14 th April 2007 Space Robotics Workshop ICRA071 The Rover Concept for the ESA ExoMars Mission...

14th April 2007Space Robotics Workshop

ICRA07 1

The Rover Concept for the ESA ExoMars Mission

IEEE-ICRA 2007 workshop on Space RoboticsRome, 14 April 2007

G. Gianfiglio, M. van Winnendael, J. Vago, P. Baglioni (European Space Agency)F. Ravera (Alcatel Alenia Space Italia) L. Waugh - EADS Astrium Ltd (UK)


ICRA07 2

The Rover Concept for the ESA ExoMars MissionComplementary Remarks

By L. Joudrier ESA-Robotics Section

Automation and Robotics Section (TEC-MMA)


ICRA07 3

Forewords

Presentation of Rover – see proceedings for the mission details

All material presented is subject to change due to the on-going and coming industrial studies.

Additional pieces of information aiming to be potential seeds for discussions during this workshop.


ICRA07 4

Presentation Outline Forewords ExoMars Mission

Objectives Status Overview

ExoMars Rover Current baseline Vehicle overview Payload Support Equipment Pasteur Payload Surface Operations RHUs & Planetary Protection

Considerations about the ExoMars Rover Locomotion subsystem Navigation Autonomy Planetary Protection


ICRA07 5






ICRA07 6

Mission Objectives ExoMars is the first ESA led robotic mission of the Aurora

Exploration Programme, combining demonstration of key enabling exploration technologies with major scientific investigations

Main technology demonstration objectives:

Safe Entry, Descent and Landing of a large size payload (Descent Module)

Surface mobility (Rover) and access to the subsurface (Drill)

Main scientific objectives:

Search for traces of past and present life and characterize

Martian chemistry and water distribution

Improve the knowledge on Martian environment and identify

surface hazards to future human missions


ICRA07 7

Mission Status

Phase B1 on-going

Started in October 2005 with AAS-I as Prime Contractor

Extended to consider several options.

Selection of Major sub-contractors is completed.

ASTRIUM UK responsible for the rover

Selection of sub-contractors completed soon

SRR just completed

Implementation Review is next (May 2007)

Phase B1 to be completed by end of 2007

Integrated Locomotion-Navigation Rover Prototype

Launch date: 2011 unlikely so target is 2013 with back up 2015/2016 launch opportunity.


ICRA07 8

Mission Overview

Launch a Descent Module to Mars with supporting spacecraft infrastructure for LEOP and Cruise Phase

Baseline: (Carrier + DM + Rover) Soyuz from Kourou + MRO Option 1: additional Soyuz for a relay orbiter (MRO back-up) Option 2: Ariane5 for ExoMars + carrier upgraded as orbiter (MRO back-up)

Release Descent Module into Mars atmosphere for automatic Entry, Descent and Landing (EDL) on Mars surface

Latitudes between –15º and +45º, all longitudes / Altitude ≤ 0 m relative to the MOLA zero level Option: vented / non-vented airbag landing system

Egress of the Rover from the landed module

Accomplish Rover surface operations

180 sols minimum, 10 experiment cycles, ~1km distance between experiment

locations


ICRA07 9






ICRA07 10

Rover Current Baseline

Concept with RHUs Concept without RHUs

Mass ~ 180 kg (including Drill, SPDS and ~8kg Pasteur Payload) Average Power ~ 120 W (by Solar Array assuming RHUs

availability) X-band communication link for DTE and UHF band for Proxi-link

with MRO Two Thermal Control solutions still under trade-off: with and

without RHU’s


ICRA07 11

Rover Vehicle Locomotion

6 wheels chassis TTC

X-band for DTE• 2 redundant transponders • 2 redundant SSPA• 1 RFDN• 1 Small HGA (30cm dish, 24dBi

gain) UHF band for data relay with MRO

• Internal redundant Proximity-1 compliant transponder

• 1 LGA (quad helix)• 1 RFDN

Power Solar Arrays Battery (Rechargeable, Li-Ion) PCDU

Thermal Control System (TCS) Two options under trade-off (with and

without RHUs) Loop Heat pipes, Radiators, Passive

Thermal Switches

Navigation Cameras (Nav. Cam, Haz. Cams) Navigation sensors Navigation Software (CNES)

Structure Integrated units Deployable mast for Cameras, IR

Spectrometer and sensors SA support and mechanisms


ICRA07 12

Subsurface drill includes a miniaturised IR spectrometer for borehole investigations (Ma_Miss DIBS)

Drill Box

Drill BoxPositioner

Surface Rock Corer

Surface Rock Corer Positioner (Arm)

Drill Box

Drill BoxPositioner

Surface Rock Corer

Surface Rock Corer Positioner (Arm)

Payload Support Equipment Sample Acquisition System – To obtain surface and subsurface samples for analysis;

includes a subsurface drill with rod exchange and positioning mechanism & a sample delivery mechanism, plus a surface rock corer (TBC)

SPDS – To prepare and present samples to all analytical lab instruments; includes distribution mechanisms and a milling station


ICRA07 13

Rover Scientific Payload: Pasteur

Analy

tica

l Lab

.

Conta

ct

Suite

Rem

ote

CONTEXT

- PanCam- IR Spectrometer- Ground Penetrating Radar

- Close-up Imager- Mössbauer- Raman-LIBS external optical heads

- Microscope IR- Raman - LIBS Spectrometers- XRD

ORGANICS/LIFE

- MOD/MOI - GC-MS - Life Marker Chip

ENVIRONMENT

- Dust & H2O Vapour Suite- Ionising Radiation- UV Spectrometer- Meteo Package

INSTRUMENTS SUPPORT

EQUIPMENT

Drill System(Surface and 2 m depth)Includes Borehole IRS

Sample Preparation & Distribution System

(SPDS)

To be accommodated into GEP

The instruments development is under the responsibility of relevant National Agencies

The current total mass of the Pasteur Payload Instruments exceeds the 8 kg allocation: if necessary instruments de-scoping will be implemented in line with the available resources (Payload Confirmation Review)


ICRA07 14

Rover Surface Operations

The Surface Mission is composed of a sequence of Experiment Cycles (up to 10)

An Experiment Cycle consists of:

Identifying the location at which to perform the Measurement Cycle (from Ground Control)

Traveling to the new location (distance about 1 km between locations)

Performing a full Measurement Cycle using all instruments

Transmitting scientific, housekeeping and navigation data to the Relay Orbiter/Earth (Data volume ~ 1Gbit per Experiment Cycle) During night the Rover goes into a

sleep mode and resumes operations the following day


ICRA07 15

Planetary Protection &

Radio-isotope Heating Units

RHUs: Accommodation/location inside the internal enclosure is subject to trade-off between easy late access, proper heat distribution and interfaces with the Rover TCS

Planetary Protection: ExoMars is a class IVc mission allowing to search for past life and organic molecules in “special regions”. This is a major driver of the mission design, AIV, especially considering possible need of late access due to RHUs.The sterilization concept is under study.The PP mission class may be revised into IVb class (TBC).


ICRA07 16






ICRA07 17

Locomotion Subsystem 1/2

ExoMars current baseline is the RCL-type E with formula 6*6*4+4W

Simple and light weight design passive articulated suspension

No internal averaging mechanism

Wheel-walking/peristaltic mode possible allowing highest mobility (Reuse of the motors necessary for deployment)

BUT

Static stability issue depending of CoG (40 deg requirement)

Eventually less performing compared to other concepts (Type D, Crab, R-bogie)

Possible improvements:

Formula 6*6*6+4W or 6*6*6+6W

RCL Type-D

RCL Type-E


ICRA07 18

Locomotion Subsystem 2/2

ExoMars mobility requirements:– 25 cm step obstacle

– 25 deg slope on specific soil

– 40deg stability any direction

Improvement of traction & obstacle crossing capabilities:– Use of terramechanics to define optimum wheel design (Single Wheel Testbed built within

R&D activity “Rover Chassis Evaluation Tools”)

– Possible use of flexible wheels [Richter ASTRA06]

– Improved design of articulated suspension via simulation tools and prototyping.

Optimising the mass and power requirements remains a challenge at the expense of the scientific payload and desirable higher locomotion capabilities. Locomotion risks due to unknown rough terrain are mitigated by high locomotion capabilities and (conservative) navigation.


ICRA07 19

NavigationBaseline is the use of the CNES Autonomous Navigation Software.

Accurate localisation is key. Visual Odometry & target tracking are required.

Solutions to definition target coordinates on ground by PIs to be experimented.


ICRA07 20

Autonomy

ExoMars will require high degree of autonomy : Ground Control Staffing, amount of Telemetry to download, large distance traverses.

At least level E3 on the ECSS E70 autonomy scale (event driven reactive systems with some re-planning).

ESA Relevant R&D Activities (non exhaustive):

ESA Functional Reference Model (FRM) based on a 3-layered controller

architecture (Mission-Task-Actions) equivalent to deliberative-executive-functional

layers.

MUROCO: Formal specification and verification Tool [Kapellos-ASTRA06]. Use

ESTEREL formal language to specify/Verify the rover behaviour (state machine

composing the actions and tasks).

MMOPS: On-board planning/re-planning and scheduling tool [Woods-ASTRA06]

On-board model checking (just started) will allow advanced FDIR.

3DROV (on-going): full planetary rover simulator


ICRA07 21

Planetary Protection

Based on the facts that: During AIV process, 80 % of the bio-burden is brought by the AIV operators. Sterilisation “kills the spores but does not remove the bodies” that may trigger organic molecule sensitive sensors designed to detect traces of past life.

ESA has initiated a feasibility study on Robotized AIV that would allow to reduce to the minimum the number of operators in the AIV clean rooms.

Robotized AIV is very challenging activity where space robotics and Earth state of the art robotics would be joined.


ICRA07 22

Conclusion

ExoMars mission and rover current baselines have been briefly presented.

They will evolve along with the industry work.

Some relevant ESA R&D activities about rover have been presented to provide inputs to the discussion

14 th April 2007 Space Robotics Workshop ICRA071 The Rover Concept for the ESA ExoMars Mission...

Documents

Transcript of 14 th April 2007 Space Robotics Workshop ICRA071 The Rover Concept for the ESA ExoMars Mission...