post launch assessment reviewtarleton state university i post launch assessment review 2012-2013...

Tarleton State University

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Post Launch Assessment Review

2012-2013 NASA USLI

“I have learned to use the word 'impossible' with the greatest caution.”

~ Wernher von Braun


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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.


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Table of Contents Foreword ..........................................................................................................................ii

Project Summary ............................................................................................................. 1

Flight Analysis Summary ................................................................................................. 2

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

On-site Pre-launch Simulations ................................................................................ 2

Variances Between Actual and Predicted Flight Data ............................................... 3

Recovery Electronics Data ....................................................................................... 4

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

Vehicle Layout and Specifications ............................................................................... 5

Vehicle Data Analysis .................................................................................................. 6

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

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

Science Value ............................................................................................................... 12

Simulation Analysis ....................................................................................................... 12

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

Educational Engagement .............................................................................................. 13

Budget Summary .......................................................................................................... 14

Lessons Learned ........................................................................................................... 14

Summary of Overall Experience .................................................................................... 15


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Table of Figures

Figure 1: Launch Vehicle ................................................................................................. 1

Figure 2: Simulated Launch Vehicle ................................................................................ 3

Figure 3: Simulated Flight Data ....................................................................................... 3

Figure 4: Stratologger Altimeter Data .............................................................................. 4

Figure 5: Exploded View of Vehicle ................................................................................. 5

Figure 6: Frames of Video Footage ................................................................................. 6

Figure 7: SMD Payload Design ....................................................................................... 7

Figure 8: Atmospheric Data ............................................................................................. 8

Figure 9: Frequency of Data Collection ........................................................................... 8

Figure 10: ARTCOS Images ........................................................................................... 9

Figure 11: Key-Fob Video Camera Screen Shot ........................................................... 10

Figure 12: Ground Station GUI ...................................................................................... 10

Figure 13: Payload Post-Flight ...................................................................................... 11

Figure 14: Google Flight Path Overlay .......................................................................... 11

Figure 15: Probability Density and Cumulative Density of Rocket Apogee ................... 12

Figure 16: Schools Influenced by Tarleton's Educational Outreach Program ............... 13


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List of Tables

Table 1: Project Design Summary ................................................................................... 1

Table 2: Flight Summary Chart ....................................................................................... 2

Table 3: Flight Stage Simulations .................................................................................... 3

Table 4: Simulated and Actual Launch Conditions .......................................................... 4

Table 6: Budget Overview ............................................................................................. 14

Table 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.

Table 1: Project Design Summary

Summary

Team Name Tarleton Aeronautical Team Motor Used Cesaroni L1720 WT-P Payload Science Mission Directorate Rocket Height (Length) 97.5 inches (8 feet 1.5 inches) Rocket Diameter 5.525 inches Rocket Mass Mass without Motor 30.3125 pounds Wet Mass 37.6875 pounds Dry Mass 33.80625 pounds Altitude Reached (Scoring Altimeter) 5,311 feet

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 Actual

Off-Rail

Time 0.280s .29s

Velocity 77.839fps 78fps

Altitude 10ft 10ft

Drogue Deployment

Time 18.151s 18.7s

Velocity 2.041fps 17fps

Altitude 5260ft 5388ft

Main Deployment

Time 89.233s 73.2s

Velocity 63.957fps 90.78fps

Altitude 700ft 695ft

Impact

Time 147.930s 107.65s

Velocity 10.241fps 15.38fps

Altitude 0ft 0ft

Table 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

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

scoring rubric.


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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 10.241fps 0ft 973ft Table 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


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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 Actual

Temperature 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.

Figure 4: Stratologger Altimeter Data


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Vehicle Analysis Summary

Vehicle 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

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

63 degrees.


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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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-10

0

10

20

30

8:42:00 AM 8:42:43 AM 8:43:26 AM 8:44:10 AM 8:44:53 AM 8:45:36 AM 8:46:19 AM

W/m

2

Ultraviolet Radiation

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

2324252627282930

8:42:00 AM 8:42:43 AM 8:43:26 AM 8:44:10 AM 8:44:53 AM 8:45:36 AM 8:46:19 AM

inH

g

Pressure


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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.

Figure 9: Frequency of Data Collection

20

30

40

8:42:00 AM 8:42:43 AM 8:43:26 AM 8:44:10 AM 8:44:53 AM 8:45:36 AM 8:46:19 AM

% R

HHumidity

0

500

1000

8:42:00 AM 8:42:43 AM 8:43:26 AM 8:44:10 AM 8:44:53 AM 8:45:36 AM 8:46:19 AM

W/m

2

Solar Irradiance

84

86

88

90

8:42:00 AM 8:42:43 AM 8:43:26 AM 8:44:10 AM 8:44:53 AM 8:45:36 AM 8:46:19 AM

Fah

ren

he

it

Temperature

Figure 8: Atmospheric Data


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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.

Figure 10: ARTCOS Images


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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.

Figure 12: Ground Station GUI


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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.

Figure 14: Google Flight Path Overlay


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Science Value The 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 Analysis All 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.

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


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Atmospheric Modeling Preliminary 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.

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 Presentation

o Problem Solving Lesson

o 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. Cost

Testing/Prototyping $13,972.23 Outreach $3,669.77 Final Build $4,007.21 Travel to Competition $8,200.00 Total $29,849.21

Table 5: Budget Overview

On Pad Cost Est. Cost

Recovery $951.47

Structure/Propulsion $1,189.61

Payload $1,866.13 On 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

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


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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.

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