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Lunar Exploration Transportation System (LETS)


Lunar Exploration Transportation System (LETS) Baseline Design Presentation 1/31/08 – PowerPoint PPT presentation

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Title: Lunar Exploration Transportation System (LETS)

Lunar Exploration Transportation System (LETS)
  • Baseline Design Presentation
  • 1/31/08

  • Current CDD Summary
  • Team Disciplines
  • Technical Description of Baseline Design
  • Assessment of Baseline Design using CDD
  • Recommended Changes to the CDD
  • Statement of Work (SOW) Summary

Team Disciplines
  • CDD Team
  • Eddie Kiessling
  • Technical Assessment Team
  • Nick Case and Matthew Isbell
  • Partnering Universities Team (SOW)
  • Seth Farrington

CDD Summary
  • Level 1 Requirements
  • Figures of Merit
  • Surface Objectives
  • Concept Design Constraints

Level 1 Requirements
  • Landed Mass TBD
  • 1st mission landing site is polar region
  • Design must be capable of landing at other lunar
  • Minimize cost across design
  • Launch Date NLT September 30th 2012
  • Mobility is required to meet objectives
  • Survivability 1 year
  • Lander/Rover must survive conops.
  • The mission shall be capable of meeting both SMD
    and ESMD objectives.
  • The lander must land to a precision of 100m 3
    sigma of the predicted location.
  • The lander must be capable of landing at a slope
    of 12 degrees (slope between highest elevated leg
    of landing gear and lowest elevated leg)
  • The lander shall be designed for g-loads during
    lunar landing not to exceed the worst case design
    loads for any other phase of the mission (launch
    to terminal descent).

Proposed FOMs
  • Surface exploration
  • Maximized Payload Mass ( of total mass)
  • Objectives Validation Ratio of SMD to ESMD 2
    to 1.
  • Conops Efficiency of getting data in
    stakeholders hands vs. capability of mission.
  • Mass of Power System of total mass.
  • Ratio of off-the-shelf to new Development
  • Minimize cost

Surface Objectives
  • Single site goals
  • Geologic context
  • Determine lighting conditions every 2 hours over
    the course of one year
  • Determine micrometeorite flux
  • Assess electrostatic dust levitation and its
    correlation with lighting conditions
  • Mobility goals
  • Independent measurement of 15 samples in
    permanent dark and 5 samples in lighted terrain
  • Each sampling site must be separated by at least
    500 m from every other site
  • Minimum determine the composition, geotechnical
    properties and volatile content of the regolith
  • Value added collect geologic context information
    for all or selected sites
  • Value added determine the vertical variation in
    volatile content at one or more sites
  • Assume each sample site takes 1 earth day to
    acquire minimal data and generates 300 MB of data
  • Instrument package baselines
  • Minimal volatile composition and geotechnical
    properties package, suitable for a penetrometer,
    surface-only, or down-bore package 3 kg
  • Enhanced volatile species and elemental
    composition (e.g. GC-MS) add 5 kg
  • Enhanced geologic characterization (multispectral
    imager remote sensing instrument such as
    Mini-TES or Raman) add 5 kg

Concept Design Constraints
  • Surviving Launch
  • EELV Interface (Atlas 401)
  • Mass
  • Volume
  • Power
  • Communications
  • Environments
  • Guaranteed launch window
  • Survive Cruise
  • Survive Environment
  • Radiation
  • Thermal
  • Micrometeoroids

Concept Design Constraints
  • Lunar Environment (_at_ poles and equator)
  • Radiation
  • Micrometeoroid
  • Temperature
  • Dust
  • Lighting
  • Maximize use of OTS Technology (TRL 9)
  • Mission duration of 1 year
  • Surface Objectives
  • Reference Dr. Cohen

Mars Viking Lander
  • First robotic lander to conduct scientific
    research on another planet
  • Dry Mass 576 kg
  • Science 91kg
  • Dimensions 3x2x2m
  • Power
  • 2 RTG
  • 4 NiCd
  • Survivability
  • -V16yrs 3mo
  • -V23yrs 7mo

Baseline Assessment
  • Structures
  • Thermal Systems
  • Payload and Communications
  • Power Systems
  • GNC
  • Concept of Operations

  • EELV Interface
  • Titan III which delivered the Viking lander is
    comparable to the Atlas V-401
  • The lander shall be designed for g-loads during
    lunar landing not to exceed the worst case design
    loads for any other phase of the mission (launch
    to terminal descent).
  • Comparable G-load launch spikes
  • The lander must be capable of landing at a slope
    of 12 degrees (slope between highest elevated leg
    of landing gear and lowest elevated leg)
  • Landing platform designs for Viking could also
    apply to LETS design

  • Lunar Environment (Radiation, Micrometeoroid,
    Temperature, Dust)
  • Thermal cycles vary greatly
  • Viking thermal cycles were approx. max 17F, min
  • LETS can expect a thermal cycle approx. max 373
    K, min 126 K,
  • Resistance to dust abrasion
  • Viking used a silicon paint to protect the
    surfaces from Martian dust
  • LETS could use a similar product
  • Landed Mass (TBD)
  • Viking required a bio-shield and a
  • LETS will not require these items
  • Viking structural frame used lightweight aluminum
  • LETS could benefit from major advances made in

Thermal Systems
  • Viking Thermal System
  • Passive
  • Geometry
  • Internal thermally controlled compartment
  • Structurally integrated thermal sinks
  • Increased or Decreased Surface Area where
  • Thermal Coatings
  • Proper infrared emittance
  • Proper solar absorbance
  • Thermal Compartment
  • Critical equipment will be housed in compartment
  • Temperature will be dependent upon operating
    temperatures of critical equipment
  • Insulation
  • Thermal control between equipment and environment
  • Radiation shield
  • Active
  • Heaters
  • Continuous operation
  • Thermostatically controlled

Thermal Systems
  • LETS Thermal System
  • Different Thermal Cycles
  • Heaters and Insulation changes to accommodate
    different thermal cycles
  • Statically charged lunar dust increases the
    absorptance of radiator surfaces
  • Use of polarized surfaces/coatings to reduce
    lunar dust accumulation

Payload and Mobility
  • Scientific Options
  • Measure 15 samples in the dark and 5 samples in
  • The Viking Lander did not move, but it used an
    SSRA with a boom, collector head, and shroud
    unit, capable of collecting a variety of material
  • Each sampling site separated by 500 m.
  • The Viking Lander did not have this capability.
  • Determine composition, geotechnical properties,
    and volatile content of regolith.
  • The Viking Lander used an X-ray Fluorescent
    Spectrometer (XRFS) to perform a chemical
  • Enhanced geological characterization
    (multi-spectral imager remote sensing
  • The XRFS plus a remote sensing instrument may be
    used for this function.

  • Camera Options
  • Viking Lander camera system
  • Looked at surface and was able to measure optical
    density of the atmosphere
  • Geologically characterize the surface
  • Look for macroscopic evidence of life
  • LETS camera system
  • Observe electrostatic dust on the horizon
  • Study change in lighting conditions and the
    effects of surrounding environment
  • Aid in Earth observation and control of data

  • Transmission options
  • Direct transmission used by Viking
  • Relay from Viking Orbiter to Earth
  • UHF linked used to transmit data at speeds of
    4000 and 16000bps
  • Transmission Criteria for LETS
  • gt 1 Earth day to transmit data
  • Limit of no slower than 4000bps
  • Transmission Path Options
  • Direct transmission from the Moon to Earth
  • Storage of data until DLS is obtained
  • Lunar orbiter to relay data to earth

  • The lander must land to a precision of 100m 3
    sigma of the predicted location.
  • Viking Orbiter/Lander separation until the
    Lander was on the Martian surface
  • The propulsion system along with a navigation
    system consisting of radars, gyros,
    accelerometers, etc to guide the Lander through
    Mars atmosphere and a soft accurate landing on
    the Martian surface.
  • GNC was not responsible for any operations after
  • LETS Operations will commence upon landing, and
    will continue for the duration of the mission.
  • The lander must be capable of landing at a slope
    of 12 degrees
  • GNC in conjunction with structure will ensure
    that the Lander can function on a 12 degree
  • Mobility is required to meet objectives
  • GNC will be responsible for rover and SSR

Power Systems
  • Operational Period
  • Viking Mars Lander was 90 days
  • LETS will be 365 days
  • Power Required Systems
  • Viking Lander
  • Telemetry
  • Communication
  • Thermal systems
  • Instrumentation
  • Ascent and descent operations
  • Caution and warning systems
  • Power conditioning
  • Regulate power
  • Power storage
  • LETS will be required to supply power to similar

Power Systems
  • Power Supply Options
  • Solar Cell
  • Battery
  • RTG

Power Systems
  • Radioisotope Thermoelectric Generator (RTG)
  • Nuclear Yield
  • Fuel Plutonium 238
  • Nominal Heat Generation Rate
  • 682 Watts
  • Weight Dimensions
  • 15.4 Kg (34 lbm)
  • 53 cm x 41 cm (23 in x 16 in)
  • Power Output
  • 35 to 780 Watts

Power Systems
  • Advantages
  • ASRG/SRG (Nuclear)
  • Constant Power Supply
  • Thermal Output can be utilized for thermal
  • Requires Fewer Batteries
  • Solar Panels
  • Minimize Cost
  • High Power to Weight Ratio
  • Clean Energy
  • Politically Safe
  • Disadvantages
  • ASRG/SRG (Nuclear)
  • Political Affairs
  • Nuclear Waste
  • Hazardous / Contamination
  • Expensive
  • Solar Panels
  • Degrade Over Time
  • Non-constant Power Supply
  • No Thermal Output
  • Susceptible to Lunar Environmental Conditions
  • Requires Many Batteries

Concept of Operations
Concept of Operations
SOW Committee
  • Statement of Work for Partners
  • Software
  • Communications

Statement of Work
  • Sample Return Vehicle
  • Southern University (SU)
  • Mobility Concepts

SOW Committee
  • Software Protocols
  • Computer Aided Design (CAD)
  • Unigraphics NX as standard for UAH and Southern
  • CATIA as standard for ESTACA
  • CAD Translation Options
  • TransMagic
  • Professional Documents
  • MS Office
  • Text Documents MS Word
  • Spread Sheets MS Excel
  • Slide Presentation MS Power Point

SOW Committee
  • Communication Protocols
  • Meetings
  • One meeting per week required
  • Minutes will be required
  • UAH and ESTACA
  • Teleconference, or a web-based video chat
  • UAH and Southern University
  • Video conference, teleconference, or web-based
    video chat
  • Note Minute template will be provided
  • File Sharing Protocols
  • WebCT Primary
  • Basic Email - Secondary

IPT Schedule
Spring 2008 Schedules Spring 2008 Schedules Spring 2008 Schedules
Activity UAH Southern University
Classes Start January 7 January 8
MLK Holiday January 21 January 21
Mardi Gras Holiday - - - - - - - - January 4-5
Founders Day - - - - - - - - March 10
Spring Break March 17-23 March 17-24
Last Day of Classes April 22 April 25
CDD Recommendations
  • No Recommended Changes