Outline “Modeling the MER Mission”

1

“Modeling the MER Mission”

Chin SeahNASA Ames Research Center

April 22, 2005 Agent-Based Modeling & Simulation of Organizations and Work Practice

2

Outline

• Mars Exploration Rover Mission• Mission Operations Modeling• MER Brahms Model• Brahms Model Affecting Design of Mission

Operations• Predictive Model of Mission Operations• Lessons Learned


3

Mar Exploration Rover Mission“Find Past Existence of Water”

•• Mars Exploration Rovers (MER)Mars Exploration Rovers (MER)– Spirit (MER-A) at Gusev Crater

• Reached Mars on Jan 4, ‘04– Opportunity (MER-B) at

Meridiani Planum• Reached Mars on Jan 25, ‘04

– 90 day mission which was extended.•• Science PayloadsScience Payloads

– Panoramic Camera:• Providing the geologic context

– Rock Abrasion Tool• Grinding Outside of Rocks

– Mössbauer Spectrometer• Identifying Iron-Bearing Minerals

– Miniature Thermal Emission Spectrometer

• Identifying Minerals at the Site


4

What is Mission Operations?“The control of one or more information

gathering devices on board a vehicle in space and the associated operation of the

vehicle systems in order to support information gathering.”

Wall, S. & K. Ledbetter, ’91Design of Mission Operations for Remote Sensing

(Magellan Mission to Venus)


5

Why Work Practice Modeling for Mission Operations?

• New designs for – Facilities– Organization– Processes

• Complex work system– Scientists and Engineers– 24*7– Multiple Time Zones– Data Systems (new & legacy)

• Design close to implementation stage

• Trial and error of design during Operations Readiness Tests


6

Where did data for model come from?

• JPL’s Tactical Timeline in Excel spreadsheets, design specifications, software documentation, etc.

• Participated in Mission Design Team’s design sessions

• Interviewed people that were part of MER mission operations.

• Observed JPL’s Operational Readiness Tests.

2


7

What to model?• Organizational Structures and Roles• Operational procedures for roles• Engineering and Science decision

making and planning• Rover on Mars

– Receive commands from Earth (Uplink)

– Command execution– Science Payload/Instrument

• Capture of Science data– Send data back to Earth (Downlink)

• Flow of Mission data– From Downlink to Uplink to

Downlink of science and engineering data

– Creation, flow and use of intermediate data

– Communication between people, and between people and systems

• Uplink rover command generation

Activ ity Name Location 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9

UHF Passes MGS Odyssey MGS Odyssey

DTE Sol n-1 DTE period DFE

Night T ime Rover Operations Night T ime Rover OperationsSleep Wakeup

Pre-Comm Session Sequence Plan Reviews

Sol n-1 Day Sequence Plan Review SMSA Sol n-1 Day Sequence Plan Review

Science Sol n Context Meeting 264-550 Science Sol n Context Meeting

Sol n-1 Night Sequence Plan Review SMSA Sol n-1 Night Sequence Plan Review

Real-T Ime Monitoring SMSA Real-T Ime Monitoring Real-T Ime Monitoring

Downlink Product Generation

Telemetry Processing Telemetry Processing

Image Processing Image Processing

Tactical Science Assessment/Observation Planning 264-550 Tactical Science Assessment/Observation Planning

Science DL Assessment Meeting 264-550 Science DL Assessment Meeting

Tactical End-of-Sol Engr. Assessment SMSA Tactical End-of-Sol Engr. Assessment

Engineering Skeleton Activity Plan Update 264-425 Engineering Skeleton Activity Plan Update

TDL/TAP/TUL Session 264-425 TDL/TAP/TUL Session

DL/UL Handover Meeting 264-450 DL/UL Handover Meeting

SOWG Meeting 264-550 SOWG Meeting

Activity Refinement / Sequence Assignment264-425 Activity Refinement / Sequence Assignment

Uplink Kickoff 264-425 Uplink Kickoff

Activity Plan Integration & Validation 264-425 Activity Plan Integration & Validation

Sequence Plan Roundtable 264-425 Sequence Plan Roundtable

Sequence Development 264-425 Sequence Development

Activity Plan Approval Meeting 264-425 Activity Plan Approval Meeting

Integrate & Validate Sequences 264-425 Integrate & Validate Sequences

Master/Submaster Walkthru 264-425 Master/Submaster Walkthru

Command & Radiation Approval 264-425 Command & Radiation Approval

Margin Margin

Sol n Radiation SMSA Sol n Radiation

Nominal Surface Tactical Timeline


8

Mission Operations at JPLMission Operations at JPL– 50 Science Team Members– 30 Engineering Team Members

• Two Rover Teams (MER A & B)– 25 STM & 15 ETM per Rover Team

• Two Shifts per Martian Day/Sol– Shift handovers

• 4 floors within building• 90-Sol Minimal Mission Duration

– Jan 2004 - Mar 2004– MER A & B Operations overlap– Different Time Zones (2 on Mars,

PDT at JPL)

MER Organization


9

MER Organization Model


10

SAP

SAP

SAP

SAP

PUL

Scientist

Scientist

Scientist

PlanPlan

PlanPlan

PlanPlan

SOWGChair PlanPlan

TAP

CE

SOWGChair

SAP

SAP

PlanPlan

PlanPlan

PUL

Engineer

MAPGEN

PlanPlan

MAPGENPlanPlan PlanPlan

TAP

PUL

RSVP RSVP

PlanPlan PlanPlan

PUL

RP

RSVP

PlanPlan

SIE

RSVP

PlanPlan

Uplink Tools Process Flow(Similar to traditional “Order Processing”)


11

MER Information Model


12

Clock, Schedule and Agents

Mars Clock Object

Broadcasts time when match Timeline

Schedule Group Agent

Timeline Object

Reads Mars timeMatch Timeline with Mars time

CIP Clock Object

Schedule Object Mission Operations Activity Conceptual

Object

Activity happens withinTimeline

Reads Associated Schedule

Contains mission

operations activities

Activity Name 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9

UHF Passes MGS Odyssey MGS Odyssey

DTE Sol n-1 DTE period DFE

Night Time Rover Operations Night Time Rover OperationsSleep Wakeup

Pre-Comm Session Sequence Plan Reviews

Sol n-1 Day Sequence Plan Review Sol n-1 Day Sequence Plan Review

Science Sol n Context Meeting Science Sol n Context Meeting

Sol n-1 Night Sequence Plan Review Sol n-1 Night Sequence Plan Review

Real-TIme Monitoring Real-TIme Monitoring Real-TIme Monitoring

Downlink Product Generation

Telemetry Processing Telemetry Processing

Image Processing Image ProcessingTactical Science Assessment/Observation Planning Tactical Science Assessment/Observation Planning

Science DL Assessment Meeting Science DL Assessment Meeting

Tactical End-of-Sol Engr. Assessment Tactical End-of-Sol Engr. Assessment

Engineering Skeleton Activity Plan Update Engineering Skeleton Activity Plan Update

DL/UL Handover Meeting DL/UL Handover Meeting

SOWG Meeting SOWG Meeting

Uplink Kickoff Meeting Uplink Kickoff Meeting

Activity Expansion and Review Activity Expansion and Review

Activity Plan Integration & Validation Activity Plan Integration & Validation

Activity Plan Approval Meeting Activity Plan Approval Meeting

UL1/UL2 Handover UL1/UL2 Handover

Build & Validate Sequences Build & Validate Sequences

Margin 1 Margin 1

Command & Radiation Approval Command & Radiation Approval

Margin 2 Margin 2

Sol n Radiation Sol n Radiation

Is timeline over?

Start

next

task? Do I start my shift?

Contains timeline activities

3


13

MER Clock Model


14

Simulation of MER Clock

Match Timeline


15

Issues of Modeling a Mission Operations

• Actual Work Practice was different from design– We know this from our theory of work practice– How useful is model in design?

• Unable to predict workflow failure– Round-Trip data tracking issue not identified

• This could have been identified and solved in model design but …

Much detail about mission data and systems neededApril 22, 2005 Agent-Based Modeling & Simulation of

Organizations and Work Practice16

How Useful is Model in Design?

• Synchronizing Communications of Key Personnel– People could not verbally

communicate information because they needed to be in different places at the same time for meetings

• People’s work hours were too long– A shift was about 8 to 10

martian hours


17

Other Uses of MER Brahms Model

• Procedures for Mission Operations Personnel• Assist in Mission Operations Planning.

– Creation of huge paper poster• Analysis of Mission Operations

– Mars-based time versus Earth time (24 x 7 & 8 hours)

• Simulation Visualization– Timeline view of information on Rover Activity

Plan– Communication networks creation and growth


18

Predicting Workflow Failure:SAP and MAPGEN Scenario

Tactical ActivityPlanner

ConstraintEditor

SOWGChair

MAPGEN

PlanPlan

SAP

SOWG Chair

PlanPlanMAPGEN

Tactical Activity Planner

SAP User Interface

Activity 3

Observation 2

Activity 2

Activity 1

Observation 1

Without Sequence or Timing Constraints

With Sequence and Timing Constraints

Interface � Specification

4


19

What have we learned?• How to model Mission Operations Systems• Level of detail to model

– More narrow/deep or more broad/shallow• Use of BRAHMS?Representation

+ Mars time vs. Earth time+ Multiple MER teams+ Systems+ Information flow+ Plans and schedules

Usefulness for mission designers- Not easy to retrieve information- Not easy to change model- Difficult to model things- Difficult to determine needed level- Difficult what-if scenarios

Outline “Modeling the MER Mission”

Documents

Transcript of Outline “Modeling the MER Mission”