H2M Minimal Architecture A Minimal Architecture for Human Missions to Mars An Update Future In‐Space Operations (FISO) Teleconference September 14, 2016 Hoppy Price John Baker Firouz Naderi  Jet Propulsion Laboratory California Institute of Technology An Input to NASA’s Human Space Flight Planning H2M Minimal Architecture • This work provides thoughts on two subjects: 1. 2. A technical mission architecture, and  What it takes to make that architecture executable • We hope aspects of this work will be useful to  the human  space flight planning process Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only 2 Why Yet Another Mars Architecture? H2M Minimal Architecture NRC Pathway(s) Inspiration Mars Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only 3 Defining a Multi-decade Executable Program The Science and the Art An executable program requires balancing several (sometimes competing) constraints:  Technical feasibility  Fiscal affordability  Stakeholders’ interest horizon  Acceptable risk  International and private sector engagement  Political realism across several administrations Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only 4 Two Competing Constraints Meet Head on H2M Minimal Architecture 1 2 Limit on the HSF Annual Budget Delivering on a Time Horizon That Anyone Cares About How Do You Stay Affordable H2M Minimal Architecture and yet deliver engaging missions within interest horizon of stakeholders? Step-wise introduction of complexity at Mars 1. Break up the program into phased mission campaigns  First Campaign: Mission to the Mars System (land on Phobos)     We have proposed limited Mars vehicle testing at the Moon/cis-lunar space prior to the first Mars campaign Second Campaign: Short Surface Stay on Mars (~1 month) Third Campaign: Long Surface Stay on Mars (one year) Continuing Missions: Move toward a permanent presence   Each mission builds on the infrastructure from the previous mission On-ramp new technologies (e.g. ISRU, food production) over time 2. Minimal Architecture  Rely on the set of elements already under development by NASA (SLS, Orion, DSH, SEP) and avoid complex new developments (such as nuclear fission surface power and ISRU) where possible Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only 6 To spread the cost (required cash flow) and the risk, break up the challenges of crewed travel to Mars into two separate campaigns H2M Minimal Architecture 2 1 Challenges of Round Trip Travel to Mars Orbit Challenges of Landing and Taking Off From Mars with Crew Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only Mars as Seen from Phobos Building Blocks of a Minimal Architecture Mars Surface Elements Launch In‐Space Propulsion Crew Quarters 26t payload Mars Lander SLS EUS 100KW SEP Tugs In‐Space  Chemical Stages Orion 26t Landed Cargo Module(s) Deep Space  Habitat Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only 9 Increasing the Likelihood that it Can be Implemented • H2M Minimal Architecture Mission architectures need to be checked for affordability – Mission costs need to be verified by a non‐advocate third party • • For the Journey to Mars to remain in the interest horizon of  stakeholders, humans need to get to the Mars system in the early 2030’s Much can be learned from ISS in the next decade, but NASA needs to plan  for the ISS end game and repurposing those funds • Gaining Experience at the Moon/cis‐lunar space can be beneficial;  however, the extent of activities should be weighed against any delays in  the time table for human presence at Mars • A coherent long‐term strategy (beyond the 5‐year budget cycle)  needs to be articulated – Engage potential international partners – Outline opportunities for private sector participation – Keep other stake holders interested Pre‐Decisional Information ‐‐ For Planning and Discussion Purposes Only 10 Mission to?Mars-Grbit a q. . and H2M Phobos Landing Concept Minimal Architecture Attributes of the campaign  Precursor to Mars landing campaign  Proves out method for getting to Mars orbit and back  Uses 4 SLS launches  Pre-position assets in Mars system with SEP tugs prior to crew arrival  Round trip crew mission ~2 ½ years; ~300 days at Phobos H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 12 Phobos Mission Concept 4 SLS Launches Mars Phobos Phobos Base Pre-placement 100 kWe SEP Tug SEP Payload: Phobos Habitat ~300 days Deimos ~3.5 years 100 kWe SEP Tug ~75 days ~75 days SEP Payload: TEI Stage + Phobos Transfer Stage (PTS) TEI MOI ~3.8 years HMO Deep Space Hab + TEI Stage Deep Space Hab (DSH) MOI Stage ~200 - 250 days EUS Orion ~200 - 250 days TMI HEO Crew launch 1 2 3 Architecture was analyzed for a crew of 4 Entry 4 Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 13 Getting Cargo to HMO and Phobos Mars Phobos 100 kWe SEP Tug 100 kWe SEP Tug Pre-placement ~3.5 years SEP Payload: Phobos Habitat ~3.8 years HMO SEP Payload: TEI Stage + Phobos Transfer Stage (PTS) HEO 1 2 Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 14 Getting Crew to HMO Mars Phobos MOI Deep Space Hab (DSH) Orion EUS + MOI Stage HMO ~200 - 250 days TMI HEO Crew launch 3 4 Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 15 Getting Crew from HMO to Phobos and Back to HMO Mars Phobos Base Phobos ~300 days Deimos HMO Deep Space Hab + TEI Stage HEO Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 16 H2M Phobos Base Concept Minimal Architecture  Supports a crew of 4 Orion 100 kWe SEP tug Transfer stage  for Orion  Could be relocated to different sites  Could be re-used by future crews Docking node and airlock Common habitat design H2M Landing leg module Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 17 Coming Back to Earth Mars Phobos Phobos Base Orion+ PTS HMO Deep Space Hab + TEI Stage TEI ~200 - 250 days HEO Entry Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 18 Mars Short Surface Stay Campaign H2M Minimal Architecture H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only One Month Mars Surface Stay H2M Minimal Architecture Attributes of the Campaign  Architecture re-uses the Phobos approach for getting crew to HMO and back to Earth (already tested in 2033)  The lander requires 2 additional SLS launches relative to Phobos mission, bringing total SLS launches to 6 - Lander entry mass ~75t with 26 t useful landed mass - Crew of 4 to the surface for ~1 month stay - Can utilize cargo lander sent to support the 2nd surface mission  Return from Mars surface is achieved through a two-step ascent to High Mars Orbit (HMO) - MAV takes crew from surface to Low Mars Orbit (LMO) - Then boost stage takes crew in MAV to High Mars Orbit (HMO) - This minimizes MAV propellant load and enables 26 t lander  This is a pathfinder for following missions which will have H2M >1 Earth year stay on the Martian surface Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 20 Short Surface Stay Concept 1 month surface stay; Crew of 4 to surface; 6 SLS launches Mars Cargo lander for next mission arrives in time to be used by 1st crew Complete set of mission elements MAV-to-HMO boost stage MAV-to-HMO boost stage; TEI Stage 100 kWe SEP Tug Rover & supplies Crew lander MAV to LMO ~1 month stay LMO MAV-to-HMO boost stage Aerobrake to LMO Boost stage Crew lander MAV MAV to HMO TEI Stage Aerocapture into HMO 100 kWe SEP Tug Habitat resupply module Inject to Mars Loiter in HEO HMO DSH resupply module DSH MOI Stage Lander TEI ~450 days ~200 - 250 days Orion EUS TMI ~3.8 years ~200 - 250 days Total round trip ~ 900 days Crew lander ~3.5 years MOI HEO EUS T= -3.8 years 1 2 Earth T= -3.3 years T= -2 years T= -2.5 years 3 4 T= -6 months 5 Crew launch T= -2 days Architecture was analyzed for a crew of 4, all of whom land on Mars Entry 6 Departure stage for crew lander Pre-Decisional Information -- For Planning and Discussion Purposes Only 21 Third and Fourth Launches Sending Crew Lander to Mars Mars 26 t Lander 75t Entry Mass Lander with 4 Crew Aero-capture into HMO HMO Inject to Mars HEO ~1 month surface stay Lander  w/o Crew MOI Orion + DSH  With 4 Crew Loiter in HEO 2-crew Lander 6 EUS T= 0 T= -2 years T= -2.5 years 3 Crew transfer 4 Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 22 Return to Earth Mars Lander Aerobrake to LMO Boost stage to take MAV from LMO to HMO LMO After ~1 month on surface, MAV takes crew to LMO Boost MAV to HMO HMO TEI 1 ~200 - 250 days Entry Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 23 Descent/Ascent Vehicle (DAV) H2M Minimal Architecture Can support crew of 2 for 28 days, or crew of 4 for 6 days Crew cabin Ascent propulsion Descent propulsion 8m 10 m MAV Ascent H2M Minimal Architecture Launch Landed Configuration Pre-Decisional Information -- For Planning and Discussion Purposes Only 24 EDL Concept for Blunt Body Mars Lander H2M Minimal Architecture Jettison Backshell Entry Peak Heating Abort to orbit capability Hypersonic Aeromaneuvering Supersonic Retro-Propulsion Heatshield jettison Powered Descent Note: There are no deployable decelerators or parachutes. Ground Acquisition Touchdown H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 25 Six Vehicles to Enable Crewed Missions to Mars Surface (Short Stay) Vehicles H2M Minimal Architecture # Vehicles per Mission Orion 1 SLS 6 SEP Tug 2 ~100 kWe Deep Space Habitat (One is a resupply version) In-Space Chemical Propulsion Stage Mars Lander 2 3 1 Pre-Decisional Information -- For Planning and Discussion Purposes Only H2M Minimal Architecture 26 One-Year Surface Mission H2M Minimal Architecture 10 SLS Launches  Builds on the short-stay architecture but adds two additional landers - Four additional SLS launches (2 per cargo lander) are needed - 1st cargo lander carries a pressurized rover and other supplies  This arrives early enough to be used for the 1st surface mission - 2nd cargo lander carries the surface habitat - 3rd lander with MAV carries a crew of 4 to the surface Cargo and  logistics Entry Configurations Surface  habitat Each lander descent stage includes 25 kWe (at Mars) arrays and batteries Landed Configurations Pre-Decisional Information -- For Planning and Discussion Purposes Only H2M Minimal Architecture 27 Long-Stay Surface Mission Concept H2M 1 Year Surface Stay; Crew of 4; 10 SLS Launches Minimal Architecture ~400 t injected to Mars (155 t is propellant); 26 t MAV + 58 t useful cargo landed on Mars Complete set of mission elements Mars MAV-to-HMO boost stage; TEI Stage 4-crew Lander Surface habitat MOI TEI DSH resupply module (contingency) ~400 days DSH MOI Stage ~200 - 250 days Orion EUS ~200 - 250 days TMI 3 ~3.5 years 4-crew Surface Lander habitat T= -4 years T= -3.5 years 4 5 T= -3 years 6 T= -2.5 years 7 HEO EUS for Earth departure T= -5 years EUS for Earth departure EUS for Earth departure 2 MAV to HMO HMO ~3.8 years 1 MAV Lander TEI Stage Habitat resupply module Rover/ Supplies LMO Boost stage Lander SEP Tug T= -5.5 years MAV to LMO ~1 year surface stay Aerocapture into HMO Rover/ Supplies Lander Surface habitat MAV-to-HMO boost stage MAV-to-HMO boost stage Aerobrake to LMO (also backup for previous mission) SEP Tug Rover/ Supplies Direct entry Mars landing Direct entry Mars landing T= -2.1 years 8 T= -2 years Crew launch T= -6 months 9 T= -1 day Acronyms: DSH = Deep Space Habitat EUS = Exploration Upper Stage HEO = High Earth Orbit HMO = High Mars Orbit LMO = Low Mars Orbit MAV = Mars Ascent Vehicle MOI = Mars Orbit Insertion SEP = Solar Electric Propulsion TEI = Trans‐Earth Injection 10 Entry H2M Minimal Architecture Earth Pre-Decisional Information -- For Planning and Discussion Purposes Only 28 The Integrated Program H2M Minimal Architecture Fitting Together the Puzzle Pieces ISS Cislunar Phobos Lander H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 29 H2M Notional Timeline Orion Second Crewed Flight Minimal Architecture Crew to Mars (1 month surf. stay) Orion First Long stay in Mars Crewed Flight Lunar orbit Sim 2 Mars Sim 1 Crew to Phobos SLS Initial Test Crew to Mars (1 year surf. stay) Crew to Mars (1 year surf. stay) 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 Build Up Infrastructure FLIGHT GAP! Earth Cislunar Mars SEP Demo (e.g. ARRM) Robotic Sub-Scale Mars Lander Test: EDL Test Crewed Moon Landing ISS Extension End Pre-Decisional Information -- For Planning and Discussion Purposes Only H2M Minimal Architecture 30 Notional SLS Flight Scenario 105 t SLS CY Europa Lander Europa Clipper Uncrewed Missions Lunar Proving Ground Phobos & 2ND Mars Landing Minimal Architecture 130 t SLS 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 EM-1 1ST & 3RD Mars Landings H2M DSH to Lunar orbit Un-crewed Mars ½ scale EDL test Crewed test of Mars Lander at the Moon EM-2 EM-4 ARCM EM-3 Acronyms and Abbreviations: ARCM = Asteroid Redirect Crewed Mission Chem = Chemical non‐cryogenic propellants CY = Calendar Year DSH = Deep Space Habitat EDL = Entry, Descent, and Landing EM = Exploration Mission EUS = Exploration Upper Stage Hab = Mars Surface Habitat ISS = International Space Station LEO = Low Earth Orbit MAV = Mars Ascent Vehicle SEP = Solar Electric Propulsion Tug Sim = Simulated Mission SLS = Space Launch System Mars Sim 1 Mars Sim 2 SEP w/ chem stages DSH SEP w/ Phobos Habitat SEP 1 Orion for Phobos SEP Cargo 1&2 Mars Lander Cargo Lander DSH SEP 2 EUS MAV EUSs for DSH Orion Landers Hab Orion SEP 1 Cargo for 1ST Lander Mars EUS Landing H2M Minimal Architecture Commercial Training Flights in LEO ISS LEO Lunar Proving Ground Mars Orbit Pre-Decisional Information -- For Planning and Discussion Purposes Only Mars Surface 31 Cost “Sanity Check” H2M Minimal Architecture  Aerospace Corporation performed the first-look cost assessment  Cost estimates were based on models and analogy - Used model developed for NRC Pathways to Exploration study - As technical concepts mature, grassroots rather than model-based cost assessments should be performed for budget commitment  We have recently updated the 2013 Aerospace cost assumptions to be consistent with the current 2016 budgets  The flight gap after ISS was addressed by adding in 4 additional Lunar Proving Ground missions to what was in the original study  Overall long-term affordability can still be achieved, possibly rescoping the 2033 mission, but there is a funding spike in the early 2020’s that results from developing new systems whileH2M still funding ISS Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 32 Assumptions H2M Minimal Architecture  Staging Orbit - Possible to stage in cislunar space to go to Mars but there is a performance penalty (months and delta-v of 100’s m/s) - High Earth Orbit is the best staging orbit for performance  No Re-use for Initial Missions - New systems for each mission allow for the design to evolve and improve over multiple versions (alla Apollo, etc.) - Unlikely to be an economic benefit until designs have significant flight history and in-space refurbishment technologies mature  ISRU Not Used… at first - Storable prop results in use of current technology and more feasible MAV design with abort-to-orbit capability - Significantly reduces need for pre-placement of infrastructure before humans walk on Mars - Significantly reduces cost - ISRU utilization will be landing site dependent. - We have yet to fully understand the implications of ISRU Pre-Decisional Information -- For Planning and Discussion Purposes Only H2M Minimal Architecture 33 JPL Minimal Architecture H2M with ISS to 2024, first Mars landing in 2037 Minimal Architecture Original Aerospace Corp. estimate based on 2013 cost assumptions used for NRC “Pathways” study NASA Human Space Flight Annual Budget Mars Landing Mars Landing Short Surface Stay Long Stay 2037 Mars Landing 2046 Phobos Landing 2033 Long Stay 2041 Legend (crewed missions): ISS Lunar orbit test Flat budget line Phobos long stay Lunar landing test  for Mars lander Current Programs ISS to 2024 Mars surface short stay Support Costs Commercial crew training flights in LEO These costs assume no international partner contributions.  It is expected  that international participation could reduce costs somewhat. Pre-Decisional Information -- For Planning and Discussion Purposes Only Mars surface long stay H2M Minimal Architecture 34 JPL Minimal Architecture H2M with ISS to 2024, first Mars landing in 2037 Minimal Architecture JPL revised estimate based on 2016 updates to cost assumptions used for NRC study NASA Human Space Flight Annual Budget Mars Landing Mars Landing Short Surface Stay Long Stay 2037 Mars Landing 2046 Phobos Landing 2033 Long Stay 2041 Legend (crewed missions): ISS Lunar orbit test Flat budget line Phobos long stay Lunar landing test  for Mars lander Current Programs ISS to 2024 Mars surface short stay Support Costs Commercial crew training flights in LEO These costs assume no international partner contributions.  It is expected  that international participation could reduce costs somewhat. Pre-Decisional Information -- For Planning and Discussion Purposes Only Mars surface long stay H2M Minimal Architecture 35 Options for Reducing the Early 2020’s Funding Peak H2M Minimal Architecture 1. Rescope the 2033 Mars orbit mission to be an opposition-class short-stay mission (~570 days) - ~30 days in Mars orbit - Phobos (and Deimos) would not be visited - Requires a second Trans-Earth Injection stage  In lieu of the Phobos transfer stage - Includes a Venus flyby on the return trip, which requires a large deployable sunshade for thermal control 2. Delay the Phobos and Mars landing missions by 2 years H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 36 H2M Option for 2033 Short-Stay Orbit-Only Minimal Architecture ~570 day round trip, including Venus flyby gravity assist NASA Human Space Flight Annual Budget Mars Landing Mars Landing Short Surface Stay Long Stay 2037 Mars Landing 2046 Mars Orbit 2033 Long Stay 2041 Legend (crewed missions): ISS Lunar orbit test Flat budget line Mars orbit short stay Lunar landing test  for Mars lander Current Programs ISS to 2024 Mars surface short stay Support Costs Commercial crew training flights in LEO These costs assume no international partner contributions.  It is expected  that international participation could reduce costs somewhat. Pre-Decisional Information -- For Planning and Discussion Purposes Only Mars surface long stay H2M Minimal Architecture 37 H2M NASA Human Space Flight Annual Budget Option to Delay Phobos to 2035 and Mars Landing to 2039 Mars Landing Long Stay Mars Landing 2043 Short Surface Stay Phobos Landing 2039 2035 Minimal Architecture Legend (crewed missions): ISS Lunar orbit test Flat budget line Phobos long stay Lunar landing test  for Mars lander Current Programs ISS to 2024 Mars surface short stay Support Costs Commercial crew training flights in LEO These costs assume no international partner contributions.  It is expected  that international participation could reduce costs somewhat. Pre-Decisional Information -- For Planning and Discussion Purposes Only Mars surface long stay H2M Minimal Architecture 38 This work was aimed at showing an example (an existence proof) that journeys to Mars using technologies that NASA is currently pursuing are plausible on a time horizon of interest to stakeholders and without large spikes in the NASA budget. Takeaway 39 H2M Minimal Architecture Supplemental Material H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 40 Deep Space Habitat Concept H2M Minimal Architecture  Could support a crew of 4 for 500 days (transit to Mars and back)  Mass is approximately 30 t.  Requires solar arrays and batteries for power  Attitude control would be provided by the attached propulsion stage or by Orion C Cr e EO L To  So t Nu a l  ba m De ber t pth  of  o f    D Minimal Architecture i s EC LSS H2M Pre-Decisional Information -- For Planning and Discussion Purposes Only 41 Solar Electric Propulsion (SEP) Tug Concept H2M Minimal Architecture SEP Tug, Block 1a, 100 kWe, 16 t Xenon 8-Hall Thrusters H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 42 SLS Performance to High Mars Orbit with 100 kWe Class SEP H2M Minimal Architecture  With a single SLS launch, the 100 kWe SEP tug could deliver a 39 t payload to High Mars Orbit in about 3.3 years  The knee in the curve corresponds to adding Earth spiral-out to the beginning of the mission  There is a lot of flexibility in launch dates - Doesn’t have to launch at traditional Mars opportunities H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 43 In-Space Chemical Propulsion Stage Concept H2M Minimal Architecture  Would need 3 units, one each for - Mars Orbit Insertion (MOI), - MAV Boost Stage (MBS), and - Trans-Earth Injection (TEI)  MMH/MON-25 biprop stage with ~250 kN thrust pump-fed engine; similar in size to the Titan II second stage or Proton 3rd stage or Dnepr 2nd stage - Could use two RS-72 engines as an alternative H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 44 Features of Example MAV Design H2M Minimal Architecture  Simple single-stage non-cryo high-heritage biprop system (MMH/MON-25) -   Fully fueled to allow for abort capability during EDL and, after landing, provide for return to orbit without requiring interaction with any Mars surface infrastructure Docking hatch Ascent would be to Low Mars Orbit (LMO) -  Hinged nosecone would protect docking system from dust and debris Concept is to be able to support a crew of 2 for 28 days, a crew of 3 for 14 days, or a crew of 4 for 7 days -  Must dock with boost stage in LMO to return to High Mars Orbit (HMO) Moldline concept is aerodynamic -  Briz-M stage was used as an analog for mass and propellant capacity Briz-M does stage outer toroidal tanks, but that benefit was not used here Single pump-fed engine (example is sized at 250 kN) Seating would be reclined and on one level No airlock – Apollo LEM style Hinged ogive  nose cone EVA hatch Pressurized crew  cabin Briz‐M shown  as propulsion  analog H2M 250 kN engine  Minimal Architecture based on RS‐72 Pre-Decisional Information -- For Planning and Discussion Purposes Only 45 Assumptions for Mars Lander Descent Stage Propulsion H2M Minimal Architecture  Pump-fed MMH/MON-25 bipropellant system for EDL - 6 engines at 250 kN thrust/engine 6 spherical Ti tanks 12:1 Throttle capability Engines gimballed ~60° off vertical for final descent  Reduce soil/surface erosion directly underneath the vehicle  Blow debris out and away rather than up  Vehicle would be clocked to blow debris in directions away from nearby assets  Separate RCS biprop thruster system for TCMs, aerocapture periapsis raise, orbit adjustments, de-orbit burn, and EDL 3-axis control H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 46 Mars Logistics Lander Concept ARM derivative solar arrays H2M Minimal Architecture Pressurized rover with wheels folded Cargo  payload Landing legs extended after  landing for ground clearance ATHLETE Rover lowered on  platform with cables H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 47 EDL Trajectory for Blunt-Body Lander Concept H2M Minimal Architecture 10 sec tick marks Time goes in this direction 4 minute total EDL duration Pre-Decisional Information -- For Planning and Discussion Purposes Only H2M Minimal Architecture 48 Selected EDL Monte Carlo Results H2M Minimal Architecture    ~20 t of propellant is used Crew experiences ~6.5 g Backshell separation and SRP is at ~Mach 3.8 and 4 kPa Propellant Mass (kg) without SIAD Propellant Mass (kg) with SIAD LDSD derived SIAD could save ~4 t of propellant Entry Peak aerodynamic deceleration H2M Minimal Architecture SRP initiation Landing Pre-Decisional Information -- For Planning and Discussion Purposes Only 49 SLS Two-Launch Scenario H2M Minimal Architecture  The first SLS launch would deliver the Mars-bound payload to an elliptical High Earth Orbit (HEO) - This launch is flexible and not constrained to a Mars departure window  The second SLS would be launched with no payload, but it would have a docking kit on the EUS - The could be 6 months or more after the 1st launch but is constrained to a conjunction-class Mars departure window  The EUS from the second SLS would rendezvous and dock with the payload from the first launch  The EUS would be restarted at perigee to inject the payload to Mars  This avoids the development and mission cost of a separate Earth Departure Stage H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 50 SLS EUS Upgrade for Multiple-Launch Concept H2M Minimal Architecture  To enable the two-launch scenario for the SLS Block 2, the EUS would need to be upgraded for the following features: - A ~2-day loiter time in Earth orbit  Extra insulation and boil-off capability  Solar array or LOX/LH2 fuel cell for extended power - Docking ring and semi-autonomous docking capability  Could be a kit that is carried like a primary payload - RCS thrusters for docking  Could be included in docking kit  A single plane of thrusters (unbalanced) can perform translation, although not fuel efficient EUS EUS Multiple‐Boost  Docking Kit H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 51 Conservative C₃ for Mars missions SLS Estimated Performance for Trans-Mars Injection (TMI) with single or multiple launches H2M Minimal Architecture 2nd EUS Limited EUS Current design point  for crew departure Current design  point for lander EUS 1st EUS Limited H2M Minimal Architecture C₃ (km²/s²) Pre-Decisional Information -- For Planning and Discussion Purposes Only 52 Concept for Descent/Ascent Vehicle (DAV) Transit to High Mars Orbit H2M Minimal Architecture Mars 3. Aerocapture maneuver (no crew) 4. Jettison aerocapture heat shield (if needed) 5. In High Elliptical Mars Orbit (no crew) Earth Cruise solar array (redeployable) 2. Cruise to Mars (no crew) 1. TMI burn (no crew) H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 53 Crewed Mars Descent/Ascent Vehicle Concept H2M Minimal Architecture Orion Descent/Ascent Vehicle MAV  boost  stage Crew transfer to  Descent/Ascent Vehicle In High Mars Orbit (HMO) MAV Ascent to Low Mars Orbit (LMO) Crew transfer from MAV in HMO MAV MAV boost phase  from LMO to HMO Landed  Configuration H2M Minimal Architecture Lander and MAV propellants in this  example are MMH and MON‐25. Pre-Decisional Information -- For Planning and Discussion Purposes Only 54 Concept for MAV Ascent, Transfer to Deep Space Hab, H2M and Preparation for Trans-Earth Injection Minimal Architecture 3. Boost Stage takes MAV to HMO 1. MAV ascent to Low Mars Orbit 2. MAV docks with Boost Stage Mars 4. Crew transfer to Orion in High Mars Orbit 5. Vehicle configured for Earth return Pre-Decisional Information -- For Planning and Discussion Purposes Only H2M Note: Boost Stage was previously delivered by SEP cargo flight to Minimal Architecture HMO and aerobraked down to LMO. 55 SLS Block 2 Launch Concepts for Minimal Architecture all 8.4 m fairings except for lander H2M Minimal Architecture EUS Earth departure configuration  for lander (from HEO) MAV  boost  stage TEI  stage TransHab logistics  resupply TransHab MOI  stage SEP  tug SEP  tug TEI and boost stage  cargo launch TransHab resupply  cargo launch Lander to HEO using back‐ shell as payload fairing Docking kit for EUS to  use as departure stage MOI stage and TransHab launch to HEO Launch #1 Launch #2 Launch #3 Launch #4 Launch #5 Orion with crew H2M Launch #6 Minimal Architecture Launches #4 and #6 have limited launch periods.  The other launches have flexible launch dates. Pre-Decisional Information -- For Planning and Discussion Purposes Only 56 Notional Crewed Mars Transit Vehicle Configuration H2M Minimal Architecture EUS Orion Orion TransHab MOI stage Earth departure configuration for crew TransHab MOI stage  (or TEI stage) Earth/Mars transit configuration H2M Minimal Architecture Pre-Decisional Information -- For Planning and Discussion Purposes Only 57 Notional SEP Tug Cargo Flight Configurations H2M Minimal Architecture SEP tug TEI stage MAV  boost  stage SEP tug In‐space propulsion stages in this  example use mono‐methyl hydrazine  (MMH) and MON‐25 propellants.   SEP tug uses xenon propellant. Pre-Decisional Information -- For Planning and Discussion Purposes Only TransHab logistics  resupply H2M Minimal Architecture 58 Background References Humans to Mars           Price, H., Baker, J., Naderi, F., “A Minimal Architecture for Human Journeys to Mars,” New Space Vol. 3, No. 2, June 2015. Price, H., Baker, J., Strange, N., Woolley, R., “Human Missions to Mars Orbit, Phobos, and Mars Surface Using 100-kWe-Class Solar Electric Propulsion,” AIAA Space 2014 Conference, San Diego, CA. Price, H., Manning, R., Sklyanskiy, E., Braun, R., “A High-Heritage Blunt-Body Entry, Descent, and Landing Concept for Human Mars Exploration,” AIAA SciTech 2016 Conference, San Diego, CA. The Humans to Mars Report 2016, Explore Mars, Inc. Human Exploration of Mars, Design Reference Architecture 5.0, NASA-SP-2009-566, July 2009. Human Exploration of Mars, Design Reference Architecture 5.0, Addendum, NASA-SP-2009566-ADD. Human Exploration of Mars, Design Reference Architecture 5.0, Addendum 2, NASA-SP-2009566-ADD2. Aldrin, B., Mission to Mars, National Geographic, 2013, ISBN 978-1426210174. Geels, S., “System Design of a Mars Ascent Vehicle,” M.S. Thesis, Dept. of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, 1990. Woodcock, G., “An Initial Concept of a Manned Mars Excursion Vehicle for a Tenuous Mars Atmosphere,” NASA Technical Memorandum X-53475, MSFC, June 7, 1966. Pre-Decisional Information -- For Planning and Discussion Purposes Only 59