1.0 mission overview - spacegrant.colorado.edu€¦ · web viewin 2009, the global community...

Colorado Space Grant Consortium

GATEWAY TO SPACEFALL 2011

DESIGN DOCUMENT

Team Six-Pack

Written by:Calder Lane, Courtney Ballard,Janelle Montoya, Matt Cirbo,

Ian Thom, Thomas Green

November 5 2011Revision C

Gateway to Space ASEN/ASTR 2500 Fall 2011

Table of Contents

1.0 Mission Overview...............................................................................................................32.0 Requirements Flow Down..................................................................................................43.0 Design.................................................................................................................................64.0 Management.....................................................................................................................115.0 Budget...............................................................................................................................136.0 Test Plan and Results........................................................................................................147.0 Expected Results...............................................................................................................208.0 Launch and Recovery.......................................................................................................20

of 22 November 5, 2011Rev C


1.0 Mission Overview

The Sun has heated Earth since its birth, providing almost all the energy it, and everything on it, uses to live. This is caused by electromagnetic radiation, which is reflected, absorbed and often transformed to allow organisms to use it. Plants have used photosynthesis to grow, and when consumed, the energy is transferred. Fossil fuels were once plants, and it is an effective fuel for now. However, it is running out. A more efficient method is also clear: utilize technology to emulate plants, using sunlight directly to create useable energy. This technology is already available in the form of the solar panel. However, huge fields and perfect conditions are necessary to have a decent amount of power. This is because the atmosphere that allows life to continue blocks some of the energy.

At high altitude, the radiation from the Sun is much more intense due to the lack of atmosphere that normally blocks the higher energy electromagnetic waves and reduces the visible ones. At this higher altitude, solar cells will operate far more efficiently. The Earth receives approximately 1367.7 W/m2 from the Sun at the edge of the atmosphere, a proven value known as the solar constant. In 2009, the global community consumed 132,000 terawatt hours, with the average growth rate at about 5 percent per year. [1] If a satellite with a total solar cell area of 1 km2 could be launched into orbit and achieve a total efficiency of just 20 percent, 2.439 terawatt hours of electricity could be generated per year from that area alone. In an era where energy has become a problem, a source of clean and limitless energy not dependent upon the weather on Earth would be a redefining factor in our planets energy generation capabilities.

However, a problem presents itself: How will this energy be transferred to the surface? One possibility is microwave transmission; however the components cost thousands of dollars and are far too heavy for a balloon to carry. Another method, the one we have selected to investigate, is transfer via a laser. As a concentrated beam of EM radiation, a laser could beam this energy back to Earth. [2] A strong enough laser, or one of a different energy level, would be less affected by the atmosphere. Such a laser could be directed at receivers on the ground, transferring energy in the same way normal sunlight does, with the impact of the photons on a photovoltaic cell. While current solar panels have a low efficiency, with improvements or a different reception system, this method could provide a clean, renewable and reasonably efficient method of energy collection. In order to provide a proof of concept and preliminary efficiency test, a small scale model using a less powerful laser and a typical solar panel could be used to determine the possible efficiency of this mode of energy transfer and its applicability in modern society.

The mission for Project Helios is to design, build, test and launch a balloon satellite. Said satellite shall record data on the efficiency of transmitting energy collected with solar panels via a laser as the satellite reaches increasing altitudes and passes through different atmospheric layers. The satellite shall reach near-space, survive the descent from near-space and be in retrievable condition for data analysis. In addition, the balloon satellite shall collect temperature data and have an onboard camera to take pictures during flight.



[1] Energy - Consumption'!A1 "Consumption by fuel, 1965–2008" (XLS). Statistical Review of World Energy 2009, BP.[2] http://www.laserfocusworld.com/articles/print/volume-42/issue-1/features/photonic-frontiers-photonic-power-delivery-photonic-power-conversion-delivers-power-via-laser-beams.html

2.0 Requirements Flow Down

In order for Project Helios to be successful, a slew of requirements must be met. A long list was given in the Request for Proposal. Many of these were incorporated in to our mission statement or directly addressed below. Level 0 requirements one and two are taken directly from the RFP. From our mission statement, the following four requirements were derived. All of these except four can be traced back to the RFP as well. Four fulfills the requirement for an additional payload given in the RFP and is the focus of our mission.

1 Final flown weight of BalloonSat Helios shall not exceed 850 gramsa Lightweight materials shall be utilized in lieu of heavier selections. However, such

materials shall be durable enough to ensure the satellite remains intact during launch and descent.

b All electrical components shall be designed and arranged in such a manner as to minimize the size of the external structure to reduce weight and increase durability without additional structure where possible.

c In the case of unavoidable excess, a negotiation shall be made with another team for a portion of their unused mass, increasing the maximum mass limit of BalloonSat Helios.

2 A maximum of $250 provided by the class shall be used in purchasing necessary components.a Research shall be done to identify and purchase quality components for low prices.b Where possible, components shall be made and/or assemble by the team to eliminate costs

of pre-fabrication.c In the case of additional costs exceeding the provided funds, personal funds shall be used

and no compensation sought.

3 BalloonSat Helios shall be able to record 90 minutes of data during its ascent to 30 km and remain intact during the following descent.a Durable materials that can withstand the shock experienced during burst and the

continuous motion during all other points of the flight shall be used.b A carbon-fiber rod shall be used to maintain alignment between the two satellite structures,

and the entire structure shall be tested to ensure it maintains its integrity during ascent and does not harm itself during descent.

c Foam shall be used to ensure all electrical components are insulated from shock due to motion of the BalloonSat.

d All electrical components shall be able to continue their proscribed tasks at temperatures down to -10oC, and shall have little to no drop in performance due to temperature where possible.

e An active heating system shall be fabricated and utilized to maintain a temperature of more than -10oC in the top structure.


http://en.wikipedia.org/wiki/BP

http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2008/STAGING/local_assets/2009_downloads/statistical_review_of_world_energy_full_report_2009.xls#'Primary


f A radiating heating system shall be utilized in the bottom box to keep the microcontroller functioning and recording data.

g Insulating foam shall be used to maintain a temperature above -10oC in the upper box and in an appropriate range for the effective use of all electrical components.

4 BalloonSat Helios shall record data on the efficiency of transfer of energy with lasers.a A system of nine solar panels on the top of the first structure shall gather energy from the

sun during ascent. The gathered energy shall then be run through a system designed and built by the team to provide energy to a 50mW laser.

b A 50mW laser shall be emitting light from the bottom of the first structure toward a filtered solar panel on the top of the second structure.

c The energy collected by the solar panel on the second structure shall be measure with a volt and ammeter to provide the necessary data for the calculation of watts.

d Upon retrieval, the data shall be collected and analyzed. The watts received by the lower panel shall be compared to the known and tested emissions from the laser. This data shall also be compared to testing done on the ground to compare the change in efficiency.

5 During the fight, a HOBO data logger shall collect internal and external temperature data.a The HOBO shall be preprogrammed and placed in the top structure of BalloonSat Helios

with a temperature probe within and a second sticking out of the structure about 1-2 cm.

6 During flight, a Canon SD780 shall take pictures of the exterior environment.a The Canon SD780 firmware shall be hacked to allow the camera to record images at 10

second intervals during the entire flight.



3.0 Design

In order to transmit energy wirelessly between two satellites, several instruments and special design features have been integrated into Helios. They have been integrated individually into the structure of Helios. By preventing a system from being solely dependent upon another, the risks of satellite wide failure can be mitigated. The satellite’s photo imaging system (Canon SD780 IS), its onboard storage, and its software operates independently of other systems, and the HOBO sensor operates autonomously, providing accurate temperature data and imagery in the event of system failure. Sufficient wattage to power the transmission system has been achieved using nine high grade solar cells of uniform area. The solar cells have been divided into 3 sets of 3 cells, where each cell has been wired to its set in parallel, and each set of cells has been wired to the others in series. By wiring the solar cells in such a manner, a high enough voltage to charge the battery can be achieved. The solar cells have been attached to the structure using hard points on the satellite and have been integrated into the structure to assure attachment throughout flight. The remaining inconsistencies in voltage have been addressed by a 3.7 volt 2600 mAh (milliamp hour) lithium ion battery. The battery shall output a constant stream of electrons that powers the 50mw 650nm laser beam. A red light filter on the top of the receiving satellite shall deflect most of the sunlight. A smaller receiver satellite below the main satellite contains a photovoltaic panel which shall convert the laser radiation back in to electricity. A voltmeter/ammeter PCB board shall route the raw electricity produced by the cell and the corresponding data to an Arduino microprocessor through its analog output. The circuit shall process the data at intervals and store it in real time. Data shall be stored in numerical form, 8 bits per character, on a 16 gigabyte micro SD card contained within a micro SD card shield. In addition to intelligent design optimizing radiant heat, an onboard heater is being used, drawing power from three 9 volt lithium batteries. This shall ensure the continued operation of the satellite. The structure of the satellite is supported by a cross pipe, two figure eight knots and a paper clip. The data retrieval satellite has been attached to the flight line using the same configuration, and is reinforced with two carbon fiber rods attached to hard points on the main satellite. This shall ensure its continued attachment to and alignment with the main satellite.

The lower box of Helios contains an Arduino Uno microcontroller to record the amperage and voltage output as a function of time. Power shall be received from the solar cell on the data retrieval satellite. This data shall be taken by recording the voltage and amperage readings from a voltmeter/ammeter at frequent time-intervals. It shall then be logged and stored for later collection on the micro SD card contained within the card shield. Photos that the Canon SD780 IS digital camera takes shall be saved to the SD card inside the camera. Data from the microcontroller, the camera, and the HOBO data logger shall be uploaded to a computer after retrieval of Helios. After said upload, the power output data shall be compared to the known power output of the laser. Through this comparison, the efficiency of wireless transfer of energy by lasers can be determined.

Measuring solar efficiency presents one big problem, the movement of the sun. By orienting the satellite on its vertex and using a hexagon to support the internal mechanisms, this problem has been minimized by exposing a greater percentage of each



cell. This configuration shall keep the panels more accurately oriented toward the Sun, which shall generally be above, not next to the satellite. This satellite also integrates two separate flight modules, to test the system over a significant distance, which is the first step toward transmitting power back to the surface of the Earth. An adjustable laser focus, included in the laser, has been used to diffuse the light to a beam wide enough to generate significant power, while two carbon fiber rods have been used to ensure continued alignment of the satellites.

Our team, Team Six Pack, elected to test the effectiveness and efficiency of laser transfer of energy as its additional scientific experiment (Requirement 4, see Requirements Flow Down). By using solar panels on the top of the first structure, the satellite shall gather energy from the sun during its ascent. This energy shall be emitted from the bottom of the first structure and into the filtered solar panel atop the second structure. The energy collected shall be measured with a volt and ammeter for analysis of the viability of a large-scale system similar to this. The goal is to collect data on this and to have it in working order after landing, which is expected after several different forms of testing.

The flight string attachment is composed of PVC through the center of the BalloonSat and secured using washers and paper clips on each end so that it shall not pull through the BalloonSat or interfere with the flight string. Our design includes an internal heater as well as insulation, which shall maintain an internal temperature above -10°.

After all modifications, the final design did exceed 850 grams (Requirement 1). Though lightweight materials are being utilized as opposed to those that are heavier, the excess weight was unavoidable, primarily due to our numerous systems. Electrical components were arranged to minimize the size of the external structure, thereby reducing the weight while increasing durability and a negotiation for an additional 50 grams was made.

Data shall be collected for 90 minutes as the satellite ascends to 30 km and the satellite shall remain intact during the descent that shall follow (Requirement 3). This data shall be collected and determined by temperature data from the GPS attached to the flight string as well as the HOBO and external temperature cable (Requirement 5). Required hardware to collect images, temperature measurements as well as to heat the BalloonSat, has been incorporated into the design, including a Canon SD780, which shall take pictures at intervals of 10 seconds during the entire flight (Requirement 6). Also, the structural integrity of our single structure composed of two parts has been tested to confirm that carbon fiber rods and other structural design components are appropriate and shall survive the landing.

The main structural composition is composed of foam core and other spare parts have been incorporated into the parts list and budget, giving us the total cost. A United States flag decal as well as team contact information are located on the outside of the structure and all units are being recorded in metric. Arrangements have been made so that the majority of the team shall be present at launch and the BalloonSat shall be recovered by a minimum of one member. Safety procedures that the team has outlined have been followed and all hardware shall be turned in in working condition.



The budget manager has kept a detailed budget and kept track of receipts and expenses to be given to Professor Koehler. With a budget of $250, the team shall purchase components necessary for the completion of our satellite design. No parts had to be made by the team to avoid and eliminate costs involved in the ordering process. We have also excluded living objects from our design component. Each of these components shall allow our team to meet the requirements as set forth in the RFP.

Box Diagram:


Switch

3V 25mA Solar Panels (9)

3V 22mASolar Panel

50mW 650nm Laser

Rechargeable Battery

9-volt Battery

Arduino UnoMicroprocessor

Micro SD Shield

Micro SD Card

AttoPilot Current/Voltage

Sensor

HOBO

Thermometer

Barometer

Hygrometer

Li-Ion Battery

SwitchRechargeable

Battery SD CardCamera

Switch

Switch

9-volt Battery (3)

Switch Heating Circuit

Red: PowerBlue: CDHGreen: Science


Final Parts List:

Part Part Numbers Provided by/Bought from:

HOBO Data Logger H08-007-02 #628299 Gateway to SpaceFoam Core, Insulation, Aluminum tape, Switches, and Flight tube

Not Applicable Gateway to Space

Canon SD780 IS camera (SD780) Gateway to SpaceHeater Not Applicable Gateway to Space9V Lithium Batteries Not Applicable Supermarket (Target)Arduino Uno DEV-09950 www.sparkfun.comAttopilot Current/Voltage Sensor

SEN-10644 www.sparkfun.com

MicroSD Shield DEV-09802 www.sparkfun.comPowerfilm 3V 25mA Flexible Solar Panel (9)

Mp3-25 www.solarhome.org

Powerfilm 3V 22mA Flexible Solar Panel

Mp3-20 www.solarhome.org

50 mW 250 nm Laser 1M635C1-3-1245 www.ankaka.comCarbon Tubing OD-48 www.dragonplate.com3.7 Volt 2600 mAh LG Li-Ion 18650 Battery

18650 www.megabatteries.com


http://www.megabatteries.com/

http://www.dragonplate.com/

http://www.ankaka.com/

http://www.solarhome.org/

http://www.solarhome.org/

http://www.sparkfun.com/




4.0 Management

Team Six-Pack shall have team meetings every Sunday and Thursday at 4:00 PM and 1:30 PM respectively. Extra meetings shall be organized or rescheduled as needed. The meetings shall either take place in the Engineering Center or in a reserved ITLL study room. The tasks shall be divided between the teams members so that no member is fully responsible for a single task. This shall ensure that the quality of every aspect to our mission shall be checked by a minimum of two team members. Calder Lane shall be the team leader because he possesses the most prior engineering experience which allows him to better oversee each aspect of our mission.

Name Contact Info Main Position Secondary Position

Calder Lane [email protected]

Team LeaderElectrical

Science

Courtney Ballard [email protected]

Thermal Structure

Thomas Green [email protected]

Science Programming/CDH

Ian Thom [email protected]

Structure Safety

Matt Cirbo [email protected]

Programming/CDH Thermal

Janelle Montoya [email protected]

Management and Budget

Electrical

Schedule:

Date Time Task: DueFri 9/9 4:00 PM -HW 03Sun

9/113:30 PM -Project decision

- Distribution of proposal responsibilitiesTues

9/139:30 AM -Unification and editing of proposal rough draft

-Proposal questions-Discuss date for ITLL shop certification

Th 9/15 1:30 PM -Finalization of project proposal for turn-in, Assign specializations-HW 04, CoDR Slides

Fri 9/16 12:00 PM -Turn in project proposal to Prof. Koehler ProposalFri9/6 1:30 PM -Unification of CoDR Presentation Final Draft.

-Assign presentation speaker order/run through pres.Th 9/22 1:30 PM -Finalize HW 04

-HW 06Tues

9/2711-4 PM(By appt.)

-Meet with Prof. Koehler to order hardware and turn in HW 04

HW 06 (Before class)HW 04 (At appt.)



-Distribute responsibilities for CoDR after appointment

Th 9/29 1:30 PM -HW 05 (Due 10/11)-DD Rev A/B-Begin Construction on structures and electronics

Tues 10/4

9:30 AM -Pre-Critical Design Review (pCDR) DD Rev A/B

Th 10/6 9:30 AM -pCDR-Teams 6-10

Th 10/6 1:30 PM -Construction (cont.)Sun

10/93:30 PM -Have all components to assemble

-Construction (cont.)-Ground test laser and solar panels

Th 10/13

1:30 PM -Complete prototyping design-DD Rev C

Th 10/20

1:30 PM -Complete cold test-LRR Presentation

Tues 10/25

9:30 AM -Pre-Launch Inspection (Bring all hardware)

Th 10/27

9:30 AM -In-Class Mission Simulation Test (Bring BalloonSat)

Th 10/27

1:30 PM -Finish LRR Presentation

Tues 11/1

9:30 AM -Launch Readiness Review (LRR) LRR Pres. and DD Rev C 7AM

Th 11/3 1:30 PM -Design Review-LRR Cards

Fri 11/4 8-1 PM (By appt.)

-Final Weigh-in and Turn In BalloonSat BalloonSat DLC 270A & LRR Cards

Sat 11/5 4:45 AM -LAUNCH DAYTh

11/101:30 PM -Data Analysis, Begin DD Rev D

Th 11/17

1:30 PM -Final Presentation, Assign speaking roles

Th 11/24

1:30 PM -Finalize Final Presentation/run through pres.-Finish DD Rev D

Tues 11/29 & Th 12/1

9:30 AM -Final presentations and reports Final Pres (11/29 @ 7 AM)

Sat 12/3 9-4PM -Design Expo DD Rev D, Team Vids

Tues 12/6

9:30 AM -Hardware Turn-In

Given that we are required to complete our mission within one semester, Team Six Pack plans to meet at least twice a week. Two meetings per week shall allow us to effectively use the time that is available to us. It is also expected that every team member be present at each meeting to further make the most of the time that we have. The final



weeks leading up to launch shall most likely involve meetings on a daily basis to ensure that the payload is ready to launch.

5.0 Budget

Item Cost Weight Provided by/ Bought from

HOBO Datalogger Provided 30 grams Gateway to Space ClassFoam Core and Aluminum Tape

Provided 130 grams Gateway to Space Class

Canon SD780 IS Provided 130 grams Gateway to Space ClassHeater Provided 100 grams Gateway to Space ClassFlight/Test batteries Some provided

Some bought with personal funds

150 grams Gateway to Space Class

Flight Tube Provided 10 grams Gateway to Space ClassSwitches Provided 20 grams Gateway to Space ClassDry Ice Bought with

personal fundsNot launched Supermarket

Arduino Uno $29.95 70 grams SparkfunAttoPilot Voltage and Current sense breakout 180

$19.95 20 grams Sparkfun

Micro SD Shield $14.95 30 grams SparkfunMicro SD Card Donated <1 gram The Lane FamilyPowerfilm 3V 25mA Flexible Solar Panel (9)

$62.55 27 grams www.solarhome.org

Powerfilm 3V 22mA Flexible Solar Panel (1)

$6.75 3 grams www.solarhome.org

50mW 650nm Laser $18.04 100 grams www.ankaka.comCarbon Tubing $49.00 10 grams dragonplate.com3.7 Volt 2600 mAh LG Li-Ion 18650 Battery

$24.95 50 grams www.megabatteries.com

Total shipping and Handling

20.76

Total 247.30 880 grams*

*Negotiated for an additional 50 grams



6.0 Test Plan and ResultsA variety of tests were performed on Helios in order to ensure that it would

function properly during all parts of flight. The first tests conducted on our balloon satellite were the structural tests. During all of the structural tests, Helios was filled with a simulated weight, bringing the total weight to 850 grams. The first structural test was the whip test. A string was passed through both satellites to simulate the flight cord, and the satellite was then spun around to simulate the turbulence of flight. Next, the drag test, a more accurate model of the predicted landing mode for Helios, was performed. Helios was dragged along the ground at moderate speed. This test caused no damage to the structure. The third structural test was the drop test. During this test, we dropped our satellite from a height of 20 meters. Helios survived with only minor damage to the overall structure. Both of these tests showed that it will survive the forces experienced during landing.

Another test that Helios underwent was the cold test. Helios was activated and then placed inside a cooler filled with five pounds of dry ice. It was then left inside for approximately two hours. This simulated the cold environment that it will pass through as it travels into the upper atmosphere. We removed the satellite from the cooler once the allotted time was complete. From this test we were able to determine that the heater and thermal insulation systems were functioning and sufficient. The internal temperature of the satellite never went below 15°C, which can be noted in graph 1, and no systems shut down due to cold. The run time of the mission was also shown to be at least two hours, but likely more as the batteries still had charge.

of 22 November 5, 2011Rev CHelios undergoing the whip test.

The drag test being conducted on Helios.

Helios after falling a height of 20m.

Preparing to conduct the drop test on Helios.


The readings of the external temperature that the HOBO recorded were inaccurate compared to what the temperature actually was during the test. This was due to the external thermometer being in contact with the Styrofoam cooler for the duration. This contact resulted in the external temperature readings being significantly higher than they actually were. When the cold test was over, Helios was removed from the cooler and the HOBO’s external thermometer was exposed to room temperature air, resulting in a sudden temperature increase near the 8000 second mark on graph 1. When we pulled Helios out we also noted that there were ice crystals on the carbon fiber rods connecting the upper and lower structures, an indication that the cooler must have gotten below 0°C.

Since the external reading from the HOBO was not representative of the actual temperature during the cold test, another test was conducted to ensure the external thermometer records correctly. The HOBO’s external thermometer was placed in a small pile of snow. The external thermometer recorded a temperature of 1°C, showing that the external HOBO records accurately despite the misreading during the cold test. Then, after being in the snow for a little over 270 seconds, the HOBO’s external thermometer was removed from the snow and placed in someone’s hand in order to reheat it. The temperature recorded by the HOBO increased significantly at that point. The data we retrieved from this test can be seen in graph 2. Since the internal thermometer worked properly during the cooler test, we can conclude that it functions properly.

During the cooler test, the camera took over 600 pictures during the two hour span, which shows that the camera functions properly. One of the photos taken during the cold test can be seen to the right.

The rest of the tests performed on BalloonSat Helios were to ensure the systems function properly. The first of these was to make sure that the Arduino microprocessor was able receive data from the lower solar panel for the duration of the flight. This test was conducted during the cold test. When Helios was placed in the cooler, the Arduino was activated and began to record the voltage readings from the AttoPilot sensor. To start, the voltage recorded was around .385 volts because the lower solar panel was still partially exposed to sunlight as the satellite was placed into the cooler. As soon as the cooler was sealed, the solar panel was no longer exposed and the voltage dropped to around .37 volts. The dry ice began to sublimate and fog was produced, causing more of the laser light to be diffracted. As time progressed, the dry ice stopped sublimating because the internal pressure of the system reached equilibrium with the vapor pressure of dry ice. The voltage output of the lower solar panel then increased from .37 volts to .38 volts and then up to .385 volts towards the end. This increase was due to less light from the laser being diffracted by the fog as it dissipated. All of the data recorded in this test can be seen in graph 3.

The second systems test that was implemented ensured that Helios can detect a noticeable change in voltage due to the laser. To conduct this test, we took the satellite to a sunlit area. The satellite was angled so that sunlight could hit the lower solar panel.


One of over 600 photos that were taken to test the camera during the cold test.


Once it was in the proper orientation, the Arduino microprocessor was switched on and allowed to record for about 12 seconds. With just the sunlight shining on it, the solar panel was able to produce around .38 volts. Then after 12 seconds the laser was switched on and the voltage output of the solar panel jumped to .405 volts. The laser was left on for around 15 more seconds, during which the solar panel produced a constant voltage of .405 volts, except for two times when people walked in front of Helios. At 27 seconds the laser was turned off, which caused a drop in the voltage output. The Arduino microprocessor was switched off immediately after that. All of the data recorded from this experiment can be seen in graph 4.

We then tested to ensure that the laser could properly function solely on energy collected by the satellite. To perform this test, the unfocused laser was pointed towards the bottom solar panel while it was turned off. Then the solar panels were connected to the circuit. Once they were able to provide power, the laser was switched on and it functioned properly.

The alignment of Helios’ two structures was also tested. The lower solar panel and laser system needs to remain aligned while being shaken. For this, the entire system was placed on the vibration table in the ITLL. The frequency of the vibrations was increased and decreased repeatedly. The frequency was also allowed to remain at a set value where the vibrations appeared most violent. The voltage, as seen in graph 5, remained reasonably constant once the voltage itself had settled. From this, we can see that the alignment is set, and the voltage measured will not depend on the motion of the structures.

With all these tests, some additional factors became clear. We discovered the voltage and current sensor shows no current. We believe this is because the current is too small to register. We are only expecting milliamps, and likely should have selected a lower current board, perhaps 45A instead of 180A. To resolve this, we will find the resistance of the circuit and use the voltage to calculate amperage after recovery. We also found that the Arduino typically has a small period where it shows higher-then-expected voltage for the first few seconds, encouraging us to be wary of the earliest data points.

Safety:

During all of the tests and construction, safety was a priority. Whenever anyone was using a Xacto knife, they always cut away from themselves and used caution. When the carbon fiber rod was sawed in half, the person sawing wore safety goggles. Whenever the laser was turned on, no team member looked directly into the beam and it was not pointed towards any reflective surfaces. When clipping wires, the tips were held to make sure they didn’t fly off and hit anyone. During all parts of testing and construction, everyone used common sense.




0 1000 2000 3000 4000 5000 6000 7000 8000 9000

-20

-10

0

10

20

30

40

Cold Test HOBO Temperature Readings

InternalExternal

Time (Seconds)

Tem

pera

ture

(°C

)

Graph 1: This graph shows the temperature readings on the inside and the outside of Helios during the cold test. Point 1: Helios is placed in the cooler, HOBO sensors are still warm. Point 2: External HOBO sensor is against Styrofoam wall, which reaches equilibrium temperature with the dry ice. Point 3: Heater reaches maximum temperature. Point 4: External sensor is removed (causing error) and test ends.

1

2

31

41



Graph 2: This graph shows the data collected during the second test of the external thermometer of the HOBO. Point 1: HOBO is turned on and external sensor is placed in snow. Point 2: HOBO’s sensor cools to temperature of the snow. Point 3: HOBO’s sensor is removed and placed in someone’s hand. Point 4: Test ends.

0 50 100 150 200 250 300 35005

101520253035

External HOBO Test #2

External

Time (seconds)

Tem

pera

ture

(°C

)1

2 3

4



0 1000 2000 3000 4000 5000 60000.34

0.35

0.36

0.37

0.38

0.39

0.4

Cold Test Voltage

Voltage

Time (seconds)

Vol

tage

(Vol

ts)

Graph 3: This graph shows the voltage measured by the AttoPilot in the lower box during the cold test.Point 1: Helios is being placed in cooler, extraneous light is hitting the solar panel. Point 2: Fog in the cooler is settling. Point 3: Fog has settled and the voltage slowly increases. Point 4: Test ends and Helios is removed from the cooler.

Graph 4: This graph shows the change in voltage due to the laser while the panel is also exposed to sunlight.Point 1: Voltage produced from the solar panel just being in direct sunlight. Point 2: Laser is switched on. Point 3: Person momentarily blocks light from the sun. Point 4: Laser is switched off. Point 5: Test ends.

0 5 10 15 20 25 30 350.36

0.37

0.38

0.39

0.4

0.41

Voltage with and without Laser

Voltage

Time (seconds)

Vol

tage

(Vol

ts)

4

3

2

1

1

2 3

4

5



0 500 1000 1500 2000 25000.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

0.76

Vibration Test

Voltage

Time (Seconds)

Vol

tage

(Vol

ts)

1

Graph 5: This graph shows the change in voltage due to the vibration of the satellite.Point 1: Laser is switched on for base reading and the table is switched on after 200 seconds. Point 2: Voltage settles after typical excess when Arduino begins recording.Point 3: Test ends after table is shut off.

23


7.0 Expected ResultsAfter retrieval of Helios, our team hopes to have retrieved data that will allow us

to determine the plausibility of a wireless energy transfer in a similar manner on a larger scale. Whether it is from a satellite to Earth or between satellites in orbit, determining the efficiency of such a transfer could prove or disprove the need for further research into a topic such as this. We have simulated the retrieval of data from the payload through several forms of ground tests, each of which have given us an idea of what to expect after the payload Helios is retrieved.

We expect that the solar cells will perform with an increased efficiency due to the increased solar intensity that is present in near space. Since the Earth’s atmosphere, weather and other obstructions decrease the amount of sunlight present to be gathered by solar cells on Earth’s surface, this atmospheric change shall provide a higher voltage output for the solar cells of Helios. However, this change will not be measured; it will simply allow for a longer run-time for the laser as the battery is charged more quickly.

Our team also expects the laser diode to wirelessly transmit energy to the lower structure of the BalloonSat. Realistically speaking, we hope to achieve a measurable efficiency that can support our claim that this energy transfer is possible. When testing the functionality of the laser diode connected to the solar panels, it was observed that when more of the panels were exposed to sunlight, the beam from the laser was more intense. We know that not all of the panels will be exposed to sunlight at all times, but the increased light intensity mentioned previously should provide a beam intense enough for energy transfer with sunlight directed toward at least one panel.

The laser efficiency is expected to increase as the atmosphere becomes less dense, for similar reasons as why the solar panels on the top structure will produce more energy. This result was seen in the cold test when a thick layer of fog was present in the early stages of the test (See Cold Test Voltage Graph). As time progressed, the data gathered from the Arduino Uno shows an increase in voltage as the fog inside of the cooler began to clear. Although it is reasonable to assume that energy will be transferred and the efficiency will improve, we are unsure as to whether or not the energy transferred will be a large portion of the emitted laser light. Our team predicts a 10% efficiency of transfer at best due to the data we have been gathering.

Another expectation is that the basic parts of the BalloonSat Helios shall function properly. We expect the HOBO data logger to record information regarding internal and external temperatures during flight, and that the internal temperature shall remain well above that of the external temperature thanks to a functional heater. The camera is also expected to continuously take pictures during flight as it has been during ground testing.

Most importantly, our team expects both structures of Helios to remain intact during flight. Given that we have chosen carbon fiber rods to connect the two, we expect that they will not break when stress is applied to the rods during ascent, burst and descent. We also expect the laser to remain aligned with the solar cell on the bottom box to ensure that we will have data to analyze after retrieval. Should this happen, we will have successfully completed our flight mission.



8.0 Launch and RecoveryLaunch day is expected to be November 6th, weather permitting. On launch day,

all team members shall be present, excepting Thomas Green, who has other commitments. The team shall wake up 3 hours before launch, then follow Professor Koehler to the launch site in Winsor, CO. Professor Koehler shall arrive with Helios an hour before launch, accompanied by attending team members. Upon arrival, we shall make ourselves as useful as possible in facilitating launch. Ian Thom shall be responsible for payload launch while Calder Lane and Janelle Montoya shall be responsible for documentation. After launch, all attending team members shall assist in recovery the satellite, with Calder Lane and Matt Cirbo travelling with Professor Koehler in the lead vehicle. Ian Thom will drive separately, transporting Janelle Montoya and Courtney Ballard as well. Helios will be found and returned to Boulder after landing.

Data retrieval shall be conducted later upon return to Boulder. We shall remove the Micro SD card from the SD Shield and use an adapter to save the readings on a team member’s computer. The HOBO data shall be offloaded via the Keyspan system to Ian Thom’s laptop. The SD card in the camera will also be removed, and the pictures downloaded to a team member’s computer. During our meeting on the 10 th of November we shall analyze our data using conversion factors and use it to create several Excel documents, keeping in mind trends and errors we discovered during testing. We will also review the HOBO data and photos. However, in the case of a delayed launch, the data analysis may also be delayed by up to a week.


1.0 mission overview - spacegrant.colorado.edu€¦ · web viewin 2009, the global community...

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