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O N T R O L LE D D O U M E N TUNCLASSIFIED - UNLIMITED

QINETIQ/S&DU/SPACE/URD0601962/0.d Page 1 of 1Baseline Requirements Document UNCLASSIFIED - UNLIMITED 02 February 2007

O N T R O L LE D D O U M E N T

Baseline Requirements Document

Title: Mars Energetic Radiation Environment Models (MEREM) - BaselineRequirements Document

Document reference QINETIQ/S DU/SPACE/URD0601962/0.dProject reference: Parent project: QINETIQ/KI/SPACE/20/258

Prepared by: Dr Dave Rodgers, Dr Fan Lei & Dr Pete Truscott

Signature:

Date:

Authorised by: Dr Petteri Nieminen

Signature:

Issued by:Sector/location/telephone/fax:

Security & Dual-Use Sector, Space DivisionRoom G081, A8 Building

QinetiQ, FarnboroughTel: 01252 393290 Fax: 01252 396330

AbstractThe general baseline requirements are presented for Mars Energetic Radiation Environment Model(MEREM) software tool which will be used to predict the radiation environment in Martian orbits, aswell as on the surface of the planet and its moons.

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Page 2 of 2 QINETIQ/S&DU/SPACE/URD0601962/0.d02 February 2007 UNCLASSIFIED - UNLIMITED Baseline Requirements Document


Record of changesThis is a controlled document. Additional copies are obtained through the issuing authority. In theevent of copying locally, including electronically, mark each document Uncontrolled Copy. Fullissues and page amendments are identified on this page. Forward proposals for change in writing tothe issuing authority.

Issue Date Detail of changes0.a0.b0.c0.d

17 August 200623 September 200614 January 200702 February 2007

First draft for discussion at technical progress meetingUpdated draft following QPM comments

Updated following comments from Ana Keating

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Table of contents

1 INTRODUCTION 41.1 Contractual 41.2 Purpose of the Document 41.3 Background 41.4 Scope of the Software 41.5 Definitions, acronyms and abbreviations 41.6 References 52 REQUIREMENTS ANALYSIS 62.1 Functions and performance 72.2 Operational and maintenance requirements 102.3 Verification and validation requirements 113 DESIGN CONSTRAINTS 124 CRITICAL FUNCTIONS 125 LOWER LEVEL SOFTWARE ENGINEERING STANDARDS 126 SYSTEM PARTITIONING 12

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1 Introduction1.1 ContractualThis baseline requirements document has been issued by QinetiQ Ltd for ESA/ESTEC under contract19770/06/NL/JD (ESA Technology Research Programme).

1.2 Purpose of the DocumentThis document describes the baseline requirements for the Mars Energetic Radiation EnvironmentModel (MEREM) software tool which will be used to predict the radiation environment in Martianorbits, as well as on the surface of the planet and its moons.

1.3 BackgroundThe role of the MEREM (Mars Energetic Radiation Environment Model) software is to permit the

assessment of the Martian radiation environment for orbital spacecraft and Mars planetary andmoon landers or habitats. Hence consideration needs to be given to environmental factors thataffect biological matter (especially people) and equipment, both in Martian orbits and on the surfaceof the planet or its moons.

When being used for mission analysis, the results of MEREM will normally be fed into detailedsimulations to generate estimates of doses, displacement damage, SEU rates, biological doseequivalents etc. As part of the SPENVIS system, MEREM will be able to export its results directly intovarious pre-existing simulation tools.

It is intended that the users of MEREM should ultimately be mission designers and planners, as wellas space radiation effects scientists. However, it is noted that the software is, at the request of the

Customer, to be based on the Geant4 radiation simulation toolkit, which is more accuratelyconsidered as an advanced research tool.

1.4 Scope of the SoftwareThe envisaged software will provide new physics simulation in the Geant4 radiation transport toolkit.It is intended that these be used with Geant4 v8.2 or later [??].

1.5 Definitions, acronyms and abbreviationsESA European Space Agency

ESTEC European Space Technology Centre

Geant4 C++ toolkit for Monte Carlo simulation of high-energy, fundamental particletransport, developed by an international collaboration led by CERN.

GUR general user requirement

OO object-oriented

UR user requirement

URD User Requirements Document

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1.6 References[1] ECSS-E-40 Part 1B: Space engineering - Software - Part 1: Principles and requirements

[2] ECSS-E-40 Part 2: space engineering - Software Part 2: Document requirements definitions(DRDs)

[3] Statement of work: MarsREM, ESA ITT/A0/1-4944/05NL/JD, 2005

[4] Proposal: MarsREM Martian Radiation Environment Models,QinetiQ/S&DU/SPACE/BID051997, 2005

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2 Requirements analysisThis requirements analysis follows the procedure described in the ECSS standard for spaceengineering software [1,2], as tailored by the statement of work [3] for this project.

Figure 1 shows the first-level decomposition of the applications that will form the MEREM system,and these applications are cross-referenced to the different requirements in the subsequent sectionsof this document. The term MEREM framework refers to the interface and graphing applications(idMEREM, ieMEREM, GA), as well as other input data used to help define source particle andgeometry conditions. Note that this figure is not intended to be exhaustive, and so does not includeall details of the inputs to and outputs from the MEREM applications, which will be defined in thesoftware design.

MEREM framework (Spenvis-based)

idMEREMGraphical User

interface for dMEREM

ieMEREMGraphical User

Interface for eMEREM

GASpenvis graphing

applications

dMEREM

application

eMEREM

application

CSV Spenvis-formatdata files

Source particle data

Atmospheric +

Geology data

Figure 1: Definition of the different utilities and applications forming the Mars Energetic RadiationEnvironment Model (MEREM).

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2.1 Functions and performanceUR ID Description of Requirement Importance ModuleUR 1 The software shall calculate the radiation environment

of Mars arising from both primary particles of galacticand solar origin and the secondary particles producedfrom the interaction of primary particles with matter inand around Mars.

Essential e & dMEREM

UR 2 The software shall provide rapid assessment of differentmission options

Essential eMEREM

UR 3 The software shall provide accurate analysis for specificcases

Essential dMEREM

UR 4

4.14.24.3

The software shall provide the radiation environment:

In Mars OrbitOn the Martian surfaceOn the surfaces of the Martian moons (the environmentshall be averaged over the surface of the moon ratherthan a surface dose-map).

Essential

e & dMEREMe & dMEREMdMEREM

UR 5

5.15.2

5.3

5.45.55.65.75.8

The software shall model the dependence of theradiation environment on:

Solar cycle phaseOrbit (for orbital environments)

Surface latitude, longitude and altitude (for surfaceenvironments)Space weather conditionsSurface climateSurface weather conditionsLocal magnetic field*Variations in surface composition

EssentialEssential

Essential

EssentialEssentialDesirableDesirableEssential

e & dMEREMe & dMEREM

dMEREM

e & dMEREMe & dMEREMdMEREMdMEREMdMEREM

UR 6 The software shall model the dependence of theradiation environment on the Martian orbital positionaround the sun

Desirable eMEREMdMEREM

UR 7

7.17.2

7.37.47.57.6

The software shall take at least the following user inputparameters:

DateDuration of exposure, e.g. number of orbits or time spenton surfaceSurface location on Mars (for surface environments)Spacecraft orbit (for orbital environments)Space weather index e.g. solar wind velocityUser-defined surface composition

EssentialEssential

EssentialEssentialEssentialEssential


e & dMEREMe & dMEREMe & dMEREMeMEREM

*Considered important for electron contribution to dose.

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UR ID Description of Requirement Importance ModuleUR 8

8.18.28.38.48.5

Outputs from the software should include the followingdata:

Neutron / proton flux spectrum as function of energyIon flux spectrum (including protons) as function of LETElectron flux spectrum as function of energyX-/-ray flux spectrum as a function of energyShort-lived particles (e.g. Muons and Pions)

EssentialEssentialEssentialEssentialDesirable

e & dMEREMe & dMEREMe & dMEREMe & dMEREMe & dMEREM

UR 9

9.1

9.2

9.3

The software shall output the radiation environment dueto primary and secondary particles:

The fluxes or dose due to the combined primary andsecondary populationsPrimary radiation populations

Secondary radiation populations (including albedo fromthe surface and atmosphere)

Essential

Essential

Essential

e & dMEREM

dMEREM

dMEREM

UR 10 The software shall output data concerning the directionof radiation populations, i.e. flux as a function of energyand angle for the different populations

Desirable e & dMEREM

UR 11 There shall be a module providing a graphical userinterface

Essential ieMEREM &idMEREM

UR 12 The software shall be easy to use for mission designersand planners

Essential eMEREM

UR 13 The software service shall be web-based Essential MEREMframework

UR 14 There shall be a module defining the primary radiationenvironment in the vicinity of Mars.

Essential MEREMframework

UR 15

15.115.2

15.3

Primary sources of radiation shall include:

Galactic Cosmic RaysSolar Energetic Particles (This will be linked with the ESASEPEM contract activity if possible, but as a baseline, 1/Rvariation will be used provisionally with appropriatewarning provided)Solar X-rays (Digitised versions of example flares?)

EssentialEssential

Essential


dMEREM

*

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UR ID Description of Requirement Importance ModuleUR 16

16.116.216.316.416.5

There shall be a module defining:

The Martian atmosphereThe Martian surface topologyThe Martian geologyThe Martian climateThe geology of Martian moons

EssentialEssentialEssentialDesirableEssential

e & dMEREMdMEREMe & dMEREMe & dMEREMdMEREM

UR 17 There shall be a module calculating the modification ofthe primary environment and the production ofsecondary radiation components through interactionwith the Martian atmosphere and with surfaces.


UR 18 The software shall be interfaced with existing radiation

shielding and effects simulation tools at the SPENVISweb-site


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2.2 Operational and maintenance requirementsUR ID Description of Requirement Importance ModuleUR 19 The code shall be capable of being operated as part of the

SPENVIS system


UR 20 For detailed analysis, requiring long simulation times,scripts shall be able to be downloaded from SPENVIS to alocal machine so the software can be run there.


UR 21 Where possible, existing SPENVIS modules shall be usede.g. for defining the primary populations.


UR 22 The code shall be maintained to the end of the study,including the warranty period.

Essential MEREMframework +e & dMEREM

UR 23 The software shall be modular, allowing the separateupdating of modules for:

GUI Primary radiation environment Atmospheric and surface models Radiation simulation engine

Essential MEREMframework +e & dMEREM

UR 24

UR 24.1UR 24.2

Communication between modules shall be via data filesof well-defined formats.

G4 user-Interface (UI) commandsSPENVIS CSV-format


UR 25 The interface between modules shall be defined in theInterface Control Document.

Essential MEREMframework + e& dMEREM

UR 26 The software shall be expandable to allow additionalprimary environment models and additional surface oratmospheric models to be introduced.

Desirable e & dMEREM(eMEREM means newdatabase)

UR 27 The software simulation software shall be based on thelatest Geant4 toolkit release (currently version 8.2) or use

physics simulation results from the toolkit.


UR 28 The simulation models shall operate under Linux OS andg++ compiler recommended for use with the Geant4release.


UR 29 The software shall be maintained for two years followingdelivery.


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2.3 Verification and validation requirementsUR ID Description of Requirement Importance ModuleUR 30 Verification and validation shall take place in accordance

with ECSS-E-40A.

Essential MEREM

Framework + e& dMEREMUR 31 Validation shall include comparison between the rapid

and detailed analysis techniques.Desirable e & dMEREM

UR 32 Validation shall include comparison with results ofanother radiation transport code.


UR 33 The code shall be accepted after completing anacceptance test that demonstrates the correct operationof key aspects of the code.


UR 34 The user shall have visibility of the software source code. Essential e & dMEREM

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3 Design constraintsThe MEREM software will be run as part of the SPENVIS suite. This involves constraints on the inputand output of data (UR19) which are expected to follow the standard SPENVIS formats.

Requirements UR2 and UR3 are not expected to be compatible in the light of feasible run times forexisting commonly available computers. Hence it is envisaged that two key applications will performthe computations to fulfil the requirements for radiation environments other than UV:

dMEREM for detailed analysis of individual cases.

eMEREM for rapid assessment of many cases.

It is possible that the user interfaces (idMEREM and ieMEREM) may share common elements (e.g.webpages), and the distinction between the two is used in order to clarify function rather than content.

As a hosted system, SPENVIS is not an appropriate location for running very long simulations and sothe capability to download scripts (UR20) to be run on the local machine is important for detailedanalysis.

The ultraviolet radiation environment shall be a consideration from the literature review andtechnical reporting during the contract. It is understood from discussions between the ESA TechnicalOfficer and LIP staff that this, rather than the development of a specific software application, was theinitial intention of the Statement of Work.

4 Critical functionsThere is a requirement that the software be based on the Geant4 toolkit (UR27) this software isitself is an evolving software toolkit developed by academic research institutes, and not intended tobe used to safety-critical applications. The MEREM system software is therefore not part of a safety-critical system for missions and so there are no specific requirements on reliability of the code arisingfrom critical systems. It is expected that the role of the code in design and planning will be overbefore a mission is launched.

5 Lower Level software engineering standardsThere are no specific requirements regarding computer languages or protocols.

6 System partitioningSubdivision of the software into components as expressed in UR11, UR 14, UR 16 and UR17 requiresthe separate modules for, GUI, primary radiation environment, atmospheric and surface models, andradiation simulation engine (see introduction to section 2).

Because the number of software modules is small, a system configuration items list is not required.

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WP2100 brd v0.d.pdf