Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October...

60
www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006

Transcript of Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October...

Page 1: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 1

The MECA ProjectReasoning Agents on Mars

Leo Breebaart (S&T)

12 October 2006

Page 2: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 2

The MECA Consortium

TNO Human Factors• Human behaviour and performance in technical high-demand environments;

methods to attune the environment to (momentary) human capacities.

S&T bv • Software development company with specific expertise on creating system

health management applications.

OK Systems• Software development company focusing on technology areas of AI, user

interfaces, databases and web-based systems (specially scheduling systems).

EADS-ST• Technologies, development, production and utilization of manned and

unmanned space missions, including experiments, space transportation systems, propulsion systems and support of these systems concerning operations, maintenance and mission handling.

Page 3: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 3

Project Goal

The MECA Project aims to:

• Provide support to and increase autonomy of astronauts while:– Executing complex tasks– In a hostile and large unknown environment– Possibly disconnected from Mission Control

Page 4: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 4

Objective & Vision

Objective: support mission goals (without injury or loss of life) by• empowering the cognitive capacities of human-machine teams

during planetary exploration missions. • in order to cope autonomously with unexpected, complex and

potentially hazardous situations.

Vision: crew support that • acts in a ubiquitous computing environment • as “electronic partner”, helping the crew

– to assess the situation, – to determine a suitable course of actions to solve a problem, – to safeguard the astronaut from failures.

Page 5: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 5

MECA and Agents

Where does agent technology fit in?

• A MECA System can be considered as an instance of a group of software agents.

• The MECA Architecture will make use of the outcome of agent technology research.

Page 6: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 6

This presentation

• Phase 1 (2005-2006)– “MECA 2017”– RB: Requirements Baseline

• Phase 2 (2006-2007)– “MECA 2007”– Demonstrator Prototype– Refined RB

Page 7: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 7

Why the need for support?

• Current astronaut support rather antiquated.

• Long-distance manned explorations impose new challenges.

Page 8: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 8

Background

Page 9: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 9

State of the Art

LAPAP SCOPE

Our legacy:…

But MECA should extend this….

Operational Procedures Hardcopy +

Page 10: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 10

MECA design process

Background • Operability-based design• Anticipate new Intelligent Interfaces• Anticipate new HFE standard

Approach• Human-Operation centered• Enabling Technology focus• Iterative process (specify-test-refine

cycles)• From abstract to detailed specifications• Sound theoretical and empirical foundation

10 -- 25 yrs

Page 11: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 11

Example Scenario

Human and System Health Management

Page 12: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 12

EVA 2 astronauts 2km from habitat, sample collection for scientific experiment.

Habitat

= MECA unit

Page 13: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 13

MECA indicates a problem with the temperature regulation of one of the space suits.

Habitat

Page 14: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 14

Astronaut, MECA and spacesuit collaborate on finding the cause of the failure.

Habitat

• MECA interrogates spacesuit to obtain more parameters for diagnosis.

Page 15: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 15

The heater of the space suit is damaged and cannot be repaired locally.

Habitat

Page 16: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 16

MECA simulates the consequences of the broken heater.

Habitat

• MECA predicts that astronaut has to be brought to habitat and has a risk of fainting.

Page 17: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 17

Astronaut's MECA Unit and Habitat MECA Unit reschedule and plan safe return.

Habitat

• Habitat is preparing for treatment of hypothermic astronaut (preparing and activating resources)• Astronaut MECA asks for help of transporting astronaut (since he is likely to faint)

Page 18: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 18

MECA Rovers respond to call for help, MECA habitat chooses rover

Habitat

• MECA habitat chooses rover that has enough power/resources to pick astronaut up and transport to habitat (fuel, location, speed, pressurized or unpressurized rover etc.).

Page 19: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 19

MECA communicates adjusted schedule to astronaut(s) in the right manner (keeping in mind cognitive task load).

Habitat

• Hypothermic astronaut has a high task load due to high stress levels, MECA Unit shall adapt communication according to task load and affective state.• The astronaut accompanying him can be given information in a different manner.

Page 20: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 20

Astronaut faints before rover arrives. MECA communicates fainting of astronaut.

Habitat

Page 21: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 21

Astronaut has fainted earlier than predicted, MECA rover has to find a way to pick up astronaut (sensemaking).

Habitat

Page 22: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 22

MECA of fainted astronaut and other astronaut collaborate to get fainted astronaut in rover

Habitat

Page 23: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 23

Hypothermic astronaut is transported to habitat by rover.

Habitat

Page 24: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 24

Hypothermic astronaut is in habitat being treated.

Habitat

Page 25: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 25

Iterative Requirements Analysis

MECA Requirements

Refine HMC Performance

Simulation-Based Evaluation

Envisioned Technology

Human Factors Knowledge

OperationalDemands

PrototypeCurrent

Technology

System DesignReview

Comments

ScientificDiscourse

Page 26: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 26

Operational Demands

MECA shall take account of:

• the high-level operation goals – e.g., safe return to earth

• the environment – e.g., radiation and social monotony

• task performance – e.g., people will get seriously ill

Page 27: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 27

Human Factors Demands

• Cognitive Task Load

• Situation Awareness and Sense Making

• Diversity of Cognitive Capacities

• Trust and Emotion

• Collaboration

• Crew Resource Management

• Decision Making

Page 28: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 28

Envisioned Technology (1)

habitatMEVhabitatfacility

MCC

Orbiter

crewrover

= meca unit

An infrastructure will be available for automatic distribution of data, software and reference documents.

Page 29: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 29

Envisioned Technology (2)

• MECA shall make use of this infrastructure and can cope with possible failures

• Continuous analysis and extrapolation of emerging technologies, e.g. – multi-agent systems– automatic planning and scheduling– model-based health management

• Technical requirements, such as– maturity– graceful degradation– maintainability– fault tolerance

Page 30: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 30

Requirements Baseline

Generic task level requirements

• Implement key Human Factor knowledge.• Enhance autonomy of individual actors and groups of

actors. • Support collaboration among the different actors. • Hardware and software systems must be highly reliable. • Manage environmental information.

Page 31: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 31

Current Requirements

• Different types of requirements:– task level, – functional, – user interface, – technical interface, – operational and – technical requirements.

• All requirements are linked to use cases.

Page 32: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 32

Use Case Template

ID 78

Title Hypothermic astronaut

Level Level 0

Goal Treat hypothermic astronaut that is on EVA…

Actor Personal MECA, MECA habitat, astronaut in habitat, rover..

Pre-condition Astronaut on EVA is hypothermic

Post-condition Hypothermic astronaut is in medical facility being treated

Frequency Not frequent

Main success scenario

Personal MECA detects hypothermia and communicates to hypothermic astronaut …

Alternative scenario

.. , Doctor is not in habitat, MECA will ask astronaut_1 to prepare…

Comment Derived from  RefDoc3…

Page 33: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 33

Outline of Functional Requirements

Process MECA function

Information Gathering detect needs for operations and training

Goal Setting select and prioritize goals for operations and training

Plan Generation or Selection generate plans, or select pre-generated plans and procedures, for operations and training

Plan Evaluation evaluate operational and training plans

Prepare for Execution prepare the resources for executing operational and training plans

Execution execute operational and training plans

Processing Evaluation of Results

evaluate execution results for operational and/or training purposes

Page 34: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 34

Incremental and Iterative Prototyping

• Human-, task- and context-driven design and evaluation.

• Both MECA and the humans will show mutual adaptive behaviour, which effects should be well tested with realistic scenarios.

• Prototyping, simulation and testing is therefore essential to establish a sound and coherent set of requirements.

• A game-based simulation environment can provide an effective platform for testing the human-machine collaboration (e.g. the Unreal Tournament game-engine) in combination with other simulators.

Page 35: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 35

Evaluation Criteria

• Long-term human in the loop effects• Standard usability measures

– effectiveness – efficiency – satisfaction – learnability

• Human experience measures, such as – situation awareness (perception, comprehension and

projection)– trust (persistence and behavioural competence,

servitude, and the understanding of the machine)– emotion (arousal and valence)

Page 36: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 36

Break?

• Break!

Page 37: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 37

Background

habitatMEVhabitatfacility

MCC

Orbiter

crewrover

= meca unit

Reasoning will involve complex system behaviorand scarce resources

Page 38: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 38

Background

• Time is a scarce resource• Control of a wide array of tasks and experiments• Control of each task and experiment is complex

– Nominal -- Correct sequence of steps– Off-nominal -- Detect, isolate, and compensate failures

• Summary: – Optimize crew time by supporting control activities

• Check plan execution• Support control of complex equipment especially in the case of

malfunctions• Resource usage

Page 39: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 39

Human decision making

Process UnderControl

Understand Act

•Situational awareness, e.g.:• Warning: At current rates, resources will be depleted within two days…

MECA Unit

• Must reduce load by 10% but must also generate more oxygen…• I lowered the consumption, but I still don’t see any change..

Complex, uncertain, and dangerous world

plan

Page 40: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 40

Traditional support

Operational procedure:

verify

action

Next action

okay

Notokay

off-nominal proceduresguided bymission control

Based on operational procedure and Mission Control

Page 41: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 41

Operational procedures

Nominal control

Off-nominal:Fault detection, isolation,repair

Operational procedures:•Huge pile of papers•No feedback of payload

Page 42: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 42

The 2017 MECA system

• The 2017 MECA system helps the astronaut to make the right decisions in situations that :– Are novel, or near-novel, e.g., because equipment is

failing– Are complex, e.g., effects of the decision are hard to

predict• Intricate interactions between processes, systems,

components, …• The effects are noticeable only late in time

– Require human--human and human--machine cooperation

Page 43: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 43

Automated support

Process UnderControl

Understand Act

MECAUnit

plan

•Improve situational awareness by interpretation measurement data, in particular: fault diagnosis

•Determine alternative plan (e.g., repair, reconfiguration)

•High level plan --> control action•Monitor plan execution

Page 44: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 44

Automated support

Validate success of plan step

Automatic fault detection and isolationAdequate repair procedurespresentation of background info

Automatic (re)plan

Page 45: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 45

Automated support

• Operational procedure is generalized by Actions of a Plan– Plan describes pre- and postconditions– Postconditions used for verification plan step and diagnosis

• Automated diagnosis

• Automated reconfiguration (repair, or redundancy management)

pre post pre post pre post

Supply pressure to fuel and oxidizer

Pb = high

Page 46: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 46

Layered Reasoning

Page 47: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 47

2017 MECA: Collaboration

Process UnderControl

Understand Act

PUC

Understand Act

I need your capabilities to repair the equipment

Resource level fromteam mate is enough tocomplete task…

Page 48: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 48

Plan-based Architecture

PUCstate

PUC

Health mode &

Resource

Healthestimation

Resourcemonitor

Plan representation

goal

subgoal subgoal

task task

Plan/schedule

Reconfiguresystem

PossibleActions,Safety

constraints,utility

Derivecapabilities

Goals

Page 49: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 49

MECA Unit Functional Decomposition

MMI

procedureexecutor

(PE)

what-ifsimulation &

rehearsal (PR)

executionmonitoring (SM)

sense-making

reconfiguration(CO)

physical equipment/facility interface (DA)

planning &scheduling

(PS)

derivecapabilities

(SA)

health &status

monitoring(FDIR)

inter-faceto

otherMECAunits

CTL

resourcemanager

healthmonitoring

plan

model

status+

history

collaboration

(simulated) PUC

other MECAunits

other MECAunits

usecases

Page 50: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 50

Software Architecture

Page 51: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 51

MECA 2017 is not MECA 2007!

For example MECA 2017 (‘Real’ MECA) MECA 2007 (Demonstrator)

Software Technologies Make generic choices: ontologies, agents, intelligent reasoning support.

Choose specific instantiations: OWL/RDF, Jade, Uptime.

Hardware Platforms Wearable / ubiquitous / brain-jack interface...

Tablet PC / Laptop.

Autonomy of components in Process under Control

Components can be independently autonomous (i.e. non-MECA intelligence).

No (interface to) 3rd-party intelligence, all autonomy implemented / controlled by MECA.

Reasoning Optimal combination of proactive and reactive.

Combination of proactive and reactive.

Unit complexity Completely hierarchical systems-of-systems nature of MECA Units.

Only simple aggregation and limited levels of containment for MECA Units.

Cooperation Adaptable to dynamic leadership, based on model on teamwork.

Limited models of teamwork.

Cognitive task load Aware of task load based on physiological sensors , imposed loads, and actual astronaut reactions.

Limit awareness of task load based on limited indicators.

Page 52: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 52

Challenge Areas

• Data Architecture: how to ensure worldviews of different levels of MECA Units remain compatible? How is the worldview represented?

• (Unit) Collaboration: how to synchronize, authenticate, de-conflict, negotiate work share, re-plan when two MECA Units ‘meet up’?

• Good interfaces will be key!

Page 53: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 53

Ontologies and reasoning

• Use ontologies to describe and reason about:– Design of MECA– Capabilities and Domains

• Equipment (PUC, Resources)• Environment• Tasks• Time• Communications• etc...

• Formal ontology representation allows:– automated validation of instance data– generation of documentation, templates, code– fit in with future “semantic web” approaches

Page 54: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 54

Ontology example

@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .@prefix meca: <http:///esa.int/meca#> .

# OWL Classes:

meca:Unit a owl:Class ;

# Owl Properties:

meca:isPersonalUnit a owl:DatatypeProperty; rdfs:domain meca:Unit; rdfs:range xsd:boolean .

meca:autonomyMode a owl:ObjectProperty; rdfs:domain meca:Unit .

meca:synchronisationPolicy a owl:ObjectProperty; rdfs:domain meca:Unit.

Page 55: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 55

Planning & Scheduling - Design Concepts

• Mission objectives are predefined, and default general plans are arranged before mission begins.

• Short term goals and plans will be decided and controlled autonomously by crew during the mission, adapting to changing circumstances.

• Continuous planning, scheduling and rescheduling of the tasks assigned to a heterogeneous team is a complex process that consumes time and determines the chances of success.

• MECA should assist in the generation of plans, reduce the overload of crewmembers, check constraints and conditions, and optimize the usage of time and resources.

• Crewmembers should have quick and easy access to all information related with plans, be able to evaluate alternatives and make changes.

Page 56: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 56

Planning & Scheduling - External Interfaces

Page 57: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 57

Planning & Scheduling - Internal Components

• Rule system: editable by users, enabling explanation of decisions• Inference Engine: using Rules to generate and optimize Plans and Schedules• Representation: in a format that facilitates distribution & collaboration

Page 58: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 58

Demonstrator – First Design Iteration

• Decompose scenario into Sequence Diagrams (bring time dimension into play, identify actors)

• Decompose scenario into Activity / State Diagrams

• Illustrate actor timelines with storyboards

• Identify order and depth to which storyboards are to be implemented

Page 59: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 59

Demonstrator – Software Proposals

• Application Framework: Use EADS Java Framework for personal MECA Unit GUIs.

• Use Jade for implementing agent-aspects of Units themselves.

• Use Uptime for Model-Based Programming: autonomous planning, reconfiguration and fault diagnosis.

• Use RDF/XML+OWL for Knowledgebase.• Use Students’ models for PuC Components• ...

Page 60: Www.CrewAssistant.com 1 The MECA Project Reasoning Agents on Mars Leo Breebaart (S&T) 12 October 2006.

www.CrewAssistant.com 60

Questions?

Photo: E

SA

/Aurora