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



Multiple Lander 1 Rover

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


•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 +


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


•(same as above) •(same as above)



•Dry mass penalty•Complex comm•Complex power•Limited individual science payload

Alternative Mobility ConceptsLand On Wheels (LOW) +


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


•Comm relay stations•Maximize data return•“Intelligent” data analysis/gathering

•Dry mass penalty•Complex comm•Comm/pwr required for each lander/pen/rover



•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

Documents

Lunar Exploration Transportation System (LETS) Customer Briefing 12-17-2007 LETS go to the Moon!