Colorado Space Grant Consortium



Colorado Space Grant Consortium

Gateway to Space

Fall 2006

Design Document

Echo III

Written by:

Andrew Berg, Shawn Carroll, Cody Humbargar,

Jade Nelson, Jared Russell, Austin Williamson

November 30, 2006

Revision D

Revision Log

|Revision |Description |Date |

|A |Conceptual Design Review |10-09-06 |

|B |Preliminary Design Review |10-17-06 |

|C |Critical Design Review |11-09-06 |

|D |Analysis and Final Report |11-30-06 |

Contact Information

Andrew Berg – andrewtheberg@

Shawn Carroll – shawn.carroll@colorado.edu

Cody Humbargar – cody.humbaragar@colorado.edu

Jade Nelson – jade.nelson@colorado.edu

Jared Russell – jared.russell@colorado.edu

Austin Williamson – Austin.williamson@colorado.edu

Table of Contents

1. Mission Overview……………………………………………………………….…...…4

2. Design………………………………………………………………………….….....….4

3. Management…………………………………………………….…………………...…10

4. Budget…………………………………………………………………………………..12

5. Test Plan and Results………………………………………………………………..….12

6. Expected Results….………………………………………………………………..…...17

7. Launch and Recovery……………………………………………………………..……17

8. Results and Analysis……………………………………………………………………19

9. Ready for Flight……………………………………………………………………...…23

10.0 Conclusions and Lessons Learned……………………………………………..………24

11.0 Message to Next Semester……………………………………………………………..24

Mission Overview

“Sound at the Outer Reaches”

For our primary science mission, Team Echo III plans to measure the decline in acoustic transmissivity of the atmosphere with relation to altitude. In addition to the implementation of the standard hardware provided by COSGC, our team will incorporate an infrared photography system, which will capture images of Earth in that spectrum.

Since we have two cameras at our disposal, we have decided to compare the infrared photographs of our secondary camera, with the main camera. With our IR camera we hope to capture impressive photographs of the earth in this spectrum. We will face the cameras in the same direction to allow comparison and identification of various surfaces.

For our experiment we want to find out what kind of effect the atmosphere has on how sound travels though the air. Our sound system will test a method for minimizing the noise caused by turbulence, abrupt changes in atmospheric pressure and also vibration transmitted through the structure as well.

With our sounding system, we expect to verify that declining atmospheric pressure, not a drop in temperature alone, impairs the transmission of sound. The results should show this decline to be linear.

2.0 Design

The basic form of this structure will be a 10 by 14.5 by 15 cm rectangular prism. Since the optics portion of this mission depends on comparison between images taken with the regular and IR camera, both cameras need to be mounted facing the same direction, and as close to one another as possible. In order to keep the center of mass as close to the spatial center as possible, the flight tube will be inserted as close to the back of the cameras as possible, and batteries place as near the back face as possible. On the interior, the science experiment needs to be isolated from vibration and shock transmitted through the structure. To that end, the tube containing that experiment will be set away from the other components, and suspended from flexible insulation at each end.

The remaining components will be grouped as tightly as possible to each other to minimize contact with the near-vacuum of our destination. The grouping is arranged with signal flow and minimizing wire length in mind. Individual parts of the instrumentation for this mission will slide in as a unit, to enable ease of access to all components. Insulation that is used for locating each piece should both prevent open atmosphere from interloping among the components and will provide a measure of shock and vibration protection.

Noise isolation is a big concern with this experiment because the movement noise and wind noise could interfere with data collection. There are three features which serve this purpose. First, the experiment is shock mounted as a unit. Being soft-mounted to the interior of the tube further isolates the pickup transducer. A rubber washer bridging the gap between output transducer and the pickup tube structurally insulates the source from the pickup.

Control of atmospheric variables is also essential to this experiment. Control of atmospheric venting should eliminate noise created by turbulence and wind on the exterior of Echo Sat III, and eliminate humidity as a variable. The vent to external atmosphere, placed near the pickup transducer, will be a hole through insulation and foam-core, with a desiccant packet compressed between the layers, causing all breathing of the box to pass through it.

For the structure of the CubeSat Echo III will need one sheet of foam core for all of our design iterations. For the optics portion of the experiment we will use the one given camera, plus one additional with which we will take infrared pictures. These cameras will be attached to a timing circuit that is, whose tallest part is 22 mm. For the sounding experiment Echo III will be using the Rat and Cockroach Banisher Kit to produce a tone. This we will obtain through and it is 50x30 mm by about 15 mm high. To pick up the sounds emitted by the Rat/Roach Kit we will be using a Condenser Microphone Kit with Pre-amp, also from . The preamp’s signal will then be rectified to a DC voltage, which the HOBO is capable of logging. Fluctuations in the DC current will then give insight into the transmissivity at that given time. Echo III will also have a tube and washer system so the cord can pass through the system. We will use the provided heater broken into a line rather than a block to promote even heat distribution. The provided HOBO will log data for all of our measurements.

Weight has been a serious challenge given the amount of electronics contained in our satellite. We found that in addition to having almost three times the life expectancy (in terms of mA-Hrs); they are ten grams less massive each. Similarly, we saved 7 grams for each alkaline AA battery replaced with lithium. In place of some switches, we opted for pull tabs, and we cut away excess metal from protruding component leads and excess wire.

Part List

|Name |Description |Part Number |Supplier |

|Cockroach Banisher |A simple oscillator with piezo driver |FK929 |Qkits |

|Condenser Microphone |Condenser Microphone with Preamp |FK648 |Qkits |

|Rectifier |Converts Audio Signal to DC Voltage |N/A |ITLL |

|Switches |For controlling power-on of all systems |N/A |JB Saunders |

|Various Electronic |Hook up wire, capacitors, diodes |N/A |ITLL |

|Aluminum Tape |Sealant |N/A |CoSGC |

|Sounding Structure |½” PVC T |N/A |McGuckins |

|Foam Core |Lightweight Structural Material |N/A |CoSGC |

|Insulation |Closed-Cell Foam |N/A |CoSGC |

|Vinyl Tubing |4.5mm ID for Flight Tube |N/A |McGuckins |

| | | | |

|Plastic Washers |Prevents Flight tube Tear-Through |N/A |McGuckins |

|Batteries |9v Lithium (3 per run), AA Lithium (2 per run)| |Batteries Plus |

|Heater Components |Power Resistors, and cabling |N/A |CoSGC |

|Timing Circuit |Initiates Exposure of cameras |N/A |CoSGC |

|Camera 1 |APS Camera |N/A |CoSGC |

|Camera 2 |35 mm Camera, Olympus |PC-550 |Target |

|IR Filter (pass) |Photography Filter, passes IR spectrum |RM-72 |47th Street Photo |

|HOBO |Data Logger | |CoSGC |

|Film |35mm(IR) and APS | |Western Camera |

|Desiccant |Condensation Control |N/A |Circuit City |

| | | | |

Illustrations:

Back Open Right

Open View of Top and Right side. Insulation is not shown.

Functional Block Diagrams

3.0 Management

Organization Chart

[pic]

|System/Project |Task |Team Member |Projected Completion |Due |

|Science |Decide on Experiment |All |9/19/2006 |Complete |

|Power |System Overview | |9/19/2006 |Complete |

|Structure |3d Models (Preliminary) |Berg |9/19/2006 |Complete |

|Optics |Filter Choice/System Overview |Jade |9/19/2006 |Complete |

|Main |CoDR |Austin |9/20/2006 |Complete |

|Main |Proposal |Cody |9/20/2006 |Complete |

| |ATP/Feedback |CoSGC |9/28/2006 |Complete |

|Main |Complete System Designs Rev A |All |9/29/2006 |Complete |

|Main |Finalize BOM |All |9/29/2006 |Complete |

|Main |Finalize Mass and $$ Budget |Cody |9/29/2006 |Complete |

|Science |Complete System Designs Rev A |Shawn + Jared |9/29/2006 |Complete |

|C&DH |Complete System Designs Rev A |Cody |9/29/2006 |Complete |

|Power |Obtain Power Requirements |Jared |9/29/2006 |Complete |

|Structure |3d Models (Add mass + density) |Berg |9/29/2006 |Complete |

|Power |Complete System Designs Rev A |Jared |9/30/2006 |Complete |

|Structure |Complete System Designs Rev A |Berg and Austin |9/30/2006 |Complete |

|Optics |Complete System Designs Rev A |Jade |9/30/2006 |Complete |

|Structure |Fabricate Test Structure |Austin |10/6/2006 |Complete |

|Main |Design Document Rev A |All |10/8/2006 |Complete |

|Main |CDR + Design Document Rev B |All |10/15/2006 |Complete |

|Main |Test: Bench (Individual Systems) |By System |10/19/2006 |Complete |

|Testing |HOBO |Cody |10/19/2006 |Complete |

|Testing |Science, with Data logging |Berg |10/19/2006 |Complete |

|Testing |Structural (Drag, Whip, Shock…) |Austin |10/19/2006 |Complete |

|Testing |Optics with Timing and IR |Jade |10/19/2006 |Complete |

|Science |Complete Individual Systems |Shawn + Jared |10/19/2006 |Complete |

|C&DH |Complete Individual Systems |All |10/19/2006 |Complete |

|Power |Complete Individual Systems |Jared et al |10/19/2006 |Complete |

|Optics |Complete Individual Systems |Jade/Cody |10/19/2006 |Complete |

|Structure |Fabricate Test Structure (Revised) |Austin |10/20/2006 |Complete |

|Main |Integrate Systems |All |10/20/2006 |Complete |

|Main |Test: Bench (All together now!) |All |10/21/2006 |Complete |

|Main |Integration into Structure |Berg and Austin |10/21/2006 |Complete |

|Testing |Drop |All |10/22/2006 |Complete |

|Testing |Whip |All |10/22/2006 |Complete |

|Main |Test: Op-Shock |All |10/23/2006 |Complete |

|Testing |Cold |All |10/24/2006 |Complete |

|Structure |Fabricate Final Structure |Austin |10/25/2006 |Complete |

|Testing |Mission Testing |All |10/27/2006 |Complete |

|Main |Test: Op-Cold |All |10/29/2006 |Complete |

|Main |Design Document Rev C |All |11/7/2006 |11/9/2006 |

|Main |LRR |All |11/7/2006 |11/9/2006 |

|Main |Turn In |All |11/7/2006 |11/10/2006 |

|Hardware |Acquire all hardware |All |ASAP- 9/30/2006 | |

4.0 Budget

| Team Echo III Budget |  |  |

|Item Bought |Price |Left |

|Starting |  |$275.00 |

|Rat and Cockroach Banisher Kit |$48.60 |$226.40 |

|Condenser microphone kit with pre-amp |  |  |

|IR filter |$47.45 |$178.95 |

|Advantix Film x2 |$15.12 |$163.83 |

|PVC and tubes |$1.29 |$162.54 |

|IR Camera + Batteries |$64.71 |$97.83 |

|HOBO Batteries |$4.08 |$93.75 |

|Film processing (tests) |$15.38 |$78.37 |

|3 Lithium 9V |$22.47 |$55.90 |

|Film processing (mission) |approx $30 |$25.90 |

|Dry Ice |approx $5 |$20.90 |

|Extra |$20.90 |$0 |

|Team Echo III Mass |  |  |  |

|Item |Weight (g) |Left |Total |

|Starting |800 g |800 |0 |

|Flight Tube |7g |793 |7 |

|Foam Core Structure/ Aluminum Tape |71g |722 |78 |

|Camera with battery and film |126.3 |595.7 |204.3 |

|Timing circuit with battery and switch |68g |527.7 |272.3 |

|Heater |29.2g |498.5 |301.5 |

|9 volt battery |36g x3 |390.5 |409.5 |

|Flag |1.6g |388.9 |411.1 |

|HOBO |34.7g |354.2 |445.8 |

|Science (Sound) |38g |316.2 |483.8 |

|Second camera with battery |210g |106.2 |693.8 |

|Insulation | 16g |90.2 |709.8 |

|IR filter system |52g |38.2 |761.8 |

|IR film |22g |16.2 |783.8 |

|Washers |7g |9.2 |790.8 |

5.0 Test Plan and Results

Test Plan:

• HOBO Testing

In order to test HOBO we will need to take control data for comparison to experimental data. Internal and external temperature will be recorded while the sensors are manipulated. We’ll try holding the sensor with our hands, breathing upon it, and placing it in a freezer. If HOBO is working properly then we should be able to see changes in sensor level which coincide with these actions. Relative humidity readings should also correlate and show variation.

• Sounding Equipment

Similarly, one set of data will be taken with this system in a known environment, so that comparison can be made later. Testing will include obstructing the transmission path, and recording data with no output from the piezo. With this information, we can subtract some noise, and account for issues experienced during flight.

• Structural Testing

There will be three parts of the structural testing. Part one will be shock testing and will be done by dropping the satellite’s foam core structure around 20 feet onto concrete. Part two will be drag testing and will be done by dragging structure by its flight tube while walking. Part three will be the whip test. For this the structure will be attached to flight string and swung around in a circular motion, with sudden changes in direction. This test will show that the flight string interface is sufficiently robust for flight. Shock testing will first be performed with dummy weights, which will simulate the appropriate stresses, without exposing our actual systems to risk of damage.

• Optics Testing

On board camera systems will be tested with the timing circuit. This testing will use film so that issues with the optics can be discovered before flight, and to ensure functionality of the IR filter.

• Integration Testing

After individual systems are confirmed functional they will be integrated. Once integration is complete, testing will begin to clear the satellite for launch. The first test of integrated systems will be a dry run with data collection and pictures taken. After the whole has been tested outside the structure, it will be mounted inside the structure. Part two will be simulated temperature testing. Using a Styrofoam cooler and dry ice the satellite will undergo a flight period of time under cold conditions to check for power failure or system failure as a result of environment factors.

Test Results:

|Echo III Testing Log |Completed (Y/N) |Notes |Issues |

|HOBO Control Internal |Yes- Passed |Com channel 3 |Low Battery |

| | | | |

|HOBO Control External |Yes- Passed |Select proper input for data |Low Battery |

| | | | |

|HOBO Internal |Yes- Passed |None |None |

| | | | |

|HOBO External |Yes- Passed |None |None |

| | | | |

|Sounding Equipment Control |Yes- Passed |Test was able to show the |Hard to analyze because it is hard to testing |

| | |static noise that the equipment will |completely silent environment, can apply trend |

| | |pick up |line to help |

| | | | |

|Sounding Equipment Variable |Yes- Passed |Data shows voltages changes when |None |

| | |variable was applied | |

| | | | |

|Structural Shock |Yes- Passed |Internal structure was almost unchanged |No padding on camera panel could cause issues |

| | |and structure has crunch zones at the | |

| | |corners | |

| | | | |

|Structural Drag |Yes- Passed |None |None |

| | | | |

| Structural Whip |Yes- Passed |Knots will be used to hole flight string|Knots pulled through washers. Knots need to be |

| | |in place |doubled tied |

| | | | |

| Optics |Yes- Passed |None |Pictures taken at different times and space is |

| | | |needed for lens to extend |

| | | | |

| Optics With IR Filter |Yes- Passed |None |Needs a lot of light |

| | | | |

| Integration Dry Run |Yes- Passed |Timing circuit a little off |Voltage and temperature channels were |

| | | |switched, fixed for cold test |

| | | | |

|Integration With Variable Temperature (Cold Test) |Yes- Passed |Internal temperature was over 120 and |N/A |

| | |external temperature reached -92 degrees| |

| | | | |

Cold Test

[pic]

[pic]

As can be seen from our test log and graphs, our testing went very well. One common problem was low batteries. In the cold test, lithium batteries were used, and worked much longer then alkaline ones. Therefore on launch day we will use brand new lithium batteries to insure we have sufficient power for the entire mission. During the first whip test, the knots were not tied large enough for the washers that were used. So smaller washers were bought and the knots were made larger, to prevent this from happening at launch. During the dry run, voltage and external temperature channels were accidentally switched, so data is wrong, but this was fixed for cold test, and we got accurate data. Getting useable data from the volts produced by the sound was an initial concern, but fitting a trend line to the data seems to show an almost flat amplitude curve, which seems reasonable. A running average will likely show a slight curve that tracks temperature inversely, which is also reasonable. With our testing done we are now ready for launch.

6. Expected Results

Since sound waves are alternating regions of compressed and rarefied air, the average amplitude of those waves should vary directly with atmospheric pressure. Our signal is AC rectified to DC, which should translate to an average SPL which tracks ambient pressure. Atmospheric pressure affects the speed of sound propagation also, which could be measured by comparing phase angle to the distance between sensor and source. An additional variable is temperature, which may need to be factored in, depending on the magnitude of a curve discovered in the data. This iteration of sounding test is more concerned with the feasibility and sensor performance in a small satellite.

If comparing the voltage data with ambient pressure yields a linear relationship, then this concept will be proven functional. It would show the mounting of electronics, source, and sensor internally and logging of the output with a simple logger to be quite viable. Then the next step will be to think about spectral analysis. We could use a similar design, but with a sound recorder rather than voltage meter, and excite the source with alternating pink and white noise, thereby showing spectral loss, rather than strictly amplitude. Alternatively, different variables could be explored, including humidity and temperature.

If no change in amplitude is recorded, then there are a few possible causes of failure. Firstly, inadequate venting of external atmosphere into the sound chamber would result in sluggish pressure change response or no change at all. A failure of shock mounting would be characterized by excessively ragged voltage readings. This could be remedied with a better shock mount system, or a change in circuitry which compresses the noise floor out of the measured range, or which filters out undesirable frequencies.

This is a first, incremental step in design of a useful sounding device. Improvements to noise filtration and data richness can be made in later revisions.

7. Launch and Recovery

|Things to do before launch day |Completed |

|Replace HOBO battery |  |

|Replace Camera Batteries |  |

|Insert tab into 2nd Camera |  |

|Glue washers on |  |

|Seal all edges with aluminum tape |  |

|Re-glue HOBO external temp. |  |

|Set HOBO for Delayed Start | |

Launch Day Plan

On launch day we will all meet at school at the designated time. Andrew, Austin and Jared will all be driving to the site. At the launch site, one member of the team will have a video camera/ still camera to tape all that is going on. We will all work together to insure the satellite is ready to launch. Once launched, all members are planning on going on the chase. However, Andrew and Austin will not be returning to school so the return vehicle will be Jared’s.

Check List to be completed prior to launch

|Launch day schedule |Time to complete by |Completed |

|Meet at school | L – 2h 30 |  |

|Arrive at launch site | L – 1h 30 |  |

|Connect new 9v batteries | L – 1h 30 |  |

|Insert film in both cameras | L – 1h 30 |  |

|Turn on Sat. to insure it works | L – 1h |  |

|(check internal LEDs) | | |

|Place Aluminum Tape along unsealed edge | L – 1h |  |

|Turn on IR camera by pulling tab | L – 10 min |  |

|Push IR flash button 3 times | L – 10 min |  |

|Turn on Regular camera and insert | L – 10 min |  |

|Shut satellite and seal remaining edge | L – 5 min |  |

|Turn on satellite | L – 5 min |  |

|Launch | Launch |  |

| |  |  |

Recovery Plan

At the recovery sight we will be very careful not to disturb other groups as we gather our information. As soon as the satellite is opened we will, plug in the HOBO to the computer and download the data, so as to not lose it. We will then remove the film in both cameras, to ensure its safety. After we are done at the site we will return to school.

Launch and Recovery

When launch day finally arrived we were all really excited to see our satellite work. We arrived at the launch site about an hour and a half prior to launch. All of us were getting a little nervous as we watched the sun rise. Jared was the designated photographer, and he filmed us at the site. When the satellites were brought out we began setting up for flight. This is when we found out that IR film is different then standard film for automatic cameras. During our dry run, we attributed the blank IR film to a failure of the camera to load properly and engage the sprocket holes on the film. But as with the dry run, the camera couldn’t register it, so we tried many different things to fix this problem. In the end we had to settle with putting in normal film. After this we started up the HOBO and buttoned up our payload. The balloon then took off and we watched it sail away into the sunrise.

Then the real fun began. Everyone in our group went on the chase, so we split into two cars. We drove the two hours out to Sterling, hoping that we could see the landing. We were a little late, but when we reached the landing site we all ran out to our balloon. Once we opened it up, we realized that the batteries had popped out of the IR camera. But we took the satellite back to the cars and took the data off the HOBO. Once we got this data off, we all celebrated. We completed the day by cleaning up, and heading back to school.

8.0 Results and Analysis

1 Science Experiment

Unfortunately, we were unaware of some sensor issues at EOSS involving non-linear quantization errors during A/D conversion of the sensor voltage. Since the exact nature of the error is unknown, its effect on our data correlation is also unknown. It’s conceivable that a device such as ours could assist in such a correlation, once we track down our own issues. But that would have to wait for a second flight.

Before flight, we expected a 1:1 proportional correlation between ambient pressure and sounding voltage. A scatter plot should appear as a line with a positive slope of 1. Instead we found the best fit to be a 3rd order polynomial (Data Figure 1). This suggests a non-linearity—one which we will be unable to track down without additional flight.

Data Figure 1

[pic]

Below you’ll find a chart that shows the data curves for Barometric pressure (Courtesy EOSS) and sounding voltage. A correlation is clearly visible, but with a few issues. Between 8:47 and burst at 9:22 there is a rise in sounding voltage that does not align with any features in the barometric pressure curve. The altitude at this point is between 76,096 ft ASL and 98,832 ft ASL. This likely corresponds to an area of high winds or other disturbance that would cause additional noise in the sound pickup. The massive dip in voltage between 9:40 (30,200ft ASL) and 10:10 (4,300), could be caused by a similar lack of external noise, or another environmental factor. External temperature is a possibility, since it shows a similar shaped dip between 9:15 and 9:40, but that feature occurs considerably earlier..

At first, we thought the time difference between the two graphs was due to a delay in pressure equalization between the interior and exterior of the payload. This delay is especially noticeable on the ascent portion of the data. Upon reflection, fifteen minutes of delay seems awfully high. However, to ameliorate both variables we will alter the shock mounting to improve isolation, and add additional atmospheric venting to prevent equalization lag.

Because communication with the GPS receiver was interrupted after landing, the EOSS data isn’t logged at a constant rate after 9:58:47. However, the time readings can be interpolated to every thirty seconds, and since the payload was on the ground at that point, altitude data can be accurately interpolated as constant. This thirty second interval was a source of difficulty, as out measurements were made every six seconds. By taking a time average of the voltage data over a sliding period of 90 seconds, we removed some external noise, similar to the effect of a low-pass filter. Rather than go through all 1890 data points, we opted to write a macro with VBA in Excel that would take every fifth data point from our average voltage data, starting with the time that the EOSS GPS transmitter initially logged, and output it to a new column of data for a reading of the voltage at the same times that the GPS was reporting altitude. Thankfully, our readings were at such an interval that they matched exactly with the times from the GPS.

The next step was to take the altitude data and convert it into pressure. As discussed above, the EOSS data for barometric pressure is not accurate. However, taking commonly accepted values from and graphing the data can lead to a line of best fit with a very close correlation to the data that has an equation that can be used to predict values of barometric pressure for the reported altitude. Using this equation, we generated a barometric pressure value for every reported altitude data point, and graphed it as so, giving the correlation shown in the figure.

Data Figure 2

In order to isolate our issues, we would need to fly the payload again. There are too many variables and not enough data. The above chart is encouraging, but not definitive.

The tropopause is clearly visible on our temperature chart (Data Figure 3), at the lowest temperature point during ascent. This occurred at about 42,000 ft, based on the data from EOSS, which we reached at around 7:55 am. Above the tropopause, the temperature actually begins to go back up until descent begins, with its wind-chill galore.. Though the comparison might be useful, we did not acquire permission to use the Temperature vs. altitude graph available at the EOSS website in advance, so it is not here contained. It can be found at the following web address:



Our internal temperature stayed quite comfortable throughout the trip. We credit this to a compact design, and limited venting to the exterior. (See Data Figure 3)

Data Figure 3

[pic]

Below is a chart that shows relative humidity internal to the payload (Data Figure 4). Since all venting took place through desiccant, it is not surprising that the humidity does not change hugely once the payload is activated. There are slight variations that track internal temperature.

[pic]This is some other flight information that was gathered.

|Max ascent rate |1501.313 (fpm) |

|Max decent rate |-9944.234 (fpm) |

|Average ascent rate |801.2416678 (fpm) |

|Average decent rate |-2582.367769 (fpm) |

|Peak Altitude |98832.02 ft. |

|Launch time |7:26 am |

|Burst |9:36 am |

|Touchdown |Approx. 10:20am |

9.0 Ready for Flight

In response to our problems with last-minute assembly and power on, the external switch will control the camera power. The battery retention door on the IR camera has been modified to prevent slippage. One additional, but not immediately necessary fix, would be to electrically separate the two cameras by using a dual pole relay instead of a single pole. This would avoid a poorly understood problem. For reasons unknown, when one camera quits taking pictures, the other one does also.

The payload should be stored in a cool place away from sunlight, with a temporary seal around the access flap to avoid, as much as possible, particulate matter settling on the interior IR filter.

Before a second flight, all batteries should be replaced (lithium batteries whenever possible). The canister of the IR film must be modified for loading. Cut the metal contact area from the exterior of a standard 35mm canister. Adhere this to the IR canister in the appropriate orientation using double-sided tape. Do not use hot glue. The filter should be cleaned with a soft, anti-static cloth, inside and out. If more than a month has passed, the pull through washers should be inspected for looseness, as should the corner glue joints. Likewise, check the connections at the timing circuit.

Payload activation requires that the structure remain open until as close to launch as possible. The HOBO can be launched in advance, but film must be loaded just before launch to prevent fogging of the IR film. Once film is loaded and the camera in place, turn on the camera and press the remaining button on the top of the camera three times. Once this is done, do not allow the camera to power off. The timing circuit must be activated within 5 minutes of this operation.

Add additional atmospheric venting, and we are going to modify shock are mounting to better isolate experiment

10.0 Conclusions and Lessons Learned

This project taught us a lot. Because of our experiment, we spent a lot of time learning about circuits, oscillators, amplifiers, and rectifiers, so we know a lot more about electronics now, in addition the little bits of knowledge from the class. Above all, however, we learned to never take a system for granted. Throughout the semester the camera system was a minor irritation to us in comparison to the experiment because we assumed that, with the proper equipment, it would work without much complaint. This was a mistake. Had we the chance to do it all again, we would spend as much time on the camera system as we did on the experiment, testing it thoroughly to ensure its proper operation. We would also devise a better method of initializing the camera system, including mounting the IR camera upside down so that the flash button could be accessed from the exterior. On the other hand, we accomplished something meaningful by taking a vague idea to realization. We built it, and it worked, even if not perfectly.

One thing that worked well for our group was breaking up our heating system. Rather than using the block of heaters, which was constructed in class, our group hooked our heaters up separately in. Doing so allowed us to disperse them throughout the satellite, which ultimately was a more efficient way to evenly heat the box. Also, it is a good idea to place one of the heaters near the hobo.

11.0 Message to Next Semester

Building a balloon satellite is very exciting and rewarding, but it can also be very stressful.

Consider off-the-shelf products that come ready to run. Our group decided to do a sounding experiment that required lots of custom circuits, and this proved to be tricky and extremely time consuming. Tim May is an excellent resource, but he will not do your project for you. If we could go back, I think we may have chosen a project that would have been more readily available off-the-shelf. On the other hand, we learned a great deal because it was not strictly off the shelf. Keep It Simple Stupid (KISS Rule) will help your group keep its schedule.

Keeping your schedule is the essential. One of our biggest sources of failure was the lack of time for dry run analysis. As the semester progresses, it is imperative that you stick to your schedule so thorough testing and analysis can be completed. Failure on launch day is no fun. Don’t take any system for granted. If our group had stuck to the schedule and had more time, proper analysis of our dry run failure most likely would have resolved our last minute camera failures.

Hooray for lithium batteries. On average, lithium batteries are less massive and have a larger power capacity than their alkaline counterparts. The batteries are a little pricey, but were a savior not only to our power system, but to our mass budget as well.

[pic]

-----------------------

Experiment Power

Sounding Device

HOBO Power

Internal Temperature

Relative Humidity

External Temperature

HOBO

Heater 3

(To Heater Power)

Heater 2

(To Heater Power)

Dual Pole Switch

Op-Amp

Switch

Rectifier/filter

Microphone/Preamp

Microphone power

Pull tab

(To Heater 3)

(To Heater 2)

Heater 1

Heater Power

Camera 2 Power

Camera 1 Power

Camera 2

Camera 1

Dual Pole Switch

Timer

Timer Power

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download