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Sound TestSound Test

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Testing and Integration of a Rocket-Launched Video Imaging Platform

Testing and Integration of a Rocket-Launched Video Imaging Platform

IniTech EngineeringIniTech Engineering

Apoorva Bhopale Susan Schmidt Rob Wingo Brian LoveApoorva Bhopale Susan Schmidt Rob Wingo Brian Love

1 May 20021 May 2002

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Project BackgroundProject Background

• Project is sponsored by Applied Research Labs• Main Objective:

– Prove the validity of a rocket launched balloon as a telecommunications platform

• Possible uses, disaster relief, drug interdiction, inexpensive “throwaway” satellites

• Rocket is to be launched this summer

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Overview of the Presentation Overview of the Presentation

• Goals to accomplish – Description of each goal– Work completed for each goal

• Future work

• Questions

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Semester Goals Semester Goals

• Design and build payload canister with mountings for electronics

• Size and build drogue chute

• Test balloon buoyancy

• Test Electronics

• Test balloon deployment

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Flight ProfileFlight Profile

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Chute SizingChute Sizing

Brian Love

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Drogue ChuteDrogue Chute

• Required to deploy balloon after ejection• Will be used to slow descent after operations

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SizingSizing

• Previous work concluded that a small chute will deploy the balloon

• Limiting factors for design are descent constraints

Considerations• Weight of payload• Altitude• Allowable impact

velocity

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AlgorithmAlgorithm

2

2

tdVC

WA

2

2 2

4 tdVC

Wd

2

2

1td AVCWD

D = drag forceW = weightρ = air densityCd = coefficient of dragA = areaVt = terminal velocity

4

22 d

rA

r = chute radiusd = chute diameter

dt

td C

mgV

VC

Wd

2

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2

m = massg = gravitational acceleration

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CalculationsCalculations

altitude(m) air density(kg/m^3) impact velocity(m/s) mass(kg) Cd diameter(m) diameter(in)1000 1.1 3 4.5 1.5 2.751361112 108.3213036

Standard Atmosphere

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Chute DesignChute Design

116”

Weight: 14.2 oz.

108”

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Balloon TiltBalloon Tilt

• Weight drop of 11 oz. from 25 to 14 oz.

• Balloon used was ~1/4 scale

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Neutral BuoyancyNeutral Buoyancy

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CalculationsCalculations

R

PTRTP

STPneededdiff TTT

kgmass

Vballooninmass

payloadballoon

STPballoonair

4~

*

Need mass air inside balloon 4kg less than the STP valuefor neutral buoyancy

balloon

neededneeded V

mass

R

PT

neededneeded

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Temperature DifferenceTemperature DifferenceTemperature Difference for Neutral Buoyancy

0

5

10

15

20

25

30

35

40

45

0 2000 4000 6000 8000 10000 12000

Altitude (m)

Te

mp

era

ture

Dif

fere

nc

e (

de

g C

)

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ConsiderationsConsiderations

• Absorbed solar energy

• Air circulation inside balloon

• Descent rate of inflated balloon vs. chute

• Thermal updrafts

• Need experimental data to prove theoretical

• Testing difficult on ground

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Payload CanisterPayload Canister

Susan Schmidt

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Initial Avionics CanisterDesign

Initial Avionics CanisterDesign

• Canister made of 4.25 inch

PVC pipe

• Covered in carbon fiber

• Electronic components

secured with bubble wrap

• Plexiglas bottom

for camera

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Previous Canister Design Changes

Previous Canister Design Changes

• Components hit canister walls and each other

• Bubble wrap was not sufficient vibration control

• Foam was then used to secure items

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Issues with Past DesignsIssues with Past Designs

• Carbon fiber blocks radio waves

• Electrical components not secure

• Plexiglas fogs at higher altitude

• Plexiglas cracks easily

• Component constraints cannot handle temperatures of high altitudes

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Requirements for the Avionics CanisterRequirements for the Avionics Canister

• Structural integrity

•Limit component vibration

•Airtight seal

• Temperature control

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Structural IntegrityExternal Material Options

Structural IntegrityExternal Material Options

• Metals– Possible Shrapnel

– Weight

• Porous materials, i.e. wood– Airtight seal

• Plexiglas– Cracks easily

• Lexan– High cost

– Availability

And the winner is…

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PVCPVC

• Weather Resistant• High strength to weight ratio• Corrosion Resistant• Good thermal insulator• Self-extinguishing• Low cost!!

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Internal StructureInternal Structure

• High impact resistance• Used to stabilize internal components• Used for the camera viewing area

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Limit Component VibrationLimit Component Vibration

• Two 0.09” thick Lexan perpendicular

boards

• Secured components with nuts and bolts

• Ends capped with hobby plywood

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Airtight SealAirtight Seal

• Change in pressure from sea level to higher altitudes cause fogging on the Lexan

• Seal end of canister with Teflon Tape

• Teflon tape for extruding connections

• Pump in Nitrogen through a gas fitting

• Inert gas replaces the water vapor

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Temperature ControlTemperature Control

• Camera’s operating range: -1.1°C to 37.77°C• Above 8,000 feet the temperature drops

below this operating range• The rocket test in summer will not reach

this altitude• The temperature limits of the components

must be evaluated for higher flights

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ElectronicsElectronics

Rob Wingo

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Electronic ComponentsElectronic Components

• Accelerometer board

• GPS/Video Overlay board

• GPS receiver

• Video camera

• Telemetry system

• Batteries

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Semester ObjectivesSemester Objectives

• Connect all of components and make work

• Range test telemetry system

• Find problem with power source

• Determine how to use accelerometer board as an event trigger

• Mount electronics in canister

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Component ConnectivityComponent Connectivity

• Successfully connected all components

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Range Test: First tryRange Test: First try

• Unsuccessful

• Assumed power problem

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Range Test: Second tryRange Test: Second try

• Made adjustments to power supply and connectivity board

• Still unsuccessful

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Range Test: Third tryRange Test: Third try

• Re-soldered connectivity board

• Still unsuccessful

• Contacted transmitter manufacturer

• Discovered range can be drastically reduced by ground effects

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Ground Effect ProblemGround Effect Problem

• Transmitter designed for aerial use only

• Will not be able to accomplish range test on ground

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Balloon DeploymentBalloon Deployment

Apoorva Bhopale

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Balloon DeploymentBalloon Deployment

• Objectives– Determine a method to pack the balloon– Determine an adequate amount of black powder

to eject the canister

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Balloon SizeBalloon Size

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Suggested MethodSuggested Method

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Pyrotechnic EjectionPyrotechnic Ejection

• Advantages– Reliable– Lightweight– Used extensively

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Possible Failure Modes of the Ejection

Possible Failure Modes of the Ejection

• Too Little Black Powder– Does not clear ejection tube

• Inhibits the rockets main chute deployment

• Payload crashes with the rocket

• Too much Black Powder– Rocket tube explodes– Drogue chute rips from balloon– Burnt drogue chute or balloon

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Theory of Pyrotechnic EjectionTheory of Pyrotechnic Ejection

TR

VdPWP **

• Wp =Weight of Black Powder (lbs)• dP = Ejection Charge Pressure in Psi• V = Free volume in cubic inches• R = Combustion gas constant 22.16 ft-

lbf/lbm-R• T = Combustion gas temperature, 3307

degrees R

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Test FootageTest Footage

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Conclusions From Test Conclusions From Test

• Place Canister closest to the ejection charge

• Use 7 grams of Black Powder

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ConclusionConclusion

• Design and build payload canister with mountings for electronics

• Size and build drogue chute

• Test balloon buoyancy

• Test Electronics

• Test balloon deployment

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Future WorkFuture Work

• Verify range of the transmitter another way– Possibly send it back to manufacturer

• Test the deployment method in a rocket• Determine a way to sever connection

between balloon and canister• Neutral Buoyancy test• Setup accelerometer board to be used as

event trigger

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AcknowledgementsAcknowledgements

• Dr. Ronald Stearman• Dr. Martin Barlett• Dr. Jennifer Lehman• Danny Linehan• Daniel Parcher• Rick VanVoorhis• Lixin Gong

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QuestionsQuestions