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Mars or Bust Preliminary Design Review. 12/8/03. Mission Description. Based on the Design Reference Mission from NASA ( Hoffman and Kaplan, 1997; Drake, 1998 ) Modified to narrow scope of project. Key Assumptions for Design. Only first uncrewed Habitat Focusing on surface operations
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Mission Description • Based on the Design Reference Mission from NASA (Hoffman and Kaplan, 1997; Drake, 1998) • Modified to narrow scope of project
Key Assumptions for Design • Only first uncrewed Habitat • Focusing on surface operations • Launch, transit, Mars entry not designed • Interfaces with external equipment • Rovers, power supply, ISRU unit • Crew will use Habitat on arrival
Overall Project Goal • Establish a Martian Habitat capable of supporting humans
Overall - Level 1 Requirements • Support crew of 6 • Support 600 day stay without re-supply • Maintain health and safety of crew • Minimize dependency on Earth
Launch and Deployment Requirements • 80 metric ton launch vehicle • Recommended Total Habitat Mass < 34,000 kg (includes payload) • Deploys 2 years before first crew • Land, deploy, operate, maintain all systems • Setup and check-out before crew arrives • Standby mode for 10 months between crews • Operational lifetime of greater than 15 years
Redundancy Requirements • Mission critical: 2-level redundancy • Life critical: 3-level redundancy • Auto fault detection and correction • Modular • Easily repairable • Electronic and mechanical equipment • Highly autonomous • Self-maintained or crew maintained • If possible self-repairing • All systems in Habitat must have low failure rates
Operations Requirements • Gather information about Mars • Ease of learning • System similarity • Common software and hardware • Real time science activity planning • Integrate In-Situ Resource Utilization System
Mission Architecture • Systems Engineering and Integration • Structures • Command, Control, and Communications (C3) • Power Distribution and Allocation • Environment Control and Life Support Systems (ECLSS) • Mission Operations and Crew Accommodations • Automation and Robotic Interfaces • Extra Vehicular Activity Systems (EVAS) • Thermal Control • In-situ Resource Utilization Unit (ISRU) and Mars Environment
Organizational Chart Project Manager Systems Engineering and Integration Mission Operations Crew Accommodations Thermal EVAS Robotics and Automation ISRU Power CCC ECLSS Structures
Systems Engineering and Integration Team • Primary: • Juniper Jairala • Tim Lloyd • Tyman Stephens • Support: • Meridee Silbaugh • Jeff Fehring • Keith Morris
Systems Engineering and Integration Responsibilities • Establish habitat system requirements • Delegate top-level subsystem requirements • Review and reconcile all subsystem design specifications • Ensure that all habitat subsystem requirements are met • Ensure proper subsystem interfaces
Mars Environment and In-Situ Resource Utilization (ISRU) Primary • Heather Chluda Support • Keagan Rowley • Keric Hill
Mars Environment Summary • Responsible for collecting data on the Mars Environment • Provides a consistent data set on the Mars Environment for the Habitat design group to use. • Thermal, Radiation, Pressure, Atmosphere, Wind, etc.
Mars Environment Characteristics The Habitat will encounter a wide range of environment characteristics during its surface stay on Mars
Temperatures • Diurnal variation at Viking Lander sites • Seasonal variation: -107 to -18°C winter to summer lows
Radiation • GCR BFO dose equivalent for solar min and max vs. altitude SPE Dose: 5 cSv/yr GCR BFO Dose: 22.3 cSv/yr GCR Skin Dose: 24.7 cSv/yr LEO BFO Limit: 50 cSv/yr LEO Skin Limit: 300 cSv/yr
Future Considerations • More detailed temperature and radiation data for specific landing site • Determination of topography of landing site and exploration area • More detailed information from upcoming Mars missions
ISRU Subsystem Summary • Responsible for interface between habitat and ISRU plant • ISRU will provide additional oxygen, nitrogen, and water for habitat use • Non-critical system, demonstration for future mission use
ISRU Level 2 Requirements • Provide additional nitrogen, water and oxygen • Byproducts of propellant production used as backup oxygen, nitrogen, and water • Storage tanks and pipes for the ISRU shall tolerate leaks within limits • Propellant production shall be automated • Acceptable temperatures shall be maintained in storage tanks and piping • Storage interfaces must be compatible with habitat • Pumping systems shall have adequate power to transport oxygen, nitrogen and water to the habitat • Piping and storage tanks must be shielded from Mars Environment • Connections to storage tanks and ISRU tanks must be performed using robots or humans
Future Considerations • Radiation shielding effects of Martian soil • Safe haven soil shelter designs • Mass benefits of using ISRU plant for consumables on future missions
Structures Subsystem Team • Primary: • Jeff Fehring • Eric Schleicher • Support: • Jen Uchida • Sam Baker
Structures Subsystem • Overall layout • Volume allocation • Pressurized volume • Physically support all subsystems • Radiation shielding • Micro-meteoroid shielding • Withstand all loading environments
Level 2 Requirements • Fit within the dynamic envelope of the launch vehicle • Launch Shroud Diameter = 7.5 m • Length = 27.7 m • Structurally sound in all load environments • Acceleration • Vibration • Pressure • Easily repairable • Stably support all other systems • Interface with other systems • Structures Mass < 20744 kg
Structures Inputs and Outputs • Heat escapes through the structure • Cabin air escapes through the structure • Trace contaminants from the structure • Telemetry data collected by CCC
Structures Overview • Pressure Shell • Trusses • Leg Supports • Chassis and Wheels • Radiation Shielding • Safe haven • Supports for other subsystem components • Other Structures • Hatches • Vents • Windows • Seals
Overall Layout ECLSS Tanks Top Floor: personal space, crew accommodations Radiator Panels Airlocks (3) Bottom Floor: lab, equipment, storage, safe haven Chassis, wheels, and leg supports underneath habitat
Pressure Shell • Assume aluminum shell • Assume a hollow cylinder, radius 3.5 m • Thickness t = P*r/fy = 1.7 mm for 10.2 psi • Assume pressure shell holds 34 tonnes • Assume launch forces similar to Atlas V • Minimum thickness = 3 mm for stability • Internal trusses carry part of the load
Supports • Assume 6 hollow tube leg supports • Support entire mass of Habitat on Mars • Mars gravity = 3.758 m/s2 • Weight = 128 kN • Maintain stability in Martian wind storm • Maximum wind speed = 127 kph • Maximum wind force = 17 kN • Maximum compressive force = 54.5 kN/leg • Dimensions of leg to minimize mass: • Length = 2 m • Radius = 13 cm • Thickness = 1 mm
Future Considerations • Design for launch loads from Magnum vehicle • Optimize truss structure • Fully design supports for all components
Power Distribution and Allocation Subsystem Team • Primary: • Tom White • Jen Uchida • Support: • Nancy Kungsakawin • Eric Dekruif
Power • Interface with the nuclear power source and other external equipment • Safely manage and distribute power throughout Martian habitat
Level 2 Requirements • Supply sufficient power with 3-level redundancy • Supply power while reactors are being put online • Transfer power from reactor to habitat • Distribute power on a multi-bus system • Provide storage and interfaces for rovers/EVA suits • Interface with transit vehicle power sources • Regulate voltage to a usable level • Include a fault protection system • Provide an emergency power cutoff • Mass must not exceed 3249 kg (including in-transit power)
Input/Output • Input: • Power from reactor • Info/control from CCC • Output: • Power to habitat • Heat to thermal Habitat Thermal All Subsystems Heat Power Cargo Lander CCC Power EPDS Info/control Power PS Info/control
Mars Surface Power Allocation • Allotted ~25kW • Potential to use power allocated to other systems (DRM)
Reactor Reactor Bus 1 Conditioning Regulation Bus 2 Distribution Bus 3 Charge Control ECLSS Thermal EVAS Robotics Storage Life/Mission Critical Sys. Structures Mission Ops CCC System Schematic