The Space Station currently is being designed to maximize crew safety through fault tolerance, safehaven provisions, and crew delivery and return using the Space Transportation System (STS). Studies have identified the need for assured crew return capability through a space-based  lifeboat  that is always available for use in contingencies encompassing (1) medical emergencies, (2) Space Station failures, and (3) interruption of STS services. This paper reviews major mission, operational, and system requirements and the process for evaluating a range of practical vehicle and operational options. It describes flight and ground system design concepts and the major trade studies being performed to select the best end-to-end system that will provide a basis for design and development. Flight vehicles include capsules with ballistic and low lift/drag characteristics and lifting body aerodynamic-shaped designs. Ground systems emphasize the use of existing resources

Fraser, George F.

English

Embry-Riddle Aeronautical University

The Space Congress® Proceedings 1990 (27th) 90's - Decade Of Opportunity Apr 25th, 2:00 PM - 5:00 PM Paper Session II-A - Space Station Assured Crew Return Vehicle (ACRV) System and Operational Considerations George F. Fraser Space Transportation Systems Division Rockwell International Downey, California Follow this and additional works at: https://commons.erau.edu/space-congress-proceedings Scholarly Commons Citation Fraser, George F., "Paper Session II-A - Space Station Assured Crew Return Vehicle (ACRV) System and Operational Considerations" (1990). The Space Congress® Proceedings. 17. https://commons.erau.edu/space-congress-proceedings/proceedings-1990-27th/april-25-1990/17 This Event is brought to you for free and open access by the Conferences at Scholarly Commons. It has been accepted for inclusion in The Space Congress® Proceedings by an authorized administrator of Scholarly Commons. For more information, please contact commons@erau.edu. SPACE STATION ASSURED CREW RETURN VEHICLE (ACRV) SYSTEM AND OPERATIONAL CONSIDERATIONSGeorge F. FraserSpace Transportation Systems DivisionRockwell InternationalDowney, CaliforniaJanuary 1990ABSTRACTThe Space Station currently is being designed to maximize crew safety through fault tolerance, safe- haven provisions, and crew delivery and return using the Space Transportation System (STS). Studies have identified the need for assured crew return capability through a space-based "lifeboat" that is always available for use in contingencies encompassing (1) medical emergencies, (2) Space Station failures, and (3) interruption of STS services. This paper reviews major mission, operational, and system requirements and the process for evaluating a range of practical vehicle and operational options. It describes flight and ground system design concepts and the major trade studies being performed to select the best end-to-end system that will provide a basis for design and development. Flight vehicles include capsules with ballistic and low lift/drag characteristics and lifting body aerodynamic-shaped designs. Ground systems emphasize the use of existing resources.1. INTRODUCTIONDuring Space Station Phase B studies, con­ sideration was given to enhancement of crew safety through the use of a space-based crew return vehicle. NASA initiated assured crew return capability studies in 1986 and assessed space- and ground-based crew rescue approaches. The NASA studies concluded that space-based rescue was required; this conclusion was supported by several major independent study groups, including the National Research Council, Aerospace Safety Advisory Panel, and the NASA Critical Evaluation Task Force activity at the Langley Research Center.• OBJECTIVE - TO DEFINE AN ASSURED MEANS OF CREW RETURN FROM SPACE TO SUPPORT SPACE STATION PERMANENT MANNED PRESENCE» ACRC STUDIES INITIATED IN FY 1986 FINALIZED FY 1988> TWO APPROACHES ADDRESSED* SPACE-BASED ~ RESPOND IN MINUTES/HOURS* GROUND-BASED - RESPOND IN WEEKS/MONTHS• IN-HOUSE ACRC STUDY CONCLUDED SPACE-BASED RESCUE SYSTEM WAS NECESSARY FOR DEFINED MISSIONS* CREW RETURN FOR MEDICAL REASONS* NEED FOR STATION EVACUATION* NSTS SERVICE INTERRUPTION• CONCURRENT STUDIES BY VARIOUS INDEPENDENT GROUPS SUPPORTED THE NEED FOR SPACE-BASED RESCUE SYSTEM* 1987 NATIONAL RESEARCH COUNCIL REPORT* 1989 AEROSPACE SAFETY ADVISORY PANEL REPORT* CRITICAL EVALUATION TASK FORCE, ETC,2. NASA ACRV STUDY PROCURE- MENT PLANS BEING IMPLEMENTEDAs a result of studies that identified the need for a space-based rescue system, NASA is con­ tracting for ACRV systems studies.Two contracts for combined Phase A1 and optional Phase B studies are planned with dura­ tions of 6 and 12 months, respectively. These contract studies, each valued at $6 million, com­ mence in April 1990 under the management of the NASA JSC Project Office.• COMBINED PHASE A' & PHASE B OPTION ON ONE CONTRACT• PHASE A' FIRST 8 MONTHS• PHASE B "HARD" OPTION ADDITIONAL 12 MONTHS• EXERCISE OPTION DURING PHASE A'• FIRM FIXED-PRICE CONTRACTS PLANNED• ESTIMATED VALUE $6M (PER CONTRACT)• PHASE A' - $1.5M « PHASE B - $4.5M• START APRIL 1990• RESPONSIBLE ORGANIZATION: ACRV PROJECT OFFICE - JOHNSON SPACE CENTER4-213. MISSION REQUIREMENTS AND SYSTEM IMPACT DEFINEDThe NASA studies identified three missions requiring return of the Space Station crew using an ACRV. The missions that are combined into sets to develop requirements encompass:* Return of a sick or injured crew member* Return of the complete Space Station crew following a need for evacuation* Return of the crew following interruption of STS servicesThe most significant mission requirements that impact the system design include crew size,time constraints (including return of crew to a medical facility), and crew life support and accel­ eration limits. These key requirements influence the landing site selection; entry and landing modes; and the vehicle shape, size, number, and subsystem designs.MISSION REQUIREMENTMEDICAL MISSION• TIME LIMIT • 24 HR FROM DECISION • 6 HR MISSION * CREW ACCELERATION LIMITS • ENTRY» LANDING • SICK CREWSS FREEDOM CONTINGENCY• EVACUATION TIME LIMIT• STATION CONDITIONS • CREW SIZE - 8STS SERVICES INTERRUPTED• CREW SIZE - 8 \COMBINED MISSIONSSYSTEM IMPACTLANDING SITE SELECTION & SARCONTROLLED ENTRY MODERATE LID CAPSULE OR LIFTING BODY IMPACT VELOCITY CONTROL MINIMUM CREW SIZE - 2 MEDICAL & EGRESS PROVISIONSGROUND SUPPORT & CHECKOUT ON-ORBIT OR GROUND LOITER CAPABILITY CONTROLLED SEPARATION VEHICLE SIZE/NUMBER OF VEHICLES .. VEHICLE SIZE/NUMBER OF VEHICLES AS FOR STATION CONTINGENCYNUMBER OF USES OVER 30 YEARS4. WIDE RANGE OF CONCEPTSCONSIDEREDA wide range of concept options encompass­ ing ballistic entry compatible shapes, controllable capsules, and aerodynamic lifting body vehicleshas been assessed relative to the ability of these systems to satisfy key mission requirements. Concepts have also been evaluated in terms of maturity and program impact to converge on the most promising representative configurations.DROPOUT: i NOW REENTRY \INFLATABLE DEP LOVABLE LIFTING BODYNASP (NATIONAL AEROSPACE PLANE)HOTOL (HORIZONTAL TAKEOFF & LANDING)SHUTTLE (SMALL) RUSSIANSHUTTLE (LARGE) RUSSIANSHUTTLE JAPANESESINGLE-PERSON ESCAPE CAPSULESDEFICIENT IN CRITICAL AREASBALLISTIC SHAPES STRONG CONTENDERSLIFTING-BODY SHAPES STRONG CONTENDERS4-225 . STUDIES PLANNED TO VALIDATE MISSION REQUIREMENTS AND ASSESS OPTIONSRepresentative vehicle configurations in a range of aerodynamic performance categories are being evaluated in terms of their ability to satisfymission requirements and assure crew safety in an affordable system. A range of operating modes and system designs will be considered, encompassing ballistic and controlled entry; con­ ventional parachute and parasail deceleration systems; and land terrain, water, or runway landings.DELIVERY TO SPACE STATIONELVDELIVERY(OPTION)SPACE TITAN 4 SHUTTLE OROTHERSLAND OR WATER LANDING & LAND-BASED HELICOPTER RECOVERYEMERGENCY ACRV MISSIONS TO RETURN CREW IF:1. MEDICAL EMERGENCIES REQUIRE IMMEDIATE RETURN OR EXCEED SPACE STATION CAPABILITIES2. ACCIDENT/FAILURECONTINGENCY EXCEEDS SPACE STATION SAFETY CAPABILITIES3. NSTS LAUNCHES INTERRUPTED6. REPRESENTATIVE VEHICLES ASSESSED RELATIVE TO REQUIREMENTSThe assessment of representative vehicles is based on their merit relative to meeting mission or programmatic requirements and providing desirable system attributes.Key mission requirements—including time constraints, crew size, and acceleration limits— are combined with the needs for simplicity, reli­ ability, and cost effectiveness to establish desired system characteristics. These characteristicsencompass aerodynamic shape, automation, and control.Representative systems are being assessed. Significant discriminators are the abilities to satisfy entry constraints, site access, complexity, and cost.Of the candidate representative designs, only the ballistic entry capsule is incompatible with defined requirements due to the excessive accel­ eration experienced on entry. Major factors influ­ encing the evaluation of remaining concepts include degree of complexity, maturity of the knowledge base and its impact on program risk, and the relative development and life-cycle costs.MISSION REQUIREMENTSCREW MEDICAL SPACE STATION EVACUATIONSTS SERVICES INTERRUPTEDCREW SAFETY MINIMUM LCC & AFFORDABLESYSTEM CHARACTERISTICS DESIREDSIMPLE RELIABLE• AVAILABLE• ROBUSTMAINTAINABLE COST-EFFECTIVECREW: 2 MISSION: 24 HR TRANSPORT: SHR ENTRY fl: «4 LANDING: 2-10CREW: 441 EVAC:15-30MENTRY (j:<4 LANDING: 5-15ENTRY g:<4 LANDING: 5-15• SICK CREW INFLUENCES AUTOMATION• CONFIGURATION PACKAGING SENSITIVE DECONDtnONINO INFLUENCES AUTOMATION• ENTRY 0 REQUIRES ENTRY LIFT• CONTROLLED LANDING REQUIREDREPRESENTATIVE VEHICLESBALLISTIC WITH SEPARATE PROPULSION- AUTOMATION DESIRABLE- ENTRY fl INCOMPATIBLE- LANDING CONTROL REQUIRED• LOW COST• SIMPLE SYSTEMS• LOITER WITH SERVICE MODULELOW L/D WITH INTEGRAL PROPULSION• AUTOMATION DESIRABLE•ENTRY CONTROL• MODERATE CROSS RANGE• GOOD NSTS PACKAGING• LANDING CONTROL REQUIREDMODERATE L/D WITH SEPARATE PROPULSION• AUTOMATION DESIRABLE• ENTRY CONTROL• GOOD CROSS RANGE• MARGIN ON ENTRY• MATURE DATA BASE• MAN-RATED CONFIGURATION• EXTENDED ON-ORBIT LOITER WITH SERVICE MODULE• 2 EGRESS PASSAGES• LANDING CONTROL REQUIREDHIGH L/D WITH INTEGRAL PROPULSION• AUTOMATION DESIRABLE• ENTRY/LANDING CONTROL• LOW DECELERATION LOADS• MAXIMUM CROSS RANGE/SITE ACCESS• HORIZONTAL LANDING• MODS TO RAISE LANDING L/D4-247. RELATIVE PERFORMANCEESTABLISHED AS A FUNCTION OF AERODYNAMIC SHAPE AND ENTRY MODEThe significant performance discriminators have been identified for the representative candi­ date concepts as a function of their hypersonic lift-to-drag ratio (L/D) and entry mode.Ballistic entry capsule concepts offer potential for simplicity and low cost but are subject to highentry g, higher temperatures, and larger recovery target dispersion, possibly necessitating water landing. Low to moderate L/D capsules with controlled entry offer the opportunity for lower entry g's and temperatures, and smaller recovery targets with a resulting moderate increase in complexity and cost.High L/D configurations provide lower entry g's and temperature, excellent recovery target accuracy, and site access, but with significant increase in complexity and cost.VEHICLE OR SYSTEM FACTORENTRY (g's)GUIDANCE COMPLEXITYTRAJECTORY DISPERSIONSLANDING IMPLICATIONSCROSS RANGE IMPLICATIONSHEATING IMPLICATIONSCOST IMPLICATIONSRANGE OF L/DL/D = 0 BALLISTIC L/D < 0.25HIGH-G CONFIGURATIONS~ 8SIMPLE, SPIN VEHICLELARGE = 30 NMIWATER ONLY>4L/D < 0.5<4L/D < 0.75 L/D > 1.1LOW-G CONFIGURATIONS<3BANK ANGLE CONTROL REQUIREMENTL/D>0.1 REQUIRED FOR GOOD TRAJEC­ TORY CONTROL1-NMI SPOT SIZE ACHIEVABLELAND OR WATER OPTIONEXTRA AV REQUIRED TO ACQUIRE LAND SITES, AERO CROSS RANGE INSUFFICIENTAT L/D > 0.5 SOME SITES ACCESSIBLE WITHOUT EXTRA AVINCREASING PEAK TEMPE MATURE ————————————————nirAT L/D > 0.75 ALL SITES & CONUS: ACCESSIBLE WITHOUT EXTRA AV<2• BANK ANGLE & a CONTROL REQUIRED FOR ENTRY • 3-AXIS CONTROL REQUIRED FOR RUN­ WAY LANDINGRUNWAY ACCURACY ACHIEVABLERUNWAY LANDING IF SUBSONIC AERO CHARACTERISTICS ACCEPTABLEALLOWANCE OF EXTRA SITE ACCESS OPPORTUNITIES BY LARGE CROSS RANGE——————————————————— - INCREASING HEAT LOADLEASING CONFIGURATION COMPLEXITYrhUIVI UtoluNFROM OPERATIONS ———————————————————————4-258. WATER IMPACT WITH •PARACHUTE EECOVERY POTENTIALLY EXCEEDS CREW ACCELERATION LIMITSDecisions on water or land landing and thelanding system design are impacted by crew physiological acceleration limits that are orientatiOE-depaidentIf ;i. vdiAcb Is landed in water, the induced acceleration environment is governed by vehicle shapf water penetration angle, vertical, and hori­zontal impact velocity components, parachute swing, roll orientation, and wave state.Experience with previous manned capsule programs using parachute recovery indicates that nominal acceleration on the order of 10 g's m&y be expected, with a range from 5 to 30 g's.As this range of acceleration with a parachute recovery exceeds NASA-specified sick crew acceleration limits, controlled impact becomesnecessary.VEHICLE PIAIC €*d RESULTANT ACCELERATION (g's) TO9oMPACTPARAMETERFOOTPRINTIMPACT ANGLE (TYPICAL)HUTCH10 m m «VERTICAL4-tft9 . LAND IMPACT WITH PARACHUTE RECOVERY POTENTIALLY EXCEEDS CREW ACCELERATION LIMITSA vehicle that is recovered on land will be subject to acceleration influenced by vertical and horizontal velocity components; dynamics on landing considering velocities, terrain, orienta­tion; and vehicle shape and attenuation through vehicle and ground.Experience with the Apollo program indicates that potential accelerations imposed on vehicle and crew will exceed the NASA-defined crew physiological limits. This indicates a need for reduction in velocity on impact.COUCHINPUT12.018.0DROP I MO. 47 |4-2710. ACRV OPERATIONS SUPPORT WILL EMPHASIZE USE OF EXISTING OR PLANNED RESOURCESKey to effective and affordable operation of the ACRV are availability and cost effectiveness of operations resources for ground processing, mission support, and flight and recovery.Ground segment affordability can be achieved through effective use of NSTS, SSFreedom, expendable launch vehicles, payload processing facilities and resources, and existing search and rescue forces for ACRV recovery.Mission support availability can be assured through shared use of existing and planned support resources, plans, and training programs.Support to the flight segment will emphasize operational simplicity through use of existing support equipment inventories and technology.LOGISTICS & MAINTENANCEGROUND PROCESSINGLAUNCH PROCESSINGPOSTMISSION OPERATIONSMISSION SUPPORTREAL-TIME CONTINOUSSSCC/FLT CONTROLLERSCOMMUNICATIONS INTERFACE SYSTEM-FLIGHT RULES > FLIGHT• TECH­ NOLOGYVVPREMISSION ONE TIMECREW ACTIVITY PLANNINGFSW PRODUCTIONFLIGHT PLANNING & DESIGNTRAINING PERIODICSPACE STATION FREEDOM DRILLSLOGISTICS & MAINTENANCEFLIGHT OPERATIONS. ATTACHED OPERATIONS4-2811. MISSION AND SYSTEM TRADE STUDIES WILL RESULT IN SELECTION OF THE BEST ACRV SYSTEMThe selection of the best ACRV system to satisfy mission requirements in an affordable manner requires integrated trade studies to assess a range of system and operational options.Major trade studies that influence system andoperation decisions have been defined, as illus­ trated in the matrix. These studies will be used in the derivation and definitization of ACRV requirements.A consistent set of evaluation criteria are used to assess options to facilitate trade study deci­ sions. These key evaluation criteria are satisfac­ tion of mission requirements, crew safety, and life-cycle cost; affordability; simplicity; availabil­ ity; reliability; and robustness.INTEGRATED TRADESVEHICLE CONFIGURATIONCONFIGURATIONSCAPSULEVEHICLECREW CAPACITY4-9CORRELATION ASSESSMENTREUSABLEvsEXPENDABLEVEHICLE=11LANDvs WATER LANDINGDAYTIME ONLYvs ANYTIME LANDINGON-ORBITvs LAND OR WATER LOITERRECOVERY SITESCAPSULE• BALLISTIC• LOW L/D• MODERATE L/DLIFTING BODY• SATISFIES MISSION REQUIREMENTS• CREW SAFETY• LIFE CYCLE COST• AFFORDABLE• SIMPLE• AVAILABLE• RELIABLE• ROBUST.SYSTEM & OPERATION SELECTION12. ACRV WILL ENHANCE SPACE STATION CREW SAFETY THROUGH ASSURING A RETURN CAPABILITYIt is considered that a space-based rescue system will provide an effective means of assur­ ing Space Station crew return.Initial studies indicate that the ACRV system can be developed with current technology.System cost may be minimized through use of available hardware and operations support resources.Key to selection of the best system to satisfy needs are derivation and validation of missionrequirements and the application of consistent criteria to select the best end-to-end ACRV system and operations that assure crew safety and cost and operational effectiveness.• ACRV REQUIRED TO ASSURE SPACE STATION CREW SAFETY• LOSS OF SPACE STATION OR NSTS CREW WOULD HAVE MAJOR ADVERSE AFFECT ON OUR MANNED SPACE PROGRAM• ACRV SYSTEMS DO NOT REQUIRE TECHNOLOGY ADVANCEMENT• PROGRAM COST MAY BE MINIMIZED THROUGH USE OF AVAILABLE HARDWARE, SOFTWARE, & OPERATIONS SUPPORT RESOURCES• CONCEPT SELECTION DRIVEN BY MISSION REQUIREMENTS, CREW CONSTRAINTS, & COST• ACRV STUDIES SUPPORT SPACE STATION DECISIONS• BUDGET DECISIONS REQUIRED FOR FY 1991 & FY 1992 ACTIVITIES4-29

Paper Session II-A - Space Station Assured Crew Return Vehicle (ACRV) System and Operational Considerations

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Paper Session II-A - Space Station Assured Crew Return Vehicle (ACRV) System and Operational Considerations

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