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System Integration
by Christiano Daniel Abadi
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• Deliverables/Achievements in Spring 2000
• 8 Systems Engineering Documents
• Overall and power budgets
• Gantt Chart for Preliminary Design Review

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• 8 Systems Engineering Documents
• Description A systems-level document of UASat
  containing
• Problem Statement
• Description of participants
• General input, output, and function of the system
• Requirements
• Testing procedure
• Functional decomposition and physical synthesis
• Audience Public, Upper Management, Systems
  Engineer

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• Procedure
• Write the documents with information gained from
  Team Leaders, Team Mentors, websites, and
  other references.
• Distribute to all members, mentors, and
  administration.
• Get feedback and revise. Iterate as many rounds
  as needed.

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Contents of Documents A general block diagram
that describe the overall satellite (see OHP)
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Requirements (Disclaimer The numbers and
information in red italics are just a starting
estimate and are not meant to be accurate. Cost
requirements 1. The satellite shall cost no more
than 1,500,000, - to model, design,
build, and test. Schedule requirements 1. The
satellite should be ready to be delivered to NASA
no later than March 2004.
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Requirements (cont.) Performance
requirements Mandatory Requirements Launch
conditions from NASA 1. The satellite shall orbit
between 28.50 and 570 of inclination. 2. The
satellite shall orbit between 250 kilometers and
400 kilometers above the earth. Requirements
owned by Mechanical and Structural Analysis
(MSA) 3. The satellite, when not operating,
should withstand the temperature range of
200C to 500C. 4. The operating
temperature range shall be maintained between
100C to 200C. Restriction from the Hitchhiker
Canister (given by NASA) 5. All components of the
satellite that weigh more than 9 kg shall
withstand the force of gravity of
no less than 11 Gs. 6. All components of the
satellite that weigh less than or equal to 9 kg
shall withstand the force of
gravity of no less than 40 Gs.
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Mandatory Requirements Restriction from the
Hitchhiker Canister (given by NASA)
(cont.) 7. The weight of the satellite shall be
no more than 68 kg. 8. The height of the
satellite shall be no more than 52 cm. 9. The
diameter of the satellite shall be no more than
48 cm. 10. The center of gravity of the satellite
shall be no more than 1.27 cm from
the canister centerline. 11. The center of
gravity of the satellite shall be no more than 26
cm from the separation
plane. Preference Requirements (determined by
the SSP) Owner of requirements All
teams. 12. The lifetime of the satellite should
be no less than 1 year. 13. The units of
measurements of the satellite should be in SI
system (i.e. US, kilograms, centimeters,
seconds, 0C, (degree, minute, second for
angular units), G (gravitational force),
Kilohertz, Volts, and Watts). 14. The peak power
needed from all components in the satellite at
any instant of time shall be no
more than 30 Watts.
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Performance requirements (cont.) Owner of
requirements Guidance, Navigation, and Control
(GNC) Team 15. The orbital altitude of the
satellite should be 400 km. 16. Pointing in
accuracy of the satellite shall be no more than
10. 17. The satellite should be able to de-tumble
within 1 orbit. (De-tumbling means the
ability of the satellite to stabilize itself
after an accidental collision that tumbles the
satellite) Owner of requirements Sprite and
Lightning (SCI 1) Team and Data and Command
Handling (DCH) Team. 18. The satellite should be
able to detect and store (in the satellites
computer memory) lightning counts on average
300 occurrences per day. 19. The satellite
should be able to image (photograph) and store
(in the satellites computer memory) sprite
phenomena on average 300 occurrences per day.
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Owner of requirements Power Generation and
Distribution (PGD) Team 20. The power system will
supply DC electricity at the following voltages
28V, 15V, -15V, 5V, -5V, or 3.3V. Owner of
requirements Laser Communication (LCS)
Team 21. The laser communication devices should
transmit data uplink of 10 Mbit/sec. Owner of
requirements Tracking, Telemetry, and Command
(TTC) Team 22. The radio (QFSK Transmitter for
the amateur 2.4 GHz band) should transmit
data downlink of 2 Mbit/sec. 23. The radio
(QFSK Receiver for the amateur 1.2 GHz band,
Pascat Downlink, and Pascat Uplink) should
receive or transmit data of 9600 bits/sec.
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• Trade-off Requirements
• The cost requirement has 25 weight
• The schedule requirement has 15 weight
• The performance requirements have 60 weight

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Figure of Merits Description a number that
indicates how well the system has met all the
requirements. Calculated by summing all of the
requirements score with the weight assigned to
each requirements defined in the Weight Table.
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Standard Scoring Function (SSF) Example 1. The
lifetime of the satellite should be no less than
1 year.
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Weight Table
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• Overall and Power Budget
• There are five factors to juggle in deciding what
  instruments to
• chose
• Power consumption
• Cost
• Volume
• Mass
• Bandwidth

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Overall Budget for UASat
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Power Budget The power budget discussion between
teams has started. Negotiation on power
requirements will continue. Solutions to over
budget reduce power, rationing operation time,
redesign solar panel, etc.
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Sample graph of the power profile for each team
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Gantt Chart for the Preliminary Design
Review Helped by the MIS 578 Team Propose the
Gantt Chart for Preliminary Design Review Use the
NASAs IMAGE PDR as the template Iteratively
negotiate with all teams to reach the readiness
of PDR. Example
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• Things to do next
• Initiate discussion between Science and LCS teams
  with the rest
• of the teams in finding out what the Science and
  LCS teams want
• to do with the data.
• Find out
• What kind of data will come in (in terms of
  bytes)?
• How frequent will the data come in?
• Is there any processing done in satellite?
• What are the data processing and analysis plans?
• What to do with old data?