Preliminary Design Review Bearcat Ballistics 2018-2019 1
NASA U niversity S tudent L aunch I nitiative (USLI) ● Annual Competition hosted at the Marshall Space Flight Center ● Gives an opportunity for engineering students to collaborate on a project involving building a full scale model rocket ○ Helps students gain valuable experience in a professional setting while simultaneously completing hands-on tasks ● Our Mission: Rover Deployment with Soil Recovery and Rocket Launch at Altitude 2
Meet the Team 3
Team Launch Vehicle Requirements ● Conor is Launch Vehicle Team Lead ● Subsystems of the Launch Vehicle: ○ Motor ○ Fins ○ Recovery ○ Telemetry and Electronics ○ Computing The team shall test the recovery Recovery system must bring the rocket system’s ability to reach the ground to the ground within 90 seconds of from apogee within the 2.4.3 reaching apogee. Testing predetermined time. 4
Team Payload Requirements ● Andy is Payload Team Lead ● Subsystems of the Payload: ○ Rover Power ○ Deploy Power ○ Rover Structures ○ Deploy Structures ○ Computing ○ Excavation Simulations shall be conducted and The payload shall be capable of flight data shall be analyzed to withstanding sustained acceleration of measure the acceleration force the 3.1.4 up to 10 Gs. Analysis payload will withstand. 5
Team Safety Requirements ● Adam is Safety Team Lead ● Subsystems of Safety: ○ Training ○ Housekeeping Every team member shall return all Team members shall supplies they use while in the Rocket demonstrate good habits of Lab to the correct place prior to leaving putting supplies in their proper for the day, both as a safety precaution location for the safety of those 4.2.1 and good housekeeping process. Demonstration using the lab. 6
Team Finance Requirements ● Alex is Finance Team Lead ● Subsystems of the Finances: ○ Budget ○ Sponsorship Revenue ○ Travel Expenses ○ Reserve The budget shall be closely monitored and analyzed by the team treasurer The team treasurer shall inspect throughout the design and build the team expenses and budgeting process to ensure that the budget is not process during the length of the 5.1.1 exceeded. Inspection project. 7
Launch Vehicle Design Mission Criteria and Design Driving Factors Design Overview Simulation Trade Studies Flight Events 8
Mission Success Criteria and Design Driving Factors 1) The launch vehicle shall reach an apogee of +/- 100 ft of 5,000 ft AGL. 2) The launch vehicle shall touch down from apogee in under 90 seconds. 3) The launch vehicle shall deploy a soil sample rover payload. 4) The launch vehicle shall deploy recovery devices in order to achieve a landing energy of less than 75 ft. lbf. 5) The launch vehicle shall be constructed in a manner such that it is reusable. Primary Design Driving Factors ● rocket motor ● payload dimensions and mass ● fins ● recovery system 9
Current Design Overview ● Weight on Launch Pad (Lbs): 31.9 ● Descent Weight (Lbs): 28.0 ● Length (in): 122 ● Motor: AMW L900RR ● Thrust-to-Weight Ratio: 6.40 ● Stability Margin (at launch): 2.24 ● Rail Exit Velocity: 58.57 Center of Gravity ● Landing Energy (ft-Lbf): 70.0 72.6” from Nose ● Avg. Max Altitude (ft): 5556 Center of Pressure 89.8” from Nose 10
Launch Vehicle Design Evolution From v1 to v2 ● 8.5” length increase ● 5.8 Lb launch weight reduction ● 2” span reduction ● 0.71 Lb propellant mass reduction ● 659 ft simulated altitude gain Version Motor Length (in) Outer Launch Descent Stability Simulated diameter Mass Mass Margin Altitude (in) (Lbs) (Lbs) at Achieved Launch (ft) v1 CTI L850W 113.5 7.75 37.7 33.1 2.08 4897 v2 AMW L900RR 122 7.67 / 31.9 28.0 2.24 5556 6.26 11
Simulation Motor Max Launch Wind Temp. Altitude Accel. Angle Speed (F) Achieved (ft/s 2 ) (deg) (mph) AMW 272.2 5 5-10 65 5556 All simulations so far have been L900RR conducted using RockSim 9. The program provides useful data AMW 274.0 10 5-10 65 5321 estimating a wide variety of performance data in diverse L900RR environments AT 262.14 5 5-10 65 5768 L1150 AT 261.87 5 5-10 40 5695 L1150 12
Motor Trade Study Size Model Max. Altitude Max. Vel. Rail Exit Vel. (mm) (ft) (ft/s) (ft/s) Takeaway: AMW L900RR flies 75 AMW L900RR 5556 636.34 58.57 the closest to our target altitude and has high availability 75 CTI L3200 5645 730.88 124.88 75 AMW L1060GG 5897 676.46 61.84 75 AMW L1111ST 5749 668.85 65.42 75 AT L1150 5805 673.19 76.06 13
Launch Vehicle Airframe Trade Study Tube Material Manufacturers Dimensions Material Strength Weight (in) Description Rating (oz) Phenolic Public Missiles Dia: 6.01 Resin-Impregnated, High 36.9 Takeaway: Phenolic Tubing offers L: 48 Heat cured high strength with competitively low Phenolic Public Missiles Dia: 7.5 Resin-Impregnated, High 48.1 weight L: 48 Heat cured Cardboard LOC Dia: 7.5 Brown Kraft Paper Medium 60.91 Apogee L: 48 Fiberglass Apogee Dia: 6.01 G12 Filament Very High 97.56 Filament Tube L: 48 Wound Tube Blue Tube Apogee Dia: 5.97 High Density, Very High 41.94 L: 48 High Strength Paper 14
Launch Vehicle Fins Trade Study Material Properties Shape Result Balsa Weak. High probability of Elliptical “Ideal” shape but is not effective at damage upon impact high speeds G10 High strength. Industry Trapezoidal Offers balanced static margin standard. Difficult to cut easily modified with root and tip length. Less damage upon impact Aircraft Plywood Medium strength. Can be wrapped to strengthen Rectangular Raises static margin beyond desired limit, not aerodynamic Swept Lowers stability margin below desired limit. High probability of damage upon impact 15
Drogue Parachute Study Objective: Identify drogue parachute options Takeaway: 30 in. Public Missile is the current leading choice, given the C D and exerted force during main parachute deployment 16
Main Parachute Study Objective: Identify Main parachute options Takeaway: 130 in. Custom Fruity Chute is the current leading choice, given the C D and Kinetic Energy during launch vehicle landing 17
Launch Vehicle Electronics and Recovery Subsystem 18
Altimeter Circuit 19
Telemetry Circuit 20
Flight Events Apogee: Launch Vehicle reaches target altitude of 5000 ft. and drogue parachute deploys 510 ft. AGL: Main parachute deployed by StratologgerCF Altimeter Launch: Vehicle leaves the launch pad Landing: Launch vehicle returns to ground with less than 75 ft.-Ibf. Kinetic energy 21
Payload Design Payload Design Overview Payload Electronics Overview Weight Breakdown Ground Station Payload Trade Studies 22
Payload Mission Objectives ● Deploy safely and travel 10 feet from the launch vehicle ● Collect a soil sample ○ Sample must be at least 10 mL ○ Sample must be stored in an on-board container 23
Primary Payload/Rover Design Overview The payload consists of the rover and the rover deployment system ● Rover ○ Uses two 6” diameter wheels to propel itself ○ Collects soil with an on-board auger system ○ Resists rotation with a small set of deployable wheels ○ Measures distance travelled with an IMU and motor encoders ○ Uses an active control system to maintain heading ● Deployment system ○ Uses an 18” stroke linear actuator ○ Provides 150 lbs of force to push rover out of the rocket ○ Actuates a switch that causes the rover to power on 24
Rover Design Overview--Counter Torque Arm ● Rover will use a deployable arm to counteract the motor torque ○ Stops the motors from rotating the chassis instead of the wheels ● Arm connects to the chassis by means of a hinge ○ Hinge is spring loaded ○ A servo at the mounting point will pull a pin that deploys the arm ○ The arm will lock in place in its new position 25
Payload Design Overview--Auger ● The auger is driven by a hollow shaft motor ● The motor is mounted to the top of the chassis via extension springs ● A linear actuator pulls a cable/line to lower the auger ○ Force redirected by pulley ○ Configuration reduces required height of auger system ○ Springs allow auger to retract when actuator extends 26
Payload Launch Vehicle Interface Rover mounts to the actuator by means of an aluminum/HIPS disk with a 0.5” lip around the circumference. Rover mounts to nose cone with an identical disk. The rover is not fixed to these mounting points, but instead rests on them, allowing it to free itself upon deployment. The linear actuator is bolted to a bulkhead about 23” aft of the back end of the rover. 27
CAD Photos of Payload Interface 28
Actuator Mounting to Bulkhead 29
Stowed vs Deployed 30
Design: Structure and Housing ● The structure of the payload will be made as a 3.2x4.2x12 inch rectangular prism. ● The internal payload volume will be 144 cubic inch. 31
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