MinMars/Surface Infrastructure

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Repository of Working Models

http://svn.developspace.net/svn/minmars/users/arthur/Surface%20infrastructure/

Surface Infrastructure (Survival Infrastructure, Surface Operations, Operational Infrastructure)

Survival Infrastructure

  • Habitation
    • Thermal, Structural, Crew Facilities, Radiation, Avionics
  • Logistics
    • Resupply options, ISRU capability
  • Power Supply
    • Power requirements, system robustness

Surface Operations

  • What does the crew do when they are on Mars (other than survive)?
    • Maintenance and repair (survival)
    • Infrastructure improvements
    • Public Relations
    • Exploration
    • Science
  • How many crew members are optimal?
  • What tools & infrastructure are required?

Operational Infrastructure

  • Maintenance and Repair
    • Spares, Repair Tools, etc.
    • What is the sparing strategy?
  • Infrastructure Improvement
    • Technology Demonstrations (ISRU)
    • How can someone on Mars improve their own life?
  • Exploration Tools and Equipment
    • Robotic Assistants
    • What is the goal of exploration?
  • Science Tools and Equipment
    • Instruments and Payloads
  • Communications
    • Surface communications (Exploration & Science), Earth-Mars communications (“Public Relations”), etc.
  • EVA Infrastructure
    • Suits, Consumables, etc.
    • What is the EVA frequency & schedule?
  • Mobility Options
    • Habitat Mobility, Unpressurized Rovers, Pressurized Rovers, etc.
    • How much mobility is required?

Future Work

  • Further analysis of each segment of “operational infrastructure” to determine trade space
    • What exactly is needed?
    • What are the possible solutions?
  • Perform lit review to determine near-term capabilities for surface operations

Surface Infrastructure Update

Overview

  • Ongoing process to size all surface infrastructure elements based on previous literature
  • Key questions being analyzed
    • What infrastructure is needed?
    • Can this be done in 5 – 10 mt landed payload?
  • Focused on two types of elements
    • Cargo
      • Either pre-deployed or re-supply
      • Pre-deployed must survive 2+ years on the surface
      • How much autonomous construction is required?
    • Crewed
      • 30-day surface survival capability
      • EVA Suits and Mobility included
      • No consideration for in-space transit
  • Surface Infrastructure Categories
    • Structures
      • Pressurized & Unpressurized
      • Habitation
      • Rigid & Inflatable
    • Power
      • Minimal integrated power (for keep alive of pre-deployed elements)
      • Deployed surface power
    • Thermal
      • Minimal integrated thermal
      • Deployed surface radiators
    • Communication & Navigation
      • Mars surface network
      • Mars-Earth network
    • Life Support
      • Based on Wilfried’s assessment
    • In-situ Resource Utilization
      • Basic vs. extended capability
    • Crew systems
      • Medical
      • Hygiene
    • Maintenance & Repair
      • Facilities, Spare Parts, Raw Materials
    • Science & Exploration
      • Facilities & Tools
    • Extra Vehicular Activities
      • EVA Suits & Spares
    • Surface Mobility
      • Unpressurized Crew Mobility
      • Pressurized Crew Mobility
      • Asset Mobility
    • Consumables & Logistics
      • Initial cache & resupply
  • Cargo Landers
    • Individual units that are able to sustain initial period without interaction with other systems
      • Common structure (5m by 5m rigid cylinder) (~1mt)
      • Basic power, thermal, communications, avionics (~ 1mt)
      • Each element can carry ~3mt of payload
    • Approximately five cargo landers required
      • Deployable power & thermal systems
      • Central life support and ISRU
      • Logistics & cargo lander
      • Habitat lander(s)
      • Mobility asset (pressurized and unpressurized rovers & asset mobility)

A "Small-Package Approach" to Mars Surface Infrastructure (2mt case)

  • Sizing the Small Packages
    • “Estimated landed payload mass extensibility of the MSL EDL architecture: ~2 t (max)”
      • Mars Design Reference Architecture 5.0 Study – Executive Summary [B. Drake – Dec 4, 2008]
    • We can scale the MSL aeroshell based on a constant ballistic coefficient
      • ~30m^3 of volume available (~66 kg/m^3 cargo density)

Surface Infrastructure

  • Habitation elements
    • Habitable volume, crew accommodations, ECLSS, EVA systems, medical
    • Hard-shells & inflatables
  • Mobility elements
    • Crew mobility & infrastructure deployment (autonomously?)
  • Offloading infrastructure
    • Crane or davit could be used with mobility element
  • Logistics containers
    • Pressurized & unpressurized logistics
  • Power system
    • Addressed independently of other infrastructure

Habitation

  • A combination of inflatable and hard-shell elements
  • 3x cylindrical vertical hard-shells
    • 2m diameter and 2.5 m height (~3.2 m^2)
    • 1x EVA access and maintenance
    • 1x ECLSS equipment / mission ops
    • 1x crew accommodations (galley, WC)
  • 3x inflatables (~35 m^2 each)
    • 2x bedrooms (2 persons each)
    • 1 x common space (wardroom, exercise, medical)
  • Inflatables
    • Antarctic Habitat Demonstrator
      • 8 ft max head room
      • Floor area: 384 sq ft (24 ft x 16 ft) [35.7 m^2]
      • Packed System: 1000 lbs [455 kg]
      • 2 packages (3 ft by 4 ft by 8 ft)
      • Source: Spampinato, P. “Expandable Habitat Structures for Long Duration Lunar Missions”. 3rd Space Exploration Conference & Exhibit. Feb 2008. ILC Dover.
  • Hard-Shell Structures
    • Hard-shell cylinders should be < 1 mt to allow delivery of subsystems and should have multiple connection hatches to allow outpost assembly
      • Based on current estimates of 2.5m high by 2m diameter cylinder has a mass of ~1mt (with adapters included)

Mobility/Offloading Elements

  • Deliver two mobility chassis with integrated offloading capability (crane)
  • Crew delivered in two pressurized cabs which double as pressurized rovers
    • CMC (Crewed Mobility Chassis)
      • NASA’s current estimate for the CMC is 969 kg dry vehicle mass (3 mt payload)
      • Source: Culbert, C. “Lunar Surface Systems Project Overview.” USCC Programmatic Workshop on NASA Lunar Surface Systems Concepts. NASA. Feb 2009.
    • LSMS (Lunar Surface Manipulator System)
      • NASA’s current estimate for the LSMS is 190 kg (6 mt capability)
      • Source: Culbert, C. “Lunar Surface Systems Project Overview.” USCC Programmatic Workshop on NASA Lunar Surface Systems Concepts. NASA. Feb 2009.
    • Mobility elements used for both crew exploration and infrastructure deployment
    • Crew cab for NASA’s SPR (Small Pressurized Rover) is ~3 mt

Logistics

  • Each logistics flight will require a hard-shell container for pressurized supplies with unpressurized pallet and fluids storage
    • 2 mt for entire system (including wrappings)
    • Can we reuse the habitat hard-shell?
      • Probably not because of unpressurized logistics mass
    • Transported using mobility element and attached to outpost

Notional Deployment

  • Opportunity One
    • Flight 1
      • 2x Mobility elements with cranes
    • Flight 2
      • ECLSS Cylinder
    • Flight 3
      • EVA Cylinder
    • Flight 4
      • Crew Accommodations Cylinder
    • Flight 5
      • Common Inflatable (plus fittings)
    • Flight 6
      • Bedroom 1 Cylinder (plus fittings)
    • Flight 7
      • Bedroom 2 Cylinder (plus fittings)
    • Flights 8 – 11
      • Power
  • Opportunity Two
    • Flight 1-4
      • Logistics
    • Flight 5-7
      • Crew 1
    • Flight 8-10
      • Crew 2
  • Opportunity Three+
    • Flight 1-4
      • Logistics
    • Flight 5-10
      • Infrastructure

Notional Outpost

Notional_2mt_Case_Outpost.jpg
Notional 2mt Case Outpost

Summary/Notes/Future Work

  • Summary
    • Based on a 2 mt payload, a initial outpost appears feasible with ~10 flights per opportunity
  • Notes
    • It may be necessary to delay crews one opportunity to emplace safety stocks (crew launches on third opportunity)
    • ECLSS/mission ops systems may require two cylinders
    • DRM 3.0 ECLSS ~4.6 mt (including consumables)
  • Future Work
    • Develop point designs to ensure feasibility of each element

Surface Infrastructure for the 10 mt case

Aeroshell

  • Mass
    • Aeroshell mass set as a fraction of the payload mass (first estimate: AMF = 0.4)
    • Total mass set by launch vehicle capability (first estimate: Falcon 9 Heavy = 29,610)
    • Based on the above estimates there is 21,150 kg for payload (surface cargo + descent stage)
10mt_Aeroshell.jpg
Notional Aeroshell for the 10 mt Case
  • Shape & Volume
    • Aeroshell shape is estimated to have be a conical frustum with a base diameter of 7.0 m and a height of 6.5 m with a 20° wall angle
    • The aeroshell is assumed to be composed of two connected pieces
      • A bottom section with a height of 2.5 m (based on descent engine height) which is jettisoned
        • The useable volume of this section is a cylinder with a diameter of 5.18 m and a height of 2.5 m (52.7 m3)
      • A top section with a height of 4.5 m and a base diameter of 5.18 m (usable volume = 47.5 m3)
    • The total usable volume for the aeroshell is 100.2 m3

Descent Stage

  • Mass
    • One N2O4-MMH engine based on 26.7 kN OME
      • Isp = 316 sec
    • Delta-V for terminal descent estimated to be 1200 m/s
    • Propellant required = 6,789 kg
    • Structural mass fraction for propulsion system = 0.2
      • Note: structural mass fraction is inert mass over propellant mass
    • Landing structure is estimated to be 10% of landed mass (approx 1,436 kg)
    • These estimates allow for 11,567 kg of surface cargo to be delivered each flight
  • Shape & Volume
    • One N2O4-MMH engine based on 26.7 kN OME
    • Engine envelope of 2.5 m height by 1.5 m diameter
    • Two fuel tanks & two oxidizer tanks
      • Cylindrical with semi-spherical end-caps (3.0 m3)
    • Height: 2.5 m – Diameter: 1.4 m
    • Packaged to fit in 5.18 m diameter by 2.5 m height cylinder in lower section of aeroshell
    • Initial packaging leaves four “cargo bays” of approximately 4.0 m3 each
10mt_Descent_Stage_Packaging.jpg
Notional Descent Stage Packaging for the 10 mt Case

MinMars lander cargo capacity

  • Top section of aeroshell
    • Conical frustum
      • Available volume: 47.5 m3
      • Base diameter: 5.19 m
      • Height: 4.5 m
      • Top diameter: 1.90 m
  • Bottom section of aeroshell
    • 4 cargo bays
      • Triangular prism
      • Volume: 4.0 m3
      • Base length : 1.79 m
      • Height: 2.5 m
  • The maximum cargo volume is 63.5 m3.
  • The maximum cargo mass capacity is 11.57 mt.
  • Baseline architecture has two lander types
    • Unpressurized cargo delivery
    • Pressurized habitation & logistics module

Unpressurized Cargo Lander

  • Common descent stage with four cargo bays
  • Large unpressurized cargo is placed on top of the descent stage and contained by aeroshell
    • Inflatable habitation modules
    • Surface power systems
    • Pressurized rovers
  • Large cargo will require a means of offloading
    • Crane & surface mobility
  • How do we remove the top section of the aeroshell?

Common Pressurized Module

  • Concept: Use a common module for all habitation (hab, lab, workshop) and pressurized logistics delivery and add in necessary subsystem hardware to adapt each module to its needs
  • This concept may allow reuse of logistics modules as “hotel rooms” and eliminate the need for early inflatable modules (low TRL)
  • With large element surface mobility that is capable of transporting landers (over prepared ground) to allow connection between units would be beneficial

Initial habitat concept

  • Two floor habitat integral with top section of the aeroshell
    • Main floor is 2.5 m high with a floor area of 21 m2 (226 ft2)
    • Top floor is 2.0 m high with a floor area of 8.9 m2 (96 ft2)
    • Two floor are connected through a 1 m diameter tunnel in the middle of the floor
  • Habitat is connected to two “airlocks” which replace two cargo bays in the descent stage
    • Triangular prisms with a volume of 4m3

Initial Subsystems

  • Structures: 2400 kg
    • Based on surface area and area density from DRM 3.0 (21 kg/m2)
  • Life support systems: 316 kg
    • Based on two crew and HSMAD hardware for Wilfried’s architecture
  • Comm-info management: 320 kg
    • Taken from DRM 3.0
  • Thermal: 184 kg
    • Based on two crew and scaled from DRM 3.0
  • Total mass of generic pressurized element = 3220 kg
  • Cargo capacity remaining on lander = 8347 kg

Logistics flights

  • Pressurized logistics: 4000 kg (2 crew)
    • Estimated volume: 13-16 m3
    • Note: Usable volume on top floor is 9.6 m3
  • Unpressurized cargo: 1000 kg (spares, etc.)
    • Volume available is 4 m3
  • Furniture and interior furnishings: 2000 kg
    • Estimate (Cal Tech MSM estimated 1000 kg)
    • As logistics are used / moved (to other modules upper storage sections) habitat becomes available as living space
  • Flights 3 & 4 (opportunity 2) can be used as logistics flights and provide two 2-person habitats

Crew flights

  • Two concepts:
    • Identical habitats with all required crew accommodations in each (for two crew)
    • One habitat (galley, wardroom, hygiene) & one laboratory (medical, maintenance, etc)
  • First concept has each aeroshell pushed separately to Mars using two TMI stages each
  • Second concept has the crew join up and travel to Mars in two connected aeroshells
    • Crew all lands in habitat
  • In space power stage will be needed for transit to Mars
    • Either one or two depending on concept
  • Consumables for trip (4.5 kg/p/d for 210 days) total 3.78 mt and 12.5 – 15 m3
    • Can be stored in upper level storage area and used consumables can be jettisoned before entry to Mars
  • “Airlocks” can be modified for the trip to provide four private quarters with 4 m3 each.
  • Based on HSMAD, crew accommodations system hardware require ~2.9 mt for two crew
  • On Mars surface, top floor used for logistics storage, main floor for common area
  • Private quarters are set up in logistics modules
  • Is 21 m2 of floor space on the main floor enough for all common crew systems (galley, hygiene, operations, etc.)?
  • At Martian surface, crew will remain in habitat for ~7 days to acclimatize.
  • Then use unpressurized rovers (one per habitat in cargo bay) to transit to pre-positioned goods and work to set up base
  • Note: How do we supply surface power to Habitats before 25kW pre-positioned systems are connected?

Other thoughts

  • Inflatable modules may not be required on first flights
    • Replace with pressurized mobility?
    • Currently have 4 unpressurized rovers manifested
      • One on each cargo flight
      • One on each crewed flight
  • With four crew and a consumables requirement of 2 mt /opportunity/person:
    • Each of the following opportunities will require both flights to be logistics modules
    • Logistics modules could be adapted to be workshops, laboratories, etc. using the 2 mt set aside for furniture

Notional Flight Manifest

  • Opportunity 1 (identical flights)
    • 1 pressurized rover
    • 1 unpressurized rover
    • Surface power systems
    • Offloading hardware and large element mobility
  • Opportunity 2 (identical flights)
    • Pressurized module
    • Furniture to adapt to living quarters for two crew
    • Pressurized logistics
    • Unpressurized logistics
  • Opportunity 3 (crew)
    • One habitat (common area for four crew) flight
    • One laboratory / medical / exercise flight
    • 2 unpressurized rovers
  • Opportunity 4+ (two identical flights)
    • Pressurized module
    • Pressurized logistics
    • Unpressurized logistics
    • How are these adapted?