Aloft Stratospheric Testbed for Experimental Research on Infrasonic Activity
Courtney Ballard | Emily Daugherty | Connor Dullea | Kyle Garner | Martin Heaney | Ian Thom | Michael Von Hendy | Kerry Wahl |
Emma Young
Topic
Presenter
Project Purpose and Background
Michael
Final Design
•
Final Design Overview
Michael
•
Critical Project Elements
Courtney
•
Microphone Design and Data Collection
System
•
Thermal Analysis
Connor
•
Mechanical Design
Connor
Courtney, Michael
Project Risks
Emma
Verification and Validation
Emily
Project Planning
Emma
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
2
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
3
Develop a protoflight* high-altitude balloon payload capable
of measuring infrasonic events of frequencies between 0.1
and 20 Hz with a minimum amplitude of 0.1 Pa.
Functional Requirements:
Requirement
Designation
Description
FR.1
ASTERIA shall measure and record simulated
infrasonic sources between 0.1 and 20 Hz, with a
minimum wave amplitude of 0.1 Pa.
FR.2
FR.3
ASTERIA shall be capable of operating on a balloon
that travels to an altitude of 18 to 21 km.
ASTERIA shall operate autonomously for a minimum
of 24 hours, the duration of the mission flight.
*Protoflight: Hardware that is designed to flight standards, but may not
incorporate
all the necessary materials or testing required to be flightProject
Design
Background
Microphone
Thermal
Mechanical
Risks
V&V
Overview
Management
certified
4
Infrasound: Sound waves below the
threshold of human hearing (0.1-20 Hz)
•
•
Generated by severe weather,
earthquakes, volcanoes, meteors
Able to propagate for 1000’s of km
Current monitoring network (CTBTIMS*) is only capable of detecting
~30% of 0.1-kiloton events [Pinchon 2010]
•
•
Largest detection: Chelyabinsk
meteor
Issues with noise, mainly from wind
Current CTBT-IMS Network
[Natural Resources Canada]
Microphone
Desire to increase detection of events
•
Important for design of re-entering
spacecraft, verification of
atmospheric models, testing CTBTIMS network
Spatial Filter
CTBT-IMS station (UK)
[Alden 2013]
Design
Project
Background
Microphone
MechanicalInternational
Risks
V&V
*CTBT-IMS:
Comprehensive
Nuclear Thermal
Test-Ban Treaty
Monitoring
System
Overview
Management
5
•
>95% of bolides* produce a majority of their infrasound
at altitudes of 20-30 km. [Pinchon, 2010]
• Infrasound propagates through stratospheric channels
• Waveguides efficiently propagate signals for 1,000’s of km
• Waveguides: thermal channels in the atmosphere
STRATOSPHERE
PRESSURE WAVES (INFRASOUND)
ASTERIA
BOLIDE
GROUND STATIONS
(EXISTING)
*Bolides: Meteors that explode in the Earth’s atmosphere
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
6
Current Project: Protoflight Ready Sensor & Support Systems
Functional Requirements
VOLTAGE
ASTERIA shall collect
pressure measurements
from simulated infrasonic
sources between 0.1 and 20
Hz, with a sensitivity of
0.1 Pa.
1
TIME
Pressure
Data Out
Patm , Tatm
ASTERIA shall be capable
of operating on a balloon
that travels to an altitude of
18 to 21 km.
P, T
Microphone
Infrasound
Source
Wind
Barrier
Support Systems:
Power, Thermal,
Structural, Data
2
ASTERIA shall operate
autonomously for a
minimum duration of the
mission flight, 24 hours.
ASTERIA
Simulated Infrasound
Waves
(0.1-20Hz)
Design
Background
Microphone
Overview
Thermal
Mechanical
Risks
V&V
Project
Management
3
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
8
Steel Hoist
Ring (x3)
Structural/Thermal
22”
• Mass: 8.95 kg
Polystyrene
• Dimensions: Cylinder (24” tall, Insulation (x12)
22” diameter)
• Inner Electronics Support:
Aluminum 6061-T6 structure Nylon Tubing
(x5)
used to mount microphones,
batteries, and PIC controller
24”
• Outer Structure: Aluminum
6061-T6, Polystyrene Foam
Insulation
Three-Arm
Cap Plate (x2)
Microphone Circuit
Board (x5)
Internal Structure
Polyurethane
Wind Barrier (x5)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
9
Electronics
• Ten InfraBSU differential
pressure transducer
microphones (2 per board)
• PIC Microcontroller
• 1x Temperature Sensor
• 1x 7.4 (20.8 A-h)
• 1x 11.1 V (2200 mA-h)
• Power consumption: 3.45 W
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
10
Infrasound Pressure
Wave Propagation
(0.1-20 Hz)
ASTERIA
Wind
Barrier (X5)
Microphone System (x5)
Reduced Wind
Noise Signal
(by 15 dB)
Temperature
Sensor
Regulated Voltage (3.3V)
Temperature Signal (3.3V SPI)
Differential
Pressure
Transducer
(Active)
Regulated
Voltage (7V)
Differential
Pressure
Transducer
(Reference)
Amplification +
Low-Pass Filter
A/D Converter
Conditioned
Signals (0-1.25V)
Pressure Signals
(3.55±0.005V)
Amplification +
Low-Pass Filter
Digital Pressure
Signals (3.3V SPI)
Regulated
Voltage (±5V)
7V Regulator
A/D Converter
Regulated Voltage (5V)
Raw Voltage (11.1V)
3.3V
Regulator
Connector
11.1V
(2200mAh)
Key:
Physical Connection
Digital Signal
Analog Signal
Power
Microphone Board
Control Board
Batteries
Raw Voltage (11.1V)
Regulated Voltage (±5V)
7.4V
(20.8Ah)
Raw Voltage
(7.4V)
Regulated
Voltage (5V)
5V
Regulator
3.3V
Regulator
Digital Signals (3.3V SPI)
PIC
Controller
±5V DC/DC
Converter
Regulated
Voltage (3.3V)
PIC Controller
Board
Connector
(x5)
Digital Data
(3.3V SPI)
SD
Storage
9600-8-N-1
USART
USB-USART
Conversion
USB In/Out
Project Element
Description
Microphone Design & Data
Collection
0.01 Pa changes (0.8 μV changes) require
extensive signal conditioning and interfacing.
Infrasound Generation & Test
Equipment
Produces simulated infrasound of variable
frequencies and amplitudes.
Power Budget
Batteries must maintain power draw for 24
hours
Stratospheric Survivability of
Payload
Maintain components within -10 to 45°C in
ambient temperatures of -55 and 30°C.
Data Storage Survivability
The data storage card must be recoverable.
Mass Budget
The payload mass cannot exceed 20 kg.
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
12
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
13
Key CPEs addressed:
• Microphone Design and Data Collection
• Infrasound Generation and Testing
• Power Budget
Driving Requirements
ID
Requirement Description
Performance
DR 1.1
Detect simulated infrasound waves of amplitude 0.1100 Pa.
Transducer dynamic range of ±124 Pa
DR 1.4
Filter frequencies greater than 20 Hz.
40 Hz RC filter corner frequency
DR 1.5
Minimum ADC resolution of 0.01 Pa
0.0038 Pa (16 bit) ADC resolution
DR 1.7
Record data on a removable data storage device.
Removable MicroSD card stores data.
DR 1.8
Minimum Signal-to-Noise Ratio (SNR) of 5
System SNR of 5*
DR 3.1
Provide necessary power for a minimum of 24
hours
At least 24% margin on energy storage
*Temperature sensitivity calibration of microphone will increase the system SNR
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
14
Control Board
MicroSD
USB to
USART
PIC Microcontroller
Status
LED
Temperature
Sensor
Status
LED
Reset
Switch
Connector
7.4 V, 20.8 A-h
Main Battery
11.1 V,
2200 mA-h
Battery
Board Dimensions
x2
x5
Microphone
Signal
Conditioning
Circuit
Background
Design
Overview
Microphone
Microphone
Board
ADC
Thermal
Connector
Length
Width
Microphone
Board
4 in
3 in
Processor
Board
6 in
3 in
Temperature
Sensor
Mechanical
Risks
V&V
Project
Management
15
InfraBSU
Performance
Metric
Requirement
Frequency Response
FR 1.1
0.1 – 20 Hz
0.01 – 40 Hz
Linear Dynamic Pressure
Range
DR 1.1
0.1 – 100 Pa
±124.5 Pa
Pressure Sensitivity
DR 1.5
0.01 Pa
0.00063 Pa
Has flight heritage on August
2014 NASA HASP (High
Altitude Student Payloads)
Open Port
Differential Pressure Transducer
(Allsensors 0.5-INCH-D-MV)
Analog Voltage
Data Connection
To scale
Mechanical Filter
Battery
Connector
*Active Microphone Depicted
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
16
Dial Gauge
Synchronous
Motor and
Gears
Pressure Transducer
Adjustable Eccentric
Mechanical Filter
DAQ
Sylphon Bellows
Connective Tubing
Open Port
Steel Wool
Measured 0.044 Hz
Pressure Waves
(below 0.1 Hz
Requirement)
Thermal Insulation
Piston Bellows (NOAA)
Simulated Infrasound
Design
Waves Microphone
Background
Overview
(0.1-20Hz)
Thermal
Mechanical
Risks
V&V
Project
Management
17
To Control Board
Key
7V Regulator
0.5INCH-D-MV Pressure Transducer
Signal Conditioning Circuit
Analog to Digital Converter (ADC)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
18
Reference Transducer
Active Transducer
Open Port
Mechanical Filter
(“Closed Port”)
Diaphragm
Infrasound signals rejected;
Only payload acceleration detected
Background
Design
Overview
Microphone
Thermal
Analog Infrasound Signal
Mechanical
Risks
V&V
Project
Management
19
To Control Board
Key
7V Regulator
0.5INCH-D-MV Pressure Transducer
Signal Conditioning Circuit
Analog to Digital Converter (ADC)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
20
Differential Op Amp
Summing Op Amp & RC Filter
Amplified signal is
summed with a
reference voltage
Analog voltage signal
from transducer is
amplified to match
ADC range
RC filter
attenuates
signals ≥40 Hz
Circuit Output:
0-1.25 V Signal
(to interface with
ADC)
Key
Blue – Reference Voltage
Green – Measured Signal
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
21
To Control Board
Key
7V Regulator
0.5INCH-D-MV Pressure Transducer
Signal Conditioning Circuit
Analog to Digital Converter (ADC)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
22
Control Board
MicroSD
USB to
USART
PIC Microcontroller
Status
LED
Temperature
Sensor
Status
LED
Reset
Switch
Connector
x5
Microphone
Signal
Conditioning
Circuit
Background
Design
Overview
Microphone
Microphone
Board
ADC
Thermal
7.4 V, 20.8 A-h
Main Battery
11.1 V,
2200 mA-h
Battery
Board Dimensions
Connector
Length
Width
Microphone
Board
4 in
3 in
Processor
Board
6 in
3 in
Temperature
Sensor
Mechanical
Risks
V&V
Project
Management
23
To Microphone
Board
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
24
Power (mW)
7.4V Li-Ion
Power (mW)
11.1V Li-Ion
MicroSD
PIC
355.2
740
1124.8
740
370
11.7
61
Total Power: 3.4 W
Mission Duration: 24 hours
Total Energy: 82 W-h
Margin: 24% (at -10°C)
Background
Design
Overview
Microphone
USB to
USART
SPI Temp.
Sensor (x6)
16-bit ADC
(x10)
Quad OpAmp (x5)
DC-DC
Converter
Thermal
83.25
83.25
Active
Pressure
Transducer
Reference
Pressure
Transducer
7 V Voltage
Regulator
83.25
Total Power: 250 mW
Mission Duration: 24 hours
Total Energy: 6 W-h
Margin: 50% (at -20°C)
Mechanical
Risks
V&V
Project
Management
25
Driving Design Requirements
ID
DR.1.5
DR 1.5.2
DR 3.3.2
Background
Requirement Description
Design
Minimum ADC sampling frequency of
ADC maximum sampling frequency of
120Hz.
40Hz
Software/hardware operations and delays
less than 25ms.
Pre-flight routine checks peripheral
device health
Design
Overview
Microphone
Thermal
Projected delays total 8.2ms.
Detects ports that output a null voltage
Mechanical
Risks
V&V
Project
Management
26
Microphone Circuit Board x5
Microphone
Peripheral
Electronics
Signal
Processing
Circuit
ADC
Query
Temperature
Sensor
Response
Query
Processor Board
MicroSD Card
Response
PIC Micro
Controller
Write Data
-Circuit Board
Background
Design
Overview
Microphone
-IC Component
Thermal
Mechanical
Continuous
Onboard
Operating
Routine
-Software Routine
Risks
V&V
Project
Management
27
Temp. x6
ADC x10
LTC2470 ADC Conversion
ADC Write Time and Delay
x10
ADT7320 Temperature
Sensor Write and Delay x6
SD Card Write Operaiton
Margin
SD Card
Conversion Time
0
10
20
Time Elapsed (ms)
30
Margin
Software Timing Loop
•Required each loop under 25 ms
•Assuming Worst Case Timing Scenario
•Loop uses 8.2 ms, worst case
•Provides 16.8 ms margin, or 67%
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
✓
Project
Management
28
Driving Requirements
ID
Requirement Description
Performance
DR 1.1
Detect simulated infrasound waves of amplitude
0.1-100 Pa.
Transducer dynamic range of ±124 Pa
DR 1.4
Filter frequencies greater than 20 Hz.
40 Hz RC filter corner frequency
DR 1.5
Minimum ADC resolution of 0.01 Pa
0.0038 Pa (16 bit) ADC resolution
DR 1.7
Record data on a removable data storage
device.
Removable MicroSD card stores data.
DR 1.8
Minimum Signal-to-Noise Ratio (SNR) of 5
System SNR of 5*
DR 3.1
DR.1.5
DR 1.5.2
DR 3.3.2
Background
Provide necessary power for a minimum of 24
hours
Minimum ADC sampling frequency of 40 Hz
Software/hardware operations and delays less
than 25 ms.
Pre-flight routine checks peripheral device
health
Design
Overview
Microphone
Thermal
Mechanical
At least 24% margin on energy storage
ADC maximum sampling frequency of 120 Hz.
Projected delays total 8.2 ms.
Detects ports that output a null voltage
Risks
V&V
Project
Management
29
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
30
Key CPEs addressed: Stratospheric Survivability of Payload
Driving Requirements
ID
Description
Shall operate in ambient environment of
DR 2.5
-55 to 30°C
Maintain the temperature of internal
components from
-10 to 45°C
DR 2.6
Background
Design
Overview
Microphone
Thermal
Performance
All design components rated for
temperature range
Design includes passive thermal
control (7” of polystyrene insulation) to
keep internal components
between -5 and 32°C
Mechanical
Risks
V&V
Project
Management
31
•
Component operating
limit: -20 to 55°C
Required operating
range: -10 to 45°C
Mission Temperature Ranges
350
80
330
60
• Based on DR 2.6: Shall
maintain the temperature
of the payload components
10 ± 1° C below the
maximum and above
component minimum
specifications
Temperature, (°C)
•
margin
55°C
45°C
margin
-10°C
-20°C
310
40
20
290
2700
250-
20
230
Ambient Temperature
40
210
0
5
10
15
-50°C
20
25
Duration in Stratosphere, (hours)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
32
Absorptivity = 0.24
Emissivity = 0.90
Solar Radiation
𝑊
(ISun = 1350 𝑚2)
Radiation to Environment
(Tamb = 223K)
Internal Heat
Generation (6 W)
Conduction
𝑊
(0.025
)
Convection (0.72
𝑚𝐾
Reflected Solar Radiation
(AbledoEarth = 0.30)
Background
Design
Overview
Microphone
Thermal
𝑊
)
𝑚2 −𝐾
Radiation from Earth
(TEarth = ~300K)
Mechanical
Risks
V&V
Project
Management
33


Solidworks FEM Thermal
Analysis
Absorptivity = 0.24
Emissivity = 0.90
320
 Values from Sherwin
310
Williams white coating

Polystyrene insulation
used
 Thermal conductivity of
 17.8 cm (7”) of insulation
around internal structure

Design
Overview
Microphone
Sunset
Sunrise
300
290
280
270
Required Temperature Range
Internal heat generation
=6W
Background
Payload Internal Temperature
Temperature, (K)

Thermal
260
0.0
4.8
9.6
14.4
19.2
24.0
Flight Time, (hours)
Mechanical
Risks
V&V
Project
Management
34
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
35
Key CPEs addressed: Stratospheric Survivability of Payload
Driving Requirements
ID
Requirement Description
DR 2.1.1
Mass no greater than 20 kg
DR 2.2.1
Shall structurally interface with gondola
DR 2.7
Background
Performance
Mass of design is 8.95 kg (~55%
margin)
Payload can withstand in-flight and impact
forces of 2000 N
Design
Overview
Microphone
Thermal
Mechanical
Flexible cable attachment designed
Design includes safety factors to
survive 2000 N forces with
considerable margin
Risks
V&V
Project
Management
36
Top View
Oblique View
22”
Steel Hoist
Ring (x3)
22”
Three-Arm
Cap Plate (x2)
Aluminum 6061-T6
1.75”
3.5”
Polystyrene
Insulation
Sheets (x12)
24”
Polyurethane
Wind Barrier (x5)
3”
Background
Design
Overview
Microphone
3”
Support Arm (x3)
Aluminum 6061T6
Thermal
Mechanical
Risks
V&V
Project
Management
37
Cutaway View
22”
Exploded View
Polyurethane
Wind Barrier
(x5)
7”
Nylon Tubing
(x10)
7”
24”
Internal
Structure
Background
Design
Overview
Microphone
Microphone
Circuit Board
(x5)
Thermal
Mechanical
2”
Risks
V&V
Project
Management
38
Exploded View
Top View
1.5”
Microphone
Circuit
Board (x5)
Microphone
Battery
11.1V
Oblique View
6”
3”
7.75”
Aluminum 6061-T6
PIC Board
7.4V Battery
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
39
Driving Requirements
ID
Requirement Description
Performance
DR 2.1.1
Mass no greater than 20 kg
Mass of design is 8.95 kg (~55% margin)
DR 2.2.1
Shall structurally interface with gondola
Flexible cable attachment designed
Shall operate in ambient environment of -55 to
All design components rated for
30°C
temperature range
Maintain the temperature of internal components
Design includes passive thermal control (7”
of polystyrene insulation) to keep internal
DR 2.5
DR 2.6
DR 2.7
Background
from -10 to 45°C
Payload can withstand in-flight and impact forces of
2000 N
Design
Overview
Microphone
Thermal
Mechanical
components between -5 and 32°C
Design includes safety factors to
survive 2000 N forces with
considerable margin
Risks
V&V
Project
Management
40
Driving Requirement:
DR 2.1.1
ASTERIA shall have a mass no greater than 20 kg.
Other
Electronics
Interior
6%
Structure
8%
Wind Barrier
2%
Hoist Rings
10%
Foam
Insulation
38%
Batteries
10%
Outer
Structure
26%
Item
Mass
Foam Insulation
3.44 kg
Outer Structure
2.31 kg
Batteries
0.90 kg
Hoist Rings (x3)
0.87 kg
Interior Structure
0.72 kg
Other Electronics
0.50 kg
Wind Barrier
0.21 kg
ASTERIA Total Mass: 8.95 kg
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
✓
V&V
Project
Management
41
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
42
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
43
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
1-4: Loss of
power of
electronics
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
7a
13, 25, 26, 27
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
44
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
7b: All microphones
are unable to detect
infrasound waves
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
45
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
4: Likely
19, 20
15: Payload
temperature is not
maintained within
required range
(-10° - + 40°C)
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
46
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
47
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
3: Possible
7b: All microphones
are unable to detect
infrasound waves
2: Unlikely
1: Rare
Background
7b
1, 2, 3, 4, 8
9, 10, 11, 12
14, 15, 17,
Design
Overview
Microphone
13, 25
Thermal
21, 22, 23, 24
29, 30
7a, 26, 27, 32
31
5, 6, 16, 18,
28
Mechanical
Risks
V&V
Project
Management
48
Risk # 7b: All microphones
are unable to detect
infrasound waves
Cause:
- Oversaturation of sensor
- Ruptured diaphragm
- Extreme temperatures
- Condensation causes arcing
Consequences:
- Pressure data cannot be
collected
Pre-Mitigation:
- Severity: Catastrophic – 5
- Likelihood: Possible – 3
Background
Design
Overview
Microphone
Mitigations:
- Minimize wind
gusts seen by
sensor with
wind barrier
- Maintain
internal
temperature
with insulation
- Shield from
ambient water
vapor with
moistureresistant foam
Thermal
Mechanical
Post-Mitigation:
- Severity: Catastrophic – 5
- Likelihood: Unlikely – 2
Risks
V&V
Project
Management
49
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
50
Electronics
Testing
Microphone
Temperature
Sensitivity
Electronic Software
Integration
Integrated
Testing
Microphone
Acceleration
Infrasound
Testing
Microphone
Infrasound - NOAA
Wind Barrier – ITLL
Wind Tunnel
Microphone
Infrasound - NOAA
Integration and Flight
Duration
CDR
Structural Loading
and Data
Survivability
Software Pre- Flight
Diagnostic
Vacuum Chamber JANA
Survivability
Testing
Thermal
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
51
Gear and RPM
Control
Bellows
Motor
To Piston
Bellows
Pressure
Transducer
Volume with
Steel Wool
Purpose:
Verify the requirements for
frequency (0.1 – 20 Hz) and
amplitude (0.1-10 Pa) response is
met by the pressure transducer
Procedure &
Strategy
•
•
Vary frequency & pressure
amplitude
Self-noise characterization
Location &
Equipment
•
•
Piston Bellows - NOAA
NI 9239 DAQ, LabVIEW
Measurements
•
•
Microphone output voltage
Gear, RPM, and resulting
frequency (accurate to 1-2%)
Issues
•
Electronic noise higher than
lowest amplitude
Measured 0.044
Hz Pressure
Waves (below 0.1
Hz Requirement)
DAQ
Background
Design
Overview
To Laptop
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
52
Design Requirements
Designation
DR 2.3
Description
Operate under stratospheric pressure conditions: 5 to 8 kPa
•
Strategy
Subject critical electronic components to
stratospheric pressure
Equipment
•
Vacuum Chamber - JANA
Measurements
•
•
Chamber pressure
Output from instrument peripherals and
microphone
•
Issues
Background
Design
Overview
Safety of electronics and pressure transducer
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
53
Design Requirements
Designation
DR 2.5
Experimental
Thermal Test
Description
Operate in an ambient temperatures of
internal temperature of -10 to 45 ± 1°C
Verify the thermal model by providing
comparison data. Thermal model will be
used to verify temperature for the flight
duration
•
Procedure &
Strategy
•
Subject the payload (without electronics) to
the temperature extremes for several
hours
Compare results with thermal model
Equipment
•
•
Dry ice and large insulated cooler
Temperature sensors
Measurements
•
Internal and external temperature
-55 to 30°C and maintain
Internal
Temperature
Insulation
ASTERIA
External
Temperature
Background
Design
Overview
Microphone
Thermal
Mechanical
External
Temperature
Risks
V&V
Controlled
Environment
Project
Management
54
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
55
Project
ASTERIA
Advisor
Engineering Team
James Nabity
Project Manager
Financial Lead
Kerry Wahl
Kyle Garner
Software Lead
Michael Von Hendy
Background
Design
Overview
Microphone
Customer
CU AES
System Engineer
Emma Young
Mechanical/Thermal
Lead
Ian Thom
Thermal
Eliot Young
Manufacturing Lead
Connor Dullea
Testing Lead
Emily Daugherty
Safety Lead
Martin Heaney
Electrical Lead
Courtney Ballard
Mechanical
Risks
V&V
Project
Management
56
Testing,
General, $300.00
$450.00
Funding Source
Amount
CU AES
$5,000
Margin,
$1,478.38
Mechanical,
$915.22
Electronics,
$1,856.40
CDR Margin: ~ $1,500 (30%)
Background
Design
Overview
Microphone
Thermal
✓
Mechanical
Mechanical
• Aluminum 6061-T6
• Polystyrene Foam Core
• Fasteners
Electronics
• Differential Pressure Transducers
• Batteries
• PIC
• Data Storage (SD Card, Harness)
Testing
• Miscellaneous Testing Supplies
General
• Report Printing
• Shipping
Risks
V&V
Project
Management
57
ASTERIA
Electrical Design
Package
Software
Package
Mechanical
Design Package
Manufacturing
Package
Testing & Safety
Package
Administrative
Package
Class
Deliverables
Microphone
Circuit Board
Design
Test Data
Analysis
Package
Payload
SolidWorks
Model
Component &
Assembly
Drawing Tree
Master Test Plan
Master
Equipment List
Critical Design
Review
Microcontroller
Circuit Board
Design
Data Storage
Routine
Payload Thermal
Analysis
Package
Assembly CAD
Package
Simulated
Infrasound Test
Data
Risk Matrix
Fall Final Report
Peripheral
Component
Design Package
Pre-launch
Diagnostic
Routine
Materials
Selection
Analysis
Custom/
Purchased Parts
CAD Package
Test Safety Plan
Requirements
Flow Down
Manufacturing
Status Review
Power Budget
Real-time
Diagnostic
Routine
Payload Drag
Profile
Manufactured
Outer Structure
T-Vac Test Data
Cost Plan
Test Readiness
Review
Integrated
Electronic
System Circuit
Signal PostProcessing
Package
Impact/Draging
Force Model
Manufactured
Core Structure
Temperature/
Acceleration Test
Data
Schedule
Spring Final
Review
Key
Completed By
CDR
Background
Gondola/Payload
Interface Design
Spring Final
Report
To Be
Completed
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
58
PDR
CDR
FFR
MSR
SFR
TSR
Winter Break
Spring Break
Key
Thermal Model and
Baseline Structure
Mechanical
Electrical
Final PCB Assembly & Data
Storage Routine
Development
Software
Manufacturing
Manufacturing
Test
Test
Margin
Circuit Design and
Power Budget
Pre-Flight Check Routine
Software/Electronics
Integration
Microphone/Microcontroller
Board Development
Microphone Testing
Electronics/Structure
Integration
Core/Outer Structure
Manufacturing
Background
Design
Overview
Microphone
Thermal
Mechanical
Data Post Processing
Software Development
Risks
V&V
Project
Management
59
PDR
CDR
FFR
MSR
SFR
TSR
Winter Break
Spring Break
Key
Mechanical
Electrical
Microphone Temperature &
Acceleration Testing
Software
Manufacturing
Manufacturing
Test
Test
Margin
Piston Bellows & Wind
Tunnel Testing
Duration Test & Vac
Testing
Structural Loading and
Thermal Testing
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
60
PDR
CDR
FFR
MSR
SFR
TSR
Winter Break
•
•
•
•
Spring Break
Microphone Board Development
Data Storage Routine Development
Structure Manufacturing
Electronics/Hardware Integration
Critical Path
Key
Mechanical
Electrical
Software
Manufacturing
Manufacturing
Test
Test
Margin
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
61
Microphone Design and Data Collection
• InfraBSU sensor specifications meet requirements to measure infrasound waves
between 0.1-20 Hz, with an amplitude of 0.1 Pa
• 67% margin in software/hardware timing delays
Infrasound Generation & Test Facilities
• NOAA facilities can generate infrasound waves of frequency 0.04-20 Hz with
adjustable amplitudes from 0.1-100 Pa
Power Budget
• Batteries provide at least 24% margin for power supply
Stratospheric Survivability of the Payload
• 7 cm thick foam insulation maintains payload core to within required limits plus
±10°C on the upper and lower limit of payload components
Data Storage Survivability
• MicroSD card can withstand loads much greater than those expected during force
of impact
Mass Budget
• 55% margin
structural design
Projecton mass for final
Baseline
Overview
Feasibility
Status
Summary
Remaining
Studies
62
Team ASTERIA would like to thank:
Dr. Eliot Young
Steve Smith
Dr. Alfred Bedard
Dr. James Nabity
Trudy Schwartz
Matt Rhode
Bobby Hodgkinson
63
64
65
The purpose of the configuration:
• Determine the pointing of microphones
• House support systems
• Act as a thermal control boundary
Tetrahedron
Configuration trade study in CDD was
inconclusive
• Configuration is highly dependent on type of
microphones, spatial filter selection
• CDD determined differential pressure
sensor (microphone) and barrier (spatial
filter)
Cylinder
New trade variables:
• Minimum number of microphones required
for omnidirectional sensing
• Surface area – Important for heat rejection
• Volume – Dictates space for microphones
and support hardware
Sphere
Cube
66
Metric
Number of
microphones for
optimal signal
detection
Surface Area
Volume
Weight
Weight Rationale
Description of Metric
45%
Minimizing the number of
microphones needed while still
achieving omnidirectional
detecting capabilities reduces
complexity and cost. Fulfills FR.1.
Relates the field of view (FOV) of
the microphones to the geometry
needed to achieve full coverage
35%
Overheating of internal hardware
is a major concern. A larger
surface area allows more heat
dissipation to the surrounding
environment. Fulfills FR.2.
Surface area of the geometries
were computed using unit side
length/diameter
20%
A geometry with a large volume is
optimal for mounting microphones,
support hardware, and other
payload components.
Volume of the geometries were
computed using unit side
length/diameter
67
Trade Variable
Score 1
Score 2
Score 3
Number of
microphones
6 or more
5
4 or less
Surface area
(unit distance2)
Less than 2
2–4
Greater than 4
Volume (unit
distance3)
Less than 0.33
0.33 – 0.66
Greater than
0.66
Weight
Tetrahedron
Cube
Sphere
Cylinder
Number of
microphones
40%
3
1
3
2
Surface Area
35%
1
3
2
3
Volume
25%
1
3
2
3
Total
100%
1.8
2.2
2.4
2.6
Trade study
scoring
definitions
Trade study
results
68
Results:
• Cylinder was determined to
be the optimal configuration
• Geometry best fulfills all
three purposes of
configuration: pointing of
microphones, housing of
support hardware, thermal
boundary
Cube
Sphere
Cylinder
Tetrahedron
69
• The angle of incidence in degrees of an incoming sound wave is a function of
wavelength in meters and the diameter in meters of the pressure sensor inlet:
• Wavelength is a function of the velocity of sound in meters per second at a given
altitude (which dictates ambient temperature) and the frequency of the sound
wave in Hz:
• Varying or unknown parameters:
• Altitude (18,288 – 30,480 m)
• Standard Atmosphere Tables were used to find the velocity of sound at
stratospheric altitudes
• Sound wave frequency (0.1 Hz – 20 Hz)
• Inlet diameter (0.001 – 0.002 m)
• Specifications from vendor are TBD
The range of angles of incidence that the sensor can detect, which determines the half
angle of the microphone field of view, is 80.89 – 84.33°.
70
Nominal:
1
2𝜋𝑅𝐶
𝑅 = 1.8kΩ , 𝐶 = 2.2𝜇𝐹 → 𝑓𝑐 = 40.1906𝐻𝑧
1
𝑉𝑜𝑢𝑡
𝑋𝑐
𝑋𝑐 =
=
= 89.53% @20𝐻𝑧
2
2
2𝜋𝑓𝐶
𝑉𝑖𝑛
𝑅 + 𝑋𝑐
𝑓𝑐 =
With Variance:
𝑋𝑐 =
Effects:
Conclusions:
1
2𝜋𝑓𝐶
𝑅 = 1.8𝑘Ω ± 1% , C = 2.2𝜇𝐹 ± 1%
𝑓𝑐 = 39.3987 𝑡𝑜 41.0067𝐻𝑧
𝑉𝑎𝑟𝑖𝑎𝑛𝑐𝑒 = 0.8161𝐻𝑧 = 2%
𝑉𝑜𝑢𝑡
𝑋𝑐
=
= 89.17% 𝑡𝑜 89.88% @20𝐻𝑧
𝑉𝑖𝑛
𝑅2 + 𝑋𝑐2
Increased attenuation of higher frequencies (20Hz) at lower 𝑓𝑐 values
More noise at nearby frequencies (20-40Hz) at higher 𝑓𝑐 values
Effect can be minimized/compensated once parts are in hand
Nominal:
𝐴𝐷𝐶 𝑅𝑎𝑛𝑔𝑒 𝑃𝑎 𝑅𝑎𝑛𝑔𝑒
1.25𝑉 249𝑃𝑎
= 16
𝑅2
𝑅2
#𝑏𝑖𝑡𝑠
2
∗
𝑉
𝑅𝑎𝑛𝑔𝑒
𝑅1
𝑅1 0.02𝑉
𝑅1 = 16Ω , 𝑅2 = 1𝑘Ω → 𝑅𝑒𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 = 0.003799𝑃𝑎/𝑏𝑖𝑡
𝑅𝑒𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 =
With Variance:
𝑅1 = 16Ω ± 1% , 𝑅2 = 1𝑘Ω ± 1%
𝑅𝑒𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 = 0.003724 𝑡𝑜 0.003876𝑃𝑎/𝑏𝑖𝑡
𝑉𝑎𝑟𝑖𝑎𝑛𝑐𝑒 = 0.000077𝑃𝑎 = 2%
Effects:
With higher gain, resolution increases and clipping occurs at lower amplitude
(±122.03Pa)
With lower gain, resolution decreases and full range not used
Conclusions:
Resolution still meets requirements (<0.01Pa)
Effect can be minimized/compensated once parts are in hand
Nominal:
𝑅2
𝑅1 + 𝑅2
𝑉𝑖𝑛 = 3.3𝑉, 𝑅1 = 16.7kΩ , 𝑅2 = 3.9𝑘Ω → 𝑉𝑜𝑢𝑡 = 0.6248𝑉
𝑉𝑜𝑢𝑡 = 𝑉𝑖𝑛 ∗
With Variance:
𝑅1 = 16.7kΩ ± 1% , 𝑅2 = 3.9𝑘Ω ± 1%
𝑉𝑜𝑢𝑡 = 0.61469𝑉 𝑡𝑜 0.63495𝑉
𝑉𝑎𝑟𝑖𝑎𝑛𝑐𝑒 = 0.01015 = 1.6%
Effects:
Incorrect offset clips one side of data (+ if shift too large, - is shift too large)
Maximum wave not clipped reduced by 2Pa (122.48Pa)
2Pa zero offset
Conclusions:
Amplitude range still meets requirements (0.1Pa wave detectable)
Constant offset can be removed in post-processing
Effect can be minimized/compensated once parts are in hand
Pressure Transducer:
Effects:
0.25𝑚𝑉 249Pa
Pa
𝑂𝑓𝑓𝑠𝑒𝑡 𝑇𝑒𝑚𝑝. 𝑆ℎ𝑖𝑓𝑡 = ±
∗
= ±0.06225
50°𝐶
20mV
°𝐶
Incorporating temperature sensor error:
Pa
𝑂𝑓𝑓𝑠𝑒𝑡 𝑇𝑒𝑚𝑝. 𝐸𝑟𝑟𝑜𝑟 = 0.06225 ∗ ±0.25°𝐶 = ±0.01556𝑃𝑎
°𝐶
Constant slope means drift in zero due to temperature
Error in temperature sensor means error in zero on order of resolution (0.01Pa)
Conclusions:
Worst-case estimate still means SNR 5 requirements
System can be tested to identify individual slopes for each transducer
Full system can be calibrated to identify all temperature effects
Constant drift due to temperature can be removed with calibration
Regulator outside compensated range (0°𝐶 to 70°𝐶):
5𝑝𝑝𝑚 35𝜇𝑉
𝑉
Drift =
=
→ 7𝑉 + 3.5𝑒 − 6 ∗ −10°𝐶
°𝐶
°𝐶
°𝐶
𝑉
𝑅𝑎𝑑𝑖𝑜𝑚𝑒𝑡𝑟𝑖𝑐 𝑂𝑢𝑡𝑝𝑢𝑡 = 0.02𝑉 + (1𝑒 − 7 ∗ −10°𝐶)
°𝐶
𝑅𝑎𝑛𝑔𝑒 𝑉𝑎𝑟𝑖𝑎𝑛𝑐𝑒 = −1𝑒 − 6𝑉 = −0.01245𝑃𝑎
Effects:
Output V range decreased marginally (1.2499375V after gain)
Resolution decreased marginally (0.003799628 vs 0.003799438)
Conclusions:
Effects 5 orders of magnitude smaller than resolution requirements
Regulator drift can be calibrated for along with other effects.
Nominal:
𝐶𝑜𝑛𝑣𝑒𝑟𝑠𝑖𝑜𝑛 𝐹𝑎𝑐𝑡𝑜𝑟 𝐹 =
𝑃𝑎
𝑉
𝐹𝐴𝑐𝑡𝑖𝑣𝑒 𝑉𝐴𝑐𝑡𝑖𝑣𝑒 − 𝐹𝑅𝑒𝑓 𝑉𝑅𝑒𝑓 = 𝑃𝑎𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑂𝑛𝑙𝑦
Actual:
𝐹𝐴𝑐𝑡𝑖𝑣𝑒 + 𝐸𝑟𝑟𝑜𝑟 (𝑉𝐴𝑐𝑡𝑖𝑣𝑒 ) + 𝑁𝑜𝑖𝑠𝑒𝐴𝑐𝑡𝑖𝑣𝑒 − 𝐹𝑅𝑒𝑓 + 𝐸𝑟𝑟𝑜𝑟 𝑉𝑅𝑒𝑓 + 𝑁𝑜𝑖𝑠𝑒𝑅𝑒𝑓
Error depends on calibration from Microphone Acceleration Test
Noise = ±0.00562Pa @ 0.1-20Hz
Effects:
Combined Noise = ±0.01124Pa @ 0.1-20Hz
Conversion error results in incorrect offsets
Conclusions:
Calibration can minimize conversion error and offsets
Constant offset can be removed in post-processing
7.4V 20.8Ah Li-Ion Battery
Powerizer
Output V
Range
8.4V Peak, 7.4 Nominal, 5.0V Cut-off
Specifications
Output I Range 14A maximum
Capacity
20,800mAh
Low
Temperature
Capacity
≥70% @ -10°C (14,560 mAh)
ASTERIA Requirements
Manufacturer
Corresponding
Regulator Minimum
Input V
6.0V (5.0V+1.0V
dropout)
Corresponding
Regulator Maximum
Input V
15.0V Continuous
20.0V Surge
Nominal Current Draw 466mA
Mission Capacity
11,184mAh
Part #
LT1117-5
Input V Limit
6V to 15V
Input I Limit
900mA maximum
Output V Range
+5V±0.05V
Output I Range
5mA to 800mA
ASTERIA Requirements
Specifications
Control Board +5V Regulator
Corresponding Source V Range
8.4V Peak, 7.4 Nominal,
5.0V Cut-off
Corresponding Source I Limit
14,000mA
Nominal Output V
+5V
Nominal Current Draw
466mA
11.1V 2200mAh Li-Ion Battery
Tenergy
Output V
Range
12.6V Peak, 11.1V Nominal, 8.4V
Cut-off
Specifications
Output I Range 6.5A maximum
Capacity
2,200mAh
Low
Temperature
Capacity
≥50% @ -20°C (1,100mAh)
ASTERIA Requirements
Manufacturer
Corresponding
Regulator Minimum
Input V
8.0V (7.0V+1.0V
dropout)
Corresponding
Regulator Maximum
Input V
40.0V
Nominal Current Draw 22.5mA
Mission Capacity
540mAh
Part #
LT1021
Input V Limit
8V to 40V
Input I Limit
10mA
Output V Range
+7V±0.05V
Output I Range
10mA
ASTERIA Requirements
Specifications
Microphone Board +7V Regulator (x5)
Corresponding Source V Range
12.6V Peak, 11.1V
Nominal, 8.4V Cut-off
Corresponding Source I Limit
6.5A maximum
Nominal Output V
+7V
Nominal Current Draw
4.5mA
Part #
LT1962
Input V Limit
3.8V to 20.0V
Input I Limit
900mA maximum
Output V Range
+3.3V±0.08V
Output I Range
1mA to 300mA
ASTERIA Requirements
Specifications
Control Board +3.3V Regulator
Corresponding Source V Range
+5V±0.05V
Corresponding Source I Limit
5mA to 800mA
Nominal Output V
+3.3V
Nominal Current Draw
200mA
Part #
RS3-0505D
Input V Limit
4.5V to 9V
Input I Limit
1.316x Output V
Output V Range
±5V
Output I Range
±30mA to ±300mA
ASTERIA Requirements
Specifications
Control Board ±5V DC/DC Converter
Corresponding Source V Range
+5V±0.05V
Corresponding Source I Limit
5mA to 800mA
Nominal Output V
±5V
Nominal Current Draw
141mA
Part #
NCP508-D
Input V Limit
3.6V to 13.0V
Input I Limit
50mA maximum
Output V Range
+3.3V±0.1V
Output I Range
1mA to 50mA
ASTERIA Requirements
Specifications
Microphone Board +3.3V Regulator (x5)
Corresponding Source V Range
+5V±0.05V
Corresponding Source I Limit
5mA to 800mA
Nominal Output V
+3.3V
Nominal Current Draw
7.255mA
Part #
0.5 Inch-D-MV
Input V Range
16V max
Input I Maximum
1.5mA (3mA per
Board)
Accuracy
±0.00562Pa
Sensitivity
±0.00562Pa
ASTERIA Requirements
Specifications
Pressure Transducer (x10)
Corresponding Regulator Output V
7V
Corresponding Regulator Output I
Maximum
10mA per Board
Accuracy Requirements
±0.01 Pa
Sensitivity Requirements
±0.01 Pa
Part #
ADT7320
Input V Range
2.7 to 5.5V DC
Input I Maximum
300𝜇A per Board
Accuracy
±0.20°C
Sensitivity
0.0078°C
ASTERIA Requirements
Specifications
Digital Temperature Sensor (x5)
Corresponding Regulator Output V
3.3V
Corresponding Regulator Output I
Maximum
50 mA per Board
Accuracy Requirements
±0.32°C
Sensitivity Requirements
±0.32°C
Analog-to-Digital
Converter (x10)
Digital Temperature
Sensor (x6)
Part
Microcontroller
Part #
LTC2470
ADT7320
Part #
PIC18F8722
Sensor Output
3.3V Digital (SPI)
3.3V Digital (SPI)
Controller Input 3.3V Digital (SPI)
Conversion
Time
4ms
240ms
Conversion
Time
-
SPI Line
Capacitance
10pF (100pF Total)
2pF (12pF Total)
Maximum SPI
Line
Capacitance
400pF
Maximum SCK
Speed
2MHz
10MHz
Maximum SCK
Speed
40MHz
SPI Modes
Idle High, Read
Second / Idle Low,
Read First
Idle High, Read
Second
SPI Modes
All combinations
available
Capabilities
Specifications
Part
MicroSD Card
Part
Microcontroller
Part #
SDSDQY-004G
Part #
PIC18F8722
Device Input
3.3V Digital (SPI)
Controller Output
3.3V Digital (SPI)
SPI Line Capacitance
20pF
Maximum SPI Line
Capacitance
400pF
Maximum SCK Speed
20MHz
Maximum SCK
Speed
40MHz
SPI Modes
Idle High, Read Second
/ Idle Low, Read First
SPI Modes
All combinations available
Capabilities
Specifications
Part
Differential Op Amp
Summing Op Amp and RC Filter
𝑉2,𝑜𝑢𝑡 = 1 +
𝑅7
𝑅5
±
𝑉1,𝑜𝑢𝑡
+ 𝑉𝑟𝑒𝑓
2
𝐿: 1 +
𝑅2
𝑉 − 𝑉1
𝑅1 2
𝑉1,𝑜𝑢𝑡
0.625𝑉
=
= 62.5
𝑉2 − 𝑉1
0.01𝑉
𝑅2
62.5 = 𝐺𝑎𝑖𝑛 =
𝑅1
𝑅7
𝑅5
𝐻: 1 +
𝑅7
𝑅5
0.625 + 0.625
= 𝟏. 𝟐𝟓𝑽
2
−0.625 + 0.625
𝑅7
=𝟎→
=1
2
𝑅5
±
𝑉1,𝑜𝑢𝑡
=
𝑅1 = 𝟏𝟔𝜴 and 𝑅2 = 𝟏𝒌𝜴
𝑓𝑐 =
𝑉1,𝑜𝑢𝑡 0.625𝑉
𝑅4
=
=
𝑉𝑖𝑛
3.3𝑉
𝑅3 + 𝑅4
1
1
→ 𝑅𝐶 =
2𝜋𝑅𝐶
2𝜋𝑓𝑐
𝑅𝐶 = 0.00398
𝑅 = 𝟏. 𝟖 𝒌𝜴 , 𝐶 = 𝟐. 𝟐 𝝁𝑭
𝑅3 = 𝟏𝟔. 𝟕𝒌𝜴 , 𝑅4 = 𝟑. 𝟗𝒌𝜴
84
Specifications
ASTERIA Requirements
Part
7.4V 20.8Ah Li-Ion Battery
11.1V 2200mAh Li-Ion Battery
Manufacturer
Powerizer
Tenergy
Output V Range
8.4V Peak, 7.4 Nominal, 5.0V Cut-off
12.6V Peak, 11.1V Nominal, 8.4V Cut-off
Output I Range
##
1100 to 4400mA (0.5 to 2C)
Capacity
20,800mAh
2200mAh
Low Temperature
Capacity
70% @ -10C (14,560 mAh)
50% @ -20C (1,100mAh)
Corresponding
Regulator Minimum
Input V
6.0V (5.0V+1.0V dropout) -
1.23 8.0V (7.0V+1.0V dropout)
-
1.0
5
Corresponding
Regulator Maximum
Input V
15.0V Continuous
20.0V Surge
-
2.03 40.0V
-
3.6
0
Nominal Current Draw
466mA
##
##
%
44.
4
Mission Capacity
11,184mAh
76.8% 1.30 540mAh
49%
2.0
4
22.5mA
Specifications
Part
+5V Regulator
Part #
LT1117-5
5V DC/DC
Converter
High Current +3.3V Low Current +3.3V
Regulator
Regulator
LT1962
Input V Limit
Input I Limit
Output V Range
Output I Range
Input V
ASTERIA
Requirements
Input I
Output V
Output I
20.0V
NCP508-D
Part
Microphone Board +3.3V Regulator
Microphone Board +7V Regulator
Part #
NCP508-D
LT1021
Specifications
Input V Limit
Input I Limit
Output V
Range
Output I
Range
Input V
ASTERIA
Requirements
Input I
Output V
Output I
Specifications
ASTERIA Requirements
Part
Pressure Transducer (x10)
Digital Temperature Sensor (x6)
Part #
0.5 Inch-D-MV
ADT7320
Input V Range
16V max
2.7 to 5.5V DC
Input I Maximum
1.5mA (3mA per Board)
300A per Board
Sensor Output
10mV Radiometric Analog
3.3V Digital (SPI)
Accuracy
Self Noise Test Results Here
0.20C
Sensitivity
0.0078C
Corresponding
Regulator Output V
7V
3.3V
Corresponding
Regulator Output I
Maximum
10mA per Board
50 mA per Board
Corresponding
Interface Input V
0V to 1.25V Analog
3.3V Digital (SPI)
Accuracy
Requirements
0.005 Pa
0.32C
Sensitivity
Requirements
0.005 Pa
0.32C
Part
Analog-to-Digital Converter (x10)
Digital Temperature Sensor (x5)
Part #
LTC2470
ADT7320
Sensor Output
3.3V Digital (SPI)
3.3V Digital (SPI)
Conversion Time
5ms
240ms
SPI Line
Capacitance
10pF
2pF
Maximum SCK
Speed
2MHz
10MHz
ASTERIA
Requirements
Specifications
Power Specs
Specifications
ASTERIA Requirements
Part
ADC
Temp
Manufacturer
#
Tenergy
Maximum SPI Clock
2MHz
10 MHz
Conversion Time
4ms
240ms
Maximum Sampling
Rate
208 Samples per second
4 Samples ps
Time to Write
16 bits in X sec
512 Bytes in X seconds
Required Sampling
Rate
100 Samples per Second
6.7%
Mission Capacity
11,184mAh
71.7% 1.40 108mAh
15
1 Samples per Second
2.25
%
44.
4
54%
1.8
5
Power (mW)
355.2
PIC
740
1124.8
740
370
61
11.7
7.4 V Lithium-Ion Battery
MicroSD
USB to
USART
SPI Temp.
Sensor (x6)
16-bit ADC
(x10)
Quad Op-Amp
(x5)
DC-DC
Converter
Voltage
7.4 V
Stored Energy
20.8 A-h
153 W-h
Stored Energy
at -10°C (70%)
14.6 A-h
107 W-h
Control Board:
• MicroSD Card
• PIC Microcontroller
• USB to USART
• SPI Temperature Sensor
Microphone Boards:
• 16-bit ADC (x10)
• Quad Op-Amp (x10)
• DC-DC Converter (x1)
• SPI Temperature Sensor (x5)
Total Power: 3.4 W
Mission Duration: 24 hours
Total Energy: 82 W-h
Margin for Stored Energy at -10°C: 25 W-h (24%)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
✓
91
Power (mW)
83.25
11.1 V Li-Ion Battery
Active
Pressure
Transducer
83.25
Reference
Pressure
Transducer
7 V Voltage
Regulator
83.25
Voltage
11.1 V
Stored Energy
2200 mA-h
24.4 W-h
Stored Energy
at -20°C (50%)
1100 mA-h
12.2 W-h
Microphone System:
• Reference pressure
transducer
• Active pressure transducer
• LT1021 9V voltage regulator
Total Power: 250 mW
Mission Duration: 24 hours
Total Energy: 6 W-h
Margin for Stored Energy at -20°C: 6.2 W-h (50%)
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
✓
92
Current (mA)
MicroSD
7.4 V Lithium-Ion Battery
PIC
48
100
152
100
50
1.59
8.3
Total Current: 456 mA
Mission Duration: 24 hours
Total Energy: 11 A-h
Voltage
7.4 V
Stored Energy
20.8 A-h
153 W-h
USB to
USART
Stored Energy at 14.6 A-h
SPI Temp.
10°C (70%)
107 W-h
Sensor (x6)
16-bit ADC
Control Board Components:
• MicroSD Card
(x10)
• PIC Microcontroller
Quad Op-Amp
• USB to USART
(x5)
• SPI Temperature Sensor
DC-DC
Microphone Boards Components:
Converter
• 16-bit ADC (x10)
•
•
•
Quad Op-Amp (x10)
DC-DC Converter (x1)
SPI Temperature Sensor (x5)
Margin for Stored Energy at -10°C: 3.45 A-h (24%)
✓
93
Current (mA)
11.1 V Li-Ion Battery
7.5
7.5
Reference
Pressure
Transducer
Active Pressure
Transducer
7.5
7V Voltage
Regulator
Voltage
11.1 V
Stored Energy
2200 mA-h
24.4 W-h
Stored Energy at 20°C (50%)
1100 mA-h
0.9 W-h
Microphone System:
• Reference pressure
transducer
• Active pressure transducer
• LT1021 9V voltage regulator
Total Current: 22.5 mA
Mission Duration: 24 hours
Total Energy: 540 mA-h
Margin for Stored Energy at -20°C : 560 mA-h (50%)
✓
94
Regulator
Max. Output
Current (mA)
Max. Expected
Current (mA)
Vin
(V)
Vout (V)
LT1962
(3.3 V Regulator – Control
Board)
300 mA
210 mA
5V
3.3 V
NCP508
(3.3 V Regulator – Control
Board, Microphone Board)
50 mA
11 mA
5V
3.3 V
LT 1117-5
(5V Regulator)
800 mA
466 mA
7.4 V
5V
LT 1021-7
(7V Regulator – Microphones)
10 mA
4.5 mA
9V
7V
RS3-0505D
(DC-DC Converter – Op-Amps)
300 mA
200 mA
5V
±5 V
95
7.4 V Li-Ion Battery:
Control Board Components:
• MicroSD Card
• 100 mA max. draw
• 100 mA * 7.4 V = 740 mW
• PIC Microcontroller
• 100 mA max. draw
• 100 mA * 7.4 V = 740 mW
• USB to USART
• 8.3 mA max. draw
• 8.3 mA * 7.4 V = 61 mW
• SPI Temperature Sensor (x1)
• 0.265 mA max. draw
• 0.265 mA * 7.4 V = 1.95 mW
Microphone Boards Components:
• 16-bit ADC (x10)
• 5 mA max. draw each
• 5 mA * 7.4 V = 37 mW each
• 37 W * 10 = 370 mW total
• Quad Op-Amp (x10)
• 15.2 mA max. draw each
• 15.2 mA * 7.4 V = 112.48 mW each
• 112.48 W * 10 = 1124.8 mW total
• DC-DC Converter (x1)
• 48 mA max. draw
• 48 mA * 7.4 V = 355.2 mW
• SPI Temperature Sensor (x5)
• 0.265 mA max. draw each
• 0.265 mA * 7.4 V = 1.95 mW each
• 1.95 mW * 5 = 9.75 mW total
96
11.1 V Battery:
Microphone System:
• Reference pressure transducer
• 1.5 mA max. draw
• 1.5 mA * 9 V = 13.5 mW
• Active pressure transducer
• 1.5 mA max. draw
• 1.5 mA * 9 V = 13.5 mW
• LTLT1021 9V voltage regulator
• 1.5 mA max. draw
• 1.5 mA * 9 V = 13.5 mW
• Total power: 40.5 mW
Each of the 5 microphone systems
requires its own 9V battery.
The total power for all 5 9V batteries is:
40.5 mW * 5 = 202.5 mW
Each 9V battery has an energy capacity of
1.8 W-h. The total available energy is:
1.8 W-h * 5 = 9 W-h
97
5 V Regulator: LT 1117 (x1)
PD = (Vin – Vout) Iout
PD = (7.4V – 5V) 0.466 A
PD = 1.12 W
3.3 V Regulator: ON NCP508 (x6)
Min. Temperature:
3.3 V Regulator: LT 1962 (x1)
PD = (Vin – Vout) Iout + IGND * Vin
PD = (5V – 3.3V) 0.210 A + 0.08 A* 5 V
PD = 0.757 W
Max Temperature:
DC-DC Converter (x1):
76% Efficiency
PD = Efficiency * Iout * Vin
PD = (0.76)(0.2 A)(5 V)
PD = 0.76 W
For 6 regulators:
6(0.8 W) = 4.8 W
6(0.525 W) = 3.15 W
Lithium-Ion Battery:
PD = I * Rint = 0.5 A * 1 Ω = 0.5 W
Total Power Dissipation: 5.767W – 7.417 W (based on ambient temperature)
98
•
Pre-flight Diagnostics
• Ping all user-defined operational ports
• Verify peripheral device responds with data (not null)
•
Continuous Onboard Operating Software
• Input operational ports from pre-flight diagnostics
• Data Collection Loop
•
•
•
•
•
Define Target Sensor: SPI CS line set low to “listen”(0 V)
Configure Protocol (Active High, Clock Rising Edge, Data Falling Edge)
Full Duplicity Synchronous Serial Data Exchange
Store sensor data in local variable buffer
Change Target Sensor: SPI CS line returned to high to “passive” (3.3 V)
• Write Data to SD Card
• Compile stored data into table
• Write tabled to SD
• Change Buffers and Re-start Data Collection
• Fill a second data buffer while writing the other to the SD Card
99
SPI
Master
SCLK
SPI
MOSI
Slave
LTC2470 ADC
1..n
MISO
SS1..n
SCLK
MOSI
MISO
PICSS1..n
SSn+1
SSn+2
SCLK
MOSI
MISO
SSn+1
ADT7320
Temperature
Sensor
SPI
Slave
n+1
SCLK
SPI
Slave
MOSI
LTC2470
MISO Reference ADC n+2
SSn+2
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
1.
2.
3.
4.
5.
6.
Clock
Configuration
Slave Select
Start-up Delay
Clock Cycle
Slave Deselect
Repeat 2 – 5
for all Devices
SPI - Serial Peripheral
Interface
SCLK - Clock
MOSI - Master Out Slave In
MISO – Master In Slave Out
SS – Slave Select
V&V
Project
Management
100
ASTERIA
Specifications
Requirement
Part
LTC2470 ADC
ADT7320
Temperature
Sensor
SanDisk SDSU0008G SD Card
Maximum SPI
Clock
2 MHz
10 MHz
20 MHz
Conversion Time
4 ms
240 ms
-
Maximum Sample
Rate
208 samples per
second
4 samples per
second
-
Delay
800 ns
500 ns
Time to Write (at 1
MHz)
16 μs
24 μs
1 MB per second
Transmission Time
-
-
1 ms
Required Sample
Rate
40 samples per
second
1 sample per
second
-
Required Write
Time
< 158 μs
< 158 μs
4900 Bytes per
second
Sensor Sampling Timing Margin
Ground Circuit Components
•Margin = Run Time – Max Conversion – Write Times*N – Delay*N
•FT230X USB to UART
•Margin = 25 ms – 4 ms – 0.016 ms/sensor*10sensor –
•Only impacts upload times on ground:
0.0008ms/sensor*10sensor – 0.024ms/sensor*6 sensor –
•Not constrained by 40 Hz operating time
0.0005ms/sensor*6sensor = 20.69 ms – 1.02ms SD transfer = 19.67ms
•Not used for data collection software.
• 78% Timing Margin in sensor sampling loop
101
SD Write Speed Requirements
•Data Rate = 100 sps *(3 bytes per sensor*16 sensors+1 delimiter byte) = 4900 bytes per second
•SD Writes 512 bytes packets  n = 4900 bytes per second /512 bytes per write = 9.57 writes per seconds
•Require 10 write commands to SD card per second
•SD Card handles 512*8 bits per write/4MHz = 1.024 ms per write cycle of data transmission time
ADC and Temperature Write Requirements
•Software Required Operating Rate = 10ms
•Max write time per sensor = (10 - 4)/(2*10+3*6) = 0.1579 ms
Sensor Sampling Timing Margin
•Margin = Run Time – Max Conversion – Write Times*N – Delay*N
•Margin = 10 ms – 4 ms – 0.016 ms/sensor*10sensor – 0.0008ms/sensor*10sensor –
0.024ms/sensor*6 sensor -0.0005ms/sensor*6sensor = 5.685 ms
•Transmission time to SD card is 1 ms  Margin = 5.685 – 1.024 = 4.661 ms
•46.61% Timing Margin in sensor sampling loop, assuming 9 ms delay in SD
102
Ping
Instrument
0-3.3 V from
Instrument
Port #, Status
Cycle Power:
Peripheral
Ports
Receive
Signal
?
No
User Defined
Active Ports
Active
Status?
Yes
Yes
Port #,
Status
Unhealthy
Port
Port #,
Health
No
No
Active
Status?
Yes
GUI
-Routine
-Decision
-Hardware
-Warning
-Healthy
Status
Healthy
Port
Port #,
Health
Overall System
Health
Healthy Ports to
Operating Software
103
Port #, Health
Voltage
Measurement
Receive
Signal?
No
Healthy
Port?
Yes
Diagnostics
Yes
No
Shut Down
Port
Count
Restart
s
Yes
Onboard
Clock
Port #,
Voltage
Measurement
-Hardware
-Warning
Restart
Limit?
Write
Failure
to File
Yes
Identify
Measurement
from Port #
-Routine
-Decision
Attempt
Sensor
Restart
No
Healthy
Port?
Timing Control to
Instruments
Overall System
Health
Time
Stamp
Tabulated
Measurements
P, T Data
at Time
SD
Card
104
•
Equations in Payload Power Balance
QDirectSolarRadiation    Fsun  Asurface  I sun
QRe flectedSunlight  a    FEarth  Asurface  I sun
QConvection = h × Asurface × (Tair -Tpayload )
4
QRaiatedToEarth = s × e × FEarth × Asurface × (Tpayload
-T 4Earth )
4
QRaiatedToSpace = s × e × Fspace × Asurface × (Tpayload
-T 4Space )
𝑎 = Earth albedo (0.3)
𝛼= material absorptivity (0.24)
𝜀 = material emissivity (0.90)
𝐴 = surface area
𝐹 = view factor
𝑊
𝐼𝑠𝑢𝑛 = solar constant (1350𝑚2)
𝑇 = temperature
𝑊
ℎ = convection coefficient (0.72 𝑚2−𝐾)
𝜎 = Stefan-Boltzman constant
𝑊
(5.67 ∙ 10−8 𝑚2−𝐾4)
105






Thermal Model assumes and initial 𝜃
value of 0°, corresponding to 06:00 MST
ASTERIA is exposed to two sources of
radiation
 Direct sunlight: −10° < 𝜃 < 190°
 Reflected sunlight: all 𝜃 except 270°
 Intensity is a linear function of 𝜃
𝑊
Convection coefficient of 0.72 𝑚2−𝐾
180°
Radiation to ambient environment as a
function of altitude
 At an altitude of 18-21km ambient
temperature is ~220K (-53°C)
Emissivity: 0.90
Absorptivity: 0.24
ASTERIA 90°
21km Altitude
θ
0°
Earth
270°
106
•
Assuming Relative Wind Speed, u∞, is 0.5m/s
 min
kg
 0.0889 3
m
rmax = 0.1163
k  0.02
W
mK
kg
  1.5 10
ms
5
At 21km
kg
m3
Pr  0.72
Re 
At 18.3km
Nu  0.683 Re 0.466Pr1/ 3
h=
Assumed Constant for Air
Air Thermal Conductivity at -50°C
Air Dynamic Viscosity at -50°C
u D

Nu × k
L
hmin  0.64
W
m2 K
hmax  0.72
W
m2 K
107
•
Ambient air
temperature
based upon
average from 1821km
• Tair= -50°C
Image From: http://eesc.columbia.edu/courses/v1003/images/atmprofile.gif
108
Driving Requirement:
DR 3.2
ASTERIA shall maintain the temperature of payload components
to a range of -10 to 45°C ± 1°C (10°C ± 1°C below the maximum
and above the minimum component specifications)
Tspace
Tinterior
1
1
Radiation from Sun
2
Radiation from reflected
Sunlight
3
Convection
4
Conduction through outer
structure panels
4
6
2
5
3
7
5
6
7
Conduction through outer
structure fasteners
Conduction through foam core
insulation
Conduction through inner
electronics support structure
109
𝜏=
𝐹
4𝐹
=
𝐴 𝜋𝐷2
Maximum Shear strength of
300 series stainless steel:
10.5ksi
D = 0.25 in
tL = tP = 0.125 in
Ftot = 450 lbf (2000 N)
eT
eS
tP
Top/Bottom Plate:
Num. bolts = 6
tL
eS
Force per bolt = F = Ftot/6 = 75.0 lbf (333.33 N)
𝜏=
4𝐹
= 1.523 𝑘𝑠𝑖 (1.05𝑒7 𝑃𝑎)
𝜋𝐷2
𝜏𝑡𝑜𝑝
= 0.15
𝜏𝑚𝑎𝑥
Side Plate:
D
D
eL
eL
Num. bolts = 4
Force per bolt = F = Ftot/4 = 112.5 lbf (500.00 N)
𝜏=
4𝐹
= 2.291 𝑘𝑠𝑖 (1.58𝑒7 𝑃𝑎)
𝜋𝐷2
𝜏𝑡𝑜𝑝
= 0.22
𝜏𝑚𝑎𝑥
110
eT
𝜏=
𝐹
𝐹
=
𝐴 2𝑡𝐿 𝑒𝐿
𝐹
𝑒𝐿 =
2𝑡𝐿 𝜏
eS
tP
D
eL
tL
eS
Minimum shear of
Aluminum 6061 T6: 31ksi
D
eL
tL = 0.125 in
Ftot = 450 lbf (2000 N)
Safety Factor = 5
D
tL
eL
= Shear Area
Top/Bottom Plate:
Num. bolts = 6
Side Plate:
Num. bolts = 4
Force per bolt = F (SF)= 375.0 lbf (1666.66 N)
𝐹
𝑒𝐿 =
= 0.072 in (1.84 mm)
2𝑡𝐿 𝜏
Force per bolt = F(SF) = 567.5 lbf (2500.00 N)
𝐹
𝑒𝐿 =
= 0.048 in (1.23 mm)
2𝑡𝐿 𝜏
Using eL = 0.31 in (7.87 mm)
111
𝐹
𝐹
𝜏= =
𝐴 2𝑡𝑃 𝑒𝑆
𝑒𝑆 =
eT
tp
eS
eS
tP
𝐹
2𝑡𝑃 𝜏
tL
eS
Minimum shear of
Aluminum 6061 T6: 31ksi
tP = 0.125 in
Ftot = 450 lbf (2000 N)
Safety Factor = 5
D
= Shear Area
Top/Bottom Plate:
Num. bolts = 6
eL
D
eL
Side Plate:
Num. bolts = 4
Force per bolt = F (SF)= 375.0 lbf (1666.66 N)
𝐹
𝑒𝐿 =
= 0.072 𝑖𝑛 (1.84 𝑚𝑚)
2𝑡𝐿 𝜏
Force per bolt = F(SF) = 567.5 lbf (2500.00 N)
𝐹
𝑒𝐿 =
= 0.048 𝑖𝑛 (1.23 𝑚𝑚)
2𝑡𝐿 𝜏
Using eL = 0.44 in (11.18 mm)
112
Steel Hoist Ring
Maximum Vertical Capacity: 2450 N (550 lbs)
F = mg = 80N
Vertical Capacity = Maximum∙sin(𝜃)
At 𝜃 = 45° Vertical Capacity = 1730 N (390 lbs)
𝜃
F = mg = 80N
113
At = Tensile strength area of thread
D = 0.25 in = nominal diameter of bolt
n = Threads per inch
N = Number of threads
L = 0. 125 in = Threaded length
F = Force acting on bolt
𝜎 = Tensile strength of material
Safety Factor = 5
0.9743
𝐴𝑡 = 0.7854 𝐷 −
𝑛
𝜎
𝐹
=
=
𝑆𝐹 𝐴𝑡
𝑁 = 𝑛𝐿 =
Tensile Strength of 300 series
Stainless Steel: 120ksi
2
𝜃
𝐹
0.9743
0.7854 𝐷 − 𝑛
0.9743𝐿
𝐷−
𝐹(𝑆𝐹)
0.7854𝜎
F = mg = 80N
2
= 1 𝑡ℎ𝑟𝑒𝑎𝑑 𝑛𝑒𝑐𝑒𝑠𝑠𝑎𝑟𝑦
Using 3 threads per Hoist Ring
F = mg = 80N
114
Miniumum Shear Strength of Aluminum 6061 T6: 31ksi
do = 0.562 in (1.43 cm)
di = 0.25 in (0.64 cm)
Safety Factor = 5
𝐹(𝑆𝐹)
𝐹(𝑆𝐹)
𝜏=
=
𝐴𝑏𝑜𝑙𝑡
𝜋 𝑑𝑜 − 𝑑𝑖
80(5)
= 𝜋 1.43−0.64 = 16.1 kPa
( 100 )
di = 0.25 in
F = mg = 80N
𝜃
do =0.562 in
F = mg = 80N
115
At = Tensile strength area of thread
D = 0.25 in = nominal diameter of bolt
n = Threads per inch
N = Number of threads
L = Threaded length
F = Force acting on bolt
𝜎 = Tensile strength of material
Safety Factor = 5
0.9743
𝐴𝑡 = 0.7854 𝐷 −
𝑛
𝜎
𝐹
=
=
𝑆𝐹 𝐴𝑡
𝑁 = 𝑛𝐿 =
0.25”
L = 0.143”
0.9743
0.7854 𝐷 − 𝑛
𝐹(𝑆𝐹)
𝐷−
0.7854𝜎
F = 225 lbf (1000N)
2
𝐹
0.9743𝐿
Tensile Strength of 300
series Stainless Steel:
120ksi
2
= 1 𝑡ℎ𝑟𝑒𝑎𝑑 𝑛𝑒𝑐𝑒𝑠𝑠𝑎𝑟𝑦
D = 0.25”
F
Using 4 threads per bolt in design
116
DOW Styrofoam Brand Panel Core 20
Compressive Strength: 137,900 Pa (min. vertical)
Assumptions:
Worst-case vertical load = 10G
Interior sub-structure mass = 5 kg
Surface area of interior sub-structure bottom face = 42.09 in2 = 0.0271548 m2
𝐹 = 𝑚𝑎
𝐹 = 𝑚 ∙ 10𝐺
𝑚
𝐹 = 5𝑘𝑔 ∙ 10 ∙ 9.81 2
𝑠
𝐹 = 490.5𝑁
490.5𝑁
= 18,063 𝑃𝑎
0.0271548𝑚2
18,063 𝑃𝑎 < 137,900 𝑃𝑎
Since 18,063 Pa is less than the compressive strength of the foam, the foam will
support the interior sub-structure under a worst-case 10G load.
117
•
Outer/Interior Electronics Support Structure
• Aluminum 6061-T6 (1/8” thick)
• Thermal Conductivity: 167 W/m-K (1160 Btu-in/hr-ft2-°F)
• Fatigue Strength: 96.5 MPa (56,000 psi)
• Inexpensive: $154.71 (24” x 48” x 1/8” sheet)
•
Foam Core Insulation
• Dow Chemical Styrofoam Brand Panel Core 20
• Thermal Conductivity: 0.025 W/m-K
• Vertical Compressive Strength: 137 kPa (20 psi)
• Inexpensive: $28.34/sheet (2” x 4’ x 8’)
•
Wind Barrier
• Polyurethane foam
118
Retention using wire or zip
ties fed through holes in the
central insulation foam
layers
U-shaped stakes penetrating
the wind barrier and
embedded in the insulation
foam
Hook and loop patches
attached to the wind barrier
and insulation foam
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
119
120
121
Structural Bracket
OS_SB_01
122
Board Bracket (L)
IS_MBMB-L_01
123
Board Bracket (R)
IS_MBMB-R_01
124
Foam 1_12
OS_IF-1-12_01
125
Foam 2_3_10_11
OS_IF-2-3-10-11_01
126
Foam 4_9
OS_IF-4-9_01
127
Foam 5_8
OS_IF-4-9_01
128
Foam 6_7
OS_IF-6-7_01
129
Wind Barrier
OS_WB_01
130
Subframe Support Arm
IS_CBSP_01
131
Subframe Top/Bottom Plate
IS_TPB_01
132
Support Arm
OS_SA_01
133
Top/Bottom Plate
OS_TP_01
OS_BP_01
134
Internal Structure Assembly
135
Gear and RPM
Control
Motor
Bellows
Volume with
Steel Wool
To Piston
Bellows
Pressure
Transducer
To Laptop
136
0.044 Hz
Pressure
Wave
0.57 Hz
Pressure Wave
1.15 Hz Pressure
Wave
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
137
•
•
•
•
•
Microphone Infrasound
Testing
Microphone Acceleration
Testing
Microphone Temperature
Characterization Testing
Electronic Software
Integration Test
Wind Barrier
Power
On
SPI
Run
Diagnosti
c
Sensor
Functionali
ty
Purpose:
Verify all electronic components
function individually and meet all
electronic performance
requirements
Procedure &
Strategy
•
•
Run Test
Cases
SD
Card
Write
Power on electronics subsystem
with software loaded onboard
Run diagnostic tests and
various test cases to verify
software and electronics
respond correctly
Location &
Equipment
•
•
•
External power source
Multimeter
Digital logic probe
Measurements
•
•
•
Voltage/Current/Power
Digital Logic/Timing
Data Out
Issues
•
Improper connections leading to
improper data
Port
Check
138
•
•
•
•
•
Microphone Infrasound
Testing
Microphone Acceleration
Testing
Microphone Temperature
Characterization Testing
Electronic Software
Integration Test
Wind Barrier
Purpose:
Characterize the microphone’s
sensitivity to accelerations
Procedure &
Strategy
•
Induce low frequency
accelerations to simulate
payload motion at altitude
Location &
Equipment
•
ITLL Shaker Table
Measurements
•
•
Acceleration
Microphone output voltage
Issues
•
Saturation of sensor diaphragm
due to large response to
acceleration
Shaker Table
Assembly
Reference
Accelerometer
Pressure Transducer
Commanded
Frequency fc
139
•
•
•
•
•
Microphone Infrasound
Testing
Microphone
Acceleration Testing
Microphone
Temperature Sensitivity
Testing
Electronic Software
Integration Test
Wind Barrier
Thermometer
Varying
Environment
T °C
Purpose:
Characterize the microphone’s
sensitivity to temperature
Procedure &
Strategy
•
Expose microphone to varying
or controlled temperature
environments within
operational range (-15 to 45°C)
Location &
Equipment
•
•
•
•
Dry ice, ice water bath
Large insulated cooler
Temperature sensors
Resistive heating elements
Measurements
•
•
Microphone temperature
Microphone output voltage
Issues
•
Controlled temperature
environment
Pressure
Transducer
Voltage
Data Out
Temperature
Data Out
140
•
•
•
•
•
Microphone Infrasound
Testing
Microphone
Acceleration Testing
Microphone
Temperature Sensitivity
Testing
Electronic Software
Integration Test
Wind Barrier
Purpose:
Verify the wind noise reduction
capability of the foam barrier
filter and validate the software
model
Procedure &
Strategy
•
Embed pressure transducer
inside foam wind barrier, vary
dynamic pressure seen by
filter/transducer system
Location &
Equipment
•
ITLL Wind Tunnel, Wind Barrier
Test Article, Pressure
Transducer, Data Collection
Capability
Measurements
•
•
Dynamic pressure
Microphone output voltage
Issues
•
Saturation of the microphone at
22 m/s
ITLL Wind Tunnel
141
•
Structural
Loading and
Data Survivability
• Vacuum
Chamber
• Thermal
Purpose:
To verify the data will survive
landing loads and the structural
connections to the gondola will
withstand in flight forces
Procedure &
Strategy
•
•
Drop test - simulate predicted
impact speed (6.7 m/s)
Gondola attachment loadingforce experienced during launch
Location &
Equipment
•
•
Engineering Center Courtyard
Accelerometers
Measurements
•
•
Acceleration
Impact velocity
Issues
•
Safety during drop test
142
Design Requirements
Designation
Description
DR 2.6
Maintain structural integrity including gondola connections during
launch and parachute deployment and withstand impact forces up to
2000 N
Drop test
•
Strategy
•
Expected landing speed of 6.7 m/s (height
of 2.28 m)
Added weight will simulate electronics
Location
•
One story drop – ITLL bridge
Measurements
•
G loading - accelerometers
Issues
•
Safety – maintain perimeter around drop
site
Background
ASTERIA
Structure/Mock
Payload
Measure loading during landing to
verify the SD card will survive (max of
500g)
Design
Overview
Microphone
Thermal
Payload
Cavity
Accelerometer
Battery
Fixture to
Payload
Mechanical
Risks
V&V
Project
Management
143
Internal
Payload Test
Configuration
Drop Test
Configuration
(Side View)
Drop Test
Configuration (Top
View)
Wall
Impact
Site
Min 8
m
ASTERIA
Structure/Mock
Payload
Monitored
Perimeter
Payload
Cavity
Accelerometer
Battery
1
Story
Heigh
t
Fixture to
Payload
Impact Site –
Max Load/Shock
or
Impact
Site
Min 8
m
•
Structural
Loading and
Data Survivability
• Vacuum
Chamber
• Thermal
Purpose:
To verify the payload will survive
stratospheric pressure conditions (
5 to 8 kPa)
Procedure &
Strategy
•
Subject critical electronic
components to stratospheric
pressure
Location &
Equipment
•
Vacuum Chamber - JANA
Measurements
•
•
Chamber pressure
Output from instrument
peripherals and microphone
Issues
•
Safety of electronics and pressure
transducer
145
•
Structural
Loading and
Data Survivability
• Vacuum
Chamber
• Thermal
Insulation
External
Temperature
To verify the payload will survive
stratospheric conditions (-57 to
30 °C ) by validating the thermal
model
Procedure &
Strategy
•
•
Internal
Temperature
ASTERI
A
Purpose:
External
Temperature
Subject the payload to the
temperature extremes five hours
Compare results with thermal
model
Location &
Equipment
•
•
•
Dry ice
Large insulated cooler
Temperature sensors
Measurements
•
Internal and external
temperature
Issues
•
Maintaining the constant
temperature
Controlled
Environment
146
•
•
Integration
and Flight
Duration
Software
Pre-Flight
Diagnostic
Purpose:
Verify the pre-flight diagnostic
software will correctly detect
the problem
Procedure &
Strategy
•
Run test case scenarios to
ensure the diagnostic software
correctly detects the problem
Equipment
•
Completed payload and
electronics
Measurements
•
Software diagnostic output
147
Requireme
nt
Verification Method
Requireme
nt
Verification Method
DR 1.1
Microphone Infrasound
Testing
Electronic Software
Integration
DR 2.3
Vacuum Testing
DR 2.4
Thermal Control Testing
DR 2.5
Analysis
Structural Loading Test
DR 2.6
Inspection
DR 3.1
Demonstration
DR 3.2
Thermal Control Testing
DR 1.2
Acoustic Low Pass Filter Test
DR 1.3
Electronic Software
Integration
DR 1.4
Electronic Software
Integration
DR 1.5
Electronic Software
Integration
DR 3.3
Analysis
Flight Duration Testing
DR 1.6
Electronic Software
Integration
DR 3.4
Analysis
Flight Duration Testing
DR 1.7
Inspection
DR 3.5
DR 1.8
Electronic Software
Integration
Software Pre-Launch
Diagnostic Testing
DR 2.1
Inspection
DR 2.2
Inspection
148
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
13: Structural
integrity
compromised
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
149
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
4: Likely
25: Insufficient
budget
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
150
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
26: Cannot
interface with
test equipment
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
151
Likelihood
5: Catastrophic
Severity
3: Moderate
4: Critical
2: Minimal
5: Certain
19, 20
27: Damage to
components during
testing/
manufacturing
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
152
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
2: Unlikely
8-10: Electronic
1, 2,
3, 4, 7b
13, 25, 26, 27
component
15
failures
8, 9, 10, 11, 12
14, 17
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
153
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
2: Unlikely
11-12: Data
storage/retrieval
1, 2, 3, 4, 7b
13, 25, 26, 27
failures
15
8, 9, 10, 11, 12
14, 17
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
154
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1,14:
2, 3,Payload
4, 7b
13, 25, 26, 27
detaches
from
15
gondola
2: Unlikely
8, 9, 10, 11, 12
14, 17
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
155
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1, 2, 3,17:
4, 7b
13, 25, 26, 27
Software
15
failures
2: Unlikely
8, 9, 10, 11, 12
14, 17
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
156
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
3-4: Loss of
power
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
7a
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
157
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
21-24: Budget/
7a
schedule slips
4: Likely
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
158
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
19, 20
4: Likely
29-31: Testing
7a
delays & set-up
errors
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
3, 4, 21, 22
23, 24, 29, 30
31, 32
5, 6, 16, 18
1: Rare
Background
1: Negligible
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
159
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
5, 6, 16, 18
1: Rare
Background
5-6: Component
3, 4, 21, to
22collect
failures
23, 24, 29, 30
data
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
160
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
5, 6, 16, 18
1: Rare
Background
16-18: Software
3, 4, 21, 22
integration/
23, 24, 29, 30
schedule slip
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
161
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
1: Negligible
5: Certain
19, 20
4: Likely
7a
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
28: Testing
facility
unavaliability
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
162
Likelihood
5: Catastrophic
4: Critical
7a: Single
microphone1:are
2: Minimal
Negligible
unable
19,
20 to detect
infrasound waves
Severity
3: Moderate
5: Certain
4: Likely
7a
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
163
Likelihood
5: Catastrophic
4: Critical
Severity
3: Moderate
2: Minimal
5: Certain
1: Negligible
19, 20
19-20: Unbudgeted
7a
4: Likely
items/ Unscheduled
tasks
3: Possible
1, 2, 3, 4, 7b
15
2: Unlikely
8, 9, 10, 11, 12
14, 17
13, 25, 26, 27
5, 6, 16, 18
1: Rare
Background
3, 4, 21, 22
23, 24, 29, 30
31, 32
28
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
164
Subsystem
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Electronics
Item
InfraNMT Microphone
Contact ruggedized connector
20 s corner frequency filters
~10 s corner frequency filters
Capacitors
Battery Connector
Inter-Board 10-pin Connector (M)
Resistors
7V Regulator
3.3V Regulator
0.5" H20 Pressure Transducer
16-bit ADC
Single Supply Dual Precision Op Amp
Temperature Sensor
7.4V 20.8Ah Cell
7.4V Charger
7.4V Charging Bag
11.1V 2200mAh Cell
11.1V Charger
11.1V Charging Bag
Capacitors
Manufacturer
Dr. Johnson
Dr. Johnson
Dr. Johnson
Dr. Johnson
Part #
N/A
N/A
N/A
N/A
Digi-Key
Samtec
84-4K-ND
MMSD-05-28C-L-08.00-S-K
Linear
Mouser
Mouser
Linear
Linear
Digi-Key
AA Portable Power Corp.
AA Portable Power Corp.
AA Portable Power Corp.
Battery Junction
AA Portable Power Corp.
AA Portable Power Corp.
863-NCP508SQ33T1G
683-0.5INCH-D-MV
LTC2470IMS#PBF
LT1214CS8#PBF-ND
ADT7320UCPZ-R2CT-ND
LCH4P6S2R2WR-2P2
3P10-L1008 / CH-L7412
LI-ION-SAFER
TENERGY-11V-2200
CH-LI11.1V1.5A
LI-ION-SAFER
Quantity
6
8
6
6
50
5
5
125
5
5
12
10
13
5
1
1
1
1
1
1
20
Item Price
$150.00
$5.00
$5.00
$5.00
$0.12
$0.66
$2.47
$0.63
$10.55
$0.51
$73.88
$2.79
$6.33
$8.06
$164.95
$22.95
$19.95
$26.95
$26.99
$19.95
$0.12
Item Total
$935.00
$40.00
$30.00
$30.00
$0.00
$3.30
$0.00
$78.75
$52.75
$2.55
$0.00
$27.90
$82.29
$40.30
$164.95
$22.95
$19.95
$26.95
$26.99
$19.95
$2.40
Mechanical
Control Board
Microphone Board
Already Procured
Background
Design
Overview
Microphone
Thermal
Mechanical
Risks
V&V
Project
Management
165
Subsystem
Item
Electronics
Power On Diode
Electronics
Card Detect Diode
Electronics
Battery Connector (F)
Electronics
Battery Connector (M)
Electronics
Battery Connector (M pins)
Electronics
MicroUSB Connector
Electronics
MicroSD Connector
Electronics
MicroSD Card
Electronics
Inter-Board 10-pin Connector (F)
Electronics
Resistors
Electronics
Reset Push-button Switch
Electronics
5V 800mA Regulator
Electronics
+/-5V 300mA DC/DC Converter
Electronics
3.3V 50mA Regulator
Electronics
3.3V 300mA Regulator
Electronics
PIC18 8-bit Microcontroller
Electronics
FTDI USART-USB
Electronics
Temperature Sensor
Electronics
16MHz Crystal Oscilator
Electronics $33 Student Special (+$50 for repeated parts)
Mechanical
24" x 48" x 1/8" Aluminum 6061-T6
Mechanical
Polystyrene Foam
Mechanical
Coating
Mechanical
Fasteners
Mechanical
1/4" OD Nylon Tubing
Mechanical Buffer (Polyurethane Foam, Other Supplies)
Testing
Misc Testing Supplies
General
Final Report Printing
General
Shipping
Margin
Background
Design
Overview
Microphone
Manufacturer
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Best Buy
Samtec
Part #
SSL-LX5093TC
SSL-LX5093VC
# 0010844022
# 0050841020
# 0002082004
10118194-0001LF
2908-05WB-MG
SDSDQY-004G
IPL1-105-01-L-D-K
Digi-Key
Digi-Key
Digi-Key
Mouser
Digi-Key
Microchip
Digi-Key
Digi-Key
Digi-Key
PTS645SM43SMTR92 LFS
LT1117IST-5#PBF
RS3-0505D
NCP508SQ33T1G
LT1962EMS8-3.3#PBF
PIC18F8722-I/PT
FT230XS-R
ADT7320UCPZ-R2
ABLS-16.000MHZ-B4-T
McMaster
Lowes
Various
Various
McMaster
89015K68
96554
Thermal
5233K52
Mechanical
Risks
Quantity
1
1
2
2
4
1
1
1
5
10
1
1
1
1
1
1
1
1
1
2
4
6
2
100
2
2
1
2
1
V&V
Item Price
$1.08
$1.22
$0.47
$0.27
$0.10
$0.46
$3.60
$12.99
$2.02
$0.63
$0.21
$4.52
$17.84
$0.51
$3.52
$8.74
$2.04
$8.06
$0.35
$83.00
$154.71
$39.98
$20.00
$0.50
$3.25
$100.00
$300.00
$100.00
$250.00
Project
Management
Item Total
$1.08
$1.22
$0.94
$0.54
$0.40
$0.46
$3.60
$12.99
$10.10
$6.30
$0.21
$4.52
$17.84
$0.51
$3.52
$8.74
$2.04
$8.06
$0.35
$166.00
$618.84
$239.88
$0.00
$50.00
$6.50
$0.00
$300.00
$200.00
$250.00
$1,478.38
166