Goldeneye
University of Minnesota
University Nanosat 5
PDR Presentation
August 16th-17th, 2007
Logan, Utah
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.
Goldeneye
GPS Satellite
Mission Objectives
• Obtain Earth reflected GPS signals→
• Obtain direct GPS signals
• Process acquired data on the ground
Earth-reflected
GPS signal
Technology Demonstration
• Multifunctional applications
• Advanced science instrumentation and detector/camera technology
• Advanced solutions for miniaturized Nanosat subsystems
– Innovative GPS receiver/antenna, hardware, and algorithms
2
Mission Details: Bistatic Radar
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.)
3
RISK
Mission Timeline
•
•
Ground:
Test
payload
Integrate
with launch
vehicle
Launch
Deploy
–
–
•
Charge
batteries
Activate
systems
4 hours
5 min.
Attitude Control
Maneuvers:
· Detumble
· Despin about z-axis
· Point GPS high gain
antenna towards earth
TBD
Verify
systems
15 min.
•
Attitude
Control
Mode
Baseline
Mode
6 hours*
*Maximum time needed
to completely recharge
batteries while operating
baseline components
TBD
Transmit
Data Mode
10 min.
Experiment
Mode
36 sec.
•
Collects GPS data
Compresses GPS data
Stores GPS data
Transmit Data Mode:
–
•
Detumbles Goldeneye
Despins Goldeneye
Points GPS high gain antenna towards
Earth
Experiment 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:
–
–
–
Normal Operations Modes (duration - TBD):
Automatically enabled
Ends when pointing requirements satisfied
Baseline Mode:
–
–
–
–
–
Startup (duration - TBD):
Inhibits
release
Baseline mission: duration - TBD
Startup:
Transmits experiment data to ground
station for post processing
Extended Operations
4
Program Schedule
RISK
• Purpose: Ensure project is completed on-time
• Objective: Meet and verify requirements
5
Mission Top-Level Details:
Remote Sensing with GPS
RISK
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)
6
Mission Top-Level Details:
GPS Navigation Message
Figure adapted from, Misra and Enge
Global Positioning System:Signals, Measurements and Perfomrance
pp. 104, which is based on a figure by Frank van Diggelen
7
Requirements Flow
Mission Statement
Minimum Success
Criteria
Mission Objectives
Nominal Success
Criteria
Mission
Requirements
System Requirements
Goldeneye
Requirements
Ground
Station
Requirements
Ground Support
Equipment
Requirements
Subsystem Requirements:
· Bistatic Radar
· Attitude Determination and
Control
· Navigation
· Flight Computing
· Communications
· Power
· Structure
· Thermal Control
8
Mission Requirements
Requirement
Source
Verification
Source
Document
Test/Analysis
Number
M-1
Must meet all NS-5 requirements
MS
TBD
TBD
M-2
Must be able to collect GPS signals
O-1, O-2
TBD
TBD
M-3
Must be able to transmit data to ground station
O-1, O-2
TBD
TBD
M-4
Must be able to receive data at ground station
O-1, O-2
TBD
TBD
M-5
Must be able to process data on the ground
O-3
TBD
TBD
M-6
Must be able to design, fabricate and test Goldeneye
on the ground
MS
TBD
TBD
Three systems to accomplish the mission:
Goldeneye
Collects and
Transmits
Data
Ground Station
Receives
Goldeneye’s
Data
Ground Support
Processes
Goldeneye’s Data
Mission
Accomplished!
9
System 1 Overview: Goldeneye
RISK
The purpose of Goldeneye is to validate a GPS bistatic radar for
remote sensing applications onboard small satellites in low Earth
orbit.
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
10
System 1 Requirements: Goldeneye
Requirement
Source Verification
Source
Document
Test/Analysis
Number
GS-1
Must be able to operate in Earth orbit
M-1
TBD
TBD
GS-2
Must have onboard power supply
M-1
TBD
TBD
GS-3
Must start-up autonomously after deployment
M-1
TBD
TBD
GS-4
Must be able to determine attitude
O-1
TBD
TBD
GS-5
Must be able to control attitude
O-1
TBD
TBD
GS-6
Must be able to determine position and velocity
O-2
TBD
TBD
GS-7
Must be able to collect, store, and compress
data
O-3
TBD
TBD
GS-8
Must be able to receive transmissions from the
ground station
O-3
TBD
TBD
GS-9
Must be able to transmit data to ground station
O-3
TBD
TBD
11
System 1 Design Overview: Goldeneye
RISK
Goldeneye 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
12
Requirements: Bistatic Radar System (BRS)
Requirement
Source Verification Test/
Source
Analysis
Document Number
BRS-1
Must accept incoming GPS signals
M-2
TBD
TBD
BRS-1.1
Requires one GN3S Sampler from SiGe.
BRS-1
TBD
TBD
BRS-1.2
Requires one nadir aligned high gain LHCP antenna capable of
receiving signals at 1575MHz (L1 signal).
BRS-1
TBD
TBD
BRS-1.3
Requires GN3S software for reflected signal collection.
BRS-1
TBD
TBD
BRS-1.4
Requires one Novatel OEMV-3G GPS receiver.
BRS-1
TBD
TBD
BRS-1.5
Requires one RHCP antenna with boresight aligned to GPS
satellites capable of receiving signals at 1575MHz (L1 signal).
BRS-1
TBD
TBD
BRS-2
Must determine Earth surface conditions
NSC-1
TBD
TBD
BRS-2.1
Requires communication with flight computer.
BRS-2
TBD
TBD
BRS-2.2
Requires software GPS receiver (“Q”).
BRS-2
TBD
TBD
BRS-2.3
Requires MatLab software to process “Q” output.
BRS-2
TBD
TBD
BRS-3
Must validate experimental results.
NSC-1
TBD
TBD
BRS-3.1
Requires NOAA National Data Buoy Center data for dates and
times of reflected GPS signal data.
BRS-3
TBD
TBD
13
Design: Bistatic Radar System (BRS)
Antenna Configuration
GPS Direct Signal
Antenna
· Collects direct
GPS signals from
GPS satellites
GPS High
Gain Antenna
· Nadir Pointing
· Collects Earthreflected GPS
signals
14
RISK
Design: Bistatic Radar System (BRS)
Direct GPS
Signal Antenna
Legend
San Jose Navigation,
SA-60C Passive GPS
Antenna
HW
HW
SW
PWR
Hardware
Software
- Data Flow
MMCX
4.5 to 18 V, Expect 5V
-
- Power
5V
HW
Novatel OEMV-3G
GPS Receiver
Processed GPS Signal
RS-232 or USB
HW
Flight Computer
TBD: Windows XPe
PC/104 Footprint
Model TBD
2.7V to 3.3V, Self Regulated
HW
SiGe SE4110L
GN3S Sampler
Raw Reflected
GPS Signal
Data Compression
Routine
SW
MCX
TBD, Self
Regulated
USB
USB
If Active
Antenna
HW
HW
High Gain
Reflected GPS
Signal Antenna:
Nadir Pointing
TBD
Onboard Flash
Storage
TBD: USB Hub w/
multiple 2 gig USB
Flash drives
15
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
16
Requirements: Attitude Determination and Control
System (ADCS)
Requirement
Source
Verification Test/
Source
Analysis
Document Number
ADCS-1
Must provide on-orbit Goldeneye attitude data
GS-4, GS-5 TBD
TBD
ADCS-1.1
Must utilize a rate gyro
ADCS-1
TBD
TBD
ADCS-1.2
Must utilize a three-axis magnetometer
ADCS-1
TBD
TBD
ADCS-2
Must detumble Goldeneye on orbit
GS-4,
TBD
GS-5, GS-7
TBD
ADCS-3
Must despin Goldeneye about z-axis
GS-4,
TBD
GS-5, GS-7
TBD
ADCS-4
Must provide on-orbit directional control with a nadirfacing pointing accuracy of +/- 20 degrees
GS-4,
TBD
GS-5, GS-7
TBD
ADCS-4.1
Must provide passive directional control with gravity
gradient stabilization
ADCS-4
TBD
TBD
17
Design: Attitude Determination and Control System
(ADCS)
RISK
Objective: Maneuver from a measured attitude to a desired attitude that
will allow Goldeneye to perform the bistatic radar experiment.
Desired Attitude
Attitude Control System
Computed
Attitude
Attitude Control
Algorithms
Actuation:
Magnetic
Torquers
Attitude
Determination
Algorithms
Attitude Sensors:
Rate Gyro and
Magnetometer
Attitude Determination System
Goldeneye
Attitude
18
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
19
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"
20
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:
Inside Goldeneye
(Bottom Surface)
Z
5 Boxes
Goldeneye
Y
Y
Lightband
– I_roll > I_yaw , Therefore I_xx > I_yy > I_zz
X
X
Curtis, Howard D. Orbital
Mechanics for Engineers. Elsevier.
2005. Massachusetts. Page 539.
21
Design: Attitude Determination and Control System
(ADCS)
•
Magnetometer: Goodrich FM02
–
–
–
–
•
Rate Gyro: Honeywell HG1700
–
–
–
–
–
•
Measures magnetic field vector of
Earth
43 grams
0.33 Watts
Acquired
www.goodrich.com
Measures angular velocities about
x, y, and z axes
726 grams
5.5 Watts
2 deg/hr drift
Acquired
Magnetic Torquers: TBD
www.honeywell.com
22
Requirements: Navigation System (NAV)
Requirement
Source
Verification Test/
Source
Analysis
Document Number
Must determine position and velocity in orbit.
GS-6
TBD
TBD
NAV-1
TBD
TBD
NAV-1.2 Requires RHCP antenna capable of receiving NAV-1
signals at 1575MHz (L1 signal).
TBD
TBD
NAV-1.3 Requires transmission to FCS for logging of
x, y, z (position) and x-dot, y-dot, z-dot
(velocity) on orbit.
TBD
TBD
NAV-1
NAV-1.1 Requires Novatel OEMV-3G GPS receiver.
NAV-1
23
Design: Navigation System (NAV)
RISK
Using GPS to
determine position
and velocity
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
www.sanav.com
24
Design: Navigation System (NAV)
Direct GPS
Signal Antenna
HW
San Jose Navigation,
SA-60C Passive GPS
Antenna
Legacy design
from Nanosat-4
PWR
MMCX
4.5 to 18 V, Expect 5V
5V
HW
Novatel OEMV-3G
GPS Receiver
Processed GPS Signal
RS-232 or USB
X, Y, Z
X-dot, Y-dot, Z-dot
HW
Flight Computer
TBD: Windows XPe
PC/104 Footprint
Model TBD
Data Compression
Routine
Legend
HW
SW
-
TBD, Self
Regulated
USB
SW
Hardware
Software
- Data Flow
- Power
HW
Onboard Flash
Storage
TBD: USB Hub w/
multiple 2 gig USB
Flash drives
25
Requirements: Flight Computing System (FCS)
Requirement
Source Verification Test/
Source
Analysis
Document Number
FCS-1 Must collect all sensor data
GS-7
TBD
TBD
FCS-2 Must compress data for storage
GS-7
TBD
TBD
FCS-3 Must store collected data onboard
GS-7
TBD
TBD
FCS-4 Must determine attitude
GS-4
TBD
TBD
FCS-5 Must control attitude
GS-5
TBD
TBD
FCS-6 Must decide when to turn on bistatic radar
experiment
GS-7
TBD
TBD
FCS-7 Must be able to communicate with
Communication System
GS-9
TBD
TBD
26
Design: Flight Computing System (FCS)
RISK
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
27
Design: Flight Computing System (FCS)
Power
Switches
Heaters
Power
Manager
Current
Sensors
Temp
Sensors
Data
Storage
Device
Voltage
Sensors
Bi-static
Radar
System
USB 1.1
RS232 COM4
Flight
Computing
System
USB 1.1
RS232 COM1
Primary
Radio
Magnetometer
RS232 COM3
RS232 COM2
Rate
Gyro
Navigation
and ADCS
Torque
Coils
GPS
Reciever
Backup
Radio
28
Requirements: Communication System (COMM)
Requirement
Source
Verification Test/
Source
Analysis
Document Number
COMM-1 Must abide by applicable FCC regulations
M-1
TBD
TBD
COMM-2 Must have inhibits preventing RF emissions
before deployment
M-1
TBD
TBD
COMM-3 Must be able to communicate with Ground
Station during transmission windows
GS-8,
GS-9
TBD
TBD
COMM-4 Must be able to communicate with Flight
Computing System
GS-9
TBD
TBD
29
Design: Communications System (COMM)
RISK
Shown for one radio.
2 Radios: Kenwood TH-D7A
Second radio is the same.
• Nanosat-4 Legacy
Flight
• 380g
DC Power
Computing
System
• 54.0 x 119.5 x 43.5 mm
• 1.65 Watts (receiving)
Radio
• 26 Watts (transmitting)
Transceiver Functional Characteristics:
• Modulation: Reactance
Antenna
• Transmitting power: 5 Watts
• Frequency deviation +/- 5kHz
Modem Functional Characteristics:
• 9.6 kb/s
Whip Antenna
Whip Antenna,
13.4 inches long, for
• 440 MHz (transmitting)/144 MHz (receiving)
for receiving.
transmitting, 440 MHz
• Protocols: AX.25
144 MHz
2 Antennas:
Goldeneye
• Omnidirectional, nondeployable, on top of
Goldeneye
• Current height of transmitting antenna causes
approx. 14 cm breach of static envelopeLightband
considering other options
30
Requirements: Power System (PWR)
Requirement
Source Verification
Source
Document
Test/
Analysis
Number
PWR-1
Must have inhibits to prevent start-up before deployment
GS-3
TBD
TBD
PWR-2
Must charge batteries with solar cells
GS-2
TBD
TBD
PWR-3
Must control component activation and deactivation
GS-3
TBD
TBD
PWR-4
Must supply power to components at regulated voltages
GS-1
TBD
TBD
PWR-5
Must supply enough power to support mission
MS
TBD
TBD
PWR-6
Must protect components from transients
GS-1
TBD
TBD
PWR-7
Must protect components from overcurrent
GS-1
TBD
TBD
PWR-8
Must prevent batteries from overcharging
GS-1
TBD
TBD
PWR-9
Must mitigate short circuit failures
GS-1
TBD
TBD
PWR-10
Must monitor health
GS-1
TBD
TBD
PWR-10.1
Must monitor bus voltages
GS-1
TBD
TBD
PWR-10.2
Must monitor bus currents
GS-1
TBD
TBD
PWR-10.3
Must monitor component currents
GS-1
TBD
TBD
PWR-10.4
Must monitor component logic states
GS-1
TBD
TBD
PWR-10.5
Must monitor battery voltage
GS-1
TBD
TBD
PWR-10.6
Must receive component box temperature data from thermal control system
GS-1
TBD
TBD
PWR-11
Must transmit health data to flight computer
GS-7
TBD
TBD
31
Design: Power System (PWR)
Solar Cells
Batteries
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
Power
Manager
RISK
Satellite
Components
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
32
Design: Power System (PWR)
Sun
Solar
Panel 1
Solar
Panel 2
Solar
Panel 3
Solar
Panel 4
Solar
Panel 5
Solar
Panel 6
Batteries
15V-Loads
5V-Loads
DC/DC Power Supply
5V
15 V
Power Sources:
· Eclipse: Batteries
· Sun: Solar Cells and
Batteries
33
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
34
Design: Power System (PWR) > Power Budget
35
Requirements: Structure (STR)
Requirement
STR-1 to Must comply with Nanosat-5 program
STR-23 requirements
Source
Verification Test/
Source
Analysis
Document Number
M-1
TBD
TBD
STR-24
Must provide metal components boxes for GS-1
Goldeneye's hardware
TBD
TBD
STR-25
Must have an electrically conductive
coating on metal component boxes
GS-1
TBD
TBD
STR-26
Must have moments of inertia such that
I_xx > I_yy > I_zz
ADCS-4.1 TBD
TBD
36
Requirements 1 – 23: Structure (STR)
37
RISK
Design: Structure (STR)
Aluminum 6061-T6 Panels:
• Circular isogrid design
• Electrically conductive coating
GPS Direct
Signal
Antenna
Solar
Panels
Lightband
Interface
GPS High
Gain
Antenna
38
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
39
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 Base
Hand Calculation: s = 706 kPa
ANSYS solution: s = 723 kPa
40
Requirements: Thermal Control System (THRM)
Requirement
Source
Verification Test/
Source
Analysis
Document Number
THRM-1
Must maintain proper temperature ranges
for components to operate
GS-1
TBD
TBD
THRM-1.1
Must monitor temperature within every
component box
THRM-1 TBD
TBD
THRM-1.2
Must transmit temperature data to power
manager
THRM-1 TBD
TBD
41
Design: Thermal Control System (THRM)
RISK
• Heat sinks for components with 1 Watt power consumption
• Heaters for temperature sensitive components
• Operating Temperatures:
Viper PC-104 computer
-20 to 70 degrees Celsius
Novatel GPS receiver
-40 to 85 degrees Celsius
Kenwood TH-D7A radios
-20 to 60 degrees Celsius
GPS direct signal antenna
-40 to 85 degrees Celsius
Sanyo N-4000DRL batteries
0 to 40 degrees Celsius
Honeywell HG1700 rate gyro
TBD
Goodrich FM02 magnetometer
-55 to 88 degrees Celsius
APD D150-15/5 power supply
-25 to 85 degrees Celsius
42
Design: Thermal Control System (THRM)
Hardware:
• 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
43
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
44
System 2 Overview: Ground Station
•
•
•
•
RISK
Communicate, track, and receive data from Goldeneye
Send messages to Goldeneye
Used with amateur packet radio
Located at University of Minnesota
45
System 2 Requirements: Ground Station (GND)
Requirement
Source
Verification
Source
Document
Test/
Analysis
Number
GND-1 Must abide by applicable FCC regulations
M-1
TBD
TBD
GND-2 Must have no less than 90 degrees range in
elevation
M-3
TBD
TBD
GND-3 Must have no less than 360 degrees range in
azimuth
M-3
TBD
TBD
GND-4 Must be able to track Goldeneye in any orbit
M-3
TBD
TBD
GND-5 Must have antenna gain large enough to close M-3
link with Goldeneye
TBD
TBD
GND-6 Must be able to transmit data to Goldeneye
GS-8
TBD
TBD
GND-7 Must be able to receive data from Goldeneye
GS-8
TBD
TBD
46
Design Overview: Ground Station (GND)
Antenna
DC Power
Supply
Transceiver
TNC
DC Power Supply:
– TBD
Transceiver:
– TBD
– Receives signal from Goldeneye
– Transmits signal from PC
PC
RISK
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
47
Design Overview: Ground Station (GND)
2MCP22
(144 MHz,
Transmits)
436CP42UG
(440 MHz,
Receives)
Rotator
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
48
Communication – Link & Licensing
RISK
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.
49
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
50
Requirements: Ground Support Equipment (GSE)
Requirement
Source
Verification
Source
Document
Test/
Analysis
Number
GSE-1
Must have mechanical ground support equipment (MGSE)
M-8
TBD
TBD
GSE-1.1
Must have a lifting mechanism to lift Goldeneye from a
single point above its center of gravity
M-1
TBD
TBD
GSE-1.2
Must have a safety factor of 5
M-1
TBD
TBD
GSE-1.3
Lifting mechanism must not contact Goldeneye or nanosat
separation system
M-1
TBD
TBD
GSE-2
Must have electrical ground support equipment (EGSE)
M-8
TBD
TBD
GSE-2.1
Must monitor inhibits status
M-1
TBD
TBD
GSE-2.2
Must comply with KHB 1700.7C
M-1
TBD
TBD
GSE-2.3
Must monitor voltage of all battery cells
M-1
TBD
TBD
GSE-2.4
Must use-scoop-proof connectors
M-1
TBD
TBD
GSE-2.5
Must utilize fuse and diode protection to prevent EGSE
and usage failures from affecting Goldeneye's hardware
M-1
TBD
TBD
GSE-2.6
Must collect data from all of Goldeneye’s subsystems
M-1
TBD
TBD
51
Design Overview : Ground Support Equipment (GSE)
RISK
Electrical Ground Support Equipment
From Goldeneye:
Ports on Goldeneye:
·
·
·
·
Battery Maintenance
Remote Activation
Flight Computer
Interface
Electrical Interface
Goldeneye
·
·
·
Battery cell voltages
Inhibits status
Subsystem data
From Laptop:
·
Commands/Instructions
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
52
Launch Vehicle Interface
• Mechanical interface
RISK
• Electrical interface
– Aluminum ring protruding from
Goldeneye’s bottom structural
panel provides integration with
Lightband system
– 2 microswitches in Lightband
will actuate Goldeneye’s inhibits
– Wire pigtails from Goldeneye will
hang 12” below SIP to connect to
microswitches
Lightband
Interface
Wires from Goldeneye
connect inhibits to
microswitches
53
Program/Subsystem Risk Assessment
Overall
Program
Assessment
GSE
GND
STR
THRM
PWR
COMM
FCS
NAV
ADCS
BRS
Performance
Schedule
Cost
Safety
Testing
Manpower
Facilities
NA
Overall Subsystem Assessment
= low risk
Familiar with
design, hardware
and implementation
= medium risk
Somewhat familiar
with design, hardware
and implementation
= high risk
NA
= N/A
Not familiar with
design, hardware and
implementation
54
Relevance of GPS Bistatic Radar
• Easy implementation: requires compact, low power
existing hardware that many satellites already use.
• Reliable: Augments other data collection systems
that can be affected by weather.
• Inexpensive: Collects the same data as vital
satellites such as QuikSCAT, but at a lower cost.
55
Summer 2007 Organization
Demoz Gebre-Egziabher
PI
(Faculty: Aerospace Engineering)
Ellie Field
Student PM
Jim Pogemiller
BRS Lead
(MS: Aerospace
Engineering)
Brett
Burgstahler
ADCS Lead
Mike Brown
FCS Lead
Trevor Bain
Programmer
Katrina Faucett
COMM and GND
Lead
Mike Legatt
STR Lead
Jonah
White
STR Team
Demoz Gebre-Egziabher – PI
•gebre@aem.umn.edu
Ellie Field – Student PM
•fiel0140@umn.edu
56
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
57
Spacecraft Overview: Exploded View
Solar Panel
Batteries
GPS Direct
Signal Antenna
Radios
Flight
Computer
58
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
Solar Cells
Primer
Adhesive
Primer
Kapton
Aluminum
Honeycomb Panel
•
•
Apply primer to the back of cleaned
solar cell strings
Remove stencil and place solar cells
strings on adhesive
59
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
Side Panel: 4 Total
60
Power System: Inhibit Schematic
INH x 3
Solar Cells
INH x 3
Batteries
INH
INH
DC/DC
Power
Supply
Satellite
Components
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
61
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
Lid
Lid Gasket
Batteries
Cell Holder
Battery
Box
Mesh
Gasket
Vent Hole
Cover
Vent Hole
62
COMM: Link budget
63
Detailed Schedule
64
Integration and Testing:
Before July 2008:
Before October 2008:
BRS
Assembly
BRS Functional
Test
ADCS
Assembly
ADCS
Functional Test
NAV
Assembly
NAV
Functional Test
FCS
Assembly
FCS
Functional Test
COMM
Assembly
COMM
Functional Test
PWR
Assembly
PWR
Functional Test
STR
Assembly
STR
Functional Test
GND
Assembly
GND
Functional Test
GSE
Assembly
GSE
Functional Test
All tests performed at the
University of Minnesota,
before FCR
Before Jan. 2009
System
Integration
System Tests:
· Bakeout
· Thermal Vacuum
· Pressure Profile
· Envelope Verification
· Mass Properties
· EMC Self-Compatibility
· Electrical System Aliveness
and Functional Tests
65
Integration and Testing (table 8-1)
Structural Tests
Test
Component
Spacecraft
Margins
Strength
•Sine Burst, Yield, Ultimate
X
Sine burst at 1.2 times yield requirement, yield SF=2,
ultimate SF=2.6
Random Vibration/ Acoustic
X
0.25 gRMS from 20 to 2000 Hz (more, table 8.2)
Shock
X
100-10000 Hz, ASD levels see table 8.3
Stiffness
•Sine Sweep
X
Natural frequency 100 Hz, 0.25 gRMS from 20 to 2000
Hz
Thermal Tests
Bakeout
X
X
Thermal Vacuum
X
X
X
X
Depressurization 0.5psi/sec, Repressurization 0.3psi/sec,
SF=2
X
60 cm width, 50 cm height
X
X
50 kg
X
X
MIL-STD-461E
X
X
Physical Tests
Pressure Profile
Envelope Verification
Mass Properties
EMC Tests
Self-Compatibility
Functional Tests
Electrical System Aliveness and Functional Tests
66
Bistatic Radar System Detailed Requirements
Subsystem / Component Requirements
Method
Must accept incoming GPS signals
Antenna must be LHCP to avoid a 3dB signal loss due to reflected polarization
at the L1 signal frequency (1575.42MHz).
Design, Test
SiGe GPS Front End must accept data using the GN3S software.
Design, Test
Must determine Earth surface conditions
Must plot GPS signal characteristics as a delay vs. Doppler map
Analysis
Signal characteristics used to correlate to NOAA ocean buoy data and
QuikScat satellite data
Analysis
Must validate experimental results.
Use uncorrelated Goldeneye data to predict ocean surface conditions then
compare those conditions to NOAA buoy data and QuikScat satellite data.
Analysis
67
ADCS Detailed Requirements
Subsystem / Component Requirements
Method
Must provide on-orbit Goldeneye attitude data
Will utilize a magnetometer and a rate gyro to determine attitude.
Design, Test
Must provide data to the flight computer.
Design, Test
Must detumble and despin Goldeneye on orbit
Will utilize magnetic torquers.
Analysis
Must provide on-orbit directional control with a nadir-facing pointing accuracy of +/- 20 degrees
Will utilize magnetic torquers.
Analysis
Will use gravity gradient stabilization to augment magnetic torquers.
Analysis
68
Navigation System Detailed Requirements
Subsystem / Component Requirements
Method
Must determine position and velocity in orbit.
Will utilize OEMV-G3 GPS receiver for navigation solution.
Design, Test
Will use San Jose SA-60C GPS antenna.
Design, Test
Must provide navigation solution to the flight computer.
Test
69
FCS Detailed Requirements
Subsystem / Component Requirements
Method
Must collect all sensor data.
Must accept incoming sensor data from all sources.
Design, Test
Must compress data for storage
Will use data compression algorithm similar to WinZip.
Test
Must store collected data onboard.
Will utilize at least 2 Gb flash memory.
Analysis
Must determine attitude.
Must have algorithms to determine attitude.
Test
Must Control Attitude.
Must have algorithms to control attitude for desipinning, detumbling, and nadir
pointing.
Analysis, Test
Must decide when to turn on bistatic radar experiment.
Will compare navigation solution to a matrix of predetermined global locations
of ocean boundaries.
Analysis
Must be able to communicate with Communication System.
Requires an RS232 connection to the radios.
Design, Test
70
Communication System Detailed Requirements
Subsystem / Component Requirements
Method
Must abide by applicable FCC regulations.
Must have personnel with amateur radio licenses.
Analysis
Must contact FCC for frequency allocation and call sign.
Analysis
Must have inhibits preventing RF emissions before deployment.
Will be inhibited by four independent latching relays that are a part of the power
system’s inhibits.
Design, Test
Must be able to communicate with Ground Station during transmission windows.
Must have an antenna that receives at 144 MHz and transmits at 440 MHz
Analysis, Test
Must be able to communicate with Flight Computing System.
Must have RS232 interface between radios and flight computer.
Test
71
Power System Detailed Requirements
Subsystem / Component Requirements
Method
Must have inhibits to prevent start-up before deployment.
Must have eight independent inhibits in the configuration specified by the User’s Guide.
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.
Design, Test
Must control component activation and deactivation.
Must control power switches to each component.
Design, Test
Must supply power to components at regulated voltages.
Will use a DC/DC converter with dual outputs at regulated voltages.
Design, Test
Must supply enough power to support mission.
Must have enough solar cells and battery capacity to support mission.
Analysis, Test
Must protect components from transients.
Will utilize filters and decoupling capacitors.
Design, Test
Must protect components from overcurrent.
Must monitor current consumption of each component.
Design, Test
Must deactivate component if current draw is beyond component threshold.
Design, Test
Must prevent batteries from overcharging.
Must divert solar power to DC/DC converter when batteries are full
Design, Test
Must mitigate short circuit failures.
Must utilize a single point ground.
Design, Test
Must monitor health.
Must collect data from sensors that monitor battery voltages, bus voltages, component current, bus current, component
logic states and component box temperatures.
Design, Test
Must transmit health data to flight computer.
Must communicate with flight computer through an RS232 link.
Design, Test
72
Structure Detailed Requirements
Subsystem / Component Requirements
Method
Must comply with Nanosat-5 program requirements.
See requirements verification matrix.
Design, Analysis, Test
Must provide metal components boxes for Goldeneye's hardware.
Will use fully enclosed aluminum boxes
Design, Analysis
Will have vent holes
Analysis
Must have an electrically conductive coating on metal component boxes.
Will use Alodine
Analysis
Must have moments of inertia such that I_xx > I_yy > I_zz.
Must enable gravity gradient stabilization in orbit
Design, Analysis
73
Thermal Control System Detailed Requirements
Subsystem / Component Requirements
Method
Must maintain proper temperature ranges for components to operate.
Must monitor temperature within every component box.
Design, Test
Will use heat sinks for components that consume greater than 1 Watt.
Design, Analysis, Test
Will use heaters.
Design, Analysis, Test
74
Ground Station Detailed Requirements
Subsystem / Component Requirements
Method
Must abide by applicable FCC regulations.
Must have personnel with amateur radio licenses.
Analysis
Must contact FCC for frequency allocation and call sign.
Analysis
Must have no less than 90 degrees range in elevation.
Will use Yaesu G5500 rotator.
Design, Analysis, Test
Must have no less than 360 degrees range in azimuth.
Will use Yaesu G5500 rotator.
Analysis
Must be able to track Goldeneye in any orbit.
Will utilize NOVA software.
Analysis
Must have antenna gain large enough to close link with Goldeneye.
TBD
Analysis
Must be able to transmit data to Goldeneye.
Will use antenna from M2 inc: 2MCP22 (144 MHz).
Analysis, Test
Must be able to receive data from Goldeneye.
Will use antenna from M2 inc: 436CP42UG (440 MHz).
Analysis, Test
75
GSE Detailed Requirements
Subsystem / Component Requirements
Method
Must have mechanical ground support equipment (MGSE).
Must have a lifting mechanism to lift Goldeneye from a single point above its
center of gravity.
Design, Test
Must have a safety factor of 5.
Analysis
Lifting mechanism must not contact Goldeneye or nanosat separation system.
Design, Analysis
Must have electrical ground support equipment (EGSE).
Must monitor inhibits status.
Design, Test
Must comply with KHB 1700.7C.
Analysis, Test
Must monitor voltage of all battery cells.
Design, Test
Must use-scoop-proof connectors.
Design
Must utilize fuse and diode protection to prevent EGSE and usage failures from
affecting Goldeneye's hardware.
Analysis, Test
Must collect data from all of Goldeneye’s subsystems.
Design, Test
76