Lunar Exploration Transportation System (LETS)

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Lunar Exploration Transportation System (LETS)

• Baseline Design Presentation
• 1/31/08

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Agenda

• 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

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Team Disciplines

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

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CDD Summary

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

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Level 1 Requirements

• Landed Mass TBD
• 1st mission landing site is polar region
• Design must be capable of landing at other lunar
  locations
• 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).

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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

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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

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Concept Design Constraints

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

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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

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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

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Baseline Assessment

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

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Structures

• 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

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Structures

• Lunar Environment (Radiation, Micrometeoroid,
  Temperature, Dust)
• Thermal cycles vary greatly
• Viking thermal cycles were approx. max 17F, min
  -170F
• 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
  aero-decelerator
• LETS will not require these items
• Viking structural frame used lightweight aluminum
• LETS could benefit from major advances made in
  materials

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Thermal Systems

• Viking Thermal System
• Passive
• Geometry
• Internal thermally controlled compartment
• Structurally integrated thermal sinks
• Increased or Decreased Surface Area where
  applicable
• 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

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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

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Payload and Mobility

• Scientific Options
• Measure 15 samples in the dark and 5 samples in
  light.
• 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
  elements.
• 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
  analysis.
• Enhanced geological characterization
  (multi-spectral imager remote sensing
  instrument).
• The XRFS plus a remote sensing instrument may be
  used for this function.

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Observation

• 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
  collection

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Communication

• 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

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GNC

• 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
  landing
• 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
  slope.
• Mobility is required to meet objectives
• GNC will be responsible for rover and SSR
  deployment.

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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
  systems

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Power Systems

• Power Supply Options
• Solar Cell
• Battery
• RTG

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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

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Power Systems

• Advantages
• ASRG/SRG (Nuclear)
• Constant Power Supply
• Thermal Output can be utilized for thermal
  systems
• 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

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Concept of Operations
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Concept of Operations
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SOW Committee

• Statement of Work for Partners
• Software
• Communications

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Statement of Work

• ESTACA
• Sample Return Vehicle
• Southern University (SU)
• Mobility Concepts

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SOW Committee

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

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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

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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
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CDD Recommendations

• No Recommended Changes

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Questions?