auburn university student launch · 2019-04-26 · auburn university student launch 5 2 vehicle...

AUBURN UNIVERSITY STUDENT LAUNCH

PROJECT NOVA II

211 Davis Hall

AUBURN, AL 36849

PLAR

April 29, 2019

AUBURN UNIVERSITY STUDENT LAUNCH 2

Contents

Contents ....................................................................................................................................2

List of Tables ..................................................................................................................................3

List of Figures .................................................................................................................................3

1 Vehicle Dimensions and Motor ...............................................................................4

2 Vehicle Summary .....................................................................................................5

2.1 Airframe..............................................................................................................5

Airframe Summary ....................................................................................................5

Airframe Analysis and Lessons Learned ...................................................................5

2.2 Recovery .............................................................................................................6

Recovery Summary ....................................................................................................6

Recovery Analysis and Lessons Learned ..................................................................6

2.3 Embedded Systems .............................................................................................7

Embedded Systems Summary ...................................................................................7

Embedded Systems Analysis and Lessons Learned ..................................................7

3 Payload ......................................................................................................................8

3.1 Payload Summary ...............................................................................................8

3.2 Payload Data Analysis ........................................................................................8

4 Competition Flight Results......................................................................................9

4.1 Flight Analysis ....................................................................................................9

5 STEM Engagement ................................................................................................10

6 The Year in Review ................................................................................................12


6.1 Overall Experience ...........................................................................................12

6.2 Scientific Value and Visual Data Observed .....................................................13

7 Final Budget ...........................................................................................................14

List of Tables

Table 1: Vehicle Dimensions .......................................................................................................... 4

Table 2: Flight Data ...................................................................................................................... 10

List of Figures

Figure 1: Members of the 2019 Auburn Team with the rocket on the launch rail at competition on

April 6th 2019. ................................................................................................................................. 4

Figure 2: Rover on launch day, having travelled just far enough out of the tube to extend its sample

arm before getting stuck.................................................................................................................. 9

Figure 2: STEM Day at Sanford Middle School .......................................................................... 11

Figure 3: Grand Engineering Challenge at Auburn University .................................................... 11

Figure 5: Rocket Week at Drake Middle School .......................................................................... 12

https://tigermailauburn-my.sharepoint.com/personal/bac0037_tigermail_auburn_edu/Documents/USLI%20Team%20Leads%202019-2020/PLAR%20(2019)/PLAR%20report.docx#_Toc7170012






1 Vehicle Dimensions and Motor

This year, Auburn University’s Project Nova II built a rocket and rover to fulfill the requirements

for the NASA USLI competition. The rocket, dubbed Paradise, was a solid carbon fiber airframe

with a three-part recovery system. The rover, Trouble, was propelled with a pair of tracks and had

an extensible arm to collect a soil sample. The project launched, recovered and deployed the rover

successfully at the competition on April 6th, 2019.

Table 1 gives the basic details of the launch vehicle. More information regarding the launch vehicle

can be found in Section 2 of this report.

Paradise

Total Length 123.8 inches

Launch Day Weight 49.5 lbs.

Diameter (Inner/Outer) 6/6.125 inches

Motor Selection Aerotech L1420R

Table 1: Vehicle Dimensions

Figure 1: Members of the 2019 Auburn Team with the rocket on the

launch rail at competition on April 6th, 2019.


2 Vehicle Summary

2.1 Airframe

Airframe Summary

The primary design philosophy of the team’s vehicle body structure was to create a rocket that had

the space necessary for all payloads and recovery systems while minimizing weight. The team

found that an inner rocket diameter of 6” gave the necessary space for all of the team’s necessary

components and a wall thickness of .125” yielded the required strength. The team reduced weight

by utilizing woven carbon-fiber composite and fiberglass for the structures that were manufactured

in-house. Three separate carbon fiber tubes for the booster, main parachute, and drogue sections

were coupled together to manufacture a rocket that met both strength and safety requirements.

These were used as they were the lightest material while maintaining necessary strength. For the

rover section, it was necessary to use fiberglass for the body tube. This was done because carbon

fiber composite blocks radio signals to the rover. Fiberglass however, while heavier than the

carbon fiber, does allow radio signals while maintaining the necessary strength. The nose cone

was a tangent ogive design from an offsite manufacturer. Finally, the fins were unconventionally

small, but were designed in simulation software to produce enough stability required for flight,

which was proven in both the sub-scale and full-scale flights.

Airframe Analysis and Lessons Learned

The body frame worked as desired. One area for improvement, however, would be to cut more

accurate slots for the drag plates and nosecone interface to reduce holes in the body frame and

produce less drag. This would help us perform more accurately compared to the simulation. Along

the same lines, cutting more level body tubes would produce similar results. Different bolts were

used on different parts of the airframe. Standardizing bolts used on the rocket between sub-teams

will greatly benefit the rigidity of the rocket as the wrong sized bolt being placed in the incorrect

hole will be less likely to happen. When these did happen, the bolts enlarged the holes, making the

bolted area looser and more prone to wobble. Finally, while the fins did an adequate job for the


launch, the team noticed after burnout, the airframe started to corkscrew on the way up. The team

determined that this was most likely due to the rotating mass of the rover being dislodged from its

fixed position. Fins that are larger would have reduced the effect of the rotating rover inside the

rocket and produced and more stable and straight flight. Using these new lessons, the team will be

able to update and upgrade our designs for the future.

2.2 Recovery

Recovery Summary

The Recovery System consisted of a dual-stage, dual-system. The design had three events that

occurred during descent. The first was a redundant set of black powder charges that went off one

second after apogee. This event separated the middle section of the rocket and allowed for the

drogue parachute to deploy. This let the rocket come down in two pieces with both attached to the

drogue shock cord. The next event was to occur at 700 ft where the mechanical release in the

nosecone was supposed to activate and allowed for the nosecone to separate from the rest of the

rocket body and fall under its own parachute. This was to allow for the Payload section to be open

upon landing. The third event occurred at 500 ft, where another set of redundant black powder

charges were used to separate the lower section so that the main parachute was deployed.

Redundancy for all sections was achieved through two altimeters being used per section.

Recovery Analysis and Lessons Learned

The recovery portion of the rocket was mostly successful with all mission critical components

performing as expected. The only flaw to the flight was that the nosecone did not separate during

descent as it was supposed to. Luckily this was not a mission critical event and the rocket still

descended safely. Post flight analysis of the vehicle revealed that the nosecone gear assembly did

not fully retract which caused it to stay attached to the rocket rather than separating at 700 ft. The

cause of this malfunction was from the epoxy used to hold the servos in place yielding when the

servo motor attempted to rotate. This caused the motor to rotate away from the gear rather than

turning the gear fully. Other than this, the rest of the recovery system worked as designed. The

drogue chute was deployed at apogee and the main chute was deployed at 500 ft. Numerical

analysis of the recovery portion of the flight is presented in Section 4.1.


2.3 Embedded Systems

Embedded Systems Summary

The Embedded Braking System (EBS) was designed to control the apogee of the vehicle by

deploying two 3D printed plates embedded inside the booster coupler. EBS utilized an

accelerometer (MPU-9250) and altimeter (MPL-3115A2) which were used to calculate the apogee

of the vehicle, which it fed into a PID controller to estimate how much the drag plates must be

deployed to bring the apogee down to the target altitude. A MicroSD breakout board was used to

write data to text files on an SD card. Lastly, a planetary gear motor with an encoder was used to

drive the drag plates. An STM32F103C8T6 was used in place of an Arduino Uno, which the team

has used previously. The advantage of the STM32 board over the Uno is it contains more memory

and greater computational power, while still taking advantage of Arduino libraries written for all

breakout boards. EBS was powered with two 9V batteries, and all electronics were soldered to two

Adafruit Perma-Proto half-sized breadboards. Most of the structural parts were printed with Onyx,

with the exception of two aluminum rods used to hold the drag plates in place.

Embedded Systems Analysis and Lessons Learned

Unfortunately, EBS could not be flown actively for competition this year, due to electrical issues

on the last certification flight. The team had designed a custom passive circuit to interface the

microcontroller with the DC motor, which would allow the microcontroller to drive the motor

using 9 volts with 5-volt logic. However, there was a short in the circuit, which the team was never

able to uncover. While the system was not ready in time for competition, the team had success

with earlier subscale launches, flying the STM32 microcontroller with all of the breakout boards

connected. The team was able to gather data successfully and demonstrate that this configuration

is viable. In addition, the team has gained experience with the new microcontroller which can be

used to further refine the current system for future years.


3 Payload

3.1 Payload Summary

This year, the Auburn University team selected the deployable soil sample rover for their

payload. The rover was designed, and 3D printed out of PLA to move on a pair of treads, collect

a soil sample using a belt with buckets, and deposit said soil into a sample container. A weight

driven Rover Orientation System was implemented to unlock after separation of the nosecone to

ensure proper orientation and deployment of the rover after arrival on the ground.

3.2 Payload Data Analysis

The body tube surrounding the rover compartment was designed out of fiberglass to ensure proper

communication between the deployment control panel with the team and the rover inside the

compartment. This proved effective in allowing communication with the rover on launch day,

however, direct line of sight was required to activate the rover.

The team had taken steps for all of the rover components to be completed in the 3D printing lab

before our demonstration launch, however, unanticipated backups in the lab (and research being

allowed to skip over the queue) prevented the completion of the soil collection arm bucket system.

This led to the rover being unable to perform the essential task necessary to fulfill its purpose.

Due to an issue with the nosecone deployment system, the rover was not able to deploy under its

own power. This was due to the nosecone blocking its only possible exit point. After removing the

nosecone manually, the rover was assessed and activated despite an ineligibility to acquire any

points. The Rover Orientation System corrected the rover’s orientation successfully. The rover

was able to exit the launch vehicle, but after 1 inch of traversing the soil, one of the drive tracks

derailed, rendering the rover immobile.

The soil collection system worked as well as had been expected with the lack of collection buckets.

After the drive tracks stopped spinning, the soil collection arm extended and the DC motor that

was supposed to turn the soil collection belt activated. After the DC motor was finished turning,

the soil collection arm retracted to its flight position and the rover finished its mission.


Figure 2: Rover on launch day, having travelled just far enough out of the tube to extend its sample arm

before getting stuck.

4 Competition Flight Results

4.1 Flight Analysis

The primary altimeter used was a PerfectFlite StratologgerCF and it recorded a maximum altitude

of 4,994 ft. This was higher than our projected altitude, of 4,700 ft, because of two reasons. The

paint added to increase weight was not enough and the altitude prediction was made when the

Altitude Control System was expected to be functional for the flight.

Predicted Actual % Error

Maximum Ascent

Velocity 618 ft/s 565 ft/s 8.57%

Apogee 4700 ft 4994 ft 6.25 %


Descent Rate of

Nosecone 21.44 ft/sec N/A N/A

Descent Rate of Body 13.37 ft/sec 17.41 ft/s 30.22 %

Descent Time of

Nosecone 75.92 sec N/A N/A

Descent Time of

Body 82.83 sec 71.40 sec 13.80 %

Kinetic Energy of

Nosecone 49.96 ft-lb N/A N/A

Kinetic Energy of

Largest Body Piece 49.96 ft-lb 3,788.85 ft-lb 7483.77 %

Drift of Nosecone

(10mph) 1113.74 ft N/A N/A

Drift of Body

(10mph) 1215.12 ft 1654.87 ft 36.19 %

Table 2: Flight Data

The level of inaccuracy as well as the N/A’s in Table 2 are due to the nosecone not separating

during descent. This caused an increase descent velocity and mass values for the body and resulted

in a high kinetic energy value. The team chose to use a 10 mph estimation of the launch day wind

by using weather data from a local nearby station. The drift discrepancy is due to apogee not being

directly above launch pad and winds higher up in the atmosphere being greater than those on the

ground.

5 STEM Engagement

Over the course of this year, Auburn’s USLI team was able to engage the community through

several different outreach events. The team began by recruiting new members, through on campus

events such as Organization Week and Aeropalooza. In addition to this, the team was able to


engage young students in several different local elementary schools to get them excited about

Rocketry, Aerospace, and Engineering. For our outreach events, we used different props and

interactive displays to educate the students about different Aerospace concepts. The first display

was a demonstration of the Bernoulli Principle. We had a small fan, which was able to levitate a

small ping pong ball. We encouraged the students to attempt to get the ball to float themselves,

and used this to teach them about balancing forces, and air pressure. Another interactive display

we used was a straw rocket launcher. At this station, students were able to use straws and

playdough to create their own ‘rocket’, and then were able to launch it using a weighted rod

creating air pressure. The students loved this display, and discussed with one another the different

variables in what makes a rocket go far. Straw length, mass, and drop height were all different

variables the students postulated over as to what makes the perfect straw rocket. Students also

loved getting to see our subscale rocket. They were amazed at how big it was, and even more

amazed when they found out how big our full scale was.

Our largest event of the year was also a huge success. Rocket Week, a weeklong event held at a

local elementary school, where students design, build, and launch their own model rockets, is our

most effective way of reaching out to younger students and getting them excited about rocketry.

On Monday, we teach the students about the basics of rocket design, and about what NASA and

other companies have contributed to the industry. On Tuesday and Wednesday, we help the

students build their rockets, giving them freedom about things such as fin orientation, and allow

them to decorate and name their rockets. The students love having these freedoms and making the

Figure 3: STEM Day at Sanford Middle

School Figure 4: Grand Engineering Challenge at

Auburn University


rockets their own. On Thursday and Friday, we launch their rockets. We put each student’s rocket

on the launch pad and allow them to push the launch button once at a safe distance and ensuring

the field is clear. This is an incredible opportunity to get students excited about rocketry, and

something we will continue to do in the future.

6 The Year in Review

6.1 Overall Experience

Despite a few small setbacks, the team considered this year’s performance a success. The team

continued to improve from previous years and experienced no major problems with the main

recovery or structural elements. However, the payload and embedded systems onboard the rocket

experienced problems that prevented the mission from being a complete success. The rocket

experienced a slight corkscrew effect during the launch, which the team believes could be

mitigated by having larger fins in the future. The payload, a soil-collecting rover called “Trouble,”

was not equipped with its soil collection track due to 3D printing setbacks. This prevented the

rover from fulfilling its main purpose. Additionally, the rover’s two treads for movement slipped

off their tracks, so the rover was unable to leave the rocket body. The nosecone deployment system

also failed to operate correctly; the epoxy did not hold, allowing the servo to disconnect from the

gears. This prevented the nosecone recovery system from deploying during flight. Last, the drag

plates and related embedded systems did not fly in our competition launch due to an electrical

problem that the team was unable to solve in time. All of these small errors taught the value of

Figure 5: Rocket Week at Drake Middle School


time management and adequate testing. The team plans to prevent these problems in the future by

increasing testing and requiring all aspects of the rocket to be flight-ready well before launches.

This year’s improvements far outweigh the problems experienced. The base design of the rocket

is similar to previous years and was again proven reliable, confirming the team’s ability to

construct an effective rocket. Although the weather set back the launch timeline, in general the

team was ready ahead of previous years’ schedules, and our time management should continue to

improve in the coming years. The recovery team continued its history of success while innovating

new systems that reduce the need for black powder separations. The altitude control system,

though it did not fly, can be integrated into next year’s rocket once its electrical problem is solved.

Next year, the team hopes to continue building consistent rockets for competition while fabricating

a secondary full scale rocket for new or inexperienced team members to learn the fundamentals of

high powered, amateur rocketry while also gaining significant amounts technical experience. Our

safety team will work to maintain the team’s zero incident track record. The outreach team hopes

to continue running an exceptional social media page while maintaining relationships with local

schools and community groups that sustain the educational outreach efforts. Overall, the team is

proud of this year’s performance, and looks forward to improving and facing new challenges next

year.

6.2 Scientific Value and Visual Data Observed

Overall, the team considered this launch successful. Both the drogue and main parachutes deployed

correctly, and the rocket was recovered with no damage. However, a few slight difficulties were

observed during the launch and rover deployment process.

After motor burnout, the rocket started to corkscrew slightly. This did not occur during the earlier

flights. This was probably due to a faulty locking mechanism in the rover bay, which caused the

rover orientation system to spin during flight. This shift of weight could have caused the spinning

effect that the team observed during our competition flight. The team also hypothesized that larger

fins may mitigate this effect.

Though all essential recovery systems functioned correctly, the nosecone tabs failed to retract,

preventing the rover from leaving the rocket body. This was caused by the failure of the epoxy


used to fix the servo in place. This allowed the servo to twist away from the gears and kept the

tabs from fully moving, preventing a smooth separation of the nosecone from the rocket body.

After the nosecone was manually removed from the rocket, the rover attempted to move out of the

rocket. During this process, one side of the treads fell completely off the tracks. This prevented

the rover from fully traveling outside the rocket. This could have been caused by having too little

tension in the treads. The other side of the track slipped inward towards the rover body, which also

inhibited forward motion. The motor, however, continued running smoothly and adding tension to

the treads should correct this problem for the future. The failure of the rover’s treads to adequately

move the rover revealed a crucial design consideration for future payload designs: the treads must

fit on the rover's wheels while also providing enough tension to prevent slippage.

7 Final Budget

As repeated from the Flight Readiness Review Report, here is the final summary for the team

expenses. The team has not yet decided what to do with the budget surplus, but has several

potential plans for improving the tools or facilities available to the team.

Funding Source Donation

Alabama Space Grant Consortium $14,000

Dynetics $2,500

The Boeing Company $2,500

P3 Technologies $2,000

Barbara A Howell $25

Funding Subtotal $21,025

Subteam Expense

Vehicle $2,527

Recovery $473


Rover $533.31

Altitude Control $467.44

Education/ Outreach $3,843

Lab Supplies and Launch Fees $938.10

Promotional materials $500.00

Hotel $3,404.08

Expense Total $12,685.33

Budget Balance +$8,339.68