Introduction toSpacecraft Systems Engineering

Phat Jotikabukkana

System Engineer

SSTL, Guildford, Surrey, United Kingdom (May 2019 – March 2021)

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Course Statement

“This Spacecraft Systems Engineering Basic Course is mainly designedfor expressing and transferring an overview of the spacecraft systemengineer key knowledge and experience specifically from the THOE-2SmallSAT KHTT programme, not a pure academic syllabus. It is arequired prerequisite title before attending the further advance one.”

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• What is ‘Systems Engineering’?

• What I have learnt from SSTL?

• The first step to be System Engineer for Spacecraft Project

• Why Space Mission?

• Satellite Ecosystem and Components

• System Engineer Team

• System Engineer’s Body of Knowledge

• What’s next?

• Advance Course with workshop and real hands-on experience

Agenda

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What is “Systems Engineering”?

• Systems engineering is an interdisciplinary field of engineering and engineeringmanagement that focuses on how to design, integrate, and manage complexsystems over their life cycles. At its core, systems engineering utilizes systemsthinking principles to organize this body of knowledge. The individual outcomeof such efforts, an engineered system, can be defined as a combination ofcomponents that work in synergy to collectively perform a useful function. [1]

Systems Engineering

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[1] Credit: https://en.wikipedia.org/wiki/Systems_engineering

What I have learnt from SSTL?

“Obviously Seen”(Certainly Understood, Realized)

“Respect for Works”(Outcomes & Evidences Based, not Profile)

“You can do it!!!”

Just 3 Words/Sentences

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• Main things I have learnt from the KHTT programme (System Engineer)

• Professional Mind-set from Professional Company

• Learning from successful experiences

• Key Spacecraft Development and Test Philosophy

• Defining the right scope and doing all reasonable & trackable actions

• The way to be a professional System Engineer for Space IndustrialDevelopment in Thailand

• Working with professional technical management framework

SSTL-KHTT System Engineer

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• Attitude, Mindset, Vision, Teamwork and Communication are important

• Learning Known-Unknowns, discovering Unknown-Unknowns

• If your target is clear & sharp enough, everything is possible!!!

• Holistic view, see all scopes, know all factors, prioritize the right things, manageall risks and non-conformances

• Avoid the ‘Trap’, focus and clear ‘What?’ first, then identify and select the mosteffective ‘How?’

• Spacecraft is a very sensitive and costly system which need the most reliableheritage baseline and very neat development framework

• No-Blame, No-Stupid-Questions culture

Key Things

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Clear “What” then Identify “How”

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Mission Objectives Scope of Work Technical Management Framework

What? How?

• Vision, Target

• Objectives

• Requirements, Scope of Works

• Concept of Operations

• Development & Test Philosophy

• Technical Management Framework (with Risk &

Non-Conformance)

• Product Assurance (most compact and reliable

system without ‘nice-to-have’ things)

Requirements, CONOPs, ICD WPTK, DDVP, Gate Review, Risk Mgnt.

Exit the Maze

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Known-Knowns (all clear) : Continue to be expert

Known-Unknowns (grey area) : Learn to be Knowns

Unknown-Unknowns (totally dark) : Discover and Learn to be Knowns

Not achieved at once,

Enter

Exit

Iterative

learning/defining/refining

/updating is a “Normal

Work”

Holistic View of Problem Solving

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[2] Don’t

Stick to only 1 dimension (perspective)

Stay too close to the problems

Do

Open your mind

Think systematically

[2] Credit: https://www.robdavlin.com/2017/06/perspective-circle-or-square.html

• Every precious learning points came from this simply (but profoundly) startingpoint. [Key Motto:: “Test as you Fly and Fly as you Test”]

• Know exact reasons for everything you’ve done (Don’t follow someone else’s processwithout question)

• Best working manners: systematic and reasonable thinking (If in doubt – ask)

• Know exact ways to prove your assumption• Best quality control and quality assurance manners

• Eliminate nice to haves : simplify the design

• Achieving the mission by all breakdown milestones which consistent with the keymotto.

SSTL Philosophy

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The first step to be System Engineer for Spacecraft Project

• Create and support human needs in ‘Space Domain’

• Spacecraft missions may be broadly categorized into three main types: [3]

• Communications Missions: Earth-based and Space-exploration, e.g. Starlink, GPS

• Earth Observation Missions: Earth-based, e.g. THEOS-1, THEOS-2

• Astronomy and Space Science Missions: Mostly for Space-exploration, e.g. Hubblespace telescope, International Space Station (ISS)

+ Another Interesting Missions: Space Debris removal

Why Space Mission?

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[3] Credit: http://www.yorku.ca/bquine/pages/mission_categories.htm

• A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificialsatellite, spacecraft are used for a variety of purposes, including communications, Earthobservation, meteorology, navigation, space colonization, planetary exploration, andtransportation of humans and cargo. All spacecraft except single-stage-to-orbit vehiclescannot get into space on their own, and require a launch vehicle (carrier rocket).[4]

• A satellite is an object that has been intentionally placed into orbit. These objects are calledartificial satellites to distinguish them from natural satellites such as Earth's Moon. [5]

• A spacecraft is a vehicle or device designed for travel or operation outside the Earth’satmosphere, whereas a satellite is an object that orbits the Earth, the moon, or anothercelestial body. [6]

Spacecraft vs Satellite

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[4] Credit:

https://en.wikipedia.org/wiki/Spacecraft#:~:text=A%20spacecraft%20is%20a%20vehicle,

transportation%20of%20humans%20and%20cargo.

[5] Credit: https://en.wikipedia.org/wiki/Satellite

[6] Credit: https://chandra.harvard.edu/resources/faq/astrophysics/astrophysics-

19.html#:~:text=A%20spacecraft%20is%20a%20vehicle,

moon%2C%20or%20another%20celestial%20body.&text=The%20Voyager%20and%20Pioneer%

20spacecraft,an%20orbit%20around%20any%20object.

Satellite Ecosystem and Components

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[7] Credit: SSTL

Users

Space segment

Launch segment

Ground segment

MOCSOC

SOC

[7]

Satellite Key Sub-Systems/Components

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System Engineer Team

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At least 3 System Engineer per 1 Spacecraft project

Technical Consultant, Final decision maker for major technical changes

Technical Reviewer/Consultant for all major milestones

Spacecraft level all technical works and technical management

• The Most Important System Engineer Characteristics• Full filling the gaps, good cooperator and interpreter

• Core Knowledges and Skills• Technical Holistic Viewpoint: Space Environment, Mechanical, Electrical, Computer (Software, Hardware,

Network)

• Technical relationship understanding: Spatial-Temporal Reasoning [Multiple Intelligence]

• More Advanced Knowledges and Skills• Specific spacecraft design, Aerospace and Mechatronics

• Leadership Skills

• Please follow this way!!• Books & Tools

• KHTT Knowledges, Skills and Experiences (From Staring Point to the End of the Mission)

System Engineer’s Body of Knowledge

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• Basic Requirements

• Engineering Principle knowledges and Technical knowledges

• Key precious factors

• Mindset (Good Vision, Professional-Reasonable-Trackable Thinking, Teamwork)

• Responsibility and Honesty

• Most effective management tools (WPTK: Work Breakdown, Risk Management, DocumentControl, Knowledge-Based: Heritage, Peer-Review Process)

• Long-Term human resources development plan (S/C development is a long-term projectwhich needs solid team: low turn-over rate)

• Productive Thinking

System Engineer must have…

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• A Bible for Spacecraft System Engineer

Spacecraft Mission Analysis and Design (SMAD)

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• Spacecraft Mission Major Phases

• Project Initialization

• Project Bidding

• Design (Preliminary, Critical + Redundancy Philosophy, all failure cases and controlmechanism + Insurance)

• Production/ Manufacturing

• Integration and Test (Assembly, Integration and Test + all functions and failure controlmechanisms tests + Environmental test)

• Launch

• Launch and Early Orbit Phase (LEOP) + Commissioning

• Operations

• End-Of-Life (De-Orbit, Re-Entry and deconstruction)

System Engineer in Spacecraft Mission

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• Spacecraft Mission Major Phases

• SSTL Spacecraft Development Key Milestones (with Gate Review)

SE & Major Spacecraft Development Phases with SSTL Key Milestones

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NASA, ESA, DoDSpace Program Development Phases

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[8]

[8] Credit: Text Book “Space Mission Analysis and Design”, 3rd edition, Wiley J. Larson

and Wiley J. Larson

• Space Mission Major Phases

• 3 Major Phases (On-Ground, Launch, and In-Space)

• Key activities and Tools

• System Engineer activities for all phases

• Required documents• Mission analysis result, VCD, QSL, DDVP, DDD, System Block Diagram, CONOPs, FMECA, FDIR, SVP

(ISFTs+SEET+TVM), System Test Procedures, Test results Analysis, ICD&Technical Notes

• Quality control factors

• System Peer Review Processes, Test Procedures

Spacecraft Mission Complete Work Flow Matrix

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SE for Spacecraft Mission

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System Design, The “V” Diagram

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[9] Credit: https://connected-corridors.berkeley.edu/guiding-project-systems-engineering-process

[9]

SSTL Spacecraft (Module) Development Flow

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• High level and Mission Objective

• The objective which contains high level customer requirements.

• Requirements

• All the requirements should be captured (require management tool, e.g. excel)

• Need to have unique identifiers (e.g. THAI-MISS-010)

• Need to identify how the requirement will be verified (by Design,Analysis/Demonstration, Inspection, Test)

High Level Objectives & Requirements

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Example of Requirements

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[10]

[10] Credit: SSTL

Derived Requirements

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[11][11] Credit: SSTL

Internal derived requirements need to be produced in consultation with sub-system/module WPMs

• CONOPs is the description of the way that you are going to operate your mission

• Key elements of a mission: Space (the Spacecraft), Ground (Mission Planning,Spacecraft Control, Data Reception, Data Processing, Archiving, End User), Launch

• CONOPs is developed from mission requirements, heritage baseline (operationsand on-board functionality)

• CONOPs is used to derive System architecture (including Ground segment), allflight software requirements, Ground segment requirements

Concept Of Operations (CONOPs)

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Example: CONOPs

UsersSOC/MOC

Ground Segment

Space Segment

Launch Segment

Orbit: SSO@550 km.

High-Resolution Imaging

- Still Image/Video

High Redundancy

X-Band Payload Data Downlink

@ 160 Mbps

S-Band TC @128Kbps BPSK

S-Band TLM and logs Downlink

@ 384 Kbps QPSK

L1, L2, L3

Image Product1 GS

@ SKP

SpaceX:

Ride-Share

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• All space missions came from a set of requirements – objectives to be fulfilledwithin certain constraints such as budget and time. [12]

• All requirements must be well-defined and succinct.

• Systems Engineer plans and integrates technical solutions within the schedule andwithin budget.

• The mission analysis should describe the mission, its operations, systemconfiguration, subsystem specifications, quality assurance and reliability.

• The specifications should flow-down from systems to subsystems to componentsto parts at increasing levels of detail to ensure consistency. (V diagram concept)

Spacecraft Mission Analysis and Design

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[12] Credit: University of Surrey

• From the mission requirements and constraints, an iterative design based on atrade-off analysis is developed – often altering the mission requirements ifnecessary. [13]

• Key factors for Spacecraft System Design

• High Level Objectives/Mission Objectives/Requirements/Derived Requirements

• Orbit and Launcher/Launch Window

• Heritage Mission/Heritage Baseline

• Space Environment (Thermal and Radiation)

• Launch Vehicle Environment (Vibration and Shock)

Spacecraft Mission Analysis and Design [2]

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[13] Credit: University of Surrey

• Key Academic Knowledges

• Orbital Mechanics/ Astrodynamics (Kepler’s Laws of Planetary Motion, Newton's law ofuniversal gravitation, Newton’s Laws of Motion, Orbital Elements)

• Analysis Tool

• STK (Systems Tool Kit) by AGI (Analytical Graphics, Inc.)• Spacecraft Mission Lifetime Analysis

• ESA-DRAMA by European Space Agency (ESA)• Spacecraft De-Orbit and Re-Entry Analysis

Key Things for SMAD

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• Based on Newton's law of universal gravitation, and Newton’s Laws of Motion

• First Law: The orbit of a planet is an ellipse with the Sun at one of the two foci.[14]

• Second Law: A line segment joining a planet and the Sun sweeps out equal areasduring equal intervals of time. [14]

• Third Law: The square of a planet's orbital period is proportional to the cube ofthe length of the semi-major axis of its orbit. [14]

Kepler’s Laws of Planetary Motion

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[14] Credit: https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion

Kepler’s Laws of Planetary Motion [2]

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[15] Credit: https://www.quora.com/What-are-Keplers-Laws-1

[15]

• LEO: Low Earth Orbit

• SSO: Sun Synchronous Orbit/Polar Orbit

• MEO: Medium Earth Orbit

• GEO: Geostationary Earth Orbit

• GTO: Geostationary Transfer Orbit

• HEO: Highly Elliptical Orbit/Molniya/Tundra

• Different applications require different orbits: e.g.• Earth observation/imaging

• Telecommunications

• Navigation

• Near or deep space imaging

Type of Orbits

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[16] Credit:

https://www.esa.int/Enabling_Support/Space_Tran

sportation/Types_of_orbits

• The Keplerian orbit (which is a solution to the two- body problem) can be described by fiveClassical Orbital Elements (Keplerian Elements) which together determine its size, shape andorientation.

Classical Orbital Elements (Keplerian Elements)

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[17] Credit: http://www.lesa.biz/space-

technology/satellite/orbital-elements[17]

• The March/Spring equinox (Vernal Equinox)occurs about when the Sun appears to crossthe celestial equator northward. In theNorthern Hemisphere, the term vernal point isused for the time of this occurrence and forthe precise direction in space where the Sunexists at that time. This point is the origin ofsome celestial coordinate systems, which areusually rooted to an astronomical epoch sinceit gradually varies (precesses) over time: [18]• In the ecliptic coordinate system, the vernal point is the

origin of the ecliptic longitude.

• In the equatorial coordinate system, the vernal point is theorigin of the right ascension.

Vernal Equinox

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[18] Credit: https://en.wikipedia.org/wiki/Equinox

[19] Credit: https://www.timeanddate.com/calendar/spring-equinox.html[17]

[19]

• Sun Synchronous orbit are described by the local solar time of the Equator crossings.

• LTAN stands for Local Time of the Ascending Node and represents the time when thesatellite crosses the equator when traveling from the south pole to the north pole(ascending). This time is the time of day at that Earth location when the satellite isoverhead. For sun-synchronous orbiting satellites, this time is the same for each time zone(that is, a satellite with an LTAN of 6 am will be overhead at 6 am for every location on theequator each day. [20]

• LTDN stands for Local Time of the Descending Node.

Sun Synchronicity: LTAN and LTDN

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[20] Credit:

http://www.remss.com/support/faq/#:~:text=LTAN%20stands%20for%20Local

%20Time,when%20the%20satellite%20is% 20overhead.

[19]

• Keplerian Orbit is an “ideal” which considered just two-body problem.

• Real Orbit is considered with more perturbations:

• Geopotential Field

• Atmospheric Drag

• 3rd Body Attraction

• Solar Radiation Pressure

• Tides

• Polar Motion

• etc.

Keplerian Orbit vs Real Orbit

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[19]

• A world standard single platform software solution [21]

• Space systems are exceptionally complex and dynamic

• With so many complications in the mission environment, to design and executea successful mission, you need to…

• Integrate information and models from all domains and then

• Simulate and analyze their performance in the variable conditions that can occur inspace, on land, and everywhere in between

STK

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[19]

[21] Credit: https://www.agi.com/missions/space-operations-missions

STK Certification, Level 1

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[19]

[22] Credit:

https://help.agi.com/stk/index.htm?_ga=2.25990333.1654830633.1615889313-

184444737.1615889313#training/Day1Overview.htm

STK Level 1, Airplane sub-mission example

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[19]

STK Level 1, Spacecraft sub-mission example

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[19]

• ESA-DRAMA (Debris Risk Assessment and Mitigation Analysis) is a comprehensivetool for the compliance analysis of a space mission with space debris mitigationstandards. For a given space mission, DRAMA allows analysis of: [23]

• Debris and meteoroid impact flux levels (at user-defined size regimes)

• Collision avoidance manoeuvre frequencies for a given spacecraft and a project-specificaccepted risk level

• Re-orbit and de-orbit fuel requirements for a given initial orbit and disposal scenario

• Geometric cross-section computations

• Re-entry survival predictions for a given object of user-defined components

• The associated risk on ground for at the resulting impact ground swath

ESA-DRAMA

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[19]

[23] Credit: https://sdup.esoc.esa.int/

• Heritage Baseline is a platform (both of software and hardware) of previoussuccessful missions.

• It may be steered by Executive team or triage if not obvious

• Only one Heritage Baseline per mission, not a mixture, depending on sub-system/activity

• Heritage baseline is selected at the outset of the bid, based on:

• The closest technical solution

• Cost

• Schedule

• Risk

• Customer Profile

Heritage Baseline

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[19]

SSTL Approach to Spacecraft Design

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[19]

[24] Credit: SSTL

• QSL is used to:

• Monitor the level of changes on a satellite during the project

• Monitor the developments required

• Identify the risks

• SSTL QSL Categories:

• CAT A: Existing unit with flight heritage (or passed FRR) which has no changes, orchanges due to for example obsolescence or lead-free component changes

• CAT B: Unit that requires more than a trivial modification e.g. re-layout, modification tointerfaces etc.

• CAT C: New development

Qualification Status List (QSL)

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[19]

SSTL QSL Categorization Process

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[19]

[25] Credit: SSTL

SSTL Modeling Philosophy

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[19]

• The purpose of the DDVP is to provide a consolidated system approach to :

• Design solution

• Developments required

• Verification approach

• Iterative updating is a “normal work” for this document, as required at majorreviews up to CDR.

Design, Develop, and Verification Plan (DDVP)

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[19]

• After freezing all spacecraft technical designs (CDR), System Engineer has toattend all sub-systems MRR, TRR, TRB to catch-up and ensurecorrectness/effectiveness of all sub-systems technical specification.

Spacecraft Manufacturing

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[19]

• After all sub-systems modules are produced and ready to deliver to the AIT,System Engineer has to attend all sub-systems ARR, TRR, TRB, ARR to catch-upand ensure correctness/effectiveness of all sub-systems technical specificationand module level test results.

Spacecraft Assembly, Integration and Test (AIT)

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[19]

Spacecraft Systems Level Test Procedures Design & Planning

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[19]

• SSTL’s FMECA analysis is predominantly qualitative and is presented withoutquantitative reliability figures for the equipment. The purpose of the FMECA isto allow determination of failure modes and propagation of faults leading tosingle point failure information and an evaluation of system level redundancy.

• Criticality is determined by first assigning a Severity Rating. Severity Ratings arebased on the ratings described in the ECSS FMECA standard (ECSS-Q-30-02A),and are assigned by subsystem engineers based on qualitative assessment of thesubsystem, taking into consideration design knowledge and operationalexperience of the subsystem.

Failure Mode and Effect Criticality Analysis (FMECA)

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[19]

• FDIR is procedures/mechanisms and actions put in place to monitor the correctoperation of a system, detect any anomalies, isolate these and recover.

• FDIR is implemented as required (to protect a system from failures), to meetmission requirements. (Redundancy Policy).

• On-board automation is used as required to detect and recover from anomalies.

Fault/Failure Detection, Isolation and Recovery (FDIR)

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[19]

• TVM is a document that links User Needs with Derived Requirements and the SystemVerification process. The purpose of the TVM is to ensure that all requirements are associatedwith User Needs and that all the Derived Requirements defined for a system are verifiedthrough testing or observation.

Test Verification Matrix (TVM)

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[19]

• System Engineer have to perform testing and debugging (as a normal work) withthe S/C test procedures (draft version) prior to updating the complete versionone for the Run-for-Record Test (RfR).

• On Ground (System Engineer + Ground Segment Team)

• Integrated Systems functional Test (ISFT)• Basic Functional ISFTs

• Payload ISFTs

• FDIR ISFTs

• Systems-End-to-End Test (SEET)

• In Space (Ground Segment)

• LEOP Test

• Spacecraft Commissioning

Spacecraft Test Procedure

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[19]

• Hierarchical risk registers• Track change related risks

• Raised by anyone and once raised must be addressed

• Top level risks flow down– From technical lead / PM / core team

• Major risks rise up• To receive increased attention

• Project risk profile depends on• Customer needs and company strategy

• Formal management points• Risks should be monitored and reviewed on a regular basis

• Reviewed at various levels (WP / Sub-systems / Project)

Risk Management

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[19]

[26] Credit: SSTL

• Discrepancy Report (DR) is a process thatis established for tracking software,hardware, system, integration, test case,and facility problems in order todocument, control, and test the changesrequired for problems found.

• Engineering Change Note (ECN) is amanagement tool used to propose aconfiguration change to a ConfigurationItem.

• Bugzilla, an open-source issue/bugtracking system, can be used to keeptrack of outstanding problems,non-conformance issues.

Non-Conformance Management

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[19]

[27] Credit: https://www.guru99.com/bugzilla-tutorial-for-beginners.html

What’s Next?

• A1: Spacecraft mission design workshop

• 10 Days course with emulate spacecraft project, intense mission design & analysisworkshop

• A2: Real hands-on SQM project

• On-The-Job Training: Long period project based learning with real gate review process.

Advance Course with workshop and real hands-on experience

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[19]

Questions and Answers

Email: Phat@gistda.or.th

Thank You