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Cornell Rocketry Team
Preliminary Design Review
CRT PDR 2017
Cornell Rocketry Team
Preliminary Design Review
AIRFRAME
Cornell Rocketry Team
Preliminary Design Review
LAUNCH VEHICLE DIMENSIONS
Total Length: 104”
Airframe Tubing Outer Diameter: 5.15” Inner Diameter: 5.00”
Coupler Outer Diameter:4.998” Inner Diameter: 4.185”
Motor Mount Tube Outer Diameter:3.141” Inner Diameter: 2.995”
Fin/Centering Ring/Bulkhead Thickness: 3/32”
Cornell Rocketry Team
Preliminary Design Review
LAUNCH VEHICLE COMPONENTS
Rivet
Shear Pin
Nose Cone
and Comms
Bay
Forward
Airframe
Main and
Drogue
DRS
AV
BayBooster
Main and
Drogue
L1150-P
Tail
Cone
Retainer
Blast Charge
Cornell Rocketry Team
Preliminary Design Review
MATERIAL SELECTION
G12 Fiberglass (Filament Wound)- Airframe, Coupler, Motor Mount, Nose Cone
Provides necessary strength to resist compressive forces experienced by LV during
launch
Chose standard fiberglass over thin-walled tubing for strength and countersinking
G10 Fiberglass (Laminate) - Bulkheads and Fins
Provide higher strength to thickness ratio compared to plywood
3D Printed ABS Plastic - Avionics Sled
Easily prototyped and manufactured in Cornell Rapid Prototyping Lab
Cornell Rocketry Team
Preliminary Design Review
MATERIAL SELECTION CONT.
Kevlar - Shock Cord
Stronger than nylon and more fire resistant
▪ Multipurpose 6061 Aluminum - Motor retention
▪ Provides Strength and heat resistance to retain motor
▪ ES6209 Aeropoxy - Fin fillets
▪ Creates stronger bonds than faster drying epoxy
Cornell Rocketry Team
Preliminary Design Review
MOTOR SELECTION
75mm AeroTech L1150-P
▪ Provides sufficient thrust for LV to
reach apogee
▪ Max acceleration of 7.56 G is low
enough for DRS to remain secured
and undamaged during takeoff
Cornell Rocketry Team
Preliminary Design Review
STABILITY
▪ From tip of nose cone:
▪ Center of Gravity (CG) = 60.83”
▪ Center of Pressure (CP) = 76.811”
▪ Stability margin = 76.811" − 60.83"
5.15"=3.11 cal
Center of Gravity
Center of Pressure
Cornell Rocketry Team
Preliminary Design Review
SIMULATION DATA
Total mass - 35.4 lb
Projected Apogee - 5235 ft
Thrust-to-weight ratio – 7.71
Velocity off rod - 74.4 ft/s
Cornell Rocketry Team
Preliminary Design Review
RECOVERY SYSTEM
Cornell Rocketry Team
Preliminary Design Review
RECOVERY SYSTEM CONT.
Launch Vehicle Component Drogue Parachute Size (in.) Main Parachute Size (in.)
Forward Airframe 15” 70”
Booster Section 14” 60”
Cornell Rocketry Team
Preliminary Design Review
RECOVERY SYSTEM CONT.
Wind Speed (mph) Forward Section (ft) Booster Section (ft)
0 0 0
5 657.10 640.68
10 1314.20 1281.37
15 1971.31 1922.05
20 2628.42 2562.74
Cornell Rocketry Team
Preliminary Design Review
RECOVERY SYSTEM CONT.
LaunchVehicle
Component
Drogue
Descent
Velocity
(ft/s)
Drogue Kinetic
Energy (ft-lb)
Main and Drogue
Descent Velocity
(ft/s)
Landing
Kinetic Energy
(ft-lb)
Forward Section 85 1638.167 14.920 50.892
Booster Section 85 1382.168 16.059 49.337
Cornell Rocketry Team
Preliminary Design Review
RECOVERY SYSTEM CONT.
Parachute Deployment Method
Forward Airframe Drogue Nose Cone ejection at Apogee
Forward Airframe Main Jolly Logic Chute Release at 500 ft
Booster Section Drogue AV Bay ejection at Apogee + 2 s
Booster Section Main Jolly Logic Chute Release at 500 ft
Cornell Rocketry Team
Preliminary Design Review
NASA SL REQUIREMENTS
The vehicle will deliver the payload to an apogee altitude of 5,280 feet above
ground level
The selected motor causes the planned launch vehicle to reach the target apogee.
Ballast can be added or removed to adjust predicted apogee
The launch vehicle will be designed to be recoverable and reusable. Reusable is
defined as being able to launch again on the same day without repairs or
modifications
Durable materials are used to construct the launch vehicle. Additionally, each
component on the launch vehicle will be analyzed and tested prior to launch
All other NASA launch vehicle requirements are covered in the PDR
Cornell Rocketry Team
Preliminary Design Review
TEAM DERIVED REQUIREMENTS
Wires connecting the altimeters to the forward airframe blast charges must
separate at apogee.
Ground testing is performed to verify the wires properly separate.
The Communications bay must be accessible for construction and repair.
The nose cone coupler will be removable and riveted.
The DRS deploys successfully after the launch vehicle lands.
Ground testing is performed to ensure the rover is deployed regardless of the angle at
which the launch vehicle lands.
Cornell Rocketry Team
Preliminary Design Review
SIGNIFICANT FAILURE MODES
▪ Large kinetic energy on drogue descent rate could lead to parachute tearing
when main parachutes deploy.
▪ Sub-scale and full-scale launches are used to test parachute strength.
▪ Jolly Logic Chute Releases do not release main parachutes.
▪ Jolly Logic Parachute Releases are put in series.
▪ Separable Wiring separates prematurely so forward airframe parachutes are not
deployed
▪ Sub-scale and full-scale launches will test reliability of recovery system
Cornell Rocketry Team
Preliminary Design Review
DEPLOYABLE ROVER SYSTEM (DRS)
Cornell Rocketry Team
Preliminary Design Review
SYSTEM SUMMARY
▪ Rover▪ Two primary wheels
▪ One small support wheel for stability
▪ Long, thin chassis
▪ Sensors for object avoidance
▪ Unfolding solar panels
▪ Lead Screw Mechanism (LSM)▪ Lead screw connected to a motor
▪ Deploys rover from bottom of section
Cornell Rocketry Team
Preliminary Design Review
ROVER
▪ Primary Wheels▪ 4.75” diameter, 1.25” thick
▪ Jagged, 0.07” tall treads
▪ Rubber for increased friction
▪ Holes for LSM shafts
▪ Attached to motor horns
Cornell Rocketry Team
Preliminary Design Review
ROVER
▪ Chassis▪ 6.5” x 2.5” x 1.5”
▪ Three interlocking sections
▪ Machined from aluminum
▪ Low center of mass
Cornell Rocketry Team
Preliminary Design Review
ROVER
▪ Support Wheel▪ Prevents rover from flipping
▪ Folds to fit inside LV
▪ Extends after deployment
Rover
Motion
Wheel
Rotation
Chassis
Rotation
Support
Wheel
Cornell Rocketry Team
Preliminary Design Review
LSM
▪ Lead Screw Mechanism▪ 10.5” long, 0.25” diameter lead screw
▪ DC motor turns lead screw to deploy rover
▪ Two 11” long, 0.25” diameter guide shafts
▪ LSM secures rover during flight
Cornell Rocketry Team
Preliminary Design Review
SIGNIFICANT FAILURE MODES
▪ The rover falls from the section before landing.▪ Upwards accelerations at launch and parachute deployment.
▪ Mitigated during launch by coupler inside AV bay section.
▪ Mitigated by high holding torque of motor.
▪ Evaluated through thorough testing.
▪ The LSM guide shafts or lead screw are damaged.▪ Results in misalignment, compromises deployment.
▪ Mitigated by additional guide shafts.
▪ Force of ejection charges are directed to coupler
▪ Evaluated through shock and ground testing.
Cornell Rocketry Team
Preliminary Design Review
ELECTRICAL AND SOFTWARE
Cornell Rocketry Team
Preliminary Design Review
SYSTEM SUMMARY
▪ Modular design approach
▪ Power Distribution
▪ Distributes power to modules
▪ Controls
▪ Determines each module's actions
▪ Wireless Communication
▪ Sends signal to start LSM
▪ Motors
▪ LSM as well as rover
▪ Object Avoidance
▪ Solar Panels
Cornell Rocketry Team
Preliminary Design Review
POWER
▪ Distributes and regulates power to all modules
▪ Provides overvoltage and
▪ Provides overcurrent and overvoltage protection to other modules
▪ Must supply 5V to both microcontrollers
▪ Must supply 6V to motors
▪ LiPo batteries
▪ High energy density
▪ Lightweight
▪ Rechargeable
Cornell Rocketry Team
Preliminary Design Review
CONTROLS
▪ Determines state of system
based on data inputs
▪ LSM:
▪ Transmitter
▪ Receiver
▪ Motor
▪ Rover:
▪ Sensors
▪ Motors/Wheels
▪ Solar Panels
▪ Display
Cornell Rocketry Team
Preliminary Design Review
WIRELESS COMMUNICATION
▪ Send signal to microcontroller in launch vehicle to start LSM motor
▪ Desired minimum range of 1 mile
▪ Receiver located in launch vehicle
▪ RFM98W LoRa module will be used
▪ 2.5 mile range
Cornell Rocketry Team
Preliminary Design Review
MOTORS
▪ LSM:
▪ DC Motor
▪ Electrically isolated from Controls Module
▪ Rotates in one direction
▪ Rover:
▪ Low torque requirement
▪ Continuous Rotation Servos
▪ Simple speed and directional control
Cornell Rocketry Team
Preliminary Design Review
OBJECT AVOIDANCE
▪ Object avoidance will be implemented using proximity sensors
▪ Time of Flight Distance Sensors
▪ Mounted on front of rover
▪ Used to detect objects in path
▪ Accurate
▪ Reliable
Cornell Rocketry Team
Preliminary Design Review
SOLAR PANELS
▪ Small servo motor will unfold panels on top of the
rover
▪ Two panel design
▪ 2.75” x 2.165”
▪ Voltage output from solar panels will be shown on a
display onboard the rover
Cornell Rocketry Team
Preliminary Design Review
SIGNIFICANT FAILURE MODES
▪ Damage to electronics during launch
▪ High acceleration could damage electronics or break connections
▪ System would become inoperable or damaged
▪ Mitigated by using printed circuit boards to eliminate physical
connections
▪ Wireless communication fails
▪ Launch Vehicle lands out of range
▪ LSM would fail to activate
▪ Mitigated by range testing the communication and ensuring at least 1
mile range
Cornell Rocketry Team
Preliminary Design Review
REQUIREMENTS COMPLIANCE
▪ The DRS shall deploy from the internal structure of the launch vehicle.
▪ The LSM secures the rover inside the LV during flight.
▪ The LSM deploys the rover from the end of the section after landing.
▪ After landing, the DRS deployment shall be triggered by a remote signal.
▪ After deployment, the rover shall autonomously move 5 ft from the LV.
▪ Primary wheels move the rover
▪ Stabilizing wheel to prevent flipping
▪ Obstacle detection and steering
▪ After the rover stops, it shall deploy foldable solar panels.
▪ Servo motor actuates panels
Cornell Rocketry Team
Preliminary Design Review
COMMUNICATIONS
Cornell Rocketry Team
Preliminary Design Review
SYSTEM REQUIREMENTS
NASA SL Requirements:
Determine launch vehicle position during the flight using GPS data
Incorporate GPS and other radio transmitters into the launch vehicle
Determine the location of the launch vehicle using the GRB, SRB, and the
TRACER after landing
Utilize backup systems in case a system fails to operate as expected
Cornell Rocketry Team
Preliminary Design Review
SYSTEM REQUIREMENTS
Team-derived Requirements:
Obtain video during flight of launch vehicle through onboard camera
Camera run by Raspberry Pi
Save and transmit all flight information for vehicle tracking and post-launch
analysis
Use TRACER to write sensor data to SD card
Cornell Rocketry Team
Preliminary Design Review
ELECTRICAL COMPONENTS
Cornell Rocketry Team
Preliminary Design Review
SIMPLE RADIO BEACON (SRB)
Morse Transmission of HAM Radio Operator callsign
Requires minimal power
Utilized for simple direction finding (using “fox hunting” technique)
Transmit power at 100 mW
Cornell Rocketry Team
Preliminary Design Review
GPS RADIO BEACON (GRB)
Transmits APRS packets to handheld radio
Enable CRT to find location of launch vehicle sections to within 10 meter range
Redundancy system for Simple Radio Beacon
Transmit power at 100 mW
Cornell Rocketry Team
Preliminary Design Review
TRACER MODULE ELECTRONICS
Arduino Uno
Raspberry Pi Zero W
GPS Module
Barometer
Accelerometer
Gyrometer
Camera
LoRa Radio
SD Card
Cornell Rocketry Team
Preliminary Design Review
GROUND STATION GUI
LoRa radio will be connected to high-gain Yagi directional antenna, which will be
connected to a custom board for data formatting and then streamed to the
Ground Station Laptop
CRT GUI will utilize information obtained from the connected board to plot
velocity and location information, as well as map the rocket to assist in quickly
finding the location of the launch vehicle after landing
Cornell Rocketry Team
Preliminary Design Review
SIGNIFICANT FAILURE MODES
Short-Circuit
Detached components could cause damage to tracking systems
Prior to launch all components will be checked and wires secured to rocket
All Communications equipment will also be subject to vibration testing
Battery Rupture
Improper charging/discharging of LiPo battery can increase explosion risks
Failure could cause damage to rocket or premature nosecone ejection
Risk mitigated using smart charger that prevents overcharging
Larger capacity batteries used to prevent over-discharging
Cornell Rocketry Team
Preliminary Design Review
INDEPENDENT TEST & VALIDATION
(INTEV)
Cornell Rocketry Team
Preliminary Design Review
MISSION REQUIREMENTS
Verify that all components on board the launch vehicle are capable of completing
the mission.
Develop appropriate testing procedures that produce valuable data through
reliable and repeatable testing of components.
Build long-term, general-use testing devices to validate models and predictions.
Cornell Rocketry Team
Preliminary Design Review
PLANNED TESTING
Specific subsystem tests
Parachute Test Rig (PTR)
General test rigs
Shock Test Rig (STR)
Centrifuge
Cornell Rocketry Team
Preliminary Design Review
PARACHUTE TEST RIG (PTR)
▪ Objective: To measure drag force of a parachute at airspeeds up to 90mph
▪ Verifies: Landing kinetic energy requirements are met
▪ System level design:
Wind Tunnel Air
Flow
Parachute
Attachment
Cable
Test Parachute
Tension Force
on Electronic
Scale
Attachment
Cable around
Pulley
Cornell Rocketry Team
Preliminary Design Review
SHOCK TEST RIG (STR)
Objective: To measure the shock response of tested components
Verifies: Flight hardware responds as expected to shock during various stages of
flight (liftoff, parachute ejection, landing impact)
System level design:
Test articleMounting
Platform
Give potential
energy to
platform
Release energy
through
acceleration
(shock)
Measure
Acceleration
Cornell Rocketry Team
Preliminary Design Review
CENTRIFUGE
Objective: To test components under launch condition g-forces
Verifies: Flight hardware and components respond as expected to high levels of
acceleration (8g’s)
Hardware Design: Controls Design:
MotorMotor
ControllerBatteries
Laptop
Cornell Rocketry Team
Preliminary Design Review
PROJECT PLAN
Cornell Rocketry Team
Preliminary Design Review
TIMELINE
Cornell Rocketry Team
Preliminary Design Review
EDUCATIONAL OUTREACH
Cornell Rocketry Team
Preliminary Design Review
BUDGET- EXPENSES
Cornell Rocketry Team
Preliminary Design Review
BUDGET- INCOME