University Crest 1 > Canadian Satellite Design Challenge Critical Design Review.

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1<<University Name>>

Canadian Satellite Design Challenge

Critical Design Review

<Presenter Names>

<University Team Name><Date>

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Presentation Outline

• Mission Overview• Spacecraft Overview

– Payload(s) Description– Structure– Thermal– Power– Attitude Determination & Control– Communications– Command & Data Handling– Orbit Determination

• Assembly, Integration, and Test• Programme Management• Concept of Operations• Summary & Conclusions

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Mission Overview

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Mission Summary – ONE SLIDE ONLY

• Brief statement of mission objectives– List the payload(s) and purpose(s)

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Spacecraft Summary – ONE SLIDE ONLY

• Include an annotated graphic of your spacecraft in flight configuration– Show nominal operational attitude, and flight axes

• X+ = velocity vector; Z+ = Nadir

Death-ray antenna

Anti-satellite skewers

iPod

Solar cells


X+

Z+

Y+

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Mission Ground Track and Ground Station Access (1/2)

• Using Satellite Toolkit, show a diagram of the spacecraft ground track over the course of one day, with access to a ground station at your university.

Example for RADARSAT-2 using St. Hubert Ground Station

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Mission Ground Track and Ground Station Access (2/2)

• What is the minimum elevation angle for communications with your spacecraft?

• How many passes per day (minimum, average)

• What is the daily minimum and average contact time?

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Summary of Changes since PDR

• Summarise any changes to your mission and spacecraft since PDR– E.g., changes to any sub-system; components added or

removed; etc.

• Should be no more than two slides– Full details of the changes will appear in the relevant sub-section

later in the presentation.

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Spacecraft Overview

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System Level Configuration Trade Selection

• Summarise any changes to your trade-off analysis for any components, sub-systems, or mission elements.

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Physical Layout

• Diagram(s) showing internal physical layout– E.g., like below (does not have to be an exploded view)

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Payloads

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Payload #1: Purpose

• Give an overview of each payload or science experiment on separate slides– Why does your payload need to be put into space? Why can’t

your experiment/objective be accomplished on the ground?

– What is new or innovative about this payload experiment?

– What is the relevance of this payload to your university (or an industry partner)? Who will use the payload data - industry, grad students, or faculty?

• You should only use 1-2 slides to explain what the payload does. Please do not include slides explaining the science or theory of your payload’s objective (you can put them in the “Additional slides” at the end)

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Payload #1: Characteristics

• Physical size, mass

• Amount of data (KBytes, MBytes) produced to be down-linked per day

• Objective coverage characteristics & statistics– E.g., Earth imagery in km2/day

• What attitude and orbit position accuracy does your payload need? What happens if it doesn’t get that?

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Payload #2

• Add slide groups describing each additional payload.

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Spacecraft Structure

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Spacecraft Structural Drawings

• Show 2-D and isometric drawings of your spacecraft– Similar to Figure 1 of the DIETR (shown below)

– Verify that the outer dimensions are to spec.

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Spacecraft Structure

• Create a co-ordinate system called “Mechanical Build Co-ordinate System” at the geometric centre of the spacecraft.

• Using FEMAP (or another tool of your choice), identify the mass properties of your spacecraft including:– Total Mass

– Centre of Mass offset in X/Y/Z with respect to the Mechanical Build Co-ordinate System

– Moments of Inertia about the spacecraft Centre of Mass


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Spacecraft FEM

• Show the Finite Element Model generated using FEMAP

• List the materials assigned in the FEM and identify their mechanical properties


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Spacecraft Static Analysis

• Using the FEM, constrain the model at the launch interfaces (the rails & ends) and perform a linear static analysis by applying a body load of 12g in each spacecraft axis (±X, ±Y, ±Z) separately.

• Check the material stresses in the key structural members and report the margins of safety against yield and ultimate failure for these members


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Spacecraft Normal Modes Analysis

• Perform a normal modes analysis to determine the first three vibration modes of the spacecraft when constrained at the launch interface.

• Provide the mode frequencies and the associated mode shapes

• Show that the first vibration mode frequency is higher than 90 Hz (per DIETR-0200).


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Mass Budget

• Table(s) providing the following:– Mass of all major components & structural elements

– Sources/uncertainties – whether the masses are estimates, from data sheets, measured values, etc.

– Total mass

– Margin

ComponentNominal Mass

(g)Source Margin

Total with Margin (g)

Comments

StructureFace plates & rails 307 Measured 2% 313.14

PowerSolar Panel Plates 200 Datasheet 5% 210 2 solar panel plates @ 100g eachSolar Cells 60 Calculation 10% 66 5g/cell; 12 cells

C&HDProcessor Board 25 Datasheet 5% 26.25

etc…..

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Thermal Analysis

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Thermal Analysis

• Create a FEMAP/TMG thermal model of your spacecraft.

• Include external surfaces to account for radiation exchange to the space environment.

• If possible use simple lumped mass representations for internal components.

• Create thermal couplings to couple the internal components to the external surfaces.

• Assign component dissipations consistent with the spacecraft operations.


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Thermal Analysis

• Identify the space environment thermal fluxes (sources and sinks) acting on your spacecraft.

• Identify a worst case hot and a worst case cold, considering orbit, season (aphelion vs. perihelion), attitude, and internal dissipation.

• Run the thermal model for the hot and cold cases

• Recover the max/min temperatures for critical components (battery, payload).

• Identify the allowable temperatures and report the temperature margins for critical components.


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Power Sub-system

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Power Sub-system: Power Generation

• Spacecraft power block diagram – ONE SLIDE ONLY– Show all major power system components:

• Solar panels• Batteries• Power regulator(s)• Power distribution connections to other major components and sub-

systems (e.g., payload, ADCS components)

Separation Switches

Battery

Panel 1

Panel 2

Power Regulation

& Distribution

6.0V – 7.2V Unregulated

5.0V Regulated lines

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Power Sub-system: Power Generation

• Slides on the spacecraft power sub-system:– Location and number of solar panels – indicate whether static

or deployable

– Orbit Average Power generated• Assume sun-synchronous 10:00 and 11:00 Equator Crossing Times, for 600

km and 800 km circular orbit• How much time is the spacecraft in sun vs. eclipse?

– Batteries: number of cells, physical size, nominal voltage, storage capacity (in Ahr or mAhr), max power output (in W or mW)

– Power regulation & distribution

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Power Sub-system: Power Budget

• Summarise the power consumption of the spacecraft– List each electric/electronic unit, its power consumption modes,

power consumed in each mode, and duty cycle (in % of an orbit) for each mode (example below)

– What is the expected battery Depth-of-Discharge?

– What is the overall power margin?• = (OAP generated) / (OAP consumed)

Component

Nominal Power used

(W) Margin

Budgeted Power Used

(W) Duty Cycle

Orbit Average Power with margin (W)

Component 1 0.5 20% 0.60 100% 0.60Component 2 0.8 40% 1.12 80% 0.90Component 3 - Low 0.8 5% 0.84 50% 0.42Component 3 - High 1.5 5% 1.58 30% 0.47Total 2.39

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Attitude Determination & ControlSub-system (ADCS)

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ADCS Overview – ONE OR TWO SLIDES

• What is the nominal operational attitude of your spacecraft?

• What attitude knowledge and control accuracy do you need for payload operations or communications?

• What Attitude sensors will be used? What attitude determination accuracy will your spacecraft achieve?

• What Attitude actuators will be used? What attitude control accuracy will your spacecraft achieve?

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ADCS Control System

• Details of the ADCS control system– Sensor sampling frequency

– Actuator control frequency

– Telemetry produced

– Algorithms used

– What attitude determination/control does your mission need?• What is the driver for your requirement?

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Attitude Sensor #1..n

• For each attitude sensor:– Brief overview of the sensor

– Expected attitude determination accuracy

– Effect on the overall determination accuracy if it fails

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Attitude Actuator #1..n

• For each attitude actuator:– Overview of the actuator used

– Expected control accuracy

– Effect on the overall control accuracy if it fails

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Communications Systems

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Communications System

• One slide to summarise RF used for– Commanding uplink

– Telemetry downlink

– Science data downlink (if different from Telemetry)

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Communications: Link Budgets

• Give the link budget for each uplink & downlink channel used– You should be able to do each budget on one page only

– Space Mission Analysis & Design, Larson & Wertz, 3rd Edition, Table 13-13 gives a good basic link budget

• Clearly indicate the required transmitting/receiving characteristics for the Ground Station.– I.e., it must include everything that CSDC Management needs to

be able to procure the required Ground Station hardware (and software, if applicable).

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Communications Throughput Budget

• What is your Communications Throughput Budget?– How much data are you uplinking/downlinking? List each source

and data size.

– How is data encoded for uplink/downlink?

– What is the communications protocol overhead as a per centage of the useable data transmitted?

– How much data can you uplink/downlink during a pass? What is the average amount of data to be uplinked or downlinked per day?

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Communications Throughput Budget

• E.g., your Communications Throughput Budget should look something like the example below:

So, in this example, you would need an average of at least 24.9 minutes of contact time with your satellite each day to downlink this telemetry data.

TelemetryBytes per

measurement Frequency Bytes/Orbit Bytes/Day CommentsSun Sensor #1 9 1/minute 828 12960 Sun On/Off, Az,El positionSun Sensor #2 9 1/minute 828 12960 Sun On/Off, Az,El positionMagnetometer 16 1/minute 1472 23040 Mag Field Strength, (X,Y,Z) directionSub-total 48960

Protocol overhead 14.3% 32 bytes of overhead per 256-byte packet

Total bytes transmitted 55954 bytes per dayTotal bits transmitted 447634 bits per day

Comm rate 300 bits per second

Total Time Required 1492.1 seconds per day24.9 minutes per day

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Command and Data Handling(C&DH) Sub-system

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C&DH Architecture

• Provide an overview of the C&DH requirements and design

• Should discuss – Basic architecture

– How uplinked commands (immediate vs. time-tagged) are handled (a diagram may help).

– Brief summary of what the software has to do

– Programming language(s)

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Orbit Determination

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Orbit Determination

• What methods will you use to determine and/or predict your spacecraft’s orbital position?

• What orbit position accuracy does your payload need? Why? What happens if you can’t get that level of accuracy?

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Assembly, Integration, and Test(AI&T)

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Spacecraft AI&T Overview

• Updated plan for how the spacecraft sub-systems will be integrated and tested – prior to environmental testing

• Summary of tests to be performed on each sub-system

• Summary of tests to be performed on the integrated spacecraft

• At CDR this should include concepts for how subsystems will be integrated

– Sequence (which subsystems are needed prior to others)

– Test equipment necessary

– Test environments necessary

• The goal(s) at CDR are

– Demonstrate that you are ready for AI&T

– Demonstrate that you have a path to ensure that your spacecraft works and meets requirements – and your expectations!

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Programme Management

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Programme Schedule

• Updated development schedule to show your plan from CDR until Environmental Testing (week of September 24 – 28, 2012).

• The schedule should be “wrapped up” to 1-2 levels– Show high-level tasks only in order to make the schedule readable

• The goals of this schedule are to– Demonstrate that you will be able to complete AI&T prior to environmental testing.

– Provide tool for judges to assess trouble areas and offer ways for the team to best meet the objectives of the competition

• A Gantt chart showing task start and stop dates and durations is recommended– Schedule should include linkages between tasks to provide the team with an idea of what

happens in the overall flow when milestones are not met on time

• Please ensure your schedule is readable in the presentation

• What is your Critical Path? Where is the highest risk? What margin do you have?

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Programme Budget – Hardware

• Provide an updated table listing the costs of the spacecraft flight hardware

• Table should include– Cost of major components and hardware

– Indication of whether these costs are actual, estimates, or budgeted values

– If components are donated, give the current expected market value (excluding Payload instruments)

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Programme Budget – Other Costs

• Table(s) (same format as Hardware Budget) showing– Ground control station costs– Labour Cost (in hours)– Other costs

• Prototyping• Test facilities and equipment• Rentals• Computers• Travel

– Income• Sources of project income

• The goal of this budget is to demonstrate that you completely understand your financial requirements to build and test your spacecraft.

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Risk Management

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Risk Management

• List the top five risks which were given in the Programme Management Plan and at PDR– How have you managed/mitigated them?

– Have any risks occurred?

• Provide an updated risk table.– How has your top-five list changed since PDR?

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Concept of Operations(CONOPS)

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Concept of Operations: Operational Modes

• What are the Operational Modes of your spacecraft? How does it transition from one mode to another?– A diagram is very helpful to display this, e.g.,:

LaunchAll systems OFF

Boot-upSeparation

Safe-HoldSeek nominal attitude

Wait to hear from Ground

All systems powered up

Command from Ground…

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Concept of Operations: LEOP

• 1-3 slides detailing the operations during Launch and Early Orbit (LEOP) phase

• LEOP includes all operations following launch until you move into routine, nominal operations. E.g.,– Establish initial contact with the spacecraft

– Determine status of spacecraft sub-systems

– Determine spacecraft orbit

– Activate deployables

– Calibrate payloads, sensors, actuators

– Establish operational attitude

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Concept of Operations: Nominal

• 1-3 slides providing an updated view of spacecraft and mission operations

• Simple flow-chart diagrams are a good way to present the CONOPS

• Focus on how the spacecraft will operate, not what everyone on the team will be doing– Sample timeline of commanding events, from mission planning,

to command generation, to uplink, to execution

– Sample timeline of payload and telemetry data downlink events, from generation of data, to storage, to downlink, to analysis, distribution, and/or archiving

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Concept of Operations: Nominal Timelines

• Sample timeline of commanding events, from mission planning, to command generation, to uplink, to execution, to downlink.

• E.g., if you plan on imaging a particular area on the Earth:

• Keep in mind that it could take more than a day before your satellite is in position to be able to capture data from the objective area, and then several more hours until it can re-contact your ground station.

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Imaging request generated x xRequest encoded into commanding x xRequest prepared for uplink x xImaging Request Command up-linked xImaging occurs xData down-linked x

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Concept of Operations: Anomalies

• What anomalies can you detect, and how will you detect them?

• How quickly will you detect an anomaly?

• What is your operational response to an anomaly?

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Educational Outreach

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Educational Outreach

• Please summarise the Educational Outreach presentations you have given– Locations, approximate number of people, any local media

coverage

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Summary & Conclusions

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Summary & Conclusions

• In general include the following:– Major accomplishments

– Major unfinished work

– Next steps

– Other assistance needed?

– Why you are ready to proceed to next stage of development

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Supplementary Information

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Acronyms

• Provide a list of common acronyms used throughout the presentation.

University Crest 1 > Canadian Satellite Design Challenge Critical Design Review.

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