Lunar Exploration Transportation System (LETS) Customer Briefing 12-17-2007 LETS go to the Moon!
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Transcript of Lunar Exploration Transportation System (LETS) Customer Briefing 12-17-2007 LETS go to the Moon!
Lunar Exploration Transportation System (LETS)
Customer Briefing
12-17-2007
LETS go to the Moon!
Agenda
• IPT Class– Overall objectives– Class Flow/Schedule– Requirement Process– Review Board Membership– Technical Mentors
• Level 1 Requirements• Proposed FOMs• Surface Objectives• Concept Design Constraints• “Efficiency” Design Thoughts
– Previous Landers/Rovers– Alternative Mobility Concepts
• Final Report Requirements
Integrated Product Team Class
• Develop a system-level perspective for translating requirements into feasible solutions
• Develop oral, written, and information technology-based communication skills
• Practice the critical thinking skills required for success in a changing environment
• Acquire basic character qualities that enable individuals and teams to function effectively
Class Flow
Baseline Review (1/31/08)• Evaluate baseline per CDD• Understand CDD from
customer• Demonstrate your ability to
review board
Alternatives Review (2/28/08)• Develop alternatives to accomplish
mission• Select a concept to continue detailed
design
Detailed Design Review (4/29/08)• Develop detailed design of selected
concept• Provide prototype model to review board
Process of Requirements
• Requirements…
Review Board Membership
• Board of 6-10 government/industry/academic officials
• Review board chair selected by customer– Coordinates input from members to faculty personnel
• Review board ranks teams, does not provide input to final grades
• Time commitment– 3 reviews, 2-3 hrs. each
Technical Mentors
• Officials that provide guidance to student teams in a technical discipline
• ARE NOT members of the review board• Disciplines needed
– GN&C– Thermal– Power– Structures– Payload– Systems Engineering– Operations
• Time commitment– On-call basis
Level 1 Requirements
• Landed Mass 1450 kg + 100 kg• 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).
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
• 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
Surface Objectives
Concept Design Constraints
• Surviving Launch– EELV Interface (Atlas 431)
• Mass• Volume• Power• Communications• Environments
– Guaranteed launch window
• Survive Cruise– Survive Environment
• Radiation• Thermal• Micrometeoroids
Concept Design Constraints
• Lunar Environment (@ 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
Efficiency Design Thoughts
• Previous Landers– Surveyor – Apollo Lunar Lander– Viking– Pathfinder
• Rover concepts– Apollo Lunar Rover– Sojourner– Spirit & Opportunity– MSL
• Alternative mobility concepts
Previous Landers - Surveyor
• Atlas-Centaur Launch Vehicle
• Useful Mass was 292 kg• Mission Duration was 65
hours• Science Instruments
included: A TV camera, and strain gauges mounted on each leg shock absorber.
Previous Landers – Apollo
• Designed to transport astronauts to and from the moon
• Mass 14,696 kg• Volume 6.65m2
• Height 6.37m• Diameter 4.27m• Endurance 72 hrs• Provides life support for
2 crew
Previous Landers - Viking
• Two Viking Landers were the first spacecraft to conduct prolonged scientific studies on the surface of another planet
• Dry Mass 576kg• Dimensions 3m by 3m
by 2m• One Lander survived 6.5
yrs
Previous Landers - Pathfinder
• Flight System Launch Mass (890kg)
• Payload (25kg)• X Band Antenna• Solar Arrays• Deploys airbags which
reduce impact by as much as 40 g
• Designed to survive 30 sols with an extended mission lifetime of up to 1 year
Previous Rovers - LRV
• Lunar Roving Vehicle• Total range 35.89km• Rover mass 210kg• Useful Payload mass 490kg• Each wheel 0.25 hp DC
motor• Two 36v silver-zinc
potassium hydroxide non-rechargeable batteries with a capacity of 121 A·h.
Previous Rovers - Sojourner
• Rover Mass (10.5 kg)• Solar Powered generating 16
Watts during peak operation• Non-Rechargeable Battery which
generates approximately 300 Watts/hour
• Contains a Six Wheel Drive Rocker Bogie Design (made rover very versatile)
• Can carry approximately 1.5 kg of payload at a time
Previous Rovers – Spirit and Opportunity
• Delta II Launch Vehicle• Lander mass: 348 kg• Rover mass: 185 kg• Mission duration was 90
days• Scientific Instruments
included: Several cameras, spectrometer, alpha particle x-ray, microscopic imager, RAT, and several other tools
Previous Rovers - MSL
• Mass 800kg• Max Speed 90m per
hr• Average Speed 30m
per hr• Expected to traverse
a minimum of 6km over its two year mission duration
Alternative Mobility Concepts
LETSLETS
Other?Other?PenetratorsPenetratorsRover(s)Rover(s)Lander(s)Lander(s)
Alternative Mobility Concepts
Landing Mobility
Single Lander 1 Rover
Multiple Rovers
Penetrators
1 Rover + Penetrators
Multiple Rovers + Penetrators
Land on Wheels 1 Rover
Multiple Rovers
Penetrators
1 Rover + Penetrators
Multiple Rovers + Penetrators
Multiple Lander 1 Rover
Multiple Rovers
Penetrators
1 Rover + Penetrators
Multiple Rovers + Penetrators
Mobility Advantages Disadvantages
Single Rover •Proven technology•More OTS•Minimum ground support
•Single point of failure•Increased chances of Con-Ops (Mission) failure
Multiple Rovers •Maximize data return•Increased range/area•Increased comm area w/ networking•Faster mission completion
•Increased ground support•More complex comm•Increased dry mass•Individual science payload limited (no single large device)
Penetrators •Maximize data return•Less weight•No moving parts
•“Random” spread (penetrator not accurate)•Complex comm•Nonwired: batt & comm req•Wired: limited range•Propulsion (?)•Unproven
Single Rover + Penetrators
•Good light/dark solution•“Intelligent” data analysis/gathering•Maximize data return
•Sacrifice mass for penetrators
Multiple Rovers + Penetrators
•Maximize data return•Increased range/area•Faster mission completion•Increased comm area w/ networking
•Dry mass penalty•Complex comm•Complex power•Limited individual science payload
Alternative Mobility ConceptsSingle Lander +
Mobility Advantages Disadvantages
Single Rover(same vehicle)
•Mass savings•Less ground support
•Lower probability of mission completion and data return•Unproven technology•Rover might be damaged by landing•Rover moves with prop system
Multiple Rovers(same vehicles)
•Maximize data return•Increased range/area•Increased comm area w/ networking•Faster mission completion
•Increased ground support•More complex comm•Increased dry mass•Science payload limited (no single large device)
Penetrators •Maximize data return•Less weight•No moving parts (penetrators)•Good light/dark solution•“Intelligent” data analysis/gathering
•“Random” spread (penetrator not accurate)•Complex comm•Penetrators require comm/pwr (?)•Propulsion (?)•Unproven technologies
Single Rover + Penetrators
•(same as above) •(same as above)
Multiple Rovers + Penetrators
•Maximize data return•Increased range/area•Faster mission completion•Increased comm area w/ networking
•Dry mass penalty•Complex comm•Complex power•Limited individual science payload
Alternative Mobility ConceptsLand On Wheels (LOW) +
Mobility Advantages Disadvantages
Single Rover •Comm relay stations•Maximize data return (no single point failure)
•Mass penalty•Volumetric penalty
Multiple Rovers •Wide range/area•Comm relay•Increased data return
•Dry mass penalty•Volumetric penalty•Science individual payload limited•Complex comm
Penetrators •Wide range/area•Fast mission completion time•No moving parts•Multiple data sites (possible linking for seismic analysis)
•Dry mass penalty•Complex comm•Comm/pwr required for each lander/penetrator
Single Rover + Penetrators
•Comm relay stations•Maximize data return•“Intelligent” data analysis/gathering
•Dry mass penalty•Complex comm•Comm/pwr required for each lander/pen/rover
Multiple Rovers + Penetrators
•Maximize data return•Increased range/area•Faster mission completion•Increased comm area w/ networking
•Dry mass penalty•Complex comm•Limited individual science payload•Comm/pwr required for each lander/pen/rover
Alternative Mobility ConceptsMultiple Landers +
Final Report Requirements
• Lander development schedule– By subsystems
• Configuration drawing– Lander
– Rover concepts (Southern)
– Sample return vehicle (ESTACA)
• Concept of operations• Level 2 Requirements• CDD• Design Analysis Package• Parts List/ Vendor List