Foreword - Tarleton State University Web view“I have learned to use the word 'impossible' with the greatest ... Aerodynamic characteristics of the vehicle include an elliptical nosecone

Tarleton State University

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Foreword

To facilitate the reading of the Post Launch Assessment Review, we have mirrored the Student Launch Project Statement of Work. In the body of the PLAR, you will find extensive analysis of our SMD payload’s performance and flight data. The payload’s features are threefold; atmospheric data gathering sensors, a self-leveling camera system, and a video camera. One of the two major strengths of our payload design is the originality of our autonomous real-time camera orientation system (ARTCOS). The other major strength can be found in the originality of our self-designed Printed Circuit Board layouts. This feature alone represents over 250 man hours of work. The PCBs provide major enhancement of the signal integrity of the sensor data in addition to their space and power efficient qualities. The flight in Huntsville was a success, placing 3rd closest in altitude. We attribute this to extensive testing and 8 full scale flights at our launch field and the guidance of Pat Gordzelik, Tripoli Vice-president. Testing allowed our designs and flight protocols to mature. We would like to express our appreciation to the NASA judges, engineers, and NAR volunteers that donated their time to this incredible experience. We have enjoyed analyzing the flight performance and submit this document for your review.

Post Launch Assessment Review2012-2013 NASA USLI


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Table of ContentsForeword.......................................................................................................................... iiProject Summary..............................................................................................................1Flight Analysis Summary..................................................................................................2

Flight Simulations and Recovery Analysis....................................................................2

On-site Pre-launch Simulations.................................................................................2Variances Between Actual and Predicted Flight Data...............................................3Recovery Electronics Data........................................................................................4

Vehicle Analysis Summary...............................................................................................5

Vehicle Layout and Specifications................................................................................5Vehicle Data Analysis...................................................................................................6

Payload Analysis Summary.............................................................................................7

Data Analysis................................................................................................................7


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Science Value................................................................................................................12Simulation Analysis........................................................................................................12

Atmospheric Modeling................................................................................................13

Educational Engagement...............................................................................................13Budget Summary...........................................................................................................14Lessons Learned............................................................................................................14Summary of Overall Experience.....................................................................................15


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Table of FiguresFigure 1: Launch Vehicle.................................................................................................1Figure 2: Simulated Launch Vehicle.................................................................................3Figure 3: Simulated Flight Data........................................................................................3Figure 4: Stratologger Altimeter Data...............................................................................4Figure 5: Exploded View of Vehicle..................................................................................5Figure 6: Frames of Video Footage.................................................................................6Figure 7: SMD Payload Design........................................................................................7Figure 8: Atmospheric Data.............................................................................................8Figure 9: Frequency of Data Collection............................................................................8Figure 10: ARTCOS Images............................................................................................9Figure 11: Key-Fob Video Camera Screen Shot............................................................10Figure 12: Ground Station GUI......................................................................................10Figure 13: Payload Post-Flight.......................................................................................11Figure 14: Google Flight Path Overlay...........................................................................11Figure 15: Probability Density and Cumulative Density of Rocket Apogee....................12Figure 16: Schools Influenced by Tarleton's Educational Outreach Program................13


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List of Tables

Table 1: Project Design Summary...................................................................................1Table 2: Flight Summary Chart........................................................................................2Table 3: Flight Stage Simulations....................................................................................3Table 4: Simulated and Actual Launch Conditions...........................................................4Table 6: Budget Overview..............................................................................................14Table 7: Subsystem Budgets.........................................................................................14


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Project Summary

The Tarleton Aeronautical Team successfully designed, launched, and recovered a launch vehicle that carried the Science Mission Directorate (SMD) payload to 5,311 feet above ground level. Named “Gravity Always Wins,” the vehicle is 97.5 inches long and has a diameter of 5.525 inches. The nose cone, fins, and body sections are G10 fiberglass with the exception of the UV-T acrylic payload housing section. Aerodynamic characteristics of the vehicle include an elliptical nosecone and clipped delta fins. The vehicle incorporated a Cesaroni L1720-WT-P motor, yielding a total vehicle mass of 37.7 pounds at launch. A ballast system was used for apogee control rather than a complicated energy management system. Extensive simulation and statistical analysis provided a basis for ballast weight needed, and ultimately the system achieved elevation within 31 feet of the target altitude on launch day.

The SMD payload consists of the Atmospheric Data Gathering System (ADGS), the Autonomous Real-Time Camera Orientation System (ARTCOS), and a Keyfob Video Camera. The payload design was selected for the Science Mission Directorate (SMD) funding from NASA and received the ATK SMD Payload Design Award. The design satisfied all prescribed objectives with the addition of recording video footage. In order to maximize functionality and safety, all payload operations take place internally within the clear acrylic housing. Table 1 gives brief summary of the project design.

SummaryTeam Name Tarleton Aeronautical TeamMotor Used Cesaroni L1720 WT-PPayload Science Mission DirectorateRocket Height (Length) 97.5 inches (8 feet 1.5 inches)Rocket Diameter 5.525 inchesRocket MassMass without Motor 30.3125 poundsWet Mass 37.6875 poundsDry Mass 33.80625 poundsAltitude Reached (Scoring Altimeter) 5,311 feet

Table 1: Project Design Summary

Figure 1: Launch Vehicle


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Flight Analysis Summary

In order to facilitate efficient review of the flight analysis, the following chart shows simulated data from Openrocket and actual flight data from onboard non-scoring altimeters and video analysis. A more detailed analysis follows the flight summary chart.

Stage Simulated ActualOff-Rail

Time 0.280s .29s

Velocity 77.839fps 78fpsAltitude 10ft 10ft

Drogue DeploymentTime 18.151s 18.7s

Velocity 2.041fps 17fps

Altitude 5260ft 5388ft

Main DeploymentTime 89.233s 73.2s

Velocity 63.957fps 90.78fps

Altitude 700ft 695ft

ImpactTime 147.930s 107.65s

Velocity 10.241fps 15.38fps

Altitude 0ft 0ftTable 2: Flight Summary Chart

Flight Simulations and Recovery Analysis

On-site Pre-launch Simulations

The recovery scheme for the flight functioned properly. A two foot diameter drogue parachute deployed 5 feet below apogee and a ten foot main parachute deployed at 700 feet AGL. Although the official scoring altitude indicated 5,311 feet AGL, the rocket was configured based on simulations calculated for a target of 5260 feet AGL The target


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altitude was based on test flight data and game theory analysis due to competition scoring rubric.

Simulated rocket and flight path made using OpenRocket on launch day are shown below is shown in figures 2 and 3 as well as table 3 flight stage calulations.

Figure 2: Simulated Launch Vehicle

Figure 3: Simulated Flight Data

Stage Time Velocity Height AGL Lateral Displacement

Off-Rail 0.280s 77.839fps 10ft 0ft

Drogue Deployment 18.151s 2.041fps 5260ft 299ft

Main Deployment 89.233s 63.957fps 700ft 368ft

Impact 147.930s 10.241fp 0ft 973ft


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sTable 3: Flight Stage Simulations

Variances Between Actual and Predicted Flight Data

Several factors affect the flight path and the achieved altitude of the rocket and caused variance between actual and simulated data; these factors include wind speed, temperature, pressure, and angle of the launch rail. The achieved altitude variance is attributed to the change in these values between the expected launch time of 8:00 am and the actual launch time of 8:43:40 am. Simulations took place approximately two hour prior to launch, during which time the temperature and pressure changed. Thus these changes were not accounted for in the simulation. Another factor was the angle of the launch rod. The simulation used a launch rod angle of zero degrees while the actual launch rod was angled three degrees by the NAR official. The changes in the factors effecting ballast calculations are shown in Table 4.

Simulated ActualTemperature 550 F 570 F

Pressure 982 mbar 999 mbar

Launch Rod Angle

00 30

Table 4: Simulated and Actual Launch Conditions

Recovery Electronics Data

The recovery system includes four Stratologger altimeters that worked as programed. The primary drogue altimeter fired within 5 feet apogee while the secondary drogue altimeter fired one second after. Similarly, there are two main parachute deployment altimeters. The primary main altimeter fired at 700 feet while the secondary fired two seconds later. The altitude and velocity data are shown in Figure 4.


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Figure 4: Stratologger Altimeter Data


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Vehicle Analysis SummaryVehicle Layout and Specifications

There are three main sections referenced as the upper body airframe, the payload housing section, and the booster section. The upper body airframe serves as a coupler attachment point for the elliptical nose cone at the front end and for the payload housing section at the back end. The upper body airframe houses the 10 foot main parachute along with respective attachment and deployment hardware. The main parachute avionics are located in the coupler connecting the upper body airframe to the payload housing section.

Figure 5: Exploded View of Vehicle

The payload housing section provides a clear body section such that all payload operations can occur internally. The PCBs for the payload are mounted on an aluminum frame that is secured via bulkheads. This body section provides a coupler attachment point for the upper body airframe on the front end and one for the booster section on the back end.

The booster section houses the motor and provides an attachment surface for the fins. It provides a coupler attachment point to the payload housing section at the front end. This section also houses the two foot drogue parachute and associated attachment and deployment hardware. Clipped delta fins are epoxied into slots milled into the booster section airframe. The dimensions of the fins include a root chord of 12 inches, tip chord


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of 2.4 inches, height of four inches, sweep length of 7.85 inches, and a sweep angle of 63 degrees.

Vehicle Data Analysis

The vehicle performed well during the launch. Prior to launch, the ballast was configured for conditions predicted at 8 a.m. rather than 8:40 a.m. After re-simulation with actual launch conditions, the simulation predicted an apogee of approximately 5,315 feet, a much closer simulation to the actual launch.

Visual data observed of the flight indicated the rocket remained very stable throughout as confirmed by the slow motion video capture seen in Figure 7. Post flight assessment demonstrated the integrity of the design as there was no damage, and the rocket remained reusable.

Figure 6: Frames of Video Footage


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Payload Analysis Summary

The payload design was selected for the Science Mission Directorate (SMD) funding from NASA and received the ATK SMD Payload Design Award. The payload experiment fulfills the requirements of NASA’s SMD payload. The payload design is shown in Figure 7.

Figure 7: SMD Payload Design

Data Analysis

The flight of the payload demonstrated successful completion of ALL of the SMD requirements. This section lists each requirement and provides data to confirm the successful completion of each requirement.

3.1.3.1 The payload shall gather data for studying the atmosphere during descent and after landing, including measurements of pressure, temperature, relative humidity, solar irradiance and ultraviolet radiation

08:42:00 AM 08:42:43 AM 08:43:26 AM 08:44:09 AM 08:44:52 AM 08:45:36 AM 08:46:19 AM23252729 Pressure

inHg


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08:42:00 AM 08:42:43 AM 08:43:26 AM 08:44:09 AM 08:44:52 AM 08:45:36 AM 08:46:19 AM2025303540

Humidity

% R

H

08:42:00 AM 08:42:43 AM 08:43:26 AM 08:44:09 AM 08:44:52 AM 08:45:36 AM 08:46:19 AM0

200400600800

Solar Irradiance

W/m

2

08:42:00 AM 08:42:43 AM 08:43:26 AM 08:44:09 AM 08:44:52 AM 08:45:36 AM 08:46:19 AM82

84

86

88

90

Temperature

Fahr

enhe

it

3.1.3.2 Measurements shall be made at least every 5 seconds during descent,and

3.1.3.3 Measurements shall be made every 60 seconds after landing.

08:42:00 AM 08:42:43 AM 08:43:26 AM 08:44:09 AM 08:44:52 AM 08:45:36 AM 08:46:19 AM05

1015202530

Ultraviolet Radiation

W/m

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Figure 8: Atmospheric Data


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Figure 9: Frequency of Data Collection

The atmospheric data gathered by the payload throughout the final flight is displayed in the following graphs. Measurements are made approximately every 1.2 seconds. Frequency of data gathering is shown in Figure 9.

3.1.3.4 Surface data collection operations shall terminate 10 minutes after landing.

The payload failed to autonomously terminate measurement gathering after ten minutes, a wireless deactivation command and a magnetic switch provided secondary forms of deactivation.

3.1.3.5 The payload shall take at least 2 pictures during descent and 3 after landing, and

3.1.3.6 The payload shall remain in an orientation during descent and after landing such that the pictures taken portray the sky toward the top of the frame and the ground toward the bottom of the frame.

The ARTCOS successfully orientated the camera during descent and after landing. The pictures taken by the ARTCOS are if Figure 10. Note: these Images have not been edited in any way.


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Figure 10: ARTCOS Images

The Key-Fob video camera recorded video footage of the entire flight. A frame from the Key-Fob video captures the flight line (Figure 12).

Figure 11: Key-Fob Video Camera Screen Shot

3.1.3.7 The data from the payload shall be stored onboard and transmitted wirelessly to the team’s ground station at the time of completion of all surface operations.

Data was stored onboard the payload to micro SD cards. The ground station displayed the payload telemetry in real time as show in Figure 12. Humidity and UV measurements contained inaccurate spikes due to interference from surrounding wireless transmitters. The ground station is capable of deactivating, reactivating, and controlling the frequency of telemetry transmission. The raw data packets were displayed in the bottom window.


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Figure 12: Ground Station GUI

3.1.3.8 Separation of payload components at apogee will be allowed, but not advised. Separating at apogee increases the risk of drifting outside the recovery area.

The payload design maximizes safety by staying contained within the clear acrylic housing throughout the flight. Components are securely mounted to aluminum rails, thus no parts were damaged during the flight. A picture of the payload after flight is shown in Figure 13.

Figure 13: Payload Post-Flight

3.1.3.9 The payload shall carry a GPS tracking unit.GPS coordinates were measured by the Locosys GPS onboard the payload. GPS data was stored and transmitted at the same frequency as other payload devices. The rocket landed 1,012 feet from the launch rail according to the GPS coordinates, which are graphed in Figure 14.


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Figure 14: Google Flight Path Overlay

Science ValueThe scientific value of the rocket design centers on mathematical analyses of the rocket flight and changes in the atmospheric variables involved. A statistical analyses across a large number of simulations provides a thorough prediction model of the rocket flight under very specific conditions. In addition, research into a nonlinear model representative of atmospheric correlations holds tremendous potential in the realm of rocketry and aerodynamics.

Simulation AnalysisAll flight simulations were created using the OpenRocket software suite. This program, developed as a master’s thesis by an aeronautics student from Helsinki University of Technology, allows the user to build a three-dimensional representation of the rocket and simulate a full flight. The rocket rendering subprogram allows the user to build every component to specification of size and mass. All simulations then use the virtual rocket model, in conjunction with the desired motor and atmospheric conditions at the time of launch, to predict the flight path at each 0.01-second interval.

Considering the number of variables involved, one simulation is insufficient to provide a comprehensive representation of the expected results. That said, the prediction experimentation involved a large number of simulations to demonstrate all likely outcomes of the flight. Using the exact atmospheric measurements for the projected launch date 1000 simulations are created, totaling to over 75 MB of data. A statistical analysis across these simulations produces a projected flight path with the probabilities of meeting specific values of apogee, lateral distance, etc.


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The left side of Figure 15 demonstrates the resulting probability density curve for reaching one mile exactly. Although the probability of hitting one mile exactly is demonstrated at roughly 6%, with a larger margin of error the probability grows much higher. The right side of Figure 15 illustrates the probability of reaching an apogee below a specified height. Here the predicted accuracy of the rocket becomes more apparent. The demonstrated probability of apogee being below 5,290 feet is roughly 90 %. The results of this experiment show the importance of a large number of simulations combined with a thorough mathematical inspection in a predictive analysis.

Figure 15: Probability Density and Cumulative Density of Rocket Apogee

Atmospheric ModelingPreliminary referencing involves a prolonged and extensive process of determining cross-correlation of variables. Using over 2.9 GB of data acquired from the National Oceanic and Atmospheric Administration (NOAA) 48 variables will be modeled against one another in search of any existing relationships.

The results of the pre-flight analysis are used to improve the predictive model provided by OpenRocket simulations. A regressive model relating relevant atmospheric variables is combined with a second-by-second prediction of the flight path. These combined results more accurately show the projected flight path, as the impact of each atmospheric variable can be introduced with more validity .The flight data acquired from the four onboard altimeters can then be cross-referenced with a validated mathematical model for the flight path to check for inconsistencies. This whole analysis allows for a better understanding of anomalies causing any divergence from a predicted flight path. By introducing equations relating atmospheric variables, measurements taken on the ground are more accurately related to atmospheric conditions at higher altitudes. A more precise model will closely mirror the results of a real flight. Due to the thoroughness of this investigation most factors of uncertainty are almost entirely removed and the rocket is more easily controlled.

Future investigation into this experiment will involve modifying the OpenRocket code. As OpenRocket is open-source software, the source code has been located and retrieved free of charge. Upon determining adequate atmospheric models and a thorough validation of the model, the portion of code used to simulate atmospheric conditions will be altered for more accurate results.


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Educational Engagement

The main goals of the educational outreach activities were to inspire students and foster enthusiasm for the STEM fields including rocketry. Events were created to enlighten students about the global necessity of math, science, engineering, and technology. A rocket launch at the end of each presentation provided students with real world applications and a personal experience to reinforce the STEM concepts of each outreach event. The team encouraged interest in these subjects with the intent of increasing the number of people that choose to pursue STEM related careers.

8 Events 3 Event Styles

o Large Group Presentationo Problem Solving Lessono Rocket Fair

31 Participating Schools 1400+ Students & Teachers

Figure 16: Schools Influenced by Tarleton's Educational Outreach Program


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Budget Summary

The following chart includes the budget for the project. The task of completing the NASA USLI is a complex interdisciplinary endeavor that tests the team’s knowledge and skills, including management of a budgetTable 6 breaks down the total budget. The budget for the final vehicle build is charted in Table 7.

Cost Elemnet Est. CostTesting/Prototyping $13,972.23Outreach $3,669.77Final Build $4,007.21Travel to Competition $8,200.00Total $29,849.21

Table 5: Budget Overview

On Pad Cost Est. CostRecovery $951.47Structure/Propulsion $1,189.61Payload $1,866.13On Pad Total $4,007.21

Table 6: Subsystem Budgets

Lessons Learned

The team gained a wealth of knowledge throughout the project concerning engineering principles and what it takes to be successful in the real world. Some of the most pivotal learning experiences included the team’s understanding of how to work well in a team environment, be professional, and how to apply what’s learned in the classroom to a real world project.

The team worked together to foster good communication throughout each subsystem involved. This communication allowed for a positive working environment. The team also learned to work in an interdisciplinary manner that incorporated many diverse talents into one cohesive unit.

Through the documentation and presentations, the professionalism of individuals and the group benefitted a great deal. The importance of punctuality and preparedness for meetings and deadlines became evident early in the project to adhere to the rigorous timeline that the team created. The project timeline established a concrete set of goals and a list of plans to coordinate between various subsystems and perform schedule tests. The team learned how to


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balance expected outcomes with actual results and creatively solve problems in high pressure situations.

We developed new understanding of the engineering life cycle. The complexity of the project, managing personnel, and working within a limited budget stretched the team members to their limit. Taking a design into prototype and then production gave us new appreciation for the need for extensive testing and documentation. Meticulous documentation was kept regarding every stage of the design life cycle, but most changes came through test flights and analysis of failure modes. The team also learned to practice and implement sound purchasing and inventory process and budgeting.

Summary of Overall Experience

The USLI project has been one of the most valued learning experiences for each of the Tarleton Aeronautical Team members in their academic career. An optimized rocket design was used with the SMD payload sponsored by NASA. Though many teams employed electromechanical systems to affect the aerodynamics of their rocket, Tarleton’s submission simply relied on mathematics to predict, simulate and analyze the rocket’s flight path. A well-constructed launch vehicle with thorough mathematical analyses to achieve the third-closest apogee to exactly one mile resulted through the hard work of each team member.

The team recognized through test flights what seemed like a good decision on paper was not always the best option in implementation. The design underwent significant changes to enhance the accuracy and durability of the final product. Instances where testing significantly impacted the project included: changes from the spark ejection canister to e-matches, the adoption of a deployment bag, and the aluminum flash shielding for the avionics bays. The team also learned to scrutinize parts received due to the shipment of several incorrect orders.

The team’s payload functioned fully according to all required specifications. The project was overwhelmingly positive, and it demonstrated a massive success on the parts of all team members involved. Completing a project of this scope built a new level of confidence in the skills and abilities of the team.

The launch week at Marshall Space Flight Center was an incredible experience for everyone involved. The opportunity to meet with NASA and ATK Aerospace Group executives was a perfect culmination to the accomplishment of successfully completing the launch initiative. The project opened new doors for many team members regarding their future careers and also developed a new love and familiarity of rocketry for team members, family and friends.

Documents

Foreword - Tarleton State University Web view“I have learned to use the word 'impossible' with the greatest ... Aerodynamic characteristics of the vehicle include an elliptical nosecone