RockSat 2010 Final Report

Liquid Fuel Slosh during the Flight of a Sounding Rocket:

SLOSHSAT

SMALL Picture of team and/or RockSat payload

Sage Andorka

Dan Welsh

Zach Sears

Maurice Woods III

Motoaki Honda

Dr. Robert Walch

University of Northern Colorado

7 May 2010

1.0 Mission Statement

The primary mission of the SLOSHSAT experiment is to determine the validity of our analytical model. This model begins by assuming that our fluid is idea, in other words there is no energy lost due to heat transfer or viscosity. With these assumptions, along with the use of Euler’s equation and our continuity equation, we arrive at our final model which acts as a harmonic oscillator. These oscillations are what influence the motion of the liquid container. In order to validate our hypothesis we will measure the accelerations of a fluid filled container onboard a sounding rocket. Comparison of experimental data and mathematical modeling will allow us to check the accuracy of the analytical model.

We hypothesize that our mathematical model will accurately describe the motion of the liquid filled container. The SLOSHSAT experiment is designed to collect vertical axis accelerometer data continuously during a two-stage parabolic flight path. It is expected that the model will accurately represent the behavior of the canister-fluid system. Comparison of the data from the canisters movement to the control data will reveal if the system behaves in the manner that the model predicts. The success of the project will depend on whether the model reasonably represents the behavior seen in our data.

2.0- 3.0 Mission Requirements and Description and Payload Design

Mass

The entire canister, complete with payloads, cannot mass more than 9.07 kg. Our particular canister is being shared by UNCo and CSU. We decided to split the mass in half so each university gets 4.5 kg. The following chart is the mass of each hardware item used in the payload.

The total mass of our payload is 0.7099 Kg, 1/5 of the total mass for half the canister.

Part / Mass (kg)
device disc / 0.361
2 battery / 0.092
outer cylinder / 0.0652
inner cylinder / 0.0157
Galden 110 / 0.176kg

Physical Envelope

The canister that houses the payloads in the payload section of the rocket is 24.0 cm tall. This allowed us 12.0 cm of vertical space. The tallest part of the payload is the canister which will stand at 9.0 cm. This is 3 cm shorter than the maximum allotted height for our half. The diameter of the payload canister is 23.6 cm.

Center of Gravity

Due to time constraints while at WFF, some very crucial design requirements have to be completed prior to delivery to WFF. One requirement involves the center of gravity. The center of the payload had to be contained in a one inch cube directly in the center of the payload. When Sounding Rockets are launched, they spin with a very high frequency. If the rocket is not perfectly balanced, the rocket will wobble and the mission will be a failure. To reduce the amount of time spent on balancing the rocket by WFF engineers, all payloads have to have the center of gravity within the 1 inch cube of the payload section.

The Liquid

The liquid used in this experiment was chosen with careful considerations. WFF is very concerned about launching water on the rocket. If the liquid container were to break, then the mission would be a failure. We are launching with 20 other payloads. If our liquid were to spill in the payload section, there could be damage done to other payloads resulting in failure of their missions. As a result, the containment subsystem was designed to be fail-safe, and the liquid was carefully chosen to be as safe to all payload systems as possible. Galden 110 was donated to our project by Solvey Solexis, the makers of Galden. This product is used to cool large servers. The liquid is a nonreactive fluid that is safe for electrical devices. To test this, we dunked an operating cell phone in a sample. The cell phone continued to work and would ring when called inside the sample. The only special handling requirement for the Galden 110 is that the external environment cannot get above 110° Celsius. Because the payload section of the rocket is pressurized, the internal environment is not expected to fluctuate more than ± 25° from standard ambient (27° Celsius) temperature.

Liquid Containment Subsystem

The goal of the experiment is to determine the viability of our mathematical model. A cylindrical container partially filled with Galden 110 will be constrained by an outer container so that it may only move along the vertical axis throughout the duration of the flight. The acceleration of the liquid container will be recorded as it moves within the outer container. This data will be later used for analysis on the ground. We expect that the actual flight data will match the predictions of our mathematical model. Figure 1 shows an exploded view of the experimental apparatus; Figure 2 is a close up prototype image of the containment system.

Figure 1: Exploded Experimental Apparatus

Figure 2: Full Canister Prototype

Electrical and Data Subsystem

The power will be supplied by two 9V NiCd batteries. This computer board consists of an AVR micro controller, flash storage, a temperature sensor, an x- and y-axis accelerometer, and the z-axis accelerometer. As a safety requirement by WFF, there are two shorts in the electrical system. The other short is the G-switch. This switch is will be closed when the payload is subjected to an extreme G-force, like those experienced at launch. This switch is the final step in allowing power to the payload. The first short is for the Remove Before Flight Pin which is a short in power that will be connected by WFF engineers before launch. This is to prevent any accidental activation of payloads while the WFF engineers are performing the required tests on the payload section of the rocket. It is also a very important safety mechanism to reduce accidental sparks from payloads that could ignite the engines while finalizing construction of the rocket. Figure 3 is a functional block diagram explaining the connection between the electrical and data subsystems.

Figure 3: Block Diagram of Electronics

Concept of Operations

What the payload will do during the flight is very simple. When the payload is given to Wallops for final rocket integration, the Remove Before Flight Pin will be connected to all the others in the payload section. Prior to launch, Wallops engineers will short the Remove Before Flight Pin allowing power to the G-Switch. At launch, the G-switch will be activated due to the sudden increase of G-forces. When the G-switch is enabled data collection will begin. Upon activation the data logger will collect data until the batteries die or are disconnected. The following flow chart shows the overviews of the Concept of Operations.

Figure 4: Concept of Operation flow chart

Cost

The money for the SLOSHSAT experiment will be provided in part by a grant from COSGC, NHS Research Grant, and the UNC travel funds. A big push in our experiment is to be as conservative with our cost as much as possible. We did recycle the Electrical and Data subsystem hardware and AVR code from the RockON! workshop that was attended by students from UNCo the summer before.

Item / Cost
RockSAT Payload Slot / $7000.00
(donated by COSGC)
1-Axis Low-Range Accelerometer / $16.00
(included on RockON! board)
2-Axis Low-Range Accelerometer / $23.00
(included on RockON! board)
1-Axis High-Range Accelerometer / $12.00
(included on RockON! board)
2-Axis High-Range Accelerometer / $16.00
(included on RockON! board)
Polycarbonate Tubing / inside $05.00 outside $20.00
.1L Galden 110 / $150
Donation from Solvey Solexis
Travel for two to Wallops / $2,000.00
Total / $9,242.00 ($7,217 donated)

4.0 Student Involvement

Sage Andorka- Physics and Secondary Education

She is the Project Manager. Her responsibilities were handling reports, overseeing all testing and construction. Any design changes were to be approved by her.

Dan Welsh- Meteorology

His responsibility was to construct and test the liquid containment system, and the physical envelope that would contain the hardware. He was the acting Project Manager when Sage was student teaching.

Zack Sears- Physics Engineering

His job was to formalize the analytical model (math). He will be the lead analytical specialist when the flight data is obtained.

Maurice Woods III- Physics Astronomy

His job was to ensure the flight code and flight electronics were functioning properly.

Motoaki Honda- Physics Astronomy

His job was to aid Maurice in code and electronic maintenance.

5.0  Testing Results (1 – 2 page(s))

Stress test of liquid tank materials was performed to ensure that the liquid tank and outer container would be able to withstand the 20G environment. The test lasted for 30 seconds. We found the test confirmed that the canisters could withstand 20G.

Accelerometer integration into tank end cap test was to ensure that the new wires were connected to the accelerometer were properly functioning. We powered the accelerometer for 5 min. Test for confirmation that the accelerometer still worked and the wires could carry the voltage required.

Prototype of payload was constructed to work out any kinks in design before working with the real payload. It incorporated a prototype of liquid containment system and mock AVR.

Center of Gravity test was performed by balancing payload on a pipe that was half an inch in diameter. The center of the payload was lined up with the center of the pipe and left to balance. The payload did not fall or lean to one side confirming that the payload is centered within one half inch of the center of the payload.

Environmental testing was done on the inner canister after noticing that the original inner canister had leaked. A new inner canister was constructed and left in a hot car. Pressure built inside the canister and forced Galden through any leaks. This helped us seal any leaks that would lead to failure of the mission.

Galden was tested for inactivity by filling a syringe with 10mL and squirting onto the motherboard of a university computer. The computer continued to function normally with the Galden sitting on top of the processor.

Further more testing to come:

Life in the Day- Fully constructed payload will be hooked on to four mechanical vibrators and “shook” for 15 min.

Final Center of Gravity Check

6.0 Mission Results (4-??? pages)

This is your second major section. This section should detail your results with pictures, tables, graphs etc. This section should leave the reader with a sense of how well your payload performed and why it performed the way it did (or didn’t). This is the most important section of your report and should communicate how well your payload performed. What was learned? Did the payload function as designed. If the payload did not function as designed, failure analysis should be completed for lessons learned. Will the data you retrieved be used for a larger purpose? (i.e publication)

7.0 Conclusions (0.5 to 1 page)

This section should make conclusions from Section 6.0. This section may be difficult for those that did not get any data. If that is the case, use this section to discuss your payload failure and how your team determined the cause of failure (a summary of your full failure analysis in Section 6.0.)

8.0 Potential Follow-on Work (0.5 to 1 page)

This section should discuss briefly how this mission could continue and if it is worth continuing. A brief list of improvements or ways to learn and discover further information should be listed.

9.0 Benefits to the Scientific Community (0.5 to 1 page)

This section is pretty obvious. Discuss how and why this mission could be applied to current research in its field. Don’t be afraid to go out on a limb with your statements.

10.0 Lessons Learned (1 to 2 page(s))

Use this section to discuss what you learned from this experience and what you would not let happen if this payload were flown again. This discussion should stay focused on your mission and not so much on the program logistics. This section is extremely important because future participants will probably look at your mistakes and try to learn from them. Lessons learned are an essential part of the final documentation of a project to ensure the advancement of those involved as well. JPL puts a large value on Lessons Learned in its programs.

11.0 Appendices

Any additional figures, charts, data, or conclusions that you feel are relevant but not worth placing in the main body of this report. This is the place to show off work that was completed that could be useful as a reference to those that want more than the body presents. Go wild! J

Please try to keep with this format so it is easier for the reviewers. Please keep same font and section names. These reports are due no later than July 16, 2010 at 5:00 PM. Reports will be reviewed by Chris or Shawn. You may be asked for revision changes before they are posted online in final form. Please contact Chris Koehler or Shawn Carroll with any questions or concerns at 303-378-4765 or 720-234-4902. We understand that documentation isn’t the most exciting thing in the world, but completing this report will not only help bring closure to your project, but will preserve your effort. This completed report is a great resume builder, and will be of great benefit to future program participants.

University of Northern Colorado 7 May 2010

RockSat 2010