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UNIVERSITY OF MINNESOTA TWIN CITIES
2012 – 2013 University Student Launch Initiative Post Launch Assessment Review
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2012-2013 University of Minnesota Team
Mark A.
Senior, Aerospace Engineering and Mechanics, Team Lead
Aboto001@umn.edu
Amir E.
Senior, Aerospace Engineering and Mechanics, Financial Officer
Devin V.
Senior, Aerospace Engineering and Mechanics, Structural Lead
Tim C.
Junior, Aerospace Engineering and Mechanics, Structural Team
Nathan K.
Senior, Aerospace Engineering and Mechanics, Recovery Lead
Greg Z.
Freshman, Mechanical Engineering, Safety Officer
Vishnuu M.
Junior, Aerospace Engineering and Mechanics, Payload Lead
Hannah W.
Junior, Aerospace Engineering and Mechanics, Payload Team
Table of Contents
1 SUMMARY OF FLIGHT 4
1.1 Team Summary 4
1.2 Launch Vehicle Summary 4
1.3 Payload Summary 4
2 RESULTS 7
2.1 April 7th Crash 8
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2.2 Analysis of components 8
2.3 Summary of damage 9
3 ANALYSIS 9
3.1 Elimintaion of causes 9
3.2 Determined Failure modes 10
3.3 Root cause 10
4 CONCLUSION 11
4.1 Mitigation of future failure 11
4.2 Addendum for verification proceddure 11
4.3 Lessons Learned 12
4.5 Summary of Overall Experience 13
4.6 Education Engagment summary 13
4.7 Budget Summary 14
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1 Summary of Flight
1.1 Team Summary
Name: ‘Gopher Throttle Up’ Rocketry
School: University of Minnesota
107 Akerman Hall
110 Union St SE
Minneapolis, MN 55455
Chapter 1 Team Official: Dr. William Garrard
Team Mentor: Gary Stroick (TRA 5440 – Level 3 Certified)
1.2 Launch Vehicle Summary
Overall Length (in):
111 inches
Diameter: 6 inches Gross Weight: 524.8 oz Motor Selection: L1720 – WT Total Impulse: 3696 N-sec Recovery: Duel Deploy, ARRD
1.3 Payload Summary
Our scientific payload is a remote controlled rover Inquisitivity, based on the concept of
an extra-terrestrial space exploration vehicle and also on that of a rescue bot.
specifically, the payload is a ground deployed, 2 wheeled rover with onboard camera
and antenna. Once deployed, the rover transmits a live video feed to a ground station
where the rover can also receive commands to maneuver and investigate the terrain.
Overall Length (in):
14 inches
Diameter: 5.5 inches Gross Weight: 54 oz Power Plant: 2, 6.0 volt Servos Power Supply: NiMH 5 Cell, 6.0 volt
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Figure 1. Side and exploded view of vehicle as launched with components. The payload was not included for the test
launch.
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Figure 2. Diagram of launch trajectory with significant flight events observed.
A single event was reported at
after the craft had rolled over
apogee. Smoke could be seen
exiting the vehicle, but the
drogue chute did not deploy
Vehicle lifts off on
L1720 - WT
No further flight events
could be determined
from ground
observations
Ground impact
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Figure 3. Map of launch and crash site. Fortunately, the crash occurred in an empty
corn field where no persons were harmed or injured.
2 Results
Figure 4. Layout of wreckage components recovered. A reference of for this image can
be found in the back of this report.
500 m
Launch Site
Crash site
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2.1 April 7th Crash
During the first test launch of the vehicle, a malfunction within the drogue
deployment system prevented the drogue chute from deploying at apogee. Since the
main deployment was coupled with the drogue deployment, the vehicle did not
successful deploy any parachute upon reaching apogee.
The vehicle impacted the ground with sufficient speed to destroy all but a single
component from the flight. Because we were unable to recover any data from the
altimeters, the only results from the flight were eye witness accounts from the launch
team.
Figure 5. ARRD after being recovered from crash. The damage to it is superficial.
The ARRD design may make a good candidate for a black box.
2.2 Analysis of components
All structural components in the airframe performed as designed from launch to
apogee. At apogee when the ejection sequence was supposed to initiate, there was a
system failure which is unknown as to the origin due to the destruction of the altimeters.
With the best knowledge and observations available from video footage and
observations it is known at least one ejection charge deployed. However, because the
E-matches used to ignite the black powder during flight go off due to pressure as well as
electrical charge, the impact force which flattened the canisters could have also set off
the second charge making it impossible to determine the at what point that canister
fired.
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Figure 11. The canisters from the vehicle were found crushed after the crash,
making it impossible to determine which on fired at apogee.
2.3 Summary of damage
The damage inflicted upon the airframe was catastrophic. The airframe is
completely destroyed and all components in the crash, with the exception of the ARRD,
are not flight capable. For future flights, a completely new aircraft must be assembled.
Analysis will continue to find the cause of the failed separation, and shall be verified
though a final ground test that accurately simulates the final configuration on launch.
The payload was not aboard during the test flight, and a mass simulator was used
instead.
3 Analysis
3.1 Elimintaion of causes
From observation, it is quite clear that the drogue parachute failed to deploy from
the vehicle. The team began an investigation by identifying the key systems involved
with the deploying the parachute as well as systems who’s failure could have resulted in
a decrease in the pressure needed to deploy the drogue chute.
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3.2 Determined Failure modes
The systems built into the vehicle that can contribute to a separation failure are
summarized in the table below.
Table 1. Summary of components that could have contributed to a the failure
3.3 Root cause
At this time no single root cause for the failure of separation can be ascertained.
One charge was visually confirmed to fire so the cause for the lack of separation was
most likely a mechanical combination of several subsystems.
However, the systems that could have contributed to this have been identified are
ground testable, assuming the vehicle can be rebuilt accurately to its configuration
during the test flight.
One canister
fires
Separation Fails
System Significance Effect
Rail Buttons Does not provide an air tight seal
Gas form ejection can leak
Coupler Seal 1mm gap was observed between two tubes prior to launch
Vehicle is given a distance that could “jam” the components together
Black powder amount Was not test at final mass, only calibrated
Insufficient amount
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4 Conclusion
4.1 Mitigation of future failure
The ground tests conducted to verify that the recovery system was ready for
integration had been conducted with a sub assembled vehicle. This was done to meet
testing deadlines while other portions of the vehicle were under construction.
Although this tradecraft is recognized in high powered rocketry, the dynamics of
the chosen drogue eject system are highly experimental, and even though procedure for
adding the additional amount of black powder to calibrate for a fully weighted vehicle
was applied, its scaling may not be identical for the requirements of the experimental
channel design.
This, and the absence of the retractable rail buttons, compromised to accuracy of
the test, and more investigation must be placed in black powder amount if this
configuration is chosen again.
Lastly, the ground tests did not account for the compressive effects that occur
during launch. Future tests for all vehicles shall account for this factor. Thus, improper
management of the project has contributed to the failure and inability of the team to
meet deadlines.
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4.2 Addendum for verification proceddure
Since initial ground testing confirmed the functionality of all onboard systems, the
verification procedure must be modified to include ground testing of a fully configured
vehicle. Simply put, initial ground testing must be followed up with a final ground test
immediately prior to any flight to the upmost accuracy of real flight conditions.
This is the only method to verify vehicle funcitonality in the presence of complex
and experimental systems, and ensure mission confidence.
4.3 Lessons Learned
4.4
A table of shortcomings and mitigation procedures for next year can be
found below
Shortcoming Mitigation Plan
Insufficient testing of exerimental design
Increase the amount and varity of ground tests. Account for all variebles, and construct test articles sooner
Lack of funds till late january Begin fundraising this summer and seek additional donors
Difficulty finding appropriate launch windows in later winter
Finish test vehicle early to take advantage of clearer early winter weather
Fluxating team composition compromissed quality of work
Build a larger team to reduce the hazards of lossing a team member
Ineffectiveness of systems integration meathods slowed progress
Steamline process to build and verify test components, reduce dependency of systems on eachother to start testing sooner. Form dedicated systems integration team
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4.5 Summary of Overall Experience
In many regards, the 2012 -2013 USLI competition was the first for the Univeristy
of Minnesota. This year brought new energy to project but without the guidence needed
to overcome new hurdles that had not been anticipated in the previous year. Many
ideas from the start of the project had to be removed due to their complexity, but the
process helped the team focus on their goals.
The team overcame many financial, technical, and personal crises to make it
where they did. Although the crash may seem to marginalize the accomplishments for
the year, the truth remains that the team has improved since last year, and is poised to
continue to improve.
Overall, the experience has enlighted everyone on the complexities and details
within various engineering disciplines. It has given us the chance to pursue our own
ideas through an emprical approach that solves problems and inspires others. We have
learned how to over come failure, and how to prevent failure in the future.
4.6 Education Engagment summary
We have already begun creating new networks between the University and the
local community. We plan on doing a variety of outreach projects at local area schools.
We also plan on gaining additional community and University support through these
outreach projects. We will be working with the Center for Compact and Efficient Fluid
Power (CCEFP), North Star STEM Alliance, and the Minnesota Space Grant
Consortium (MnSGC).
Events: - Straw rockets - Plastic cup air cannons - CD Mini Hovercrafts - Water hydraulic pet racers - Air pneumatic circuit kit - Water hydraulic excavator demonstrator
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- 1 foot tall rubber based, air propelled rocket - Large Hovercraft demonstrations - Angular Acceleration demonstrations - Parachute launchers - 4 inch water propelled plastic rockets
4.7 Budget Summary
This year, the team was able to secure $8,150 in funding. Approximately $1,600
was lost in all the destroyed components in our full scale rocket, as well as $300 from
our first half-scale test rocket, and another $500 was spent but not lost on our second
half-scale test rocket (more because the leftover materials from previous years were
used up in the first test rocket). Just over $450 was spent on necessary tools as well as
$300 on extra materials used in experimental tubing techniques, preliminary designs,
and currently shelved but usable left-over materials. We also have two leftover L1720-
WT motors valued at around $200 each that will be used in future projects. The funding
that went towards our payload was just over $1,200 and is reusable for following
projects as it was not involved in the crash.
Because of the catastrophic crash, we chose to send four members instead of
seven down to Alabama to participate in the Rocket Fair and other USLI events. This
choice cut our expenses from $1800 down to $700, because we were able to use the
smaller vehicle of a team member rather than renting a van, as well as only requiring
one hotel room.
Our team currently has $2600 leftover that will go towards projects planned for
this summer as well as help kick start next year’s USLI project.
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