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Illinois Space Society 1

Critical Design Review

University of Illinois at Urbana-Champaign

NASA Student Launch 2016-2017


Overview


Launch Vehicle Summary


Flight Profile


Current Launch Vehicle Design

Lower Separation Stage

Upper Separation Stage

1) Separation at Apogee2) Drogue Deploy 2s after apogee

3) Main deploy at 700’

1) Separation at Apogee2) Bundled Payload Parachute deployed 2s after apogee

3) Full Deployment at 900’


Vehicle Major Dimensions

Overall Length: 120”

Overall Estimated Mass: 35.9 lb

Main Body OD: 6.188”

Nose Cone Length: 24”

Booster System Length: 48”

Avionics Coupler Tube Length: 14”

Payload Coupler Tube Length: 15”


Mass Statement

Mass estimate of subscale was within 5%

Total mass predicted with component breakdown

Small margin added and generous estimate made

Mass Breakdown:+Booster Tube: 18.7 lbs.+Avionics Coupler: 6.9 lbs.+Payload : 5.7 lbs.+Upper Section: 4.3 lbs.

Total: 35.9 lbs.


Static Stability Margin

Current CP Location: 90.83 in

Current CG Location: 78.26 in

Stability Margin (at liftoff): 2.03 calibers


Motor Subsystem

Motor: AeroTech L1390G-P

– Motor Diameter: 75 mm

– Liftoff Thrust: 312.8 lbf

– Total Impulse: 887.2 lbf●s

– Burn time: 2.6 sec

– Liftoff T/W: 8.71

– Off Rail Speed: 64.7 ft/s

RMS 75/3840 Casing

Fiberglass Centering

Rings

Aeropack Retainer


Booster Subsystem

Houses motor subsystem

Fiberglass fins

– Slotted between centering rings

1515 Rail buttons (2)

Houses drogue parachute


Avionics Coupler Section

U-Bolt connections for strength

¼” Threaded rods to hold payload sleds

Holds recovery electronics and ejection charges

Two rotary switches

Contains main parachute

– Deployed bundled at apogee


Avionics Bay Recovery Hardware

Parachutes

– Main: Iris Ultra 96”

– Drogue: Fruity Chutes Elliptical 18”

Black powder ejection charges

– Ignited by e-matches

½” Tubular Kevlar shock cord

Redundant altimeters

– 1 Telemetrum altimeter for altitude and tracking

– 1 Stratologger altimeter for altitude

• Will be official competition altimeter

Redundant Jolly Logic Chute Releases for main


Payload Bay

Payload electronics

Payload section recovery electronics

Mechanical landing system

3” Switchband

– Viewing holes for cameras

– 4 Rotary switches


Payload Bay Recovery Hardware

Parachutes

– Payload: Skyangle Model C2: 44”

• Held closed by redundant Jolly Logic Chute Releases until 900 ft AGL

Black powder ejection charges ignited by e-matches

½” Tubular Kevlar shock cord

Redundant altimeters

– 1 Telemetrum altimeter for altitude and tracking

– 1 Stratologger altimeter for altitude


Vehicle Verification Plan

Full verification plan found in CDR Report

Key verification milestones

– Aerodynamics verified via subscale flight

– Refinement of simulations

– Incremental testing on a component and vehicle level

– Full vehicle models verified during test flight


Subscale Vehicle

~42% scale model of flight vehicle

Similar materials and stability margin

Similar motor characteristics

Practice construction techniques


Subscale Flight Results

Subscale was launched on December 10th at a rocket launch held by Central Illinois Aerospace at Dodds Park, located in Champaign.

The ascent went smoothly, the payload section took photos, and the parachute deployed at the right moment

However, the shock cord detached from the lower section due to a failure in the adhesive bond during ejection


Subscale Results vs. Expectations

Lower than expected apogee.

– Second subscale to explore possibilities.

Descent differences due to disconnect.


Flight Profile

Apogee: 5344 ft.

Max Velocity: 689𝑓𝑡

𝑠

Max Mach Number: .61

Max Acceleration: 307 𝑓𝑡

𝑠2


Kinetic Energy

Terminal Velocities

– Booster+Avionics Coupler

• Drogue: 81.4 ft/s

• Main: 12.6 ft/s

– Payload+Nosecone

• Bundled Main: 89.1 ft/s

• Deployed Main: 20.7 ft/s

Kinetic Energies

– Avionics Coupler: 15.3 ft ● lbf

– Booster Tube: 36.3 ft ● lbf

– Payload (Camera+Landing System): 38.1 ft ● lbf

– Nosecone + Upper Airframe: 28.6 ft ● lbf

All kinetic energies are significantly lower than the competition requirement of 75 ft ● lbf


Drift Predictions

All values calculated in Open Rocket

Analysis redone with 5 degree launch angle into wind

All calculated drift distances meet the competition requirement.

Section 0 mph winds 5 mph winds 10 mph winds 15 mph winds 20 mph winds

Upper Payload

Section Drift [ft]990 1385 1780 2240 2550

Lower Booster

Section Drift [ft]1050 1425 1805 2310 2610


Flutter Analysis

Used AeroFinSim to determine if the thickness of the fins is structurally sufficient.

Takes aerodynamic drag, lifting forces, and fin geometry into account and calculates critical velocities where flutter effects occur

1/8 in fins were chosen for PDR in order to minimize weight of the rocket.

Flutter Analysis determined that 3/16 in fins are necessary.


Test Plans and Procedures

• Dimensions and weights to be verified on arrival of components

• Components and hardware inspected for quality and manually load tested

• Electronics and connections tested and inspected

• Parachute pull test

• Full scale test flight


Staged Recovery System Testing

• Ejection charges and parachutes loaded in the same manner as on

launch day

• Ballast mass used to replace fragile components

• Remote deploy: wire E-match remote firing system

• Planned to start immediately upon completion of construction

• Shear pins determined by actual weight and predicted accelerations

• Electronic testing: power lifetime, functionality, and interference


Landing Hazard Detection and Vertical Landing Payload


Payload Requirements

Identification and differentiation of three 40’x40’ tarps

– Real time data processing

– Custom software package using open source libraries

Upright landing

– Landing of rocket section housing camera

– Landing in launch orientation

Internal requirements

– 90 minutes life for electronics

– 6” or smaller diameter rocket

– 3 lb or less total weight (body tube weight not included)

Lander Section


Payload Overview

Two Subteams

– Mechanical Landing Subsystem

– Image Processing Subsystem


Mechanical Landing Subsystem Overview

Spring-loaded deployable landing legs

Fold within body tube, deploy automatically upon ejection

1. Stored within body tube 2. Deployment begins upon ejection 3. Fully deployed during descent


12” total leg length, two 6” segments

3D printed PLA legs used for prototyping

COTS springs and fasteners

3/8” Aircraft plywood bulkhead

Landing Subsystem Dimensions and Materials


Robustness of Landing System

Four leg system chosen over three legs

Tip over analysis performed to determine failure tolerance

Future testing for validation


Landing System Testing to Date

Prototype legs completed and tested for strength

Lower bulkhead/leg assembly created

Second iteration with updated leg design in progress


Landing System Future Work

Survivability drop tests

– On variety of surfaces from pre-calculated heights

Tip-over tests

Parachute drop tests

Full scale flight test


Image Processing Overview


Raspberry Pi Zero processor

Camera Module V2

– 1080p capable

– 48 x 62 degree FOV

COTS pressure sensor

Li-ion battery

3.7 V to 5 V converter

Rotary switches

Image Processing Subsystem Hardware


Electrical Schematic


Image Processing Subsystem Software

Raspbian Jessie Lite OS

SimpleCV implemented for image processing functions


Image Processing Progress to Date

Hardware components obtained

Tarp size identification analysis performed


Subscale Test Flight

Raspberry Pi, camera, converter, and battery flown on test flight

Power system design validated

Image capture and saving capability proven in flight


Subscale Lessons Learned

Additional work on camera settings required

– Decreased blurring necessary

– Color consistency improvements required

Sled layout critical, many connection constraints


Image Processing Future Work

Camera setting tuning required

Full-scale sled integration tests

Implementation and testing of blob detection algorithms

Detection testing using given tarp samples

– Ground tests

– Drop tests

– Flight tests


Questions?

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