telemetric interplanetary regolith explorer for seismic ... · pdf filetelemetric...

SPRING FINAL REVIEW

TELEMETRIC INTERPLANETARY REGOLITH EXPLORER FOR SEISMIC

INVESTIGATION OF ASTEROID SURFACES

Ian Barry

Rachael Collins

Jonathon Fraker

Patrick Haas

Tom Johnson

Austin Lillard

John Marcantonio

Scott Taylor

Aerospace Engineering Sciences

University of Colorado

21 April 2014

OUTLINE

Project Objective

Design Description

Test and Results

Communications System

Power System

Mechanical System

Systems Engineering

Project Management

2

PROJECT OBJECTIVE

MISSION CONOPS

4

18 month

travel time

Deploy Explosive

Pods (red) and

GeoPods (grey)

Surface Operations

Landing

GeoPod

records

data while

descending

2 1

2

20 minute contacts

every 2.26 hours

0.1-10 km

Range

300 min

Touchdown with

surface, data

recorded while

settling

10 min 10 days

Deploy, Descent, and Landing

14 hour

settling time

Spacecraft Orbits

Asteroid for 10 days

Explosive Pod

detonates; GeoPod

collects data with

Accel and Insts.

Science data

transmitted when link

is available with the

orbiting satellite

Accel is

turned on;

GeoPod is

separated

TIRESIAS Focus:

GeoPod

-Power

-Communication

-Internal Structure

Launch

1

Asteroid Surface

Accel and

Insts. activated

after settling

~5 min 14 hours

During this time, the power

system must regulate and

distribute power to all of the

components

Heaters are not necessary for

ground testing. Representative

loads will be used for simulation

The internal structure must

integrate the components and

the power system into the

GeoPod shell (provided by Ball)

Thermistors

w/MUX

Receiver Receiver

ADC ADC

PROJECT CONOPS

GeoPod

Accelerometer

C&DH Board

Transmitter

Accelerometer

C&DH Board

Transmitter

Internal

Structure

1 ft

3lb weight

Thermistors

w/MUX

Power

Weight dropped near fully

integrated GeoPod GeoPod detects seismic waves 3-axis accelerometer measures

response

BASIX mission will use both a

GeoPhone and an

Accelerometer

Our project will sample each axis

of the accelerometer twice to

simulate the GeoPhone,

because commercial

GeoPhones are too large,

heavy, and expensive for our

project

Ball is receiving a custom

GeoPhone

ADC converts 6 analog channels

(2 signals for each

accelerometer axis) into a digital

signal.

C&DH board samples and stores

the digital data from the ADC at

500Hz

Data from the multiplexed

thermistors (“housekeeping

data”) is sampled at 500Hz and

stored at 80 bits/s

The C&DH Board continues to

sample both the accelerometer

data and the thermistors for 15

minutes

Commands are received over

the next 20 minutes to start

transmissions of data

20 minutes represents a contact

window

Packetized accelerometer and

thermistor data is transmitted

according to received

commands

1.5

ft

Heaters

5

Level 1

Develop communication system

Store and forward accelerometer data

Receive commands from simulated mother satellite to playback telemetry

Test command and data handling with simulated seismic activity

Design internal structure to interface with shell

Level 2

Integrate communication system into GeoPod internal structure

Design and model power system with enough storage for mission duration

Level 3

Internal power system distributes and regulates power to all components

Develop fully integrated standalone GeoPod

Additions

Develop and validate thermal model

LEVELS OF SUCCESS

6

DESIGN DESCRIPTION

FUNCTIONAL BLOCK DIAGRAM

8

STRUCTURE INTEGRATION

Power Board

Receiver

Transmitter

Arduino Due

ADC Board

9 Project Objective Design

Description Comm System

Power System

Mechanical System

Systems Engineering

Project Mgmt

ELECTRONICS BLOCK DIAGRAM



Power System

Mechanical System

Systems Engineering

Project Mgmt

SOFTWARE ALGORITHM

11

Command Acceptance

Data Collection Mode

(15min Duration) Power Switching Mode Telemetry Playback Mode

Samples Accelerometer

Samples Temp Sensors

Packetizes Data

Writes Packets to Memory

Parameter Selects

Component (of 5)

Parameter Designates

On/Off

Switches Power Low/High

Parameter Selects Packet

(Playback Pointer/Retrans)

Reads Packet from

Memory

Writes Packet to

Transmitter

Project Objective Design


Power System

Mechanical System

Systems Engineering

Project Mgmt

CRITICAL PROJECT ELEMENTS

12

Element Description Satisfaction

MSN.1 Mass < 5kg Fully assembled GeoPod has a mass of 4.49 kg

MSN.2 Integration with

external shell

All components securely mount to the internal structure that

integrates with the external shell

MSN.3 Collect science &

housekeeping data

15 minutes of science and housekeeping data successfully

sampled at 500 Hz and stored in memory

MSN.4 Transmit data to

Ground Station

Equipment (GSE)

Stored data was transmitted to GSE at 38 kbps with minimal delays

and bit errors. The recorded data (3.75 MB) was transmitted in 13

minutes, which is within the 20min pass duration

MSN.5 Maintain operable

thermal range

A thermal model to bound expected component temperatures

during operation was created and validated through sand box

testing

MSN.6 Provide, regulate, &

distribute power

Batteries and Power PCB provide adequate power with 94%

efficiency for 12 days of operation

MSN.7 Provide a path to

flight

All components selected are flight ready or can be easily replaced

with spaceflight qualified components



Power System

Mechanical System

Systems Engineering

Project Mgmt

TEST OVERVIEW/RESULTS

COMMUNICATIONS SYSTEM

Max. Amplitude:

0.2 g’s

freq < 50 Hz

COMM REQUIREMENTS

Requirement Flows From Description

COM.1 MSN.3 6 channels of science data shall be sampled at 500 Hz.

COM.2 MSN.3 Science data shall be recorded such that a range of -2g to

2g is quantized with a resolution of 0.002g

COM.3 MSN.3,

MSN.4

The C&DH board shall interface with ADC, memory, power

board, and RF system.

COM.4 MSN.4 Uplink data rate shall ensure all stored telemetry is

transmitted during the 20 min contacts over 10 days

Asteroid 60o

Rotational

Period = 2.4hrs Orbital

Period =

124.1hrs



Power System

Mechanical System

Systems Engineering

Project Mgmt

DATA COLLECTION TEST Goal: Measure data collection rate (COM.1) and

characterize signal conditioning output (COM.2)

16

Measure ADC conversion frequency,

Verify sampling rate

Measure data stored,

Verify recording rate

Measure SNR and bias of data,

Verify signal conditioning output

MUX

Redesign

Verified

Timing

Verified

CCSC

Verified

Dual (20/5V)

Power Supply

9V Power

Supply

SPI Logic

Analyzer

Signal

Generator



Power System

Mechanical System

Systems Engineering

Project Mgmt

DATA COLLECTION RESULTS

17

Signal Conditioning (COM.2)

LSB of ADC = 0.15 mV

Accelerometer = 100mV/g

-50g to 50g range with 0.0015g

resolution

Software Timing (COM.1)

Required duration < 2 ms

Predicted duration = 1.126 ms

Tested duration = 1.121 ms

500 Hz met within 0.0021%



Power System

Mechanical System

Systems Engineering

Project Mgmt

TELEMETRY PLAYBACK TEST Goal: Measure effective data transmission rate (COM.4) and identify bit errors

Verify ability to transmit 3.74 MB of data in 20 min. and receive commands to transmit

18

Receiver

MATLAB Processing

Stand

Measure data transmitted,

Verify transmission rate greater than 32 kbps

Send error packets,

Verify bit error identification

9V Power

Supply

Measure delay between command

and packet receipt,

Verify response to command

Hard line to

command

Test RX

Arduino

Bytes

Sent

Memory

Read

Checksums

Calculated



Power System

Mechanical System

Systems Engineering

Project Mgmt

TELEMETRY PLAYBACK RESULTS

Data Transmission (COM.4)

38 kbps data rate achieved (> 32 kbps)

Transferred 3.74 MB of stored data in

13 min, 1.6 sec (within 20 min

contact)

Overhead consists of commanding

and MATLAB serial read

Entire mission stored data transferred

in 13 contacts or 1.25 days of

operations (Margin Factor = 8)

Successfully identified and retransmitted

5 packets (out of 15,000) each with a

single bit error

Errors most likely due to memory read

speed, not transmission

Takes 0.26sec to retransmit 5 pkts



Power System

Mechanical System

Systems Engineering

Project Mgmt

Data Type Sampling Rate Storage

Acceleromete

r (315 min)

24 kbps 56.7 MB

Geophone

(15 min)

24 kbps 2.7 MB

Housekeepin

g

(12 days)

64 bps 8.3 MB

Packet

Overhead

72 bits/pkt 2.54 MB

Mission Total: 70.24 MB

Total Transfer Time: 245 min (13 contacts)

POWER SYSTEM

POWER REQUIREMENTS

Critical Components

Batteries

Capacity and size

Power Regulation and Distribution

Efficiency and accuracy


EPS.1 MSN.3,

MSN.4

The power system shall output voltage lines at 5, 9.5, 20,

and 12 volts

EPS.2 MSN.5 The batteries shall supply power for 12 days of operations

EPS.3 MSN.1 Power Distribution board shall fit on 4.25x4.25 in. PCB

EPS.4 EPS.1,

EPS.2

The Power Distribution board must be >90% efficient



Power System

Mechanical System

Systems Engineering

Project Mgmt

POWER VERIFICATION

22

Goal: Measure regulation accuracy (EPS.1) and power board efficiency (EPS.4)

27V

Supply

12V

Supply

10-kΩ

Load

200-Ω

Load

25-Ω current

sense resistors

25-mΩ current

sense resistors

110-mΩ current

sense resistors

Measure Current and Voltage,

Verify accuracy and efficiency

33-Ω

Load



Power System

Mechanical System

Systems Engineering

Project Mgmt

VOLTAGE ACCURACY TEST

23

Req EPS.1: Voltage Lines

Voltage lines measured over a variety of input voltage ranges to determine

limiting values

9.5V regulator met within 1%

20V regulator met within 5%



Power System

Mechanical System

Systems Engineering

Project Mgmt

EFFICIENCY RESULTS



Power System

Mechanical System

Systems Engineering

Project Mgmt

Req EPS.4: 90% Efficiency

Power board efficiency was measured over varied loads

Based on error in voltage measurements and resistor values, efficiency was

measured to a 0.5% accuracy

All measured power board efficiencies > 92%

0.00

20.00

40.00

60.00

80.00

100.00

120.00

80 130 180 230 280 330

Eff

icie

ncy

Load on 5V Regulator (Ω)

Efficiency of Power Board for Varied 5V Load

Efficiency of 5V Total Efficiency

91.00

92.00

93.00

94.00

95.00

96.00

97.00

98.00

99.00

15 20 25 30 35 40 45

Eff

icie

ncy

Load on 9V Regulator (Ω)

Efficiency of Power Board for Varied 9V Load

Efficiency of 9V Total Efficiency

BATTERY DISCHARGE SETUP

248.3 Ω

(2 x 100 Ω,

1 x 50 Ω)

8 x 1.5 V

AA cells,

10-14 V

Voltage

Probe

Point

Goal: Measure battery capacity (EPS.2)



Power System

Mechanical System

Systems Engineering

Project Mgmt

BATTERY DISCHARGE RESULTS

Co

nse

rvative

Ca

pa

city: 5

10

Wh

Re

qu

ired

Ca

pa

city: 3

80

Wh

Direct Sunlight

Heats Up Batteries

Battery Capacity (EPS.2)

Required capacity of

batteries: 380 Wh

Achieved capacity of

batteries: 510 Wh

Margin of 34%



Power System

Mechanical System

Systems Engineering

Project Mgmt

POWER DISTRIBUTION BOARD

27

9.5 V Switching Regulator

Tem

pera

ture

Monitoring S

yste

m

C&

DH

Co

nn

ecti

on

s

5V Linear Regulator 20V Linear Regulator

Tra

nsm

itte

r/R

eceiv

er

Connections

PCB Size (EPS.3)

Power board must fit

within 4.25 in by 4.25 in

printed circuit board



Power System

Mechanical System

Systems Engineering

Project Mgmt

POWER DISTRIBUTION BOARD

28

9.5 V Switching Regulator

Tem

pera

ture

Monitoring S

yste

m

C&

DH

Co

nn

ecti

on

s

5V Linear Regulator 20V Linear Regulator

Tra

nsm

itte

r/R

eceiv

er

Connections

PCB Size (EPS.3)

Power board must fit

within 4.25 in by 4.25 in

printed circuit board

Power board

successfully integrated

into GeoPod Structure



Power System

Mechanical System

Systems Engineering

Project Mgmt

MECHANICAL SYSTEM

MECHANICAL REQUIREMENTS


MCH.1 MSN.2 The internal structure shall integrate with the

manufactured GeoPod shell

MCH.2 MSN.2 The power and electrical subsystems shall be accessible

for extraction without the removal of other components

MCH.3 MSN.5 A thermal model shall be created to ensure subsystems are

within operating temperatures in the testing environment

MCH.4 MSN.7 All internal structural components shall be manufacturable

using on campus resources



Power System

Mechanical System

Systems Engineering

Project Mgmt

31

MASS BUDGET

Mass Budget (MSN.1)

Actual Margin of 0.51 kg or 10.2%

Increase due to addition of wiring and battery packaging



Power System

Mechanical System

Systems Engineering

Project Mgmt

SUBSYSTEM INTEGRATION TEST

32

Requirements Satisfied

MCH.1

MCH.2

MCH.4

Power Board

Receiver

Transmitter

Arduino Due

ADC Board



Power System

Mechanical System

Systems Engineering

Project Mgmt

THERMAL VERIFICATION MODEL

33

Cold Case:

Hot Case:

Internal Structure Material:

Aluminum 6061

Subsystem

Op.

Range

[°C]

Temp at

Steady

State

[°C]

Temp

Change

[°C]

Arduino

Due/ADC

Cold: -40

Hot: 85

Cold: 21.47

Hot: 23.88

+0.47

+2.88

Power Board Cold: -40

Hot: 140

Cold: 21.46

Hot: 23.85

+0.46

+2.85

Battery Pack Cold: -20

Hot: 55

Cold: 21.55

Hot: 23.97

+0.55

+2.97

Transmitter/

Receiver

Cold: -20

Hot: 50

Cold: 21.50

Hot: 23.93

+0.50

+2.93

Thermal Operating Range (MCH.3)



Power System

Mechanical System

Systems Engineering

Project Mgmt

THERMAL VERIFICATION Goal: Isolate and measure modeled thermal conductive resistances (MCH.3)

Resistances independent of thermal loads, symmetric within bounds

Resolution of 1.7 K/W needed, 0.013 K/W achieved (quadrature addition of error in power and temperature measurements)

Various levels of integration with and without batteries

34

Measure steady-state temperatures over

representative orthant of pod

Verify modeled thermal resistances

LabView VI NI 9213 DAQ

Surface

Thermocouple Stefaan

Van Wal’s

Gravel Box

5 Interior

Thermocouples

70W Heater

115 VAC

Wall Outlet Variac

V

Calibrated to

Precision σ = 0.13 K

Power Measured

to 2mW Accuracy



Power System

Mechanical System

Systems Engineering

Project Mgmt

T5

T4

T3 T2

T1

T0

Structure Fit-

Checked and

Integrated

THERMAL TEST RESULTS

35

Internal Structure Material:

Aluminum 6061

Thermocouple

Station

Model

Temp

[°C]

Actual

Temp

[°C]

Temp

Deviance

[°C]

Temp 0 Cold: 22.28

Hot: 26.13

22.90 -0.62

+3.23

Temp 1 Cold: 22.28

Hot: 26.09

22.81 -0.53

+3.28

Temp 2 Cold: 22.27

Hot: 25.67

22.78 -0.51

+2.89

Temp 3 Cold: 22.26

Hot: 25.17

22.69 -0.43

+2.48

Temp 4 Cold: 22.26

Hot: 24.72

22.70 -0.44

+2.02

Temp 5 Cold: 22.21

Hot: 23.44

22.40 -0.19

+1.04



Power System

Mechanical System

Systems Engineering

Project Mgmt

Thermal Modeling (MCH.3)

20.00°C

21.00°C

22.00°C

23.00°C

24.00°C

25.00°C

26.00°C

27.00°C

T0 T1 T2 T3 T4 T5

Te

mp

era

ture

Thermocouple Location

Thermal Model Validation in Lab Conditions

Cold Case Hot Case Experimental

THERMAL SPACE CASE



Power System

Mechanical System

Systems Engineering

Project Mgmt

Method

Calculate bounding model

temps at different orbital

positions

1.01 AU (Perihelion)

1.5 AU

2.28 AU (Aphelion)

Conclusion

Heaters needed if Didymos

radius > ≈1.235 AU

0.6 W will maintain

subsystem temperature at

aphelion (accounted in

power system storage)

1.2 1.4 1.6 1.8 2 2.2-100

-50

0

50GeoPod Temperature vs. Orbit

Radius to Sun [AU]

Tem

pera

ture

[oC

]

Operational Range

Hot Case

Cold Case

Heaters Needed

PROJECT VALIDATION

FINAL VALIDATION TEST

38

Dropped weight

simulates weak blast

(0.2 g amplitude)

Lab noise exceeds

value expected in

space environment

Simulated 20-minute

satellite pass exceeds

required transmission rate

FINAL VALIDATION RESULTS

39

Weight-drop stimulated accelerometer, data

collected, digitized, packetized, stored, read

from memory, transmitted, received, and

processed within project parameters

Signal amplitude on expected order of

magnitude

Peak frequency content as expected

Powered by batteries regulated onboard

Operational temperature rise within

modeled bounds

Max. Amplitude:

0.2 g’s

freq < 50 Hz

SYSTEMS ENGINEERING

SYSTEMS APPROACH

41

Concept

System

Reqs.

Detailed

Design

Unit

Testing

Implementation

System

Verification

Project

Validation



Power System

Mechanical System

Systems Engineering

Project Mgmt

Understanding the specifications of

received equipment

Required for proper design. Can

cause project failures.

Managing Wiring

Mass much higher than expected

Volume allocation

Not enough detailed wiring

design early enough in project

development

Distribution of knowledge

Members became very

specialized in their

component/subsystem

Unavailability affects schedule

42

SYSTEMS PROBLEMS

Component Expected

Value

Actual

Value

Shell

Diameter

12 in 10 in

Transmit

Power

250 mW 1 W

TX/RX

Interface

TTL (3.3V) RS-422

Accel.

Sensitivity

1 V/g 100 mV/g

Component specifications



Power System

Mechanical System

Systems Engineering

Project Mgmt

Scope project quickly and effectively

Develop requirements early and

understand where they flow from

TIRESIAS did not have a strong grasp

of project scope at PDR

Fully test critical components early

Transmitter and receiver did not

behave like a typical 8N1 TX/RX

system

Memory read caused errors when

mounted on ADC Board.

Consult with advisors and peers often

Gives better understanding of system

Significantly increases likelihood of

project success

43

LESSONS LEARNED



Power System

Mechanical System

Systems Engineering

Project Mgmt

Antenna configurations in original scope

Structural design change after advising

PROJECT MANAGEMENT

ORGANIZATIONAL CHART

45

PROJECT MANAGER Rachael Collins

POWER SYSTEM ENGINEER Scott Taylor

TECHNICAL CONTRIBUTOR Ian Barry

TECHNICAL CONTRIBUTOR Patrick Haas

TECHNICAL CONTRIBUTOR Austin Lillard

MECHANICAL ENGINEER John Marcantonio

TECHNICAL CONTRIBUTOR Jonathon Fraker

COMM SYSTEM ENGINEER Thomas Johnson

TECHNICAL CONTRIBUTOR Rachael Collins

SYSTEMS ENGINEER Austin Lillard

FINANCIAL LEAD Patrick Haas

SAFETY/TESTING LEAD Ian Barry

MANUFACTURING LEAD Jonathon Fraker



Power System

Mechanical System

Systems Engineering

Project Mgmt

WORK BREAKDOWN STRUCTURE

TIRESIAS

Project Management

Comm System Power System Mechanical

System Integration and

Test

46

CDR

FFR

Work Flow

Schedule

Cost Budget

MSR

AIAA Paper

SFR

• PFR

Link Budget

Transmitter

and Receiver

Antennas

Accelerometer

Configured

ADC

C&DH SW

Sketches

Stored Data

Spacecraft

Simulation

(GSE)

Power Budget

Schematics

Power

Distribution

PCB

ADC PCB

Temperature

Sensors

Wiring Harness

CAD Models

Thermal Model

Mass and

Volume Budget

Battery Pack

Shell

Integration

Structure

Subsystem

Mounting

Frame

TRR

Testing

Procedures

Result Reports

Integrated

GeoPod



Power System

Mechanical System

Systems Engineering

Project Mgmt

PROJECT SCHEDULE

47

TEAM DYNAMICS

Success

Effective communication

Maintained and followed schedule

Technical aptitude

Finds information independently

Willing to take on tasks

Difficulties

Procrastination

Redistribution of work



Power System

Mechanical System

Systems Engineering

Project Mgmt

BUDGET COMPARISON

49

Financial Plan

Part CDR Estimated

(with Contingency) Final

Metals and Fasteners $317 $397

Batteries $353 $230

Arduino’s and Equipment for them $94 $256

Cables/Adapters $272 $114

PCBs $528 $417

Integrated Circuits, Resistors, Capacitors,

Inductors, Diodes, Transistors $344 $331

Breakout Boards and other testing

equipment $185 $161

Transmitter and Receiver - $1831

RF Equipment - $351

Total $2093 $4088

Project Overview Design Solution Comm System Power System Mechanical

System Project

Planning

INDUSTRY COST EQUIVALENT

Total Project Equivalent Cost

Team Member Semester 1

Hours

Semester 2

Hours Total Hours

Equivalent

Earnings

200%

Overhead

Barry 226 255 481 $15,031 $30,063

Collins 238 300 538 $16,813 $33,625

Fraker 218 238 456 $14,250 $28,500

Haas 259 272 531 $16,594 $33,188

Johnson 238 252 490 $15,313 $30,625

Lillard 226 243 469 $14,656 $29,313

Marcantonio 226 247 473 $14,781 $29,563

Taylor 214 252 466 $14,563 $29,125

Totals 1845 2059 3904 $122,000 $244,000

Project Total $366,000

50 Project Overview Design Solution Comm System Power System Mechanical

System Project

Planning

Entry Level Employee Rates

Yearly Wage Yearly Hours Hourly Rate

65000 2080 31.25

ACKNOWLEDGMENTS

Customer – Ball Aerospace

Joseph Hackel

Course Coordinator

Dr. Dale Lawrence

Faculty Advisor

Dr. Scott Palo

Principal Investigator

Dr. Daniel Scheeres

51

QUESTIONS?

APPENDIX

RF SYSTEM LINK BUDGET

54

PARAMETER

DOWNLINK

(FROM PROBE) UNITS Reference

(TLM & DATA)

Data Parameters

Bit Error Rate / Probablility of Bit Error 10-6 [-] Input: design requirement

Data Rate 32,000 bps (Hz) Input: based on mission / objective

Minimum Pr/No 57.75 dB-Hz Eb/No + Z + RDM in dB

Range 1 m Testing Range

Link Budget:

Transmitter Power 20 mW FMT-1 Output Power

Effective Isotropic Radiated Power --27.08 dBW Pt + Gt

Propagation Losses -25.98 dB Ll + Ls + La + Lpt + Lpr + Lp

Antenna Gain (Both Ends) -10.09 dB Gr

Received Power -63.1 dBW EIRP + L + Gr

System Noise Power -200.47 dBW-Hz k Ts

Carrier to Noise Ratio Density 137.76 dB-Hz Pr - kTs

Minimum Pr/No 57.75 dB-Hz

Link Margin 79.60 dB

MISSION BACKGROUND

55

Didymos 65803 Asteroid

• Binary System

• Primary asteroid rotates

every 2.4 hrs

• Equatorial microgravity

environment

Mission Objective

• Determine forces holding

the asteroid surface

together

• Van der Waal forces

• Characterize interior and

surface composition

EFFICIENCY RESULTS

56

Model

Results

Current

Draw

Voltage

Drop

Power

Loss Efficiency

5V LDO 26 mA 4.5 V 118 mW 53%

9.5V SR 265 mA 2.5 V 115 mW 96%

20V LDO 2 mA 7 V 14 mW 74%

Board Total 237 mW 91%

Current

Draw

Voltage

Drop

Power

Loss Efficiency

5V LDO 27 mA 4.5 V 117 mW 55%

9.5V SR 259 mA 2.5 V 88 mW 97%

20V LDO 3 mA 7 V 44 mW 50%

Board Total 248 mW 93%

Req EPS.4: 90% Efficiency

Voltage lines measured to

characterize board efficiency

43.00

43.20

43.40

43.60

43.80

44.00

44.20

44.40

44.60

93.00

94.00

95.00

96.00

97.00

98.00

99.00

100.00

9 10 11 12 13 14

Eff

icie

ncy

of

5V

(%

)

Eff

icie

ncy

of

9V

an

d O

ve

rall (

%)

Input Voltage (V)

Efficiency of Power Board

Efficiency of 9V Total Efficiency Efficiency of 5V

DATA STORAGE

57

Data formatted and stored into packets based on CCSDS standard

Original designed packet size was 8328 bits

New packet format is 1992 bits:

Memory

Amount Data Rate Storage Packets

(8328 bits) Packets

(1992 bits)

Science 20 min 24 kbps 28.8 Mb 3488.4 15,000

HK 15 min 64 bps 0.058 Mb 6.97 30

Total: Margin:

29 Mb 53%

3496

15,030

8 16 4 2 34 1920 8

Syn

c Frame ID Probe ID VCID Timestamp Telemetry Checksum

0 1992 Pros

Packet size is one page in memory

Eliminates unnecessary complexity in data collection software

BER of 1e-6 is not seen (no retrans)

Cons

More overhead (commands) when playing back telemetry

Mitigated by CLTU blocks of commands

Ball antenna tuned to 437.5 MHz

2 transmission frequencies available

to TIRESIAS

Licensed (Palo): 437.35 MHz

ISM Band: 434.79 MHz

437.35 (Palo)

Acceptable VSWR

434.79 (ISM)

VSWR could be acceptable

Decreased performance likely

Freq. (MHz) VSWR Return Loss

(dB)

GS Antenna

437.50 (Ball) 1.19 21.0

437.35 (Palo) 1.19 21.2

434.79 (ISM) 2.91 6.3

S/C Antenna

437.50 (Ball) 1.75 11.3

437.35 (Palo) 1.65 12.2

434.79 (ISM) 3.57 5.0

58

ANTENNA CHARACTERISTICS

Voltage Standing Wave Ratio (VSWR)

Operational: VSWR < 2

Maximum: VSWR < 20

SIGNAL CONDITIONING CHANGE

59

20V

Accel

3-17V

1.5-8.5V

CCSC VD LP

ADC

9V

5V

3.3V -5 to 5V

-5 to 5V

Removed Voltage Divider (No need to step

down voltage to be within ADC range)

Removed OpAmp (No negative supply rails)

Utilize ADCs high 1MΩ input impedance and -

5 to 5V range

Lower resolution of 0.0015g from

0.00052g, but still meets 0.002g

requirement

BODE – SIGNAL CONDITIONING

ADC was not powered on

60

BATTERY DISCHARGE SETUP

248.3 Ω

(2 x 100 Ω,

1 x 50 Ω)

8 x 1.5

V AA

cells,

10-14 V

Voltage

Probe

Point

BATTERY DISCHARGE RESULTS

Co

nse

rvative

Ca

pa

city:

53

0 ±

20

Wh

Re

qu

ired

Ca

pa

city:

24

8 W

h

Direct Sunlight

Heats Up Batteries

DISCHARGE INTEGRATION

VOLTAGE ACCURACY TEST

64

Req EPS.1: Voltage Lines

Voltage lines measured over a variety of input voltage ranges to determine

limiting values

5V regulator tied to voltage of 9.5V regulator: Output = 5.3 V

Outside bounds by 0.05 V due to inaccuracies in resistors

POWER REQUIREMENTS

Regulator

Type

Targeted

Voltage

Min. V Max. V Limiting Component(s)

LDO 5 4.75 5.25 ADC Power

Switching 9.5 9.0 10 Transmitter (Low Limit),

Arduino Power (High Limit)

LDO 20 18 22 Accelerometer Power

65

CHANGES TO POWER DESIGN

Changes from MSR

Design at MSROriginally using MOSFET transistors as switches

66

Related Req. Reason For Change What changed

New method

of switching

components

EPS.2

(Supply

power for

mission

duration)

Found that original MOSFET

transistors could not be

used for our project

New IC electronic switches

used to turn on/off

components

New: FDC6324 – Integrated Load Switch Old: STH310N10F7 – Power MOSFET

POWER BOARD

Req. EPS.4: Power board size

67

TEST BED

68

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