Embry-Riddle Aeronautical University Molly Stagnitti, Anthony Pritchard, Kriszelda Menez

November 30, 2012 1

Molly Stagnitti

2

RockSat-C 2013

CoDR

“Project PHIDO’s mission is to design, build, and launch an optical instrument to determine how the intensity of UV radiation changes with altitude in order to deduce an ozone density profile of the atmosphere. This profile will serve as an initial validation of the instrument functionality in a space environment.” Mission Requirements: Form a payload design utilizing an optical port from its desired function

while adhering to rocket constraints Construct the support systems, then calibrate and test the instrument Validate the device and the supporting system by rocket flight and data

collection

3

RockSat-C 2013

CoDR

Expect to correlate UV intensity to ozone density as a

function of altitude in order to compare the profile to previous data and current models

The design will benefit future senior design teams at Embry-

Riddle Aeronautical University by serving as a viable prototype for a student CubeSat-mounted photometer

4

RockSat-C 2013

CoDR 5

Team Leader Team Phido Molly Stagnitti

Science Team Greg Shinaberry

Dan McIlveen Alena Thompson

Faculty Advisor Dr. Matthew Zettergren

Sponsor Florida Space Grant Consortium

Member Team Phido Anthony Pritchard

Member Team Phido Kriszelda Menez

Data/Software Greg Shinaberry

Dan McIlveen Alena Thompson

STR Molly Stagnitti

Kriszelda Menez

OPTICS Anthony Pritchard

PMT/PS Molly Stagnitti

Anthony Pritchard Kriszelda Menez

Main Faculty Advisor Dr. Peter Erdman

RockSat-C 2013

CoDR 6

Altitude: 60km

Ozone

Density≈0

t≈933 s

Splash Down

Altitude: 95 km

Instrument Power Up

Begin Useful Data

Collection

t=0 s

Altitude: 95 km Apogee

End of Useful Data

Altitude≈110-

120km

Altitude: 52 km

Altitude: 75 km

Chute Deploys

t≈489.2 s

Altitude: 75 km

Terrier Burn: t≈5.2 s

Coast: t≈9.8 s

Orion Burn:

t≈25.4 s

End Data Collection

Shortly after

Apogee

RockSat-C 2013

CoDR 7

Calibration of the PMT with control source of light (of known photon count) allows us to correspond its current output to intensity, or number of photons

Expected counts (calibration will determine exact numbers):

▪ The PMT is a pulse-counting type detector, it emits one count per photon (expect a few MHz for intense UV source photons)

▪ Data resolution depends upon speed of microcontroller counter and design of the data collection system (team OASIS will make it 15-18 kHz for ten counts per degree resolution)

RockSat-C 2013

CoDR 8

Once photon count is found from the PMT’s current output, team OASIS will use numerical integration to calculate the density of ozone as a function of altitude

Numerical integration will yield an optical depth expression which density can be resolved from (this is unique to the UV-b band):

RockSat-C 2013

CoDR 9

RockSat-C 2013

CoDR 10

Altitude (km)

0—15 <0.5—1

15—25 1—5

25—35 4—1

35—55 1—≈0

RockSat-C 2013

CoDR 11

We have not eliminated any mission objectives

High Risk: 1. If connections are disrupted by vibration testing or launch conditions then data cannot

be collected

2. If the power system is unable to properly control the power to the detector system it will destroy our PMT

3. If the PMT breaks during vibration testing or launch conditions then data cannot be collected

Prevention Plan: 1. We will be performing vibration tests for the instrument and each of the subsystems

2. We will be performing electrical tests to ensure our power system is safe and operates as expected

3. We will protect the PMY with RTV11

12

Molly Stagnitti & Kriszelda Menez

RockSat-C 2013

CoDR 13

Interface Name Brief Description Potential Solution

STR/PLT1 This top plate that has the electrical power system mounted to it will then be mounted onto the canister top plate.

The plate will be secured using bolts.

EPS-DS/PLT1 The electrical power system and data system which includes our DC-DC converters, batteries and data system will all be placed in a housing unit that is mounted to our top plate.

The housing unit is made of aluminum. Exact dimension of the housing unit will be determined by the CDR. Four bolts at the corners of the housing secure it to the plate.

MR/PMT

The mirror will enclosed within its own housing unit to make sure that all the light is focused into the PMT housing unit. The mirror housing unit will be attached to the PMT housing unit.

The mirror housing unit will be mounted to the PMT housing unit using four small bolts.

PMT/PLT2

The detector consists of an aluminum housing unit and its bottom will be mount to a second plate deck rigidly. The PMT/high voltage supply will be secured within the housing.

Bolts will secure the housing. RTV-11 will secure the PMT/high voltage within the detector.

PLT3/STR There will be a third plate attached to the second plate using metal rods. This third plate is used to mount the whole system to the bottom plate of the RockSat-C canister.

The plate will be secured using bolts. This plate will help ensure that the second plate holding the PMT housing and mirror housing unit are at the correct height of the optical port.

RockSat-C 2013

CoDR 14

Plates Data/Power

System

Mirror/Mirror

Housing

Detector

Housing Support

Rods

Optical Port

RockSat-C 2013

CoDR 15

236.22mm

241.3mm

22.25mm

31.75mm

81.00mm There are three

plates in the

design. Each

plate has a

thickness of

6.35mm.

RockSat-C 2013

CoDR 16

The payload design consists of

several major components:

Plates

Rods

Data/Power System Housing

Detector Housing

Each of these components will be

shown in detail in the following

slides.

RockSat-C 2013

CoDR 17

1. Circuit Board:

50.8x38.1x3.175

2. Batteries

H: 46.41mm

L: 26.62mm

W: 17.50mm

3. DC-DC Converters

H: 50.01mm

L: 10.01mm

W: 24.99mm

1

2

2

2

3

3

22.225mm

152.4mm 152.4mm

RockSat-C 2013

CoDR 18

• The PMT will be secured using

RTV11, which is a white, two

component, low viscosity potting

compound that cures at room

temperature to a soft pliable

rubber.

• It’s excellent electrical

properties make it a candidate

material for both high and low

voltage electrical assemblies. It

helps cushion against

mechanical shock and vibration.

http://www.mgchemicals.com/products/rtv-

silicones/potting-compounds/rtv11/

Light

PMT Pre-amp/

Discriminator

HV Supply

RockSat-C 2013

CoDR 19

Changes: • Rod placement: Staggered the rods that connect the plates so that the structure

has a smaller risk of breaking during vibration; more stability

• PMT housing: The new housing design has been previously tested with its components, and it simplifies the design of the optical system. The hole in which the light is directed is larger than that on the previous housing and we will be able to place the PMT closer to the mirror in order to optimize focus

• DC-DC converters were changed because the total amount of voltage is now

higher for the microcontroller

• May need more batteries due to the higher amount of voltage needed for the microcontroller

RockSat-C 2013

CoDR 20

We have referenced previous data and experiments to assist us in final decisions regarding materials and component choices.

Calculations have been done in order to assure the payload will survive flight.

We are planning on performing electronic and optical tests for the separate subsystems, as well a low pressure vacuum test for the entire instrument.

21

Kriszelda Menez

RockSat-C 2013

CoDR 22

PMT

Detector

Pre-Amp/

Discriminator

Photomultiplier Tube

Counter Data

System

Data Storage/

Control System

Data System

Batteries HV Supply DC/DC

Converter

Electrical Power System

Wallops Flight

Facility Payload

Interface

RockSat-C 2013

CoDR 23

EPS/Data subsystem will have one breadboard to organize wiring, complete internal circuits, and mediate between the detector system and power system

Changes/Finalizations since PDR:

HV supply is for the 28mm PMT (larger than HV supply of 13mm PMT)

▪ Need 15 V DC-DC converter to supply input power instead of 12 V converter that would be needed for the 13mm PMT HV supply

Microcontroller needs up to 12 V input (previously assumed 5 V) ▪ Need 12 V DC-DC converter to supply input power instead of 5 V converter

that would be needed for other microcontroller

RockSat-C 2013

CoDR 24

Payload will be activated by electrical system when the command line closes the switch at T-2

Batteries

Detection System

Power Control/Data

Storage System

Wallops

Control

Data

25

Anthony Pritchard

RockSat-C 2013

CoDR 26

Input Power

Detector Outputs

SD Card Data Storage

Closes all programs and

turns off instrument

Microcontroller starts code

Detector Commands

RockSat-C 2013

CoDR 27

Initialize Microcontroller SLEEP MODE

Initialize clock and start timer.

Initialize communication between Arduino and SD Card

Initialize communication between Arduino and PMT

Record data from PMT to SD card

End communication with PMT

End communication with SD CARD.

RockSat-C 2013

CoDR 28

RockSat-C 2013

CoDR 29

RockSat-C 2013

CoDR

7-12 Low Voltage Source from PHIDO

SD CARD HOLDER

SCK

MISO MOSI

SS

PMT DIGITAL INPUT GROUND

3.3 Regulated Voltage

RockSat-C 2013

CoDR

Pin SD INPUT

1 NC Not connected

2 CS SS

3 DI MOSI

4 VDD VDD

5 CLK SCK

6 VSS Ground

7 DO MISO

8 RSV Reserved

RockSat-C 2013

CoDR

SD CARD

Voltage Input (7-12V)

Ground

All other wiring is soldered from Shield to Arduino

Breadboard for additional circuitry

PMT INPUT

Additional Potential Inputs

33

Anthony Pritchard

RockSat-C 2013

CoDR 34

A Finite Element Analysis was done

on main structure

Deformation in one of the top rods

Slight bending caused by the 25G

load

Was unable to determine exact von

Mis stresses

RockSat-C 2013

CoDR 35

Arduino microcontroller was prototyped (3 were purchased)

The rate at which the Arduino can write to the SD card

was tested in order to view our maximum sampling rate

The microcontroller meets our requirement of nearly 10 samples per degree of turn (18 kHz max) using data packets

RockSat-C 2013

CoDR 36

Write 187.62 KB/sec

Maximum Latency: 22708 μsec

Minimum Latency: 84 μsec

Average Latency: 527 μsec

Read 314.64 KB/sec

Maximum Latency: 2972 μsec

Minimum Latency: 80 μsec

Average Latency: 312 μsec

EXCEEDS MINIMUM WRITING/READING SPEED for DESIRED

INPUT SIGNAL

RockSat-C 2013

CoDR 37

Mass Budget

Subsystem Total Mass (lbf)

Plates 4.611

Rods 0.613

Screws 0.0814

Power/Data System Housing 0.896

Power/Data System Housing Lid 0.132

Microcontroller 0.0919

DC/DC Converters 0.159

Batteries 0.278

Circuit Board/Wiring 0.07

Mirror 0.310

Detector Housing 1.60

RockSat-C 2013

CoDR 38

Subsystem Total Mass (lbf)

PMT 0.099

High Voltage Supply 0.0992

Pre-amp Circuit Board 0.030

PMT Housing Lids 0.06

RTV11 0.174

Rocksat-C Canister 6.9

Ballasts 3.80

Total 20

Over/Under (0.0045)

RockSat-C 2013

CoDR 39

Power Budget (Input Requirements)

Subsystem Voltage (V) Current (A) Time On (min) Amp-Hours

Microcontroller 12 0.090 (o/p of 0.5 max) 5 0.0075

Preamp/Disc. 5 0.05 5 0.00417

12V DC-DC 24 (o/p of 12.1V) 0.0643 (o/p of 1.3) 5 0.00536

Batteries 27 (o/p of 0.0165) 5 (o/p of 0.00476)

PMT 1250 0.000125 5 1.04*10-5

HV Supply 15 ~0.025 5 0.00208

15V DC-DC 24 (o/p of 15.1) 0.0186 (o/p of 1.0) 5 0.00155

Batteries 27 (o/p of 0.0165) 5 (o/p of 0.00138)

(Batteries) Total (A*hr): (o/p of 0.00614)

With a total Amp-hour requirement of 6.14mA*hr, the 9 Volt NiMH batteries which are rated at 175 mA*hr are marginally sufficient. The short operation time and our low power requirement to the PMT system allows the instrument to easily have enough power throughout the duration of operation.

40

Kriszelda Menez

RockSat-C 2013

CoDR 41

• The power system housing, plates, and rods will all need to be manufactured

• The batteries, DC-DC converters, PMT, diffuser, and filters need to be procured

Date Event

11/29/2012 Order Parts

11/29/2012 Send in drawings for parts to Machine Shop

Receive Parts

1/8/2013 Start to implement parts together

1/10/2013 Finish implementing parts

RockSat-C 2013

CoDR 42

• Pre-amp/discriminator will be soldered next semester by Team Phido

• The high-voltage supply will be procured when we order the parts before winter break

• We anticipate about 3 revisions of the electronics

• Testing plan is in project management section

Date Event

12/4/2012 Order high-voltage supply

1/8/2013 Start soldering pre-amp/discriminator

1/15/2013 Begin testing of electronics

1/16/2013-2/14/2013 Revise electronics

RockSat-C 2013

CoDR 43

Complete? Event

Find data rate needed to produce profile for numerical analysis

Compare/Contrast microcontroller apparatuses that can potentially write to SD cards at the needed data rate

Purchase the top two potential microcontrollers to test

Construct both test microcontroller apparatuses to write and read data to SD card

Dec 3 Test the speed, efficiency and durability of each microcontroller and select best microcontroller with inputs similar to PMT

Jan 15 Using best microcontroller, write C++ code according to the code structure outline

Jan 25 Test Microcontroller code with simulated PMT input

Feb 7 Implement with PHIDO instruments and test output

Feb 20 Fine tune and finish instruments

44

Anthony Pritchard & Kriszelda Menez

RockSat-C 2013

CoDR 45

Separate Subsystem Testing Electronic tests Optical tests

Instrument Testing

Vibrational tests Low pressure vacuum tests Structural analysis test

Testing will begin on January 15, immediately after implementing the parts into the payload

RockSat-C 2013

CoDR 46

It is important to verify that the electronic devices perform as expected. Variations can easily damage the sensitive photomultiplier tube

Faux circuits imitating the power input to each electrical component (two DC-

DC converters, microcontroller, high voltage supply, photomultiplier tube, preamplifier/discriminator) will be analyzed in order to confirm their performance capabilities before integration

Microcontroller must be able to read from the PMT and write to the SD card fast enough to achieve a resolution of 10 samples per degree of turn of the rocket Tests have been conducted and are presently being conducted in order to

confirm the maximum rates. The microcontroller is connected to a computer and the SD card to observe performance

RockSat-C 2013

CoDR 47

PMT must be extensively tested before integration to discover its characteristic response to a known light input source

Intense ultraviolet light from a deuterium lamp light source will be focused

upon the photocathode with a mock optical system in order to attain expected output counts from a known solar spectrum and known intensity in order to simplify and validate post-flight data analysis

EPS Testing Scheduling: Each component will be tested when they arrive (within 3-10 weeks from

now) to ensure that they work as expected. The microcontroller is currently undergoing testing and will continue to be tested throughout construction of the photometer. The PMT is expected to be tested in full sometime in February.

RockSat-C 2013

CoDR 48

Software testing progress is interdependent upon EPS and detection system construction and integration (except for data analysis code, which has already been successfully composed and tested for the expected results model) The code for the data storage system has already been tested successfully.

The code must be modified to incorporate incoming PMT signals

Current goal of the science team is to complete code for power control to the detector system before the detector system is tested

RockSat-C 2013

CoDR 49

After subsystem level construction and testing has been completed and the payload is fully integrated, certain system tests will be performed

Low pressure test: To ensure our EPS is fully insulated and that arcing from our high voltage

detection system will not occur in the conductive low pressure atmospheric environment, this test will be performed upon the payload by team PHIDO at the Embry-Riddle Atmospheric Physics Research Lab (APRL) in March

Centroid tests: Balance analysis performed by team PHIDO of the fully integrated payload

will be performed in the APRL in order to confirm that the mass centroid lies within the 1x1x1 inch cube requirement set by UC Boulder in March

Vibration tests: Wallops flight facility will perform vibration tests to confirm the integrity of our design shortly before flight.

50

Kriszelda Menez

RockSat-C 2013

CoDR 51

Co

ns

eq

ue

nc

e

PS.RSK.1 PS.RSK.1 PS.RSK.2 PS.RSK.3

PS.RSK.2 PS.RSK.3

Possibility

PS.RSK Risk Prevention Plan

1 The whole system will not be functional if the batteries run out of power before data has been collected

Chose reliable NiMH 9V batteries, test within system

2 If connections are disrupted by vibration testing or launch conditions then data cannot be collected

Will perform vibration tests for the instrument and each of the systems

3 If it is unable to properly control the power to the detector system it will destroy our PMT

Will perform electrical tests to ensure proper operation

PS.RSK: Before

PS.RSK: After

RockSat-C 2013

CoDR 52

Co

ns

eq

ue

nc

e

DS.RSK.2

DS.RSK.1 DS.RSK.2

DS.RSK.1

Possibility

DS.RSK Risk Prevention Plan

1 The whole system will not be functional if the HV supply fails before data has been collected

Tests have been performed with HV power supplies within the housing

2 If the PMT breaks during vibration testing or launch conditions then data cannot be collected

Protect PMT with RTV11, perform vibrational tests on the system

PS.RSK: Before

PS.RSK: After

RockSat-C 2013

CoDR 53

Con

seq

uen

ce

OS.RSK.2 OS.RSK.1

OS.RSK.1 OS.RSK.2

Possibility

PS.RSK Risk Prevention Plan

1 Calibration will be disrupted if launch conditions exceed integrity of optical system structure

Optimized optical system in order to withstand launch conditions

2 The PMT will saturate if we cannot sufficiently reduce its light input to the acceptable range

Chose PMT that works best with other optical components to tailor transmittance

PS.RSK: Before

PS.RSK: After

54

Kriszelda Menez

RockSat-C 2013

CoDR

Predicted Mass: 20+/-.1 lb (with necessary ballasts)

Predicted Volume: Will roughly occupy 265 in3 cylinder. Individually, the instrument’s devices will roughly occupy a total of 70 in3

Activation: Expect at-launch activation

Optical port is required, we are using around 800 V for high

voltage supply

55

56

Molly Stagnitti

RockSat-C 2013

CoDR

Date Event

11/29/2012 Order Parts / Send in drawings for part to Machine Shop

11/30/2012 Critical Design Review (CDR) Due

11/30/2012 Receive microcontroller from Team Oasis

12/3/2012 Critical Design Review Teleconference

1/7/2013 Receive parts

1/8/2013 Start soldering pre-amp/discriminator

1/8/2013 Start to implement parts together

1/10/2013 Finish implementing parts

1/15/2013 Begin Testing on Subsystems

1/18/2013 Online Progress Report 1 Due

2/15/2013 Individual Subsystem Testing Reports Due

57

RockSat-C 2013

CoDR 58

Date Event

2/18/2013 First Payment Due

2/28/2013 Finish construction of all parts, make sure testing is finalized

3/01/2013 Begin Payload Subsystem Integration

3/12/2013 Online Progress Report 2 Due

3/29/2013 Payload Subsystem Integration and Testing Report Due

4/08/2013 Final Payment Due

4/20/2013 Calibrate payload with canister

4/26/2013 First Full Mission Simulation Test Report Presentation Due

5/8-29/2013 Weekly Teleconferences

RockSat-C 2013

CoDR 59

Date Event

6/3/2013 Launch Readiness Review Presentations

6/12/2013 Travel to Wallops Flight Facility

6/13/2013 Visual Inspections at Refuge Inn

6/14-18/2013 Integration/Vibration at Wallops

6/19/2013 Presentations to next year’s RockSat

6/20/2013 Launch Day

RockSat-C 2013

CoDR 60

Estimated Travel Costs (4 people)

Expenses Total Costs

3 rooms ($120/day) $3600

Per diem (for 4 is $50/day) $2500

Transportation (Fuel expenses round trip)

$400

Launch Support through RockSat C Program: $12,000

RockSat-C 2013

CoDR 61

Estimated Instrument Costs

Item Cost

Photometer Detector $3700

Parabolic Mirror $315

Flat mirror for calibration system $2200

High voltage power supplies $500

Low voltage DC-DC converters $100

Ultra Violet interference filters $132

Machining and Materials $1200

Misc. printed circuit boards and electronic components

$500

Flight batteries $200

Total with Travel & Launch Support: $27,347

62

Kriszelda Menez

RockSat-C 2013

CoDR 63

Find the center of gravity of whole structure

Areas of concern

Implementation of Team Oasis microcontroller with our electrical system

RockSat-C 2013

CoDR 64

Our next plans are to send in designs to the Machine Shop and come back in the Spring to implement them

Order parts before winter break

RockSat-C 2013

CoDR 65

0

5

10

15

20

25

0 50 100 150 200 250 300 350 400

% T

ran

smit

tan

ce

Wavelength (nm)

RockSat-C 2013

CoDR 66

Retrieved from http://www.espo.nasa.gov/solveII/implement.html

RockSat-C 2013

CoDR 67

Retrieved from http://tid.uio.no/ozone/plott/spectrum_thumb.png