Space Systems Overview

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Space Systems Overview

• CDR David D. Myre

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What is a Space System?

• Ground
• Spaceflight Operations
• Payload Operations (Can be separate)
• Payload Data Processing (Hubble)
• Space
• Spacecraft
• Supporting Craft (TDRSS, Progress)
• Launch
• Launch Vehicle Integration
• Launch Operations

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Tracking and Data Relay Satellite System
http//nmsp.gsfc.nasa.gov/tdrss/oview.html
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What Does a Spacecraft Look Like?

• Spacecraft appearance is almost always function
  over form
• Physical constraints
• Launch Vehicle
• Payload Fairing
• Loads
• Power Required
• Vehicle dynamics
• Mission Trajectory
• Pointing

HST
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Spacecraft Description

• Spacecraft have two main parts
• Mission Payload
• Spacecraft Bus
• Mission Payload
• A subsystem of the spacecraft that performs the
  actual mission (communications, remote sensing
  etc.)
• All hardware, software, tele- communications of
  payload data and/or telemetry and command
• There can be secondary payloads
• Spacecraft Bus
• Hardware software designed to support the
  Mission Payload
• Provides
• Power
• Temperature control
• Structural support
• Guidance, Navigation
• May provide for telemetry and command control for
  the payload as well as the vehicle bus

Mars Global Surveyor
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TDRSS 1-7 Specifications
Dimensions 45 feet wide / 57 feet
long Weight 5000 pounds Design
Lifetime 10 years Power (EOL)
1800 watts Services KU S-Band
services Launch Vehicle Space
Shuttle Orbit Geosynchronous
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Spacecraft Bus Subsystems

• Electronic Power System (EPS)
• Position and Attitude Control
• Attitude Control System (ACS)
• Guidance, Navigation and Control (GNC)
• Propulsion (OK, well call it Prop)
• Command and Data Handling (CDH)
• Data Handling (Mission Data)
• Telemetry, Tracking and Command System (TTC)
• Thermal Control System (TCS)
• Structural Subsystem

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UHF Follow-On

• Features
• Each satellite provides 39 channels for Ultra
  High Frequency (UHF) two-way communications,
• Super High Frequency (SHF) anti-jam, command and
  tracking link and communication uplink for fleet
  broadcast over UHF
• Uses S-band communications for the Space Ground
  Link Subsystem (SGLS). AFSCN TTC.
• Flights 4-10 (Block II) also carry an Extremely
  High Frequency (EHF) package for secure, anti-jam
  communications, telemetry and commanding.
• Flights 8-10 (Block III) add a Global Broadcast
  Service (GBS) package for one-way, high data-rate
  communications in place of the SHF package.
• Projected orbital operational life of 14 years
  with an on-orbit storage life of four years.
• UHF F/O Specifications
• Weight 2,600 pounds
• Orbital Altitude Geosynchronous orbit - 22,250
  miles
• Power Plant Two deployed three-panel solar array
  wings supplying approximately 2400 watts. A
  single 24-cell nickel-hydrogen (NiH2) battery
  provides power during eclipse operations (Block
  III satellites have two four-panel solar wings
  supplying approx. 3800 W and a 32-cell battery).
• Dimensions 9.5 feet high and 60.5 feet long
• launch Vehicle Atlas-Centaur space booster
• Launch Site Cape Canaveral Air Station, Fla.
• Primary Contractor Boeing Space Systems, El
  Segundo CA

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Voyager

• The twin spacecraft Voyager 1 and Voyager 2 were
  launched by NASA in separate months in the summer
  of 1977 from Cape Canaveral, Florida. As
  originally designed, the Voyagers were to conduct
  closeup studies of Jupiter and Saturn, Saturn's
  rings, and the larger moons of the two planets.
• To accomplish their two-planet mission, the
  spacecraft were built to last five years.
• But as the mission went on, and with the
  successful achievement of all its objectives, the
  additional flybys of the two outermost giant
  planets, Uranus and Neptune, proved possible --
  and irresistible to mission scientists and
  engineers at the Voyagers' home at the Jet
  Propulsion Laboratory in Pasadena, California.
• As the spacecraft flew across the solar system,
  remote-control reprogramming was used to endow
  the Voyagers with greater capabilities than they
  possessed when they left the Earth. Their
  two-planet mission became four. Their five-year
  lifetimes stretched to 12
• Between them, Voyager 1 and 2 would explore all
  the giant outer planets of our solar system, 48
  of their moons, and the unique systems of rings
  and magnetic fields those planets possess.

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Ground

• Ground Activities
• Spacecraft Flight Operations
• Payload Operations
• Payload Data Processing
• Payload Data Dissemination
• Facilitated By
• Real-Time Processing
• Payload Dissemination Infrastructure
• Powerful Payload Processing Facilities
• Mission Simulations

Can Be Merged
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Launch

• Selection
• Enough throw weight
• Enough cube (volume)
• Acceptable ride
• Good record
• Integration
• Launch loads imparted to spacecraft
• Mechanical/Electrical Integration
• Understand launch flow and count

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Space System Development

• All systems development start with a mission
  need (the Why)
• Then mission requirements are developed to meet
  this need (the What) often along with a concept
  of operations
• Note Often we make the mistake of putting the
  How in the Mission Requirement
• From 1 and 2 above develop derived requirements
  for (the How)
• Space
• Mission orbit
• Payload Types (Communications, remote sensing,
  data relay)
• Spacecraft Design
• Ground
• Facilities and locations
• Computers/Software
• Personnel/Training
• Launch segments
• Note The requirements generation process is
  often iterative and involves compromises
• Remember, Mother Nature gets a vote and her vote
  counts

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Spacecraft Development Process
Requirements Development

• Some types
• Waterfall (sequential)
• Spiral (iterative)
• Basic Sequence
• Conceptual design
• Detailed design
• Develop detailed engineering models
• Start production
• Field system
• Maintain until decommissioned
• DoD mandates integrated, iterative product
  development process

Detailed Design
Engineering Development Production
Field (IOC)
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Textbook Answer
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Serial (waterfall) Development

• Traditional waterfall development process
  follows logical sequence from requirements
  analysis to operations.
• Is generally the only way to develop very large
  scale systems like weapons, aircraft and
  spacecraft.
• Allows full application of systems engineering
  from component levels through system levels.
• Suffers from several disadvantages
• Obsolescence of technology (and sometimes need!)
• Lack of customer involvement/feedback
• Difficult to adjust design as program proceeds

http//www.csse.monash.edu.au/jonmc/CSE2305/Topic
s/07.13.SWEng1/html/text.html
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Concurrent versus serial development

• The Concurrent development and manufacturing
  processes intended to optimize overall time to
  market and development productivity.
• Incorporating customer needs/requirements into
  measurable and predictable targets ensuring that
  the product meets or exceeds expectations.
• Use simulation-led analysis and problem solving
  to design out problems and validate new designs
  before expensive prototypes and tooling are
  built.
• Product testing ahead and concurrent with
  development programs to understand and quantify
  product performance before production is
  contemplated.
• Note Also Allows full application of systems
  engineering to assure requirements are
  methodically managed from component levels
  through system levels.

http//www.iti-oh.com/TechKnowledgy/ParadigmShift.
htm
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Spiral Development

• Software Development Centric Example
• Good features
• In this approach, the entire application is built
  working with the user.
• Any gaps in requirements are identified as work
  progresses into more detail.
• The process is continued until the code is
  finally accepted.
• The spiral does convey very clearly the cyclic
  nature of the process and the project life span.
• Not so good features
• This approach requires serious discipline on the
  part of the users. The user must provide
  meaningful realistic feedback.
• The users are often not responsible for the
  schedule and budget so control can be difficult.
• The model depicts four cycles. How many is enough
  to get the product right?
• It may be cost prohibitive to tweak the product
  forever.
• Simply put Build a little Test a little!
• Can this work for every type of project?

From http//www.maxwideman.com/papers/linearity/s
piral.htm And Barry Boehm, A Spiral Model of
Software Development and Enhancement, IEEE
Computer, 1988
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Systems Engineering

• A logical process for system development
• Functional physical decomposition of system
  into logical parts
• Involves development of system requirements
• System Analysis
• Requirements Development
• Interface Requirements
• Requirements Validation
• Test Demonstration
• Simulation
• Analysis
• Physical/functional configuration audits
• Integration Test Planning
• Cradle to Grave lifecycle planning
• Treaty provisions and DoD regulations require
  disposal of satellites at the end of life.

Deep Space 1
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Systems Engineering Verification
The classic V for system development
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Spacecraft Integration and Test

• CDR David Myre

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Spacecraft Integration and Test

• Methodical process for test of spacecraft to
  validate requirements at all levels
• Sequence
• Perform component or unit level tests
• Integrate components/units into subsystems
• Perform subsystem tests
• Integrate subsystems into spacecraft
• Perform spacecraft level test
• Integrate spacecraft into system
• Perform system test when practical

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System Integration and Test

• Types
• Functional testing
• Do subsystems work together?
• Fit check payload fairing, adapter
• Environmental testing
• Thermal vacuum, shock and vibration testing
• Combined functional and environmental testing
• Usually spacecraft level thermal vacuum involved
  integrated functional testing
• Final System demo Do all segments work together,
  mainly ground and space
• Payload or system characterization
• Performance can be altered by the space
  environment
• Often performed in thermal vacuum chamber
• Can Use a combination of hardware in loop and
  simulation
• Ground Testing
• Systems like propulsion and attitude control
  cannot be operated safely on the ground
• May use stimulators for sensors like sun
  earth sensor, or star tracker.

NOAA-N Prime, 6 Sep 03
Got to the site below and play the movies if
internet connection available http//www.boeing.c
om/defense-space/space/bss/hsc_pressreleases/photo
gallery/uhf_f11/uhf11_video/uhf11_movies.html
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Summary

• Functions
• Mechanical (form and fit)
• Electrical/Electronic (power up to operational
  test)
• Process
• Starts at component level (e.g. transmitter,
  power supply)
• Continues at subsystem level (e.g. electronic
  power system, attitude control system)
• Ends with end-to-end test of entire system
• Spacecraft Challenge
• Effectively test spacecraft on the ground so it
  works in space!

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Design Verification and Qualification Testing

• Design Verification
• Validate design precepts and models
• Examine system limitations
• Build Test, Build Test
• Qualification
• Determine system suitability for mission
• Provides tool for customer to measure success of
  the enterprise
• Allows time for fixes to meet requirements may
  involve warranty period

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DoD Test Process

• Developmental Testing
• Design Verification
• Qualification
• Acceptance Testing
• Operational Testing
• Operational Assessments (OAs)
• Phased Operational Testing (OT)
• Mandated by law to protect YOU!

From COMOPTEVFORs Web Page http//www.cotf.navy.
mil/ In 1971, however, OPTEVFOR was designated
the Navy's sole independent agency for
operational test and evaluation. This move was in
response to Congressional and Secretary of
Defense initiatives aimed at improving the
defense material acquisition process.
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Types of Design/Qual Tests

• Functional
• Life Testing (could involve structural,
  thermal, illumination, power cycling, radiation
  exposure etc.)
• Component to System Level
• Often performed in between other forms of test
• Structural
• Static Tests
• Dynamic Tests
• Thermal
• Thermal cycling
• Thermal vacuum

Magellan
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Launch Flow

• Pack and Ship (Spacecraft Launcher)
• Dry run spacecraft moves, lifts etc.
• Transportation loads can be driving cases for
  spacecraft structure
• Establish launch operations
• Admin and work spaces for launch team
• Test to insure no damage during shipping
• Perform limited subsystem and spacecraft tests
• Establish communications with all players (launch
  base, groundstation)
• Perform rehearsals
• Multiple data and voice networks must be
  established
• Support spacecraft (TDRSS) must be in place

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Review

• Discussed the Segments of a space system Ground,
  Space and Launch
• Introduced major subsystems of typical spacecraft
• Introduced the concept of systems engineering
• Discussed Integration and Test of Spacecraft

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(No Transcript)
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Another View Eye Chart Anyone?
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International Gamma-Ray Astrophysics Laboratory
(Integral)
INTEGRAL is an European Space Agency mission with
instruments and science data centre funded by ESA
member states (especially Denmark, France,
Germany, Italy, Spain, Switzerland), Czech
Republic and Poland, and with the participation
of Russia and the USA
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Concurrent Development