MinMars/Surface Infrastructure

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

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)

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

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?