of catastrophic RLV failures (i.e., estimation of the number of aircraft affected) Special Use Airspace is only one of many possible airspace restrictions in NAS Bad weather phenomena can be treated as a special case of SUA (i.e., dynamic SUA) Dynamic allocation of flight plans in the future will continue be a mutual agreement between airlines and FAA and without any doubt will consider the ATC resources available (i.e., decentralized control) Dynamic airspace sectorization problems (time varying airspace sectors to balance sector loads) NEXTOR - National Center of Excellence for Aviation Operations Research 24 of 24