Of the several new initiatives being contemplated by NASA after the Space Station, a manned expedition to Mars is the most challenging, adventurous, and most rewarding. The Mars initiative envisions much more than just two or three fast trips to the surface of Mars to plant flags and return surface samples. This bold initiative is committed to the human exploration and eventual habitation of Mars, Figure 1. This paper briefly describes the SRS Manned Mars Mission and Program Analysis Study which supports this initiative. The results, to date, indicate the need for a earth-to-orbit transportation system much larger than STS, reliable long-life support systems and either advanced propulsion or aerobraking technology

Hamilton, E. C.

Johnson, P.

Pearson, J.

Tucker, W.

English

Embry-Riddle Aeronautical University

The Space Congress® Proceedings 1988 (25th) Heritage - Dedication - Vision Apr 1st, 8:00 AM Manned Mars Mission Program Concepts E. C. Hamilton SRS Technologies Huntsville, Alabama 35806 P. Johnson SRS Technologies Huntsville, Alabama 35806 J. Pearson SRS Technologies Huntsville, Alabama 35806 W. Tucker SRS Technologies Huntsville, Alabama 35806 Follow this and additional works at: https://commons.erau.edu/space-congress-proceedings Scholarly Commons Citation Hamilton, E. C.; Johnson, P.; Pearson, J.; and Tucker, W., "Manned Mars Mission Program Concepts" (1988). The Space Congress® Proceedings. 6. https://commons.erau.edu/space-congress-proceedings/proceedings-1988-25th/session-7/6 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. Manned Mars Mission Program ConceptsE.G. Hamilton, P. Johnson, J. Pearson, and W. TuckerSRS Technologies Huntsville, Alabama 35806AbstractOf the several new initiatives being contemplated by NASA after the Space Station, a manned expedition to Mars is the most challenging, adventurous, and most rewarding. The Mars initiative envisions much more than just two or three fast trips to the surface of Mars to plant flags and return surface samples. This bold initiative is committed to the human exploration and eventual habitation of Mars, Figure 1. This paper briefly describesFigure 1the SRS Manned Mars Mission and Program Analysis Study which supports this initiative. The results, to date, indicate the need for a earth-to-orbit transportation system much larger than STS, reliable long-life support systems and either advanced propulsion or aerobraking technology.IntroductionThe planning of Manned Planetary Missions is very complex and requires an understanding of the interrelationships of the many parameters associated with planetary orbits, launch windows, etc. This study envisions the transportation of many metric tons of spacecraft, propellant, and life support equipment to low Earth orbit for assembly at the Space Station into huge vehicles, Figure 2, for escapes from the Earth-Moon system on a trajectory that arrives months later at Mars. The geometry is complicated because of the orbits of Earth and Mars as indicated in Figure 3. This results in a variation in energy required, depending on the departure and arrival dates, travel time, and stay time at the planet. On some missions the stay time at the planet may be short (opposition class); other missions may require the astronauts to stay at Mars until the two planets are again inproper alignment to allow a tow energy trip back to earth (conjunction class).Figure 22022— — Mars Perihelion___ 2031 2016 2001Figure 3The complexity of the myriad of options for performing these missions, along with the equipment development lead times and logistics involved in fabrication, testing, and eventually transporting the elements to orbit, requires a rather sophisticated computer program to keep up with all the variables, Figure 4.Software ModulesUnder the sponsorship of NASA/MSFC, SRS is in the process of developing an interactive software package to determine the sensitivity of mass required in LEO, schedules, relative costs and risk, to various mission concepts and program options. The study considers the launch opportunities from 1999 to 2035. A VAX 11/780 is used to calculate the AVs required for various trajectories and stores them in the trajectory module data base. Data bases for launch vehicle design, fabrication, testing, and7-1orbital assembly, are also being developed for the transportation module and the infrastructure module shown in Figure 4. Cost, schedule, and risk module dataFigure 4are being drawn from historical data on similar projects such as Saturn stages, LEM, Space Station, and OTVs. These modules, by necessity, are not overly detailed but they provide preliminary estimates for building to a program level with enough fidelity to ensure an understanding of the program drivers. As the designs and technologies mature, the various modules may be improved. In the meantime program sensitivity to various mission options such as cryogenic propulsion versus nuclear thermal propulsion, or aerobraking versus propulsive braking at Mars and Earth, can be compared.Sensitivity AnalysisFive Manned Mars Programs have been defined for comparative analysis, each one emphasizing different objectives. They are as follows; (1) Early launch date emphasis with initial landings on Phobos/Deimos, (2) Early launch date emphasis using "split missions", (3) Mid-range launch date emphasis (referred to later as the reference program), (4) Delayed mid-range launch dates with stretched program duration, (5) Late launch date emphasis. Along with these program options several precursor mission options have been identified: 1) robotic missions, 2) manned flyby missions, 3) manned orbital missbns, 4) manned Phobos/Deimos landing missions, 5) manned Mars landing missions, and 6) unmanned cargo missions. Each mission is constructed using various trajectory/orbit options (conjunction class, opposition class, Venus swingby, circular parking orbits, elliptical parking orbits); transportation node options (LEO, GEO, high Mars orbit, Ph/D, Mars surface, Lunar surface); and transportation approach options. Figure 5 shows a typical options summary.Example Program AnalysisThe first step in program analysis is to identify the program option to be analyzed. The reference program (mid-range Mars emphasis) was chosen for this example. Each program has several options as indicated in Figure 5. Guidelines and assumptions for the reference program begin by specifying a time span for study from 1999Figure 5through 2035. The reference program should build progressively through an outpost, base, and multiple bases (or colonization). The first three manned landings are exploratory and occur at different sites. An "outpost" is accomplished when a surface habitation and laboratory module is in place and intermittently manned. A base is accomplished when three surface habitation and laboratory modules are in place and permanently manned. The capability to utilize Mars produced water, O2, H2, and propellants (LOX/LH2 or methane) occurs at the IOC of the base. The capability to export Mars produced water, O2, H2, and propellants (LOX/LH2 or methane) occurs two years after the IOC of the base. Additionally, certain events should trigger the need for technologies, i.e., the IOC of a base triggers the need for an advanced power generation system and transportation rates (Ibs/year) trigger the need for advanced propulsion. In addition to these guidelines and assumptions, milestones for the program options are shown in Figure 6. This information will allow the analyst to identify major missions and payloads (Figure 7) and create a program definition (Figure 8). A preliminary schedule is defined using trajectory opportunity data from the trajectory database. Attributes of both nominal missions and payloads are identified. (Attributes for missions and payloads are their mass, dimensions, mission type, origin, destination, flight event schedule, and precursors.) Program definition is also impacted by technology. Technology required by the reference program is compared to technology projections given in the technology database. Technologies associated with the reference program include: advanced propulsion nuclear power generation, long-term cryogenic storage, long-term exposure to the space environment, Closed Ecology Life Support System (CELSS), communications, and surface-to-orbit and orbit-to-surface payload capabilities (both at Earth and Mars). The transportation element of the reference program involves sizing of the spaceship(s), the Mars ascent and descent vechicles (manned and unmanned), and the other tranportation system infrastructure elements. Hardware and propellant masses are estimated based on sizing algorithms which use scaling factors, known masses, and7-2——— Sample FReferenceSample RMid-RangeSample ReLaterSample ReSplitSample RePhobos/Deimos1995-1999eturn mm^WMSite Surveyturn \Mf$F&zy*Site Survey.¥:<¥xx:¥x¥:W::::Xvx:x-xLEO EmphasesU rn |¥>::x%5jr\£x:%W:Site Survey^MM^M^MM2000-2004 i i i i2005-2009 i i i iiSiASxl Manned Sorties \£lmmtf\mm::S:x":x":::x":::x^xwxxi>S<xProgramss/NfiSj?*im?mrv$&#*&&x»tttt*dLunar Er2010-2014 I 2015-2019OutpOSt | brX^xXxXixiA;::::^xS^S/^SfeS^iAaIn-Situ FManned SortiesrphasesreductionOutpostmmrm&rmxl—————— L2020-2024mm&*m$tf\fi2025-2029s^y^JManned Base Phobos OperationsxW::S^^| oductionManned SortiestmmfmW!M®$mms^^LEO Emphases Programs jturn £$S&x/N£3S*x":;:|N Site Survey ji;:^!^SxmM'-^- mmmrnm&dM£O tmphasssP tog rams EJ-j1urn ^x%:xy\;&¥x%;Site Survey mcsmOutp(in ^m^rwmmf,::S :H,S3Wt teJy^s>saa^\:iOutpOSt foxManned Sortie \mrmmmrwmrw^r^mm^m^^^----^ \rtl:x%y\;!:W:;:;xy\:iManned BasePhobos Operatim^^mrmm^Manned Basef^m^^m^/\^mi^m-mmT^ManWVSSi/WSSwi:i:x:x:i:x:iA;:;:S:iWx:x:x:inedBase2030- 2034Sl^iT^xWffi:!/^!^..-...yV.^...^.....^nsLjManned BaseKi:xSi>/^:;$x:x/\s:;:xSx:S$Sx*x*x:x^j^^iiSSS^^yNt::^::^:::::/^::::::: : : : : , w : : : : : : : : : : : ;/^:S:S:S::$xy^^:SS:i'N^^x'^^Manned Phobos / Deimos Operations 1Figure 6Mission Payloads for Reference ProgramManned MSS (M) Cargo MSS (C) Mission # P / L Description Payload Mass1 M2 M3 M4 M5 MCMCM7 — CM8 ,,_.., .... .CMission Module, MEM, ProbesMission Module SVC, MEM, ProbesMission Module SVC, MEM ProbesMission Module SVC, MEM, HAB, LAB /LOG, ProbesMisson Module SVCMEM, HAB, LAB / LOG, Mars Resource Pilot Plant, LMDVMission Module SVCMEM, HAB, LAB / LOG, Mars Resource Production Plant, LMDVMission Module SVCMEM, Power Plant, Crane, Soil Mover, Boring / Mining, Phobos Resource Pilot Plant, LMDVMission ModuleMEM, HAB, LAB / LOG, Pressurized Rover, Agriculture & Fertilizer Plant, LMDV291,400lbs. (132.177 mt)218,400 Ibs. (99.065 mt)218,400 Ibs. (99.065 mt)298,400 Ibs. (1 35.352 mt)60,000 Ibs. (2.722 mt)338,334 Ibs. (1 53,466 mt)60,000 Ibs. (2.722 mt)443,934 Ibs. (201 .365 mt)133,000 Ibs. (60.328 mt)321 ,494 Ibs. (145.827 mt)60,000 Ibs. (2.722 mt)680,634 Ibs. (308.730 mt)Figure 7Earth and/or Mars orbital energy requirements. The sizing algorithms were developed assuming a most probable mission sequence.Now that the program definition has advanced to the stage where a first cut at the mission model is complete, a capture analysis is performed. First, the launch vehicle fleet and upper stage fleet are defined. Sizing of the launch vehicles and launch vehicle fleet depends on theirReference ProgramMass Delivered by UCV (mt)PROGRAM DERATION1211.078Required UCV'8 LauchedReference Program PROGRAM DEFINITIONMission Spaceship Number] Mass (mt)Payload Massto LEO (mt)902-746 10-875Reference ProgramMission I Earth Number! DeparturePROGRAM DEFINITIONStayReference Program Mission -Manned/ Trajectory -jumber Cargo ClassPROGRAM DEFINITION PagelCargoCargoOppositionOppostionOppostiorOppositionOppositionOppositionTrajectory DescriptionHT-836-238 AB Base BuildupHT-836-236 AB Cargo RightsMission DesciptioSortie, Begin Base BuildupCargo RightsPayload DescriptionMission Module. MEMMission Module. SVC... MEMMission Module SVC.. MEMMission Module SVC., MEM .HAB, LAB /LOG Module________Mission Module SVCMEM, HAB, LAB /LOGMission Module SVCMEM. HAB. LAB / LOGFigure 8capability to deliver mass to various orbits from various launch sites. Upper stage fleet elements are upper stages, space vehicles, and spacecraft. Upper stage fleet definition depends on their capability to transfer mass between orbits, planets, and moons. Fleet definition for launch vehicles or upper stages requires defining their structural mass, propellant mass, initial operational capability (IOC), end of life (EOL), expendability/re- usability, and manned/unmanned rating. Figure 9 summarizes the fleet definition for the reference program. The launch vehicle fleet has an unmanned cargo vehicle, the shuttle C and a manned vehicle, the STS. The Shuttle C will be used to deliver all payloads, upperstages, propellant, etc., that do not have a requirement to fly on a manned launch vehicle. For the Large Mars Transfer Vehicle (LMTV), both cryogenic propulsion and electric propulsion can be configured for manned or unmanned7-3Capture Model Vechicle Performance, Data Launch VechiclesShuttle C (Unmanned Cargo Vehicle)Payload Capacity (DEURET) Ibs.LEO SS (28.5 Deg., 200 N. Mi.) 100K/0 LEO Polar (90 Deg., 160 N. Mi.) 77K/0Payload Envelope (Dia. x Length) Ft. 15x60Space Tranportatlon System (STS)Maximum Passengers (Besides Crew) 4Lifetime (Flights) 100Refurbishment Intervals (Flights) 29 (Engines) Payload Capacity (DEL/RET) Ibs.LEO SS (28.5 Deg., 200 N. Mi.) 39.5K/24.3KLEO Polar (90 Deg., 1 60 N. Mi.) 1 9.3K/24.3KPayload Envelope (Dia. x Length) Ft. 15 x 60Note: Drawing Not To ScaleATransportation Infrastructure for Mars Landers _____and Other Supportive VechiclesMars LanderMEMDry Weight 52,t28Propelland Weight 80,199Total Weight 133,047Payload Capacity 15,000LMDV for Cryogenic MTVDry Weight 44,788Propelland Weight 90,912Total Weight 504,152Payload Capacity 368,452LMDV for Electric MTVDry Weight 39,612Propelland Weight 80,402Total Weight 445,874Payload Capacity 325,860Expendable Upper Stage (Centaur Class)Dry Weight 6,550Propellant Weight 45,010Total Weight 51,560Orbital Transfer Vehicle (OTV)Dry Weight 10,460Propellant Weight 58,540Total Weight 69,000Used to Retrieve Spent Stages and Deliver People to Electric MTVOrbital Maneuvering Vehicle (OMV)Dry Weight Propellant Weight Total WeightUsed in MTV Assembly In LEO6,0007,00013,000Transportation Infrastructure for Large Mars Transfer Vehicles (LMTV)Cryogenic PropulsionManned Large Cryogenic Mars Transfer VehicleUnmanned (Cargo)Large CryogenicMars Transfer VehicleDry Weight Propellant Weight Total Weight Payload CapabilityMars Orbit431,0861,141,0261,572,712133,047Mars Surface (via MEM)350,1671,222,5451,572,71215,000Mars Orbit 590,864 981,8481,572,712 504,152Mars Surface (via MEM)499,952 1,072,726 1,572,712368,452Electric PropulsionManned Large Electric Mars Transfer VehicleUnmanned (Cargo)Large Electric Mars Transfer VehicleDry Weight Propellant Weight Total Weight Payload CapabilityMars Orbit 370,845 275,288 646,133 133,047Mars Surface(via MEM) 289,926 356,207 646,133 15,000Mars Orbit 525,516 275,288 800,804 445,874Mars Surface (via MEM) 445,114 355,690 800,804 325,860Figure 9trips to Mars orbit or Mars surface. Manned Mars descent/ascent vehicles and unmanned Mars landers are used to deliver crew and payloads to Mars surface. Other expendable upper stages, orbital transfer vehicles (OTV) and the Orbital Maneuvering Vehicle (OMV) also support the program in LEO assembly, LEO to GEO transfer, and in some cases Earth to Mars transfer. Total flight events per year, total payload mass per year, total propellant mass per year, or any similar summary is provided as a part of the capture analysis. The updated program definition now consists of a mission model and the associated capture analysis.The existence of a mission model and capture results make cost analyses and/or schedule analyses possible. Typical schedules of development, life cycles, operations, etc., are found in the schedule data base and are integrated into a real timeline to yield a master schedule for the program. Network analysis, resource allocations, timelines, etc., are now generated. Precursor and/or successor relationships for missions and payloads are identified. Relative cost and scheduling is a major consideration in program analysis. Relative cost analysis is done using mission and payload cost estimating relationships (CER's), mission types, flight life, learningcurve rate, facilities costs, RDT&E cost, operations cost, first unit cost, and cost spreads. Outputs from the cost analysis include payload costs, and transportation cost.At completion of program definition, it is reviewed to determine if it has met its defined goals. For the reference program, several iterations were made to fine-tune the program. It is important to remember that this process is flexible and expandable, thus, allowing for additional analysis. Figure 8 is a good example of final program definition.Sensitivites, Parametric Outputs, and Program Definition SelectionsSensitivities to various factors exist throughout the program analysis process. Simply by flying a payload one year later could result in a less desirable opportunity, thus requiring more propellant, longer trip time, more launch vehicle support, adverse scheduling of ground facilities and transportation nodes, delay successor missions, and increase cost. Since "n" number of sensitivities are possible, it is best to identify some major areas of concern when defining program goals and assumptions. For the reference program, vehicle sizing was comprehensively7-4analyzed, varying launch dates, stay-time durations, total trip times, drop masses, and planetary capture options (aerobraking-versus-propulsive braking).Parametric outputs resulting from program analyses can be useful tools. For example, for a given mission, vehicle configuration, and trip time/stay time, propellant mass required in low Earth orbit can be plotted versus the Earth departure launch window. This information is useful in determining the permissable allowances for schedule slippage.Selection of a program definition is left up to the program analyst(s). The program definition may be iterated until a desired program is identified.SummaryCapabilities and advantages of an interactive software package for mission/program analysis has been presented. A user can employ an interactive computer terminal to investigate the impact of various changes onthe program. This software is flexible and useful in assessing the interaction of the defined program and technologies with other programs such as Space Station, Launch vehicle, lunar base, etc. To date, several parameters have been indentified as program drivers: 1) The mass in LEO requires a major improvement in cost of delivery to orbit; 2) aerobraking has a significant inpact on the mass but probably requires on orbit assembly capability approaching the complexity of the Space Station; 3) new technology in the fields of advanced propulsion, electrical power sources, and material processing will dictate the rate of build-up of the Mars base.References1. SRS Technologies Mid-Term Progress Review, "Manned Mars Mission and Program Analysis", NASA (MSFC) Contract NAS8-36653, December 1987.2. Manned Mars Mission, NASA M002 Vol. I and II, June 1986.7-5

Manned Mars Mission Program Concepts

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Manned Mars Mission Program Concepts

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