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Near-Term Mars Colonization

Near-Term Mars Colonization. -A DevelopSpace Project- May 25 th , 2008. Agenda. Transportation update Minimalist transportation concept Power update SVN update. Transportation Update. Solar Electric Propulsion (SEP). Could be used to raise from LEO to HEO

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Near-Term Mars Colonization

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  1. Near-Term Mars Colonization -A DevelopSpace Project- May 25th, 2008

  2. Agenda • Transportation update • Minimalist transportation concept • Power update • SVN update

  3. Transportation Update

  4. Solar Electric Propulsion (SEP) • Could be used to raise from LEO to HEO • System Mass = ~120% Payload Mass • Paper by Gordon Woodcock (AIAA 2004-3643) • Requires 41mT of Xenon (for 50 mt Payload) • (Annual world production = 53mT)

  5. Chemical Propulsion • Baseline • Delta-V = 4000 m/s • PMF = 0.125 • Specific Impulse = 450 sec

  6. TMI Stage Mass vs Payload Mass • From LEO, the TMI payload mass is ~50% the mass of the TMI Stage • Ideally, the TMI payload mass would be equal to the TMI stage mass to utilize one launch vehicle • Solutions • Break TMI Stage into two stages • One large & one small • Have launch vehicle place TMI stage and payload into highly elliptical orbits • Reduce TMI Delta-V to ~2600 m/s • No analysis on feasibility done yet

  7. Mars Orbit Insertion and EDL • Based on chemical propulsion & Braun’s numbers • 10% of IMLEO mass can be landed on Mars • Most common approach • Aero-capture followed by aero-assist EDL • System Masses vary greatly • DRM-1 & DRM-3 assume 28-33% of TMI Mass required for “descent system” • Mars Direct assumes 35% of TMI Mass required • Robert Braun (Georgia Tech) mentions 70% of TMI Mass required for “descent system” • 40% for orbit insertion • 30% for descent and landing

  8. In-Space Crew Considerations • How does the crew get to the surface of Mars? • Earth to LEO • Separate launch and rendezvous • Launched in transit or Mars habitat • LEO to Mars • Is a unique habitat required? • Zero-gravity concerns • Artificial Gravity

  9. Mobility Strategies

  10. Minimalist Transportation Concept

  11. Transportation Challenges Falcon 9Heavy • How do we transport crew and cargo to the Martian surface using 25 mt launch vehicles? • 25 mt is “worst-case scenario” • Larger payload capabilities would facilitate transportation and also lead to scaling benefits • Specific challenges: • Launch and LEO orbit assembly • Mars aerocapture and EDL • Ballistic coefficient (entry body mass, diameter, shape) • Altitude at Mach 3 / aeroshell separation • Propulsive descent (800 m/s assumed for now) • Final landing GN&C, landing error reduction • Hazard avoidance • Falcon 9 Heavy assumed as reference LV • ~28 mt to 300 km LEO • ~4 m x ~10 m cylinder of usable volume in shroud Image credit: Space ExplorationTechnologies, Inc.

  12. Mars Aerocapture and Entry Vehicle • Entry vehicle is based on conic blunted body • 20 degree side-wall angle • Drag coefficient: ~1.6 • L/D: ~0.3 • Total mass is 12 mt, leading to a ballistic coefficient of around 600 kg/m2 • Mach 3 altitude ~ 5 km • Final descent propulsion based on MMH / N2O4 • Isp = 320 s • 8 tanks (4 fuel, 4 oxidizer) • Cargo to surface: ca. 5 mt

  13. Cargo Transportation Concept • Transportation concept based on dual blunt-shaped entry bodies • Reduces ballistic coefficient per entry body (~ 600 kg/m2) • Allows for simple blunt-body shape • Entry bodies are launched together with additional cruise systems • Solar arrays, batteries, radiators • Entry bodies separate prior to aerocapture and aeroentry • 2 Earth departure stages are launched after the entry bodies • Stages dock to entry bodies for dual burn Earth departure • Initial analysis indicates that ~25 mt can be injected towards Mars using LOX / kerosene stages • ~10 mt useful cargo mass on Mars surface (~ 5 mt per entry body) Earth-Mars transit configuration Entry body 2 Solar array Solar array Entry body 1 TMI stack Launch configuration Earthdeparturestage 2 Earthdeparturestage 1

  14. Crew Transportation Concept Earth-Mars transit configuration • Crew transportation with entry body (cargo) and additional transit habitat • 2 sets of solar arrays, batteries, and radiators • Transit habitat is jettisoned prior to aerocapture • 2 Earth departure stages are launched separately and docked • Dual burn Earth departure • LOX / kerosene propulsion • Initial analysis indicates that 2-3 crew can be delivered to Mars surface this way • Crew can be sustained for 30+ days on surface after landing • Unpressurized mobility delivered with crew Transithab Solar arrays Solar array Entry body TMI stack Launch configuration Earthdeparturestage 2 Earthdeparturestage 1

  15. Transportation Results & Forward Work • 4-6 crew can be transported to Mars with 6 Falcon 9 heavy launches • Launch cost of ca. $ 600 Mn (ca. $ 100 Mn per launch) • 3 Falcon 9 heavy launches can deliver a minimum of 10 mt of useful mass to the Martian surface • Equivalent to 26-month consumables demand for 4 crew • Forward work: • More detailed design of aeroshell and descent stage • More detailed design of Earth departure propulsion • Including propellant type trade • Investigation of different entry body shapes

  16. Power Update

  17. Surface Power Architecture Tree Primaryenergygeneration Photovoltaicconversion (“solar”) Nuclear fission • The basic type of analyses that was carried out: • Equal energy analysis: all systems provide the same usable energy per day (for photovoltaic systems this means increased power generation during the day) Secondaryenergygeneration Not required Batteries Fuel cell +electrolysis +radioisotope Radioisotope Batteries +radioisotope Fuel cell +electrolysis Energystorage H2 + O2 Not required Batteries Not required H2 + O2 Batteries Trackingarrays? Yes Yes Yes No No Yes No Yes No N/A No

  18. Modeling • Created model for Mars solar arrays based on following major requirements: • Array must be sized for end-of-mission power requirements • If several missions go to same site, supplementary arrays are brought each mission to make up for degradation • Array must be sized to provide the required power during the year’s minimum incident solar energy period • Model Assumptions: • On Mars, optical depth of 0.4 (equivalent to hazy skies) • Tracking arrays at both locations are multi-axis and keep incident flux perpendicular to array over the day • Nighttime power of 20 kW, with daytime power enforced when sun is 12 degrees above the horizon • Mars analysis done for anequatorial location (actuallynot optimal location forsolar power on Mars): • Optimal location at 31° N, witha minimum of 6.57(kW-h/m^2/sol)and 49% daylight/sol for aperiod of 100 sols • Northern latitudes better than corresponding southern latitude

  19. Inputs: Minimum solar energy Eclipse Time Daytime/nighttime power req. Power distribution eff. Solar array eff. Degradation per year Array lifetime Optical depth Latitude Array packing density Battery type Outputs: Array area System mass System volume Model Inputs and Outputs

  20. Mars Results

  21. Mars Results Continued

  22. Other Considerations for Large Solar Array Fields on Mars • Deployment time: • Considered a 10,000 m^2 rollout array field which will provide 63kW average power for about 100kW daytime power • Assume array blankets are 2m wide for easy storage and handling by two astronauts • Assume each blanket weighs 100lbs again for easy handling • With 0.06 kg/m^2 expected array density, need only 14 blankets total • Assume astronauts can unroll array at a walking speed of 1m/s, requires only 3hrs for unrolling • Most time will be needed for unloading positioning and hookup, if assume 1hr for this for each array, total deployment time approximately 17 work hours for 2 crew • Power delivery during deployment: • If we are conservative and say deployment takes 1 week, we need either a 10kW RTG or fuel cell system to provide 10kW power over the week • RTG system would be approximately 1200kg and 0.6 m^3 • If use RFC, need 2400kg system with volume 8.4 m^3

  23. Future Work • Reassess architecture options in MinMars colony context. Previous power analysis for shorter round trip mission. • Operations considerations such as dust removal and maintenance. • Dust storm power generation.

  24. SVN Update

  25. Current SVN Folder Structure • Meetings • Folders with telecon slides • Models & Analysis • Folders with individual models and results (spreadsheets, presentations, CAD files, etc.) • Users • Folders for individual users

  26. Backup Slides

  27. July 15, 2008 Early September 2008 Mid-May 2008 Focus on fixed crew-size “toehold” onMars as alternative to exploration program Focus on expansion of “toehold”to mostly self-sustained colony In-Space Transportation(lead: Arthur) Surface Infrastructure(lead: Arthur) Surface Operations(lead: Arthur) ProjectDefinition Follow-onprojects Expansion analysis Surface Power & Thermal(lead: Chase) Outpost re-supply(lead: Wilfried) Finance and costing(lead: ?) Integration of results(lead: Wilfried)

  28. Operational Architecture Marsorbit • The overall operational architecture for the initial toehold is based on one-way flights delivering cargo and crew to the Martian surface • Potentially with an emergency return capability • Mars capture is assumed to be accomplished by aerocapture • Subsequent lifting entry and propulsive descent are used to deliver payloads to the single surface outpost site • Outpost location is subject to a variety of factors (insolation, water, elevation) • The exact size and payload capability of each lander depends on the Earth departure architecture and entry body chosen Earthorbit Earth departurearchitecture Earth departurearchitecture Earth departurearchitecture 26 months 26 months

  29. Toehold Location: Topography

  30. Toehold Location: Solar Power

  31. Toehold Location: Water

  32. General Study Objectives • Carry out an assessment of re-supply needs for the outpost given different technologies • Including high-closure life support, ISRU • Identify key re-supply drivers and carry out in-depth analyses • Identify interesting technologies with high payoff in re-supply mass reduction • Carry out initial modeling and testing of these technologies • Formulate plan for further technology development

  33. Mars Surface Habitat Architectures 1-5 Open loop Water regeneration (95%) Regenerative CO2 removal Completely dehydrated food Washing machine

  34. Mars Surface Habitat Architectures 5-9 Cryogenic oxygen Water electrolysis Water electrolysis+ Sabatier reactor Water electrolysis+ Sabatier reactor+ methane pyrolysis

  35. Mars Surface Habitat Architectures 9-13 Zirconia electrolysis + water electrolysis+ Sabatier reactor+ methane pyrolysis Zirconia electrolysis,no water electrolysis,Sabatier reactor,methane pyrolysis Zirconia electrolysis, scaled-up Zirconia electrolysis, scaled-down

  36. Preliminary Insights • Existing technologies allow for re-supply masses per opportunity of ~2 mt / person • This includes fairly conservative tare fractions on pressurized logistics and fluid re-supply • Remaining high-mass re-supply items are: • Food • Spare parts (fans, multi-filtration beds, etc.) • Hygiene & health re-supply (soap, first-aid, etc.) • Hydrogen for ISRU

  37. Food Logistics Reduction • Many options for closure of the food loop have been investigated over the decades • Two major families of options: • 1. Chemical regeneration of food from waste • Synthesized chemicals suitable for long-term ingestion include: glucose, glycerin, ethanol, formose sugars • 2. Biological regeneration of food from waste • Algae (also for CO2 regeneration) • Higher plants (wheat, corn, vegetables, etc.) • Animals (fish, chicken)

  38. Mars Wish List

  39. Transportation • Automated Mars landing and hazard avoidance navigation systems • Mars in-situ propellant production friendly rocket combustion / performance characterization (C2H4/LOX; CH4/LOX); more important if people want to come back • Large-scale (20mt+) Mars aero-entry (and EDL more generally) technology • Low mass, cost, power and ideally autonomous deep-space (out to at least ~2 AU) navigation systems (software, hardware)

  40. Power • Automated, large scale (football field+) solar array transport, surface deployment, and maintenance systems • High energy density electrical power storages systems (aiming in particular towards high energy density relative to Earth imported mass) • Mars surface internal combustion engines (LOX, plus various fuels, e.g., C2H4, CH4, CO, etc), possibly with water exhaust reclamation.

  41. Life Support, Logistics, ISRU • Mars atmosphere collection systems (at minimum CO2; adding N2 and Ar is useful; H2O depends on energy/mass intensity relative to other options) • Mars permafrost mining systems (for varying wt% H2O); note, this is much easier than mining putative lunar ice • Good, high capacity Mars surface cryocoolers (options for just soft/medium cryogens (e.g., LOX, CH4, C2H4), or also for hard cryogen (LH2)) • Earth-Mars hydrogen transport systems (not necessarily as LH2) • Basic ISRU chemical processing systems (e.g., H2O electrolysis, Sabatier, RWGS, CO2 electrolysis, ethylene production, etc.) • High closure physical-chemical life support systems (e.g., air revitalization, water recycling) • "Food system" for food supplied from Earth. Consider being able to survive on food shipped 5 years ago. • Mars surface food production systems • Simple in-situ manufacturing systems (e.g., for spare parts) • Simple raw materials production (e.g., plastics such polyethylene, epoxies, ceramics, etc.)

  42. Outpost Ops and Surface Exploration • Mars surface communication and navigation systems (e.g., for rovers), sans extensive satellite constellation • Very high data rate Mars-Earth back-haul comm system • Good Mars surface EVA suits • Data collection, analysis in support of landing site / outpost location selection • Very long distance surface mobility systems (including with people) • Solar flare / SPE warning systems

  43. Mass Budget for Habitat-1

  44. Mass allocations for Mars Direct components on surface of Mars

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