Goldeneye

University of MinnesotaUniversity Nanosat 5

PDR Presentation

August 16 th-17th, 2007Logan, Utah

2

Mission Overview

Mission Statement

The purpose of Goldeneye is to design, construct and validate a GPS bistatic radar

for remote sensing applications onboard small satellites in low Earth orbit.

Mission Objectives

• Obtain Earth reflected GPS signals→• Obtain direct GPS signals

• Process acquired data on the ground

Technology Demonstration

• Multifunctional applications

• Advanced science instrumentation and detector/camera technology

• Advanced solutions for miniaturized Nanosat subsystems

– Innovative GPS receiver/antenna, hardware, and algorithms

3

Bistatic Radar : Transmitter is not the receiver as in monostatic radar• Transmitter is the GPS satellite• Receiver is Goldeneye

• a is the range between transmitter and receiver• b + ρ is the reflected signal• From the geometry the range, ρ, to the reflection surface can be found

By analyzing the reflected signals power, Doppler shift and range variation, information about the reflecting surface can be deduced.

The science in this mission is to correlate these reflected signals with known ocean conditions, atmospheric and land conditions thereby exploring this novel application of GPS.

Example of Doppler-Shift vs Range Variation from a Reflected GPS Signal . ( S. Gleason, Remote Sensing of Ocean, Ice and Land Surfaces Using Bistatically Scattered GNSS Signals. Ph.D. Thesis. Surrey University. 2006.)

Mission Details: Bistatic Radar

4

Mission Timeline• Baseline mission: duration - TBD

• Startup:– Automatically enabled

– Ends when pointing requirements satisfied

• Baseline Mode:– Continuously runs after startup

– Includes “life support” systems only

– Charges batteries

– Receives messages from ground station

– Sends health status reports to ground station

• Attitude Control Mode:– Detumbles Goldeneye

– Despins Goldeneye

– Points GPS high gain antenna towards Earth

• Experiment Mode:– Collects GPS data

– Compresses GPS data

– Stores GPS data

• Transmit Data Mode:– Transmits experiment data to ground

station for post processing

• Extended Operations

RISK

Startup (duration - TBD):

Integrate with launch

vehicleLaunch Deploy

Inhibits release

Charge batteries

Baseline Mode

Experiment Mode

Transmit Data Mode

Normal Operations Modes (duration - TBD):

Test payload

Ground:

Attitude Control Maneuvers:DetumbleDespin about z-axisPoint GPS high gain antenna towards earthActivate

systemsVerify

systems

Attitude Control Mode

*Maximum time needed to completely recharge batteries while operating baseline components

5

Program ScheduleRISK

• Purpose: Ensure project is completed on-time• Objective: Meet and verify requirements

6

Mission Top-Level Details: Remote Sensing with GPS

Minimum Success:

• Establish Orbit

• Acquire direct and reflected GPS signals for at least 36 seconds

• Transmit GPS data to ground station

• Post-process GPS data

• Detect surface conditions on Earth– Ocean wind speed

– Wave/tidal height

Nominal Success:

• Minimum success criteria met

• Detect additional surface conditions on Earth– Ice surfaces

– Land features

– Soil moisture content

Another Possibility:

• Collect reflected GPS signals from other objects in orbit

• Analysis for the possibility of detecting other objects has been done.

• Radar cross section of reflecting object must meet certain stringent requirements (specular reflector, larger than 30 cm, etc)

RISK

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Mission Top-Level Details: GPS Navigation Message

Figure adapted from, Misra and EngeGlobal Positioning System:Signals, Measurements and Perfomrancepp. 104, which is based on a figure by Frank van Diggelen

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Requirements FlowMission Statement

Mission ObjectivesMinimum Success CriteriaNominal Success Criteria

Mission Requirements

Goldeneye Requirements

Ground Station

Requirements

Ground Support Equipment

Requirements

Subsystem Requirements:Bistatic RadarAttitude Determination and ControlNavigationFlight ComputingCommunicationsPowerStructureThermal Control

System Requirements

9

Mission Requirements

TBDTBDO-3Must be able to process data on the groundM-5

TBDTBDMSMust be able to design, fabricate and test Goldeneye

on the ground

M-6

TBDTBDO-1, O-2Must be able to receive data at ground stationM-4

TBDTBDO-1, O-2Must be able to transmit data to ground stationM-3

TBDTBDO-1, O-2Must be able to collect GPS signalsM-2

TBDTBDMSMust meet all NS-5 requirementsM-1

Test/Analysis

Number

Verification

Source

Document

SourceRequirement

Three systems to accomplish the mission:

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System 1 Overview: GoldeneyeThe purpose of Goldeneye is to validate a GPS bistatic radar forremote sensing applications onboard small satellites in low Earthorbit.

Attitude Determination and Control:Orients Goldeneye to collect experimental data

– Determines Goldeneye’s attitude

– Detumbles and Despins Goldeneye

– Points GPS high gain antenna towards Earth using magnetic torquers with +/- 20 accuracy

– Assists magnetic torquers by providing gravity gradient stabilization through Goldeneye’s moments of intertia

Data Collection, Storage, and Compression:

Acquires experimental data

– Collects raw, Earth-reflected GPS signals for 36 seconds

– Collects processed data from direct GPS signals for 36 seconds

– Compresses GPS data

– Stores GPS data

Transmitting to Ground Station:Allows validation of experimental data

– Listens for transmission window and sends stored GPS data to ground station

– Validation of the GPS bistatic radar is achieved through processing the GPS data with our own algorithms and correlating the processed data with actual ocean surface conditions

RISK

11

System 1 Requirements: Goldeneye

TBDTBDO-3Must be able to transmit data to ground stationGS-9

TBDTBDO-3Must be able to receive transmissions from the

ground station

GS-8

TBDTBDO-3Must be able to collect, store, and compress

data

GS-7

TBDTBDO-2Must be able to determine position and velocityGS-6

TBDTBDO-1Must be able to control attitudeGS-5

TBDTBDO-1Must be able to determine attitudeGS-4

TBDTBDM-1Must start-up autonomously after deploymentGS-3

TBDTBDM-1Must have onboard power supplyGS-2

TBDTBDM-1Must be able to operate in Earth orbitGS-1

Test/Analysis

Number

Verification

Source

Document

SourceRequirement

12

System 1 Design Overview: GoldeneyeGoldeneye has 8 subsystems for supporting the bistatic radar mission:

Bistatic Radar System (BRS)– direct signal GPS antenna, high gain left-hand polarized GPS antenna, GPS receiver and GPS RF

front end collector

Attitude Determination and Control System (ADCS)– magnetometer, rate gyro, active magnetic control

Navigation System (NAV)– direct signal GPS antenna and GPS receiver

Flight Computing System ((FCS)– embedded computer, data compression and storage

Communications System (COMM)– amateur packet radio system with built-in TNC

Power System (PWR)– body-mounted solar cells, inhibits, UNP-recommended NiCd battery design, DC-DC conversion,

mission mode control

Structure System (STR)– aluminum isogrid panels, solid aluminum component boxes, electrically conductive coatings,

vent holes

Thermal Control System (THRM)– Heaters, heat sinks

RISK

13

Requirements: Bistatic Radar System (BRS)

TBDTBDBRS-2Requires communication with flight computer.BRS-2.1

TBDTBDBRS-2Requires software GPS receiver (“Q”).BRS-2.2

TBDTBDBRS-2Requires MatLab software to process “Q” output.BRS-2.3

TBDTBDNSC-1Must validate experimental results.BRS-3

TBDTBDBRS-3Requires NOAA National Data Buoy Center data for dates and times of reflected GPS signal data.

BRS-3.1

TBDTBDNSC-1Must determine Earth surface conditionsBRS-2

TBDTBDBRS-1Requires one RHCP antenna with boresight aligned to GPS

satellites capable of receiving signals at 1575MHz (L1 signal).

BRS-1.5

TBDTBDBRS-1Requires one Novatel OEMV-3G GPS receiver.BRS-1.4

TBDTBDBRS-1Requires GN3S software for reflected signal collection.BRS-1.3

TBDTBDBRS-1Requires one nadir aligned high gain LHCP antenna capable of receiving signals at 1575MHz (L1 signal).

BRS-1.2

TBDTBDBRS-1Requires one GN3S Sampler from SiGe.BRS-1.1

TBDTBDM-2Must accept incoming GPS signalsBRS-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

14

Design: Bistatic Radar System (BRS)

Antenna Configuration

15

Design: Bistatic Radar System (BRS)

MCX

MMCX

USB

RISK

16

Data: Bistatic Radar System (BRS)

Mission Objective #3: Must be able to transmit data to ground station

BRS Data:

• 36 seconds of data is 640 Mb (minimum success criteria)

• 134.4 Mb after compression

• 234 Minutes required to transmit 36 seconds of data to ground

17

Requirements: Attitude Determination and Control System (ADCS)

TBDTBDGS-4,

GS-5, GS-7

Must provide on-orbit directional control with a nadir-

facing pointing accuracy of +/- 20 degrees

ADCS-4

TBDTBDGS-4,

GS-5, GS-7

Must despin Goldeneye about z-axisADCS-3

TBDTBDADCS-4Must provide passive directional control with gravity

gradient stabilization

ADCS-4.1

TBDTBDGS-4,

GS-5, GS-7

Must detumble Goldeneye on orbitADCS-2

TBDTBDADCS-1Must utilize a three-axis magnetometerADCS-1.2

TBDTBDADCS-1Must utilize a rate gyroADCS-1.1

TBDTBDGS-4, GS-5Must provide on-orbit Goldeneye attitude dataADCS-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

18

Design: Attitude Determination and Control System (ADCS)

Objective: Maneuver from a measured attitude to a desired attitude that

will allow Goldeneye to perform the bistatic radar experiment.

RISK

19

Design: Attitude Determination and Control System (ADCS)

Attitude Determination:

• Blend of magnetometer triad and rate gyro

measurements

Attitude Control:

• Active control through magnetic torquers

• Passive control through gravity gradient

stabilization (no boom)

Control Tasks:

• Detumble Goldeneye

• Despin Goldeneye

• Keep high gain antenna pointed towards

Earth with +/- 20 degrees accuracy

Dynamic Stability:

• Moment of inertia analysis for gravity

gradient stabilization

• Minimizes control authority required by

magnetic torquers

Always pointed towards Earth

20

Design: Attitude Determination and Control System (ADCS)

Attitude Determination

• Legacy design from Nanosat-4

• Attitude determination algorithm has already been validated

– Algorithm validated by using post processed space flight sensor data from the NASA/Stanford Gravity Probe B mission.

– Subject of the following journal manuscript in preparation:

• V. L. Bageshwar, D. Gebre-Egziabher, W. L. Garrard, P. Shestople, and M.

Adams, “Inertially Aided Vector Matching Algorithm for Satellite Attitude

Determination"

21

Design: Attitude Determination and Control System (ADCS)

Attitude Control

• Algorithms for detumbling

• Algorithms for despinning

• Algorithms for nadir pointing

• Moments of inertia for gravity

gradient stabilization:

– I_roll > I_yaw , Therefore I_xx > I_yy > I_zz

Curtis, Howard D. Orbital Mechanics for Engineers. Elsevier. 2005. Massachusetts. Page 539.

22

Design: Attitude Determination and Control System (ADCS)

• Magnetometer: Goodrich FM02

– Measures magnetic field vector of Earth

– 43 grams

– 0.33 Watts

– Acquired

• Rate Gyro: Honeywell HG1700

– Measures angular velocities about x, y, and z axes

– 726 grams

– 5.5 Watts

– 2 deg/hr drift

– Acquired

• Magnetic Torquers: TBD

www.goodrich.com

www.honeywell.com

23

Requirements: Navigation System (NAV)

TBDTBDNAV-1Requires transmission to FCS for logging of

x, y, z (position) and x-dot, y-dot, z-dot

(velocity) on orbit.

NAV-1.3

TBDTBDNAV-1Requires RHCP antenna capable of receiving

signals at 1575MHz (L1 signal).

NAV-1.2

TBDTBDNAV-1Requires Novatel OEMV-3G GPS receiver.NAV-1.1

TBDTBDGS-6Must determine position and velocity in orbit.NAV-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

24

Antenna:

• San Jose Navigation SA-60C

• 0.06 Watts

• Located on top outer surface of

Goldeneye

Receiver:

• Novatel OEMV-3G

• 2 Watts

• Housed in a component box

RISKDesign: Navigation System (NAV)

www.sanav.com

25

Design: Navigation System (NAV)

Novatel OEMV-3GGPS Receiver

Direct GPS Signal Antenna

MMCX RS-232 or USB

Onboard Flash Storage

HW

HW

HW

USBFlight Computer

Data Compression Routine

HWSW

San Jose Navigation, SA-60C Passive GPS AntennaTBD: Windows XPePC/104 FootprintModel TBD

TBD: USB Hub w/ multiple 2 gig USB Flash drives

Processed GPS SignalPWR4.5 to 18 V, Expect 5V 5V

TBD, SelfRegulatedX, Y, ZX-dot, Y-dot, Z-dot

HW - HardwareSW - Software- Data Flow- PowerLegend

Legacy design from Nanosat-4

26

Requirements: Flight Computing System (FCS)

TBDTBDGS-7Must compress data for storageFCS-2

TBDTBDGS-7Must decide when to turn on bistatic radar

experiment

FCS-6

TBDTBDGS-9Must be able to communicate with

Communication System

FCS-7

TBDTBDGS-5Must control attitudeFCS-5

TBDTBDGS-4Must determine attitudeFCS-4

TBDTBDGS-7Must store collected data onboardFCS-3

TBDTBDGS-7Must collect all sensor dataFCS-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

27

Design: Flight Computing System (FCS)Hardware/Software:

• Arcom PC-104 embedded computer

– 1.6 Watts

– 95 grams

– 400 MHz processor

– 5 serial ports, RS232

– 2 USB ports

– Programming language: C

– Acquired with Linux, looking for another that supports Windows for the GPS RF front end Interface Software

• Flash memory– 2 Gb required

• Software data management and test plan

– Account for all I/O

– Account for all processes associated with the I/O

– Computing Budget

RISK

28

Design: Flight Computing System (FCS)Heaters

Temp SensorsCurrent Sensors

Power SwitchesVoltage Sensors

Flight Computing System

RS232 COM4

Navigation and ADCS

RS232 COM2

Power Manager

MagnetometerRate GyroGPS RecieverTorque Coils

Bi-static Radar System

Primary Radio

Data Storage Device

Backup Radio

USB 1.1USB 1.1 RS232 COM1

RS232 COM3

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Requirements: Communication System (COMM)

TBDTBDGS-9Must be able to communicate with Flight

Computing System

COMM-4

TBDTBDGS-8,

GS-9

Must be able to communicate with Ground

Station during transmission windows

COMM-3

TBDTBDM-1Must have inhibits preventing RF emissions

before deployment

COMM-2

TBDTBDM-1Must abide by applicable FCC regulationsCOMM-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

30

Design: Communications System (COMM)2 Radios: Kenwood TH-D7A

• Nanosat-4 Legacy

• 380g

• 54.0 x 119.5 x 43.5 mm

• 1.65 Watts (receiving)

• 26 Watts (transmitting)

Transceiver Functional Characteristics:

• Modulation: Reactance

• Transmitting power: 5 Watts

• Frequency deviation +/- 5kHz

Modem Functional Characteristics:

• 9.6 kb/s

• 440 MHz (transmitting)/144 MHz (receiving)

• Protocols: AX.25

2 Antennas:

• Omnidirectional, nondeployable, on top of Goldeneye

• Current height of transmitting antenna causes approx. 14 cm breach of static envelope-considering other options

RISK

Radio

DC PowerFlight

Computing System

Antenna

Shown for one radio.Second radio is the same.

31

Requirements: Power System (PWR)

TBDTBDGS-1Must receive component box temperature data from thermal control systemPWR-10.6

TBDTBDGS-7Must transmit health data to flight computerPWR-11

TBDTBDGS-1Must mitigate short circuit failuresPWR-9

TBDTBDGS-1Must monitor healthPWR-10

TBDTBDGS-1Must monitor bus voltagesPWR-10.1

TBDTBDGS-1Must monitor bus currentsPWR-10.2

TBDTBDGS-1Must monitor component currentsPWR-10.3

TBDTBDGS-1Must monitor component logic statesPWR-10.4

TBDTBDGS-1Must monitor battery voltagePWR-10.5

TBDTBDGS-1Must prevent batteries from overchargingPWR-8

TBDTBDGS-1Must protect components from overcurrentPWR-7

TBDTBDGS-1Must protect components from transientsPWR-6

TBDTBDMSMust supply enough power to support missionPWR-5

TBDTBDGS-1Must supply power to components at regulated voltagesPWR-4

TBDTBDGS-3Must control component activation and deactivationPWR-3

TBDTBDGS-2Must charge batteries with solar cellsPWR-2

TBDTBDGS-3Must have inhibits to prevent start-up before deploymentPWR-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

32

Design: Power System (PWR)

Solar Cells:• EMCORE 607094, 192 cells

• 28% efficient

• Triple junction GaAs• Average power at least 35 Watts

Batteries:• 14 Sanyo N-4000DRL cells• Provided by AFRL

DC/DC Power Supply:• American power design D150-15/5,

88% efficient, • dual regulated outputs: 5V and 15V

Power Manager:• PIC controller• Monitors health of batteries and

hardware• Activates/Deactivates components

based on health data

RISK

33

Design: Power System (PWR)

Solar Panel 1

Solar Panel 6

Solar Panel 5

Solar Panel 4

Solar Panel 3

Solar Panel 2

Batteries

DC/DC Power Supply5 V 15 V

Sun

Power Sources:Eclipse: BatteriesSun: Solar Cells and Batteries

34

Design: Power System (PWR)

Components and Circuitry• Heaters• Inhibits• Power Switches• Voltage Monitors• Current Monitors• Temperature Monitors• Load Status Monitors• Transient Protection• Overvoltage Protection• Overcurrent Protection• Short Circuit Protection

Telemetry• Battery Voltage• Bus Voltage• Bus Current• Component Current• Load Status• Battery Box Temperature

35

Design: Power System (PWR) > Power Budget

36

Requirements: Structure (STR)

TBDTBDGS-1Must have an electrically conductive

coating on metal component boxes

STR-25

TBDTBDADCS-4.1Must have moments of inertia such that

I_xx > I_yy > I_zz

STR-26

TBDTBDGS-1Must provide metal components boxes for

Goldeneye's hardware

STR-24

TBDTBDM-1Must comply with Nanosat-5 program

requirements

STR-1 to

STR-23

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

37

Requirements 1 – 23: Structure (STR)

38

Design: Structure (STR)

Aluminum 6061-T6 Panels:

• Circular isogrid design

• Electrically conductive coating

RISK

Lightband Interface

Solar Panels

GPS Direct Signal

Antenna

GPS High Gain

Antenna

39

Design: Structure (STR)

Aluminum 6060-T6

Component Boxes:

• Housing for hardware

• 2-piece design

• Electrically conductive coating

• 2 vent holes, 0.25” diameter, size based on results of

venting analysis

40

S1.7 Design: Structure

Structural Analysis

Objective: Gain familiarity with ANSYS

• Model 1: Confirmation of ANSYS stress

deformation results by hand calculation

of compressive axial loading of simple

rectangular beam.

• Model 2: Confirmation of ANSYS stress

results by hand calculation of a

supported plate under acceleration

load.

Further Analysis:

• Brackets, component boxes, isogrid

panels, solar panels, buckling analysis

Model 1: Stress at Fixed BaseHand Calculation: s = 706 kPaANSYS solution: s = 723 kPa

41

Requirements: Thermal Control System (THRM)

TBDTBDTHRM-1Must transmit temperature data to power

manager

THRM-1.2

TBDTBDTHRM-1Must monitor temperature within every

component box

THRM-1.1

TBDTBDGS-1Must maintain proper temperature ranges

for components to operate

THRM-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

42

Design: Thermal Control System (THRM)

• Heat sinks for components with 1 Watt power consumption

• Heaters for temperature sensitive components

• Operating Temperatures:

RISK

TBDHoneywell HG1700 rate gyro

-55 to 88 degrees CelsiusGoodrich FM02 magnetometer

-25 to 85 degrees CelsiusAPD D150-15/5 power supply

0 to 40 degrees CelsiusSanyo N-4000DRL batteries

-40 to 85 degrees CelsiusGPS direct signal antenna

-20 to 60 degrees CelsiusKenwood TH-D7A radios

-40 to 85 degrees CelsiusNovatel GPS receiver

-20 to 70 degrees CelsiusViper PC-104 computer

43

Design: Thermal Control System (THRM)

• Temperature Sensors– Minco S3238PAZT36TB

– 12.7 X 31.8 X 1.3 mm

• Heaters

– Minco HK5160R157L12B

– 12.7 X 50.8 X 1.3 mm

www.minco.com

Hardware:

44

Design: Thermal Control System (THRM)

Thermal Analysis

• Transient model, 27 orbital scenarios, 1 node, sphere with same surface

area as Goldeneye

• Worst Case Hot:

– Goldeneye Surface: 75.0 degrees C (67.5 degrees avg)

– Goldeneye Payload: 75.3 degrees C (71.3 degrees avg)

– Altitude: 150 km

• Worst Case Cold:

– Goldeneye Surface: -11.0 degrees C (-7.5 degrees avg)

– Goldeneye Payload: -9.2 degrees C (-7.3 degrees avg)

– Altitude: 450 km

45

System 2 Overview: Ground Station

• Communicate, track, and receive data from Goldeneye

• Send messages to Goldeneye

• Used with amateur packet radio

• Located at University of Minnesota

RISK

46

System 2 Requirements: Ground Station (GND)

TBDTBDGS-8Must be able to receive data from GoldeneyeGND-7

TBDTBDGS-8Must be able to transmit data to GoldeneyeGND-6

TBDTBDM-3Must have antenna gain large enough to close

link with Goldeneye

GND-5

TBDTBDM-3Must be able to track Goldeneye in any orbitGND-4

TBDTBDM-3Must have no less than 360 degrees range in

azimuth

GND-3

TBDTBDM-3Must have no less than 90 degrees range in

elevation

GND-2

TBDTBDM-1Must abide by applicable FCC regulationsGND-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

47

Design Overview: Ground Station (GND)

DC Power Supply:

– TBD

Transceiver:

– TBD

– Receives signal from Goldeneye

– Transmits signal from PC

TNC (Terminal Node Controller):

– Kantronics KPC3+

– Takes signal from radio and converts to digital signal

– Sends digital signal to computer

PC:

– Dell Latitude C640 #PP01L

– Collects and stores data

– Controls TNC

– Controls rotator

– Tracks Goldeneye (NOVA software)

2 Antennas:

– M2 inc: 2MCP22 (144 MHz)Transmits to Goldeneye

– M2 inc: 436CP42UG (440 MHz)Receives from Goldeneye

RISK

48

Design Overview: Ground Station (GND)

Rotator

• Yaesu G5500 with GS-232A Computer interface

• Azimuth Range 0 to 360 Degrees

• Elevation Range 0 to 90 Degrees

• Max Rotation Speed 6 deg/sec (azimuth), 2.5 deg/sec (elevation)

• Rotates the antennas to follow Goldeneye

49

Communication – Link & Licensing

RF Link

– Signal to noise ratio: -3 dbm

– Bit error rate: TBD, based on design and outside interference

– Modulation type vs. channel distortion: TBD

Licensing

– At least level 1 technician

– Frequencies: 144/440 MHz (HAM)

– Status: Waiting to hear back from FCC about Call sign for Goldeneye, and

frequency allocation.

RISK

50

System 3 Overview : Ground Support Equipment (GSE)

• Transportation– Lifting mechanism

– Long distance travel container

• Allow complete operation of Goldeneye pre-launch– Autonomous and remotely controlled mission simulations

– Charge, discharge, equalize batteries

• Monitor Goldeneye on the ground– Pre-launch data collection through flight computer interface, electrical interface, or

radios

– Post-launch data collection through radios

• Process Goldeneye’s data on the ground– Data management plan

– Computer designated for processing data

51

Requirements: Ground Support Equipment (GSE)

TBDTBDM-1Must utilize fuse and diode protection to prevent EGSE

and usage failures from affecting Goldeneye's hardware

GSE-2.5

TBDTBDM-1Must monitor inhibits statusGSE-2.1

TBDTBDM-1Must collect data from all of Goldeneye’s subsystemsGSE-2.6

TBDTBDM-1Must use-scoop-proof connectorsGSE-2.4

TBDTBDM-1Must monitor voltage of all battery cells GSE-2.3

TBDTBDM-1Must comply with KHB 1700.7CGSE-2.2

TBDTBDM-8Must have electrical ground support equipment (EGSE)GSE-2

TBDTBDM-1Lifting mechanism must not contact Goldeneye or nanosat

separation system

GSE-1.3

TBDTBDM-1Must have a safety factor of 5GSE-1.2

TBDTBDM-1Must have a lifting mechanism to lift Goldeneye from a

single point above its center of gravity

GSE-1.1

TBDTBDM-8Must have mechanical ground support equipment (MGSE)GSE-1

Test/

Analysis

Number

Verification

Source

Document

SourceRequirement

52

Design Overview : Ground Support Equipment (GSE)

Electrical Ground Support Equipment

Battery Maintenance:

• Allows Nanosat team to charge, discharge, equalize batteries etc.

Remote Activation:

• “Master Switch” overrides Goldeneye’s onboard subsystems

• Allows Nanosat team to activate or deactivate Goldeneye

Flight Computer Interface:

• Provides subsystem data to laptop

• Allows Nanosat team to send commands/instructions to Goldeneye

Electrical Interface:

• Provides data to laptop for battery cell voltages and inhibits status

RISK

53

Lightband Interface

Wires from Goldeneye connect inhibits to

microswitches

Launch Vehicle Interface

• Mechanical interface

– Aluminum ring protruding from

Goldeneye’s bottom structural

panel provides integration with

Lightband system

• Electrical interface

– 2 microswitches in Lightband

will actuate Goldeneye’s inhibits

– Wire pigtails from Goldeneye will

hang 12” below SIP to connect to

microswitches

RISK

54

= low risk = medium risk = high risk NA = N/A

GS

E

Facilities

NAOverall Subsystem Assessment

Manpower

Testing

Safety

Cost

Schedule

Performance

Overall

Program

A

ssessment

GN

D

ST

R

TH

RM

PW

R

CO

MM

FC

S

NA

V

AD

CS

BR

S

Program/Subsystem Risk Assessment

Familiar with design, hardware and implementation

Somewhat familiar with design, hardware and implementation

Not familiar with design, hardware and implementation

55

Relevance of GPS Bistatic Radar

•• Easy implementation:Easy implementation: requires compact, low power existing hardware that many satellites already use.

•• Reliable:Reliable: Augments other data collection systems that can be affected by weather.

•• Inexpensive:Inexpensive: Collects the same data as vital satellites such as QuikSCAT, but at a lower cost.

56

Summer 2007 Organization

Demoz Gebre-Egziabher – PI

•gebre@aem.umn.edu

Ellie Field – Student PM

•fiel0140@umn.edu

57

K-12 Outreach

• Farnsworth Elementary June 1, 2007

• Exhibit at the Minnesota State Fair, September 1, 2007

• Tennant Take Your Child to Work Day June 2008

Students from Farnsworth Elementary

visiting the Nanosat lab at the University of

Minnesota

58

Spacecraft Overview: Exploded View

Radios

BatteriesGPS Direct

Signal Antenna

Flight Computer

Solar Panel

59

Solar Cell Mounting: How

Materials:

• Solar cells: Emcore triple junction GaAs

• Primer: Nusil CF6-135

• Adhesive: Nusil CV10-2568

• Kapton: 3M 1205 Acrylic Tape

• Aluminum Honeycomb Panel: Plascore,

0.05”-thick facesheets, 0.5”-thick

perforated core

Process Overview:

• Adhere kapton to cleaned aluminum

honeycomb panel

• Deaerate adhesive and apply with

primer to cleaned kapton using a

stencil

• Apply primer to the back of cleaned

solar cell strings

• Remove stencil and place solar cells

strings on adhesive

Solar Cells

PrimerAdhesive

Kapton

Aluminum Honeycomb Panel

Primer

60

Solar Cell Mounting: Where

192 Solar Cells Total

• Top panel: 60 cells

• Bottom panel: 12 cells

• Side panel: 30 cells each

Bottom Panel

Top Panel

61

Power System: Inhibit Schematic

Inhibits:• Total of 8 independent latching relays, board mounted in

different orientations• Prevent batteries from charging• Prevent solar power from reaching power supply• Prevent battery power from reaching power supply

Solar Cells BatteriesDC/DC Power Supply

Satellite Components

INH

INH x 3 INH x 3

INH

62

Electrical Systems and Power: Battery Box Design

• Batteries

– 14 Sanyo NiCd Type N-4000DRL cells, strung in series with spot welded Ni201 tabs

– 16.8 V, 4 A-hr Battery

– Kapton or Kynar insulation for Ni201 tabs

– Fuse included in battery box

• Battery box

– 6061-T651 aluminum cell holder, anodized

– 6061-T651 Al, Alodine exterior coating, anodized interior coating

– Cells fastened to cell holder using Eccobond 285, provides thermal path

– MAT301 absorbent material installed in void spaces to minimize free volume.

– Two filtered vents

– Two thermistors for temperature sensing

– Two heaters for maintaining operating temperature

• Battery Testing

– Cell level acceptance testing

– System level thermal testing followed by battery servicing

– Temperature, capacity and voltage monitoring during thermal testing

• Alodine: Mil-C-5541E Class 3

• Anodization: Mil-A-8625 “F” Type II Class 2

63

COMM: Link budget

64

Detailed Schedule

65

Integration and Testing:

All tests performed at the University of Minnesota, before FCR

66

XXBakeout

Depressurization 0.5psi/sec, Repressurization 0.3psi/sec,

SF=2

XXPressure Profile

0.25 gRMS from 20 to 2000 Hz (more, table 8.2)XRandom Vibration/ Acoustic

100-10000 Hz, ASD levels see table 8.3XShock

60 cm width, 50 cm heightXEnvelope Verification

50 kgXXMass Properties

Physical Tests

XXElectrical System Aliveness and Functional Tests

Functional Tests

MIL-STD-461EXXSelf-Compatibility

EMC Tests

XXThermal Vacuum

Thermal Tests

Natural frequency 100 Hz, 0.25 gRMS from 20 to 2000

Hz

XStiffness

•Sine Sweep

Sine burst at 1.2 times yield requirement, yield SF=2,

ultimate SF=2.6

XStrength

•Sine Burst, Yield, Ultimate

MarginsSpacecraftComponentTest

Structural Tests

Integration and Testing (table 8-1)

67

Bistatic Radar System Detailed Requirements

Must determine Earth surface conditions

AnalysisMust plot GPS signal characteristics as a delay vs. Doppler map

AnalysisSignal characteristics used to correlate to NOAA ocean buoy data and QuikScat satellite data

Must validate experimental results.

AnalysisUse uncorrelated Goldeneye data to predict ocean surface conditions then compare those conditions to NOAA buoy data and QuikScat satellite data.

Design, TestSiGe GPS Front End must accept data using the GN3S software.

Design, TestAntenna must be LHCP to avoid a 3dB signal loss due to reflected polarization at the L1 signal frequency (1575.42MHz).

Must accept incoming GPS signals

MethodSubsystem / Component Requirements

68

ADCS Detailed Requirements

AnalysisWill utilize magnetic torquers.

AnalysisWill use gravity gradient stabilization to augment magnetic torquers.

Must detumble and despin Goldeneye on orbit

AnalysisWill utilize magnetic torquers.

Must provide on-orbit directional control with a na dir-facing pointing accuracy of +/- 20 degrees

Design, TestMust provide data to the flight computer.

Design, TestWill utilize a magnetometer and a rate gyro to determine attitude.

Must provide on-orbit Goldeneye attitude data

MethodSubsystem / Component Requirements

69

Navigation System Detailed Requirements

TestMust provide navigation solution to the flight computer.

Design, TestWill use San Jose SA-60C GPS antenna.

Design, TestWill utilize OEMV-G3 GPS receiver for navigation solution.

Must determine position and velocity in orbit.

MethodSubsystem / Component Requirements

70

FCS Detailed Requirements

Test

Must compress data for storage

Will use data compression algorithm similar to WinZip.

Must be able to communicate with Communication Syst em.

Design, TestRequires an RS232 connection to the radios.

TestMust have algorithms to determine attitude.

Must Control Attitude.

Analysis, TestMust have algorithms to control attitude for desipinning, detumbling, and nadir pointing.

Must decide when to turn on bistatic radar experimen t.

AnalysisWill compare navigation solution to a matrix of predetermined global locations of ocean boundaries.

Must store collected data onboard.

AnalysisWill utilize at least 2 Gb flash memory.

Must determine attitude.

Design, TestMust accept incoming sensor data from all sources.

Must collect all sensor data.

MethodSubsystem / Component Requirements

71

Communication System Detailed Requirements

AnalysisMust have personnel with amateur radio licenses.

Design, Test

Must have inhibits preventing RF emissions before d eployment.

Will be inhibited by four independent latching relays that are a part of the power system’s inhibits.

TestMust have RS232 interface between radios and flight computer.

Must be able to communicate with Ground Station dur ing transmission windows.

Analysis, TestMust have an antenna that receives at 144 MHz and transmits at 440 MHz

Must be able to communicate with Flight Computing S ystem.

AnalysisMust contact FCC for frequency allocation and call sign.

Must abide by applicable FCC regulations.

MethodSubsystem / Component Requirements

72

Power System Detailed Requirements

Must monitor health.

Design, TestMust collect data from sensors that monitor battery voltages, bus voltages, component current, bus current, component logic states and component box temperatures.

Must transmit health data to flight computer.

Design, TestMust communicate with flight computer through an RS232 link.

Design, TestMust monitor current consumption of each component.

Design, TestMust deactivate component if current draw is beyond component threshold.

Must prevent batteries from overcharging.

Design, TestMust divert solar power to DC/DC converter when batteries are full

Must mitigate short circuit failures.

Design, TestMust utilize a single point ground.

Design, Test

Must charge batteries with solar cells.

Must connect solar cells to batteries and allow electrical power to bypass batteries when batteries are full.

Must protect components from overcurrent.

Design, TestWill use a DC/DC converter with dual outputs at regulated voltages.

Must supply enough power to support mission.

Analysis, TestMust have enough solar cells and battery capacity to support mission.

Must protect components from transients.

Design, TestWill utilize filters and decoupling capacitors.

Must control component activation and deactivation.

Design, TestMust control power switches to each component.

Must supply power to components at regulated voltages.

Design, TestMust have eight independent inhibits in the configuration specified by the User’s Guide.

Must have inhibits to prevent start-up before deployment.

MethodSubsystem / Component Requirements

73

Structure Detailed Requirements

Design, AnalysisWill use fully enclosed aluminum boxes

Analysis

Must provide metal components boxes for Goldeneye's hardware.

Will have vent holes

Design, AnalysisMust enable gravity gradient stabilization in orbit

Must have an electrically conductive coating on met al component boxes.

AnalysisWill use Alodine

Must have moments of inertia such that I_xx > I_yy > I_zz.

Design, Analysis, TestSee requirements verification matrix.

Must comply with Nanosat-5 program requirements.

MethodSubsystem / Component Requirements

74

Thermal Control System Detailed Requirements

Design, Analysis, TestWill use heat sinks for components that consume greater than 1 Watt.

Design, TestMust monitor temperature within every component box.

Design, Analysis, TestWill use heaters.

Must maintain proper temperature ranges for compone nts to operate.

MethodSubsystem / Component Requirements

75

Ground Station Detailed Requirements

Must be able to transmit data to Goldeneye.

Analysis, TestWill use antenna from M2 inc: 2MCP22 (144 MHz).

Must be able to receive data from Goldeneye.

Must have antenna gain large enough to close link w ith Goldeneye.

AnalysisTBD

AnalysisWill utilize NOVA software.

AnalysisMust have personnel with amateur radio licenses.

Design, Analysis, TestWill use Yaesu G5500 rotator.

Must have no less than 90 degrees range in elevatio n.

Analysis, TestWill use antenna from M2 inc: 436CP42UG (440 MHz).

Must have no less than 360 degrees range in azimuth .

AnalysisWill use Yaesu G5500 rotator.

Must be able to track Goldeneye in any orbit.

AnalysisMust contact FCC for frequency allocation and call sign.

Must abide by applicable FCC regulations.

MethodSubsystem / Component Requirements

76

GSE Detailed Requirements

AnalysisMust have a safety factor of 5.

Analysis, TestMust utilize fuse and diode protection to prevent EGSE and usage failures from affecting Goldeneye's hardware.

DesignMust use-scoop-proof connectors.

Design, TestMust monitor voltage of all battery cells.

Design, TestMust have a lifting mechanism to lift Goldeneye from a single point above its center of gravity.

Design, TestMust monitor inhibits status.

Must have electrical ground support equipment (EGSE ).

Design, TestMust collect data from all of Goldeneye’s subsystems.

Analysis, TestMust comply with KHB 1700.7C.

Design, AnalysisLifting mechanism must not contact Goldeneye or nanosat separation system.

Must have mechanical ground support equipment (MGSE ).

MethodSubsystem / Component Requirements