Appendix 1 to ITT 1-7010/11/NL/NAemits.esa.int/emits-doc/ESTEC/AO7037_RD2ews7010.pdf ·...

ESA UNCLASSIFIED – Releasable to the Public

Appendix 1 to ITT 1-7010/11/NL/NA

European Space Agency Agence spatiale européenne

ESTEC

Keplerlaan 1, PO Box 299, 2200 AG Noordwijk zh, The Netherlands

Tel: +31 71 565 6565 Fax: +31 71 565 5060

European Space Agency

Directorate of Technical and Quality Management

STATEMENT OF WORK

Zero Boil-Off Propulsion System Feasibility Demonstration

Reference:

TEC-MTT/2011/3762/ln/THT

Issue: 1, Revision 0

16.06.2011

ESA UNCLASSIFIED – Releasable to the Public Statement of Work Issue: 1 Zero Boil-Off Propulsion System Feasibility Demonstration Revision: 0 Date: 16.06.2011


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Table of Content

1 INTRODUCTION......................................................................................................................................... 3

1.1 SCOPE OF THE DOCUMENT ....................................................................................................................... 3 1.2 APPLICABLE AND REFERENCE DOCUMENTS ............................................................................................ 3

1.2.1 Applicable Documents (ADs) .......................................................................................................... 3 1.2.2 Reference Documents (RDs) ........................................................................................................... 3

1.3 ACRONYMS AND ABBREVIATIONS............................................................................................................ 4

2 BACKGROUND AND OBJECTIVE(S) ..................................................................................................... 5

2.1 BACKGROUND.......................................................................................................................................... 5 2.2 OBJECTIVES OF THE ACTIVITY.................................................................................................................. 5

3 WORK TO BE PERFORMED.................................................................................................................... 6

3.1 WORK LOGIC ........................................................................................................................................... 6 3.2 TASK DESCRIPTIONS................................................................................................................................ 7

3.2.1 Transversal Tasks............................................................................................................................ 7 3.2.2 Task 1: Consolidation of Requirements and Preliminary ZBO System Designs. ............................ 8 3.2.3 Task 2 Detailed ZBO System Designs ........................................................................................... 10 3.2.4 Task 3 Manufacturing and Test Preparation ................................................................................ 11 3.2.5 Task 4: Tests and Exploitation ...................................................................................................... 13

4 REQUIREMENTS FOR MANAGEMENT, REPORTING, MEETINGS AND DELIVERABLES .. 14

4.1 MANAGEMENT....................................................................................................................................... 14 4.2 REPORTING ............................................................................................................................................ 14 4.3 MEETINGS.............................................................................................................................................. 14 4.4 DELIVERABLES ...................................................................................................................................... 15

4.4.1 Documentation .............................................................................................................................. 15 4.4.2 Hardware ...................................................................................................................................... 17 4.4.3 Computer Programs and Models .................................................................................................. 18

4.5 COMMERCIAL EVALUATION................................................................................................................... 18

5 SCHEDULE AND MILESTONES............................................................................................................ 18

6 AGENCY UNDERTAKINGS.................................................................................................................... 19

6.1 CUSTOMER FURNISHED ITEMS ............................................................................................................... 19

ANNEX 1: TECHNICAL SPECIFICATION .................................................................................................. 20



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1 Introduction

1.1 Scope of the Document

This document describes the activity to be executed and the deliverables required by the European Space Agency in relation to Zero Boil-Off Propulsion System Feasibility Demonstration.

It will be part of the contract and shall serve as an applicable document throughout the execution of the work. 1.2 Applicable and Reference Documents

1.2.1 Applicable Documents (ADs)

AD1: ECSS-E-ST-31C Thermal Control

1.2.2 Reference Documents (RDs)

The following documents can be consulted by the Contractor as they contain relevant information (ECSS standards can be accessed via www.ecss.nl):

RD1: CDF-47(A) CDF Study Report Long Term Cryogenic Propulsion for Interplanetary Missions

RD2: CDF-20(A) CDF Study Report Human Mission To Mars RD3: ECSS-E-10-03A Space Engineering: Testing

http://www.ecss.nl/



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1.3 Acronyms and abbreviations

AOCS Attitude and Orbit Control Subsystem DDR Detailed System Design Review GMM Geometrical Mathematical Model KO Kick Off LEO Low Earth Orbit LOX Liquid OXygene MLI Multi-Layer Insulation PA Product Assurance PDR Preliminary System Design Review SoW Statement of Work TCS Thermal Control Subsystem TN Technical Note TMM Thermal Mathermatical Model TRP Technology Research Program TRR Test Readiness Review ZBO Zero Boil-Off



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2 Background and Objective(s)

2.1 Background

The high Specific Impulse of Cryogenic propulsion (Liquid Oxygen + Liquid Hydrogen or Liquid Methane) makes it a natural candidate for missions with high Delta V requirements (e.g Outer Solar System missions, manned exploration missions). However, the current evaporation loses of such cryogens limit the spectrum of attractive scenarios to relatively short duration missions.

The purpose of a Zero Boil-Off System is to reduce or even suppress the losses due to the venting of evaporated cryogenic fluids. The basic principle is to use a combination of passive insulation (reduce thermal bridges) and active cooling, in order to increase the payload capability of the mission.

A Zero Boil-Off System is composed of:

4 1 - Radiative Insulation. - Active Cooling

- Heat Transportation System.

- Multi-staging

5 2 - Conductive Insulation

3 6 - Passive Cooling

7 - Propellant Management Device

Note: The Propellant Management Device being a complex problem on its own it shall not be considered part of the study.

The recent technical progress in active cooling and the new exploration initiatives create an increase of interest for such a system that may enable certain mission profiles.

2.2 Objectives of the activity

The first objective of this study is to define Zero Boil-Off architectures relevant for two reference scenarios:

1. Long Term Cryogenic Propulsion for Interplanetary Missions.



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2. Human Exploration

The second objective of the activity is to design and test one subscale demonstrator that shall alleviate critical technical points of both architectures as well as putting together a development plan for such a technology.

3 Work to be performed

The tasks presented hereafter shall be considered as a overall work plan. The contractor shall undertake any activity that is necessary to obtain, demonstrate or consolidate the requirements described in Annex 1.

3.1 Work Logic

The Zero Boil-Off Propulsion System Feasibility Demonstration shall be separated into 4 sequential tasks, each concluded by a review:

- Task 1: Consolidation of requirements and Preliminary ZBO Systems Designs.

o Subtask 1.1: Analysis of the two scenarios and consolidation of requirements.

o Subtask 1.2: Review of architectures, trade-offs and preliminary designs.

Preliminary ZBO System Design Review

- Task 2: Detailed ZBO System Designs

o Subtask 2.1: Detailed ZBO System Architectures Definitions

o Subtask 2.2: ZBO Demonstrator Definition, preliminary Test Plan.

Detailed ZBO System Design Review

- Task 3: Manufacturing and Test Preparation

o Subtask 3.1: Detailed Test Plan

o Subtask 3.2: Manufacturing of the ZBO System Demonstrator and the Test Bench.

Test Readiness Review

- Task 4: Tests and Exploitation

o Subtask 4.1: Testing, exploitation of the results, correlation and application to the two identified scenarios.

o Subtask 4.3: Establishment of Work Plan for Further developments and recommendations

Final Presentation



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3.2 Task Descriptions

3.2.1 Transversal Tasks

3.2.1.1 Task 0.1: Management

Within this task, the Contractor shall carry out the management tasks described in the section 4 of the present Statement of Work. These tasks shall cover all work-packages mentioned below.

The Contractor is fully responsible for the management of possible sub-contractors and good distribution of the information inside the team in the frame of this activity.

3.2.1.2 Task 0.2: Product Assurance/Quality Assurance

No specific PA has been defined considering the nature of this activity. Nevertheless the bidder shall identify and implement a minimum set of PA activities to assess any manufacturing or test process for their future use in a final product. Tracing of unexpected problems or major non-conformances is considered as normal work.



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3.2.2 Task 1: Consolidation of Requirements and Preliminary ZBO System Designs.

3.2.2.1 Subtask 1.1: Analysis of the Scenarios and Consolidation of the Requirements

Input:

SoW.

Subtask description

During this Subtask, the contractor shall consolidate the requirements listed in Annex 1. The following activities shall be undertaken:

1) The contractor shall investigate, via bibliography or other ways, past and ongoing Zero Boil-Off System studies worldwide. The survey shall include ZBO Systems applied to propulsion, but also other applications (e.g. long life cryostat). As a minimum, the following questions shall be answered:

o For which application is this ZBO system designed?

o What is the mission profile (duration, thermal environment) of the application?

o What are the main components of the ZBO system?

o What are the mass and power budgets of the ZBO system?

o What are the expected/measured performances of the ZBO system?

o What are the maturity levels of the ZBO system and its components? What are the foreseen development plans for those ZBO systems currently?

2) The contractor shall define the main functional and design propulsion requirements for interplanetary and human exploration mission.

3) The propulsion specifications shall be flown down at Tank Configuration and Thermal Control Hardware level to define ZBO requirements.

For the execution of this subtask and to ensure that the effort is not excessive, the Agency provides as inputs two reference scenarios described in Appendix 1. The scope of this subtask shall be to review those inputs and to refine them as necessary for the remaining part of the study which focuses on the Thermal Related aspects of the ZBO System Architectures.

Output / Approval conditions: The following document shall be delivered for approval by the Agency at the end of this Subtask:

TN1: ZBO System: State of the Art Review.



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TN2: ZBO System: Review of Propulsion System, Scenarios and Requirements.

3.2.2.2 Subtask 1.2: Review of ZBO Architectures, Trade-offs and Preliminary Designs.

Input:

TN1, TN2

Subtask description

During this subtask, the contractor shall assess all the potential concepts of ZBO architectures that can meet the requirements and the mission scenarios described in TN2.

The activities of this work package shall include:

1) A review of the possible technical solutions applicable to ZBO systems in the following domains shall be made:

a. Thermal Insulation (conductively, radiatively).

b. Cooling solutions (e.g radiators, cryocoolers, vapour cooling).

c. Parasitics Interception (e.g. multi-staging)

d. Heat Transportation and re-condensation.

The Propellant Management is not part of this activity the Contractor shall use the Propellant ullage assumptions described in Annex 1.

2) For each of the two scenarios, one ZBO architecture shall be chosen, described and justified with preliminary thermal assessments.

3) In order to justify the trade-offs, a parametric spreadsheet-like model shall be created that shall permit to roughly size ZBO systems (mass, power consumption) depending on the mission (thermal environment, dimension of the tanks, duration). This critical deliverable shall permit to evaluate ZBO architectures during feasibility studies.

Output / Approval conditions: The following documents shall be delivered for approval by the Agency at the end of this Subtask:

TN3: ZBO System: Preliminary Architecture Definitions. SW1: ZBO Parametric Model.

At the end of this activity, a Preliminary ZBO System Design Review shall take place. The Data Package of this review shall include the previously established Technical Notes and Models:

PDR Data Package: TN1, TN2, TN3, SW1.



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3.2.3 Task 2 Detailed ZBO System Designs

3.2.3.1 Subtask 2.1: Detailed ZBO System Architectures Definitions

Input:

SoW

TN1, TN2.

Task description

Within this activity, the Contractor shall perform a detailed design of the two ZBO System Architecture approved by the Agency. As a minimum, following work shall be part of this task:

1) The contractor shall perform the Detailed Design of the selected Architectures, supported by necessary analysis (thermal, mechanical, CFD…). The objective is to refine the preliminary architectures identified in Task 1, close all the remaining trade-offs and define (with requirements or identified items) each component of the ZBO System (e.g. insulation, coolers). The information shall be compiled in a technical note that shall also include detailed ZBO System Budgets.

2) The Contractor shall identify the driving parameters for the architectures by performing sensitivity studies on the relevant interfaces requirements (e.g. attitude, conductive interface temperature etc.). If the impact of a parameter on the ZBO System budgets is significant, recommendation for solution at System level shall be issued.

3) A Development Plan describing the critical technical points to be validated shall be written. This note shall clearly identify the feasibility issues and the recommended way to alleviate them. A special focus shall be made on the points to be tested by the Demonstrator that will be developed in the frame of the study.

Output / Approval conditions: The following documents shall be delivered for approval by the Agency at the end of this subtask:

TN4: ZBO System: Detailed Architectures Definitions. TN5: ZBO System: Development Plan.

3.2.3.2 Subtask 2.2: ZBO Demonstrator Definition, preliminary Test Plan.

Input:

TN1



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TN4, TN5

Subtask description This Subtask is devoted to the design of one ZBO demonstrator and the preparation of the Tests. The following shall be part of this task:

1) The Contractor shall perform the detailed design of one Demonstrator, supported by necessary analyses and produce all engineering drawings for all parts that need to be manufactured or are required for testing. This Demonstrator shall as much as possible demonstrate critical items that are common to the two architectures selected in task 2.1.

In accordance with the Development Plan issued in the previous task, a preliminary test plan shall be written assuring that all identified requirements are verified by the Demonstrator.


TN6: ZBO System: Demonstrator definition and justification files. TN7: ZBO System: Final Test Plan for ZBO Demonstrator

At the end of this activity, a Detailed ZBO System Design Review shall take place. The Data Package of this review shall include the previously established Technical Notes:

DDR Data Package: TN4, TN5, TN6, TN7.

3.2.4 Task 3 Manufacturing and Test Preparation

3.2.4.1 Subtask 3.1: Detailed Test Plan

Within this task, the test and the related test setup shall be defined in detail. The Contractor has the possibility to design a test facility or to refurbish an existing one to perform all required tests. The test plan and test specification issued during design phase shall be consolidated. Test prediction of the ZBO Demonstrator in the laboratory test environment shall be performed.


Updated TN7: ZBO System: Final Test Plan for ZBO Demonstrator TN8: ZBO System: Test Facility, Instrumentation Plan and Performance Prediction.



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3.2.4.2 Subtask 3.2: Manufacturing of the Demonstrator and the Test Bench

Input:

SoW

TN6, TN7, TN8.

Task description

In this activity, the Contractor shall manufacture, assemble and install in the testing facility the Demonstrator which will be the subject of the test programme defined in the test plan. As a minimum, the following activities shall be carried out:

1) Manufacture of Demonstrator: The Contractor shall manufacture the Zero Boil-Off System Demonstrator, in accordance with the approved design and basic PA procedures adopted for this activity.

2) Refurbish an existing or built a new test facility.

3) Issue test procedures (including success criteria) according to agreed test plan and test specification.

4) Take pictures during the integration and instrumentation process.

5) The performance predictions shall be updated with respect to as-built or measured performances (e.g. MLI efficiency).


Updated TN8 (prediction part): ZBO System: Test Facility, Instrumentation Plan and Performance Prediction.

TN9: ZBO System: As built and Test Procedure for the ZBO Demonstrator Set of electronic format pictures of the ZBO Demonstrator during and after

integration.

At the end of this activity, a ZBO Demonstrator Test Readiness Review shall take place. The Data Package of this review shall include the previously established Technical Notes:

TRR Data Package: TN7, TN8, TN9.



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3.2.5 Task 4: Tests and Exploitation

3.2.5.1 Subtask 4.1: Testing, Exploitation of the Results, Correlation and Application to the two Identified Scenarios.

The work dedicated to this task shall be concentrated on the testing and requirements verification by testing.

Input:

SoW.

TRR Datapackage.

Subtask description

Within this activity, the performances of the ZBO Demonstrator shall be validated and compliance with requirements shall be verified. As a minimum, following activities are foreseen:

1) Testing of the ZBO Demonstrator.

2) Correlation of the Test Prediction Model taking into account the actual results obtained with the Demonstrator.

3) Apply this correlated model to the 2 ZBO System Scenarios to verify the requirements updated in Task 1.

Output / Approval conditions: The following document shall be delivered for approval by the Agency at the end of this Subtask:

TN10: ZBO System: Test Report of the Demonstrator. Test Data in Digital Form. TN11: ZBO System: Correlation of the ZBO Demonstrator Model and Prediction of

Performances.

3.2.5.2 Subtask 4.2: Establishment of a Work Plan for Further Studies and Recommendations

This Subtask is devoted to the preparation of the following tasks to be undertaken in order to reach the Technology Readiness required for the whole ZBO systems.

Input:

SoW.

TN4, TN10, TN11.



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Subtask description

1) Critically assess the results of the Demonstrator Tests

2) Take into account the lessons learned during the Demonstrator Tests and update:

a. The Detailed Architectures Definitions

b. The ZBO Parametric Model

c. The ZBO System Development plan.

Output / Approval conditions: Following documents shall be delivered for approval by the Agency during this task: Updated TN4: ZBO System: Detailed Architectures Definitions. Updated TN5: ZBO System: Development Plan. Updated SW1: ZBO Parametric Model.

4 Requirements for Management, Reporting, Meetings and Deliverables

The standard requirements for Management, Reporting, Meetings and Deliverables (Appendix 3 to the Contract) shall apply, taking account of the following specific requirements for the present activity, which shall prevail in case of conflict.

4.1 Management

Section 4.1 of Appendix 3 is applicable.

4.2 Reporting

Section 4.2 of Appendix 3 is applicable.

4.3 Meetings

The kick-off meeting and Preliminary System Design Review shall be held by videoconference/Webex, the Detailed System Design Review and the Final Presentation shall take place at ESA/ESTEC. The Test Readiness Review shall take place at the Contractor’s premise. Progress meetings shall be combined with reviews and/or be held by tele/videoconference.



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4.4 Deliverables

4.4.1 Documentation

4.4.1.1 Final Report

Section 4.1.1 does not apply.

4.4.1.2 Summary Report

Section 4.1.2 applies. It shall be delivered in 7 paper copies and 7 CD-ROMs.

4.4.1.3 Technical Data Package All Technical Notes shall be first delivered in draft form (1 copy) and after approval by the Agency in final version. Documents shall be delivered in a timely manner within the corresponding work package. Acrobat PDF in a searchable format and Microsoft Word shall be used for the electronic versions.



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Document identifier

Title Milestone Number of Paper copies

Electronic mean for final version

TN1 ZBO System: State of the Art Review.

Start of preliminary system design phase

1 final SearchablePDF and Word.

TN2 ZBO System: Review of the scenarios and requirements.

Start of preliminary system design phase


TN3 ZBO System: Preliminary Architectures Definition.

PDR 1 final SearchablePDF and Word.

TN4 ZBO System: Detailed Architectures Definitions.

DDR/FP 1 final SearchablePDF and Word.

TN5 ZBO System: Development Plan.

DDR/FP 1 final SearchablePDF and Word.

TN6 ZBO System: Demonstrator definition and justification files.

DDR 1 final SearchablePDF and Word.

TN7 ZBO System: Final Test Plan for ZBO Demonstrator

DDR / TRR 1 final SearchablePDF and Word.

TN8

ZBO System: Test Facility, Instrumentation Plan and Performance Prediction.

Beginning of the manufacturing / TRR


TN9 ZBO System: As built and Test Procedure for the ZBO Demonstrator

TRR 1 final Searchable

PDF and Word.

TN10 ZBO System: Test Report of the Demonstrator.

FP 1 final Searchable

PDF and Word.



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Document identifier

Title Milestone Number of Paper copies

Electronic mean for final version

TN11

ZBO System: Correlation of the ZBO Demonstrator Model and Prediction of Performances.

FP


SR Summary Report FP 1 final Searchable

PDF and Word.

AB Abstract FP 1 final Searchable

PDF and Word.

HW1 Demonstrator FP N.A N.A

A final delivery of the Technical Data Package and all other deliverable items of the contract shall be made on CD-ROM or DVD.

4.4.1.4 Executive Summary Report


Abstract

Section 4.1.5 applies. It shall be delivered in 7 paper copies and 7 CD-ROMs.

4.4.1.5 Brochure


4.4.1.6 Photographic Documentation

Section 4.1.7 applies.

4.4.1.7 Project Web Page


4.4.2 Hardware

Section 4.2 does apply.



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4.4.3 Computer Programs and Models

Section 4.3 applies and the following items shall be delivered:

Item identifier

Description Milestone / Review

Number of copies

SW1 ZBO Parametric Model PDR/FP 1 CD-ROM or DVD or Download

TMM All Thermal Mathematical Models used for justification of the Demonstrator

End of the subtask 4.1

1 CD-ROM or DVD or Download

GMM All Geometrical Mathematical Models used for justification of the Demonstrator

End of the subtask 4.1

1 CD-ROM or DVD or Download

4.5 Commercial Evaluation

Section 4.5 is not applicable

5 Schedule and Milestones

5.1 Duration The duration of the work shall not exceed 24 months from kick-off to end of the activity (delivery of the draft summary report, draft Abstract, H/W and S/W).

5.2 Milestones The following milestones shall apply for the payment plan:

- PDR - Detailed ZBO System Design Review - Test Readiness Review - Final Presentation

5.3 Reviews

The following major reviews shall be held: - Kick-off (KO) Videoconference - Preliminary System Design Review (PDR) Videoconference at the end of Task 1. - Detailed System Design Review (DDR) ESTEC at the end of Task 2. - Test Readiness Review (TRR) Contractor’s premises at the end of Task 3



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- Final Presentation (FP) ESTEC at the end of the activity

6 Agency Undertakings

Not applicable

6.1 Customer Furnished Items

Not applicable



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Annex 1: Technical Specification

A.1 System Definition and Breakdown

It is recalled that a Zero Boil-Off System can be composed of:

- Radiative Insulation.

- Conductive Insulation

- Passive Cooling

- Active Cooling

- Heat Transportation System.

- Multi-staging.

- Propellant Management Device

The Propellant Management Device being a complex problem on its own it shall not be considered part of the study.

The accommodation options of the tanks (e.g. common bulkhead or not) shall be investigated in the frame of this study which focuses on the Thermal Related architectures and hardware.

A.2 Requirements

A.2.1 Scenarios Related Requirements

A.2.1.1 Scenario A: Long Term Cryogenic Propulsion for Interplanetary Mission

Foreword

This scenario is derived from the design case 1c from the LTCP CDF Study (RD1). The purpose of the study was to design a Long Term Cryogenic Propulsion module for Interplanetary mission based on two scenarios: a Jovian Minisat Explorer and a Robotic Deimos Sample Return Mission. The latter was selected to build the following set of requiremnts.

SCAR1 The propellants to be stored are LOX/LCH4.

SCAR2 The volumes to be considered are the following: - 5m3 of LOX

- 3.6m3 of CH4



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SCAR3 The Contractor shall look into the tanks shapes and accommodation taking into accounts the maximum allowable diameter of 5m.

SCAR4 The tanks shall be considered in aluminium with a thickness of 3mm. If thicker tanks are necessary, it shall be identified and budgeted.

SCAR5 A typical interplanetary mission (without sample return) can be separated in 3 phases:

- Phase 1 - Low Earth Orbit.

- Phase 2 - Cruise Earth to Planet.

- Phase 3 - Planetary Orbit

The ZBO system shall be operational up until the end of Phase 2 (no need of Cryogenics propellant once injected on the final orbit).

SCAR6 The following durations shall be considered:

- Low Earth Orbit: 1 week.

- Cruise Earth to Planet: 6 months (to go to 1.52 AU).

SCAR7 The following external thermal environment shall be considered:

Thermal Environment – Low Earth Orbit The External Fluxes shall be computed with a proper ray-tracing tool (e.g. Thermica, ESARAD) taking into account the following parameters:

- Circular Orbit.

- Altitude 350 km.

- Inclination 51°

- Right Ascension at the Ascending Node: Drifting, the worst case has to be considered.

- Solar Constant : CS = 1425 W/m2.

- Earth Constant : CT = 268 W/m2.

- Albedo Coefficient: a = 0.25.



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Thermal Environment – Cruise Earth to Planet The only external flux to be considered comes from the Sun:

Mission Timeline Distance to Sun

Solar Constant

0 = beginning of the cruise

1 UA 1425 W/m2

6 months 1.52 UA 600 W/m2

SCAR8 The following attitude constraints shall be considered: - In phase 1 (LEO), there is no attitude constraint, it can be controlled and driven by the

Thermal Subsystem. That shall be an outcome of the study.

- In phase 2 (Cruise), the Propellant Management System imposes a Spin around the axis of the tanks 1 rpm.

SCAR9 The following assumptions concerning the ullage of the propellants shall be assumed:

- During Phase 1 (LEO), the tanks shall be considered as completely filled with propellants.

- During Phase 2 (Cruise), the propellant shall be considered located in the lower part of the tanks.

The propellant ullage shall be taken as a parameter, and the criticality of Propellant Management for ZBO purposes shall be clearly identified.

SCAR10The conductive boundaries shall be defined in the task 1, but as a starting point, the following boundaries condition shall be considered:

- The tanks are located between an Engine Frame and an Intertank structure that shall be assumed at 273K.

- The Contractor shall design the Thermo-mechanical links between those parts and the tanks to comply with the Mechanical environment (ER1) and the Boil-Off Constraints.



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Tank Assembly Intertank Structure (273K)

Engine Frame (273K)

A.2.1.1 Scenario B: Human Exploration

Foreword

This scenario is derived from the Mars Manned Mission CDF (RD2).

SCBR1 The propellants to be stored are LOX/LH2.

SCBR2 The volumes to be considered are the following:

- 55m3 of LOX

- 144m3 of LH2

SCBR3 The Contractor shall look into the tanks shapes and accommodation taking into accounts the maximum allowable diameter of 7m.

SCBR4 The tanks shall be considered in aluminium with a thickness of 3mm. If thicker tanks are necessary, it shall be identified and budgeted.



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SCBR5 The Mars and the NEO feasibility studies consider cryogenic propellants only for the Earth-NEO/Mars burn. The ZBO System shall be operational during the first phase of such a mission:

- Phase 1 Low Earth Orbit.

SCBR6 The Duration to be considered for the phase 1 is 2 months.

SCBR7 The following external thermal environment shall be considered:

Thermal Environment – Low Earth Orbit The External Fluxes have to be computed with a proper ray-tracing tool (e.g. Thermica, ESARAD) taking into account the following parameters:

- Circular Orbit.

- Altitude 350 km.

- Inclination 51°

- Right Ascension at the Ascending Node: Drifting, the worst case has to be considered.

- Solar Constant : CS = 1425 W/m2.

- Earth Constant : CT = 268 W/m2.

- Albedo Coefficient: a = 0.25.

- Right Ascension at the Ascending Node: Drifting, the worst case shall be considered.

SCBR8 The attitude can be controlled and driven by the Thermal Subsystem. That shall be an outcome of the study.

SCBR9 During the phase 1, the tanks shall be considered as completely filled with propellants.

SCBR10The conductive boundaries shall be defined in the task 1, but as a starting point the following boundary condition shall be considered:

- The tanks a located between an Engine Frame and an Intertank structure that shall be assumed at 273K.

- The Contractor shall design the Thermo-mechanical links between those parts and the tanks to comply with the Mechanical environment (ER1) and the Boil-Off Constraints.



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Tank Assembly Intertank Structure (273K)

Engine Frame (273K)

A.2.2 Functional&Performance requirements

FPR1 The Zero Boil-Off System shall guarantee:

Less than 0.1% of Total Boil-Off mass per month for Scenario A.

Less than 1% of Total Boil-Off mass per month for Scenario B.

A.2.3 Environmental Requirements

Apart from the Thermal environment described in A.2.1, the Zero Boil-Off System shall be designed to withstand the following environmental conditions:

ER1 The Zero Boil-Off System shall not be affected by a TBDkrad radiation environment.

ER2 The Zero Boil-Off System shall not be affected by typical heavy launchers (envelope TBC) mechanical launch environment.

ER3 The Zero Boil-Off System shall not be affected by typical heavy launchers (envelope TBC) depressurisation profile.

ER4 The Zero Boil-Off System shall take into account typical low Earth Orbit (e.g. atomic oxygen) and Interplanetary (e.g. Ion, electron, protons) environments.



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A.2.4 Physical & Resource Requirements

The physical resources requirements (Mass, Power) of the ZBO Propulsion System are mission dependant and shall be traded at system level. The activity performed in Task 1 shall identify at system level the physical resources acceptable for the ZBO system for the two scenarios.

A.2.5 Operational Requirements

OR1 The Zero Boil-Off System shall be autonomous in all mission phases.

A.2.6 Human Factors Requirements

N.A.

A.2.7 Logistics Support Requirements

N.A.

A.2.8 Product Assurance Requirements

No specific PA has been defined considering the nature of this activity.

A.2.9 Configuration & Implementation Requirements

N.A.

A.2.10 Design Requirements

DR1 The Zero Boil-Off System shall be constituted as much as possible of modules which are standard parts that can scale with the mission.

DR2 The dimensioning of the Zero Boil-Off System shall cover worst-case scenarios including expected physical properties degradations over the platform lifetime. If the evolutions of those properties are unknown, it shall be identified, and a material test program shall be described.

DR2 Uncertainties and margins (thermal properties, cryocoolers heat lift) shall be identified and agreed with the Agency.



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A.2.11 Verification & Testing Requirements

VT1 The Zero Boil-Off System Demonstrator shall be constituted at least of the following subsystems:

- A Tank

- An active cooling system.

- A Heat Transportation system.

- A radiative and conductive insulation system.

VT2 The Zero Boil-Off System Demonstrator shall be tested in Thermal Vacuum conditions.

VT3 The Zero Boil-Off System Demonstrator shall allow multiple testing positions with respect to gravity.

Appendix 1 to ITT 1-7010/11/NL/NAemits.esa.int/emits-doc/ESTEC/AO7037_RD2ews7010.pdf ·...

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Transcript of Appendix 1 to ITT 1-7010/11/NL/NAemits.esa.int/emits-doc/ESTEC/AO7037_RD2ews7010.pdf ·...