Gateway to Space ASEN/ASTR 2500Fall 2006
Colorado Space Grant Consortium
Gateway to Space
Fall 2006
Design Document
Axiom
Written by:
Ben Anderson, Drew Gottula, Dustin Martin, Jacob Rivera, Adam Trevizo, Stefan Quan
11-30-06
Revision D
Revision Log
A / Conceptual Design Review / 10-09-06
B / Critical Design Review / 10-17-06
C / Launch Readiness Review / 11-09-06
D / Analysis and Final Report / 11-30-06
Table of Contents
1.0 Mission Overview
2.0 Design
3.0 Management
4.0 Budget
5.0 Test Plan...... 11
6.0 Test Results...... 13
7.0 Expected Results...... 14
8.0 Launch and Recovery...... 16
9.0 Results and Analysis...... 17
10.0 Ready for Flight...... 23
11.0 Conclusions and Lessons Learned...... 23
12.0 Message to Next Semester...... 24
Page 1 of 24
Gateway to Space ASEN/ASTR 2500Fall 2006
1.0 Mission Overview
1.1 Mission Statement
The mission for the Axiom BalloonSat can be broken down into two parts; the detection and measurement of cosmic rays in near-space altitudes, and the recording of still images via a film camera and short video clips using a digital camera. The first objective will be accomplished through the incorporation into the satellite of a Geiger-Müller counter to measure the number of particles radiated from the sun or particles emitted from the collision between solar radiation and the upper atmosphere of the Earth. The second objective will be met by integrating into the BalloonSat primary and secondary camera systems; the first being a film camera to take still photographs, while the second a digital camera capable of recording short video clips.
1.2Experiment Selection
Detection of cosmic rays was selected as the science experiment for the Axiom BalloonSat for several significant reasons. First, it allows for the recording of a quantifiable set of data, in the form of Geiger counts, rather than observational data which would not result in the clear type of result that can be expected of numerical data. Second, the equipment itself for the detection of radiation, a Geiger counter, can be easily interfaced with the satellites flight computer for the storage of the data, in the form of counts. Third, the Geiger counter will expend only a small amount of the mass budget and will have minimum volume requirements. Fourth, the experiment was chosen because it can be expected to produce results.
1.3Expected Results
The aforementioned results involve a noticeable difference between the ambient radiation detected on the surface of the Earth and the ambient radiation at an altitude of approximately 30 kilometers. Theoretically, more radiation would be recorded at high altitudes than on the Earth’s surface because the radiation has less material, namely the atmosphere, to pass through before detection. Thus, the effect of the Earth’s atmosphere in absorbing and/or scattering cosmic radiation can be determined in the form of a percentage.
2.0 Design
2.1 General Requirements
Many requirements were established that dictate the design of the Axiom BalloonSat, and are met in the design of the satellite. All aspects of the design outlined in the Axiom BalloonSat proposal will be in further design revisions and will be carried out in construction.
2.1.1 The Teamshall launch a BalloonSat that weighs no more than 800 grams.
2.1.2 The BalloonSat that Axiom is proposing shall include two cameras and an experiment utilizing a Geiger counter.
2.1.3 Third, the BalloonSat will have an onboard HOBO system that will take data of the outside temperature and the inside temperature during the flight.
2.1.4 Fourth, the BalloonSat will reach a high altitude (near space) and survive the cold temperatures and not reach an internal temperature lower than zero degrees Celsius, due to the heating unit that will prevent such from happening.
2.1.5 Fifth, the BalloonSat will be constructed of foam core, and will allow for the flight string by including a rubber tube running through the center of the craft which it can pass through.
2.1.6 Sixth, the satellite will bear all pertinent contact information and the US flag. The team will practice the strictest safety precautions to prevent injury.
2.1.7 Seventh, the team will recover, examine, repair, and return the balloon sat safely to Space Grant.
2.2 Requirements (Systems)
2.2.1 Power
The power system shall provide sufficient power for the other systems to operate to the level specified by the design.
2.2.2Science
The science experiment, composed of the Geiger counter, shall record data during the balloon flight in Geiger counts per minute, which can be later graphed and analyzed.
2.2.3Thermal
The thermal system shall provide enough heat to maintain an internal temperature in the satellite of over 0 degrees Celsius, and allow for the other systems to work at the internal temperature created.
2.2.4Optics
The camera systems shall take still pictures out the side of the BalloonSat and the second camera shall record videos from the bottom of the BalloonSat. These recordings and images shall be able to be retrieved from the cameras and stored onto a computer.
2.2.5Structures
The structure shall contain, protect, and insulate all other systems while also allowing for an attachment to the flight string.
2.3 Design Overview
The design of the Axiom BalloonSat can consists of several major subsystems integrated together in the satellite. These systems include Power, Thermal, Optics, Structure, and Science.
2.3.1 Power
The power system of the Axiom BalloonSat consists of power being drawn from onboard batteries. More specifically, the components of the craft that require power will be wired to batteries. Three 12 volt batteries will be used to power the timing circuit which controls Camera 1 and the timing circuit that controls Camera 2. Three 9 volt batteries will provide power to the heater, the Geiger counter, and the BASIC Stamp.
2.3.2Thermal
The thermal system of our satellite must provide sufficient heat to keep the internal temperature of the satellite at a reasonable level for the other systems to continue to function. This will be accomplished by integrating into the satellite a small heating unit composed of 3 ceramic resistors connected in series, powered by two 9V batteries. In addition to the heating unit, the satellite will be insulated with insulating foam to prevent heat loss through the outer structure of the satellite.
2.3.3Optics
The optics system that will be onboard the Axiom BalloonSat will be comprised of two cameras.
2.3.3.1Camera 1
Camera 1 is a film camera that takes photographs at regular intervals aided by a timing circuit wired to the camera that can be set to take pictures at a regular interval determined by the team. It will face out of the side of the satellite, and take pictures along the horizon. The camera is powered by internal batteries, and the timing circuit is powered by three 12 volt batteries. It will be activated pre flight and will operate for the first 72 minutes of the flight, at which point the film will run out.
2.3.3.2Camera 2
Camera 2 is a lightweight digital camera capable of recording a large number of digital images to an internal SD card. This camera will be pointed out of the bottom of the satellite. It is powered by internal batteries and will be controlled with a second timing circuit, powered by the same 12V power supply as the first timing circuit. It is powered on by a button that is mounted on the surface of the satellite.
2.3.4Structure
The structure of the Axiom BalloonSat will be a cube, roughly 15cm x 15cm x 15cm. The outer structure of the satellite will be constructed out of foam core, a lightweight and durable material that also has insulating qualities. Ports in the outer structure will allow the cameras to be pointed out of the satellite while other ports will allows for the external sensors that will run outside of the satellite. One panel of foam core will make up the internal structure of the satellite, and will serve as extra mounting space for the internal equipment. A tube will run down the middle of the cube and will allow for the flight string to run through the center of the satellite. To deal with the condensation that will occur inside of the satellite, silica will be used to absorb the moisture that might accumulate. The silica will be in the form of packets that will be integrated into the satellite.
2.3.5Science
The science experiment that will be performed on the Axiom BalloonSat is the detection and measurement of cosmic radiation that comes into contact with the satellite. This will be accomplished with a Geiger counter that will interface with a BASIC stamp through an interface circuit that the team will build. This circuit will be made up of a unity gain follower (using an operational amplifier) and a 555 timer chip in order to convert the noisy pulse generated by the Geiger counter into a stable 4.5V wave that the BASIC stamp can detect. The microcontroller will record the counts from the counter. The Geiger counter and BASIC stamp will be powered by a 9 volt battery.
2.3 Final Parts List
2.4 Drawings
Structural Drawing (External)
(Drawings not to scale; dimensions are relative; positions are generalized.)
A—Camera 1 Window E—Switches
B—Camera 2 WindowF—Port for external sensor
C—Flight String Tube w/ WasherG—Contact Info Card
D—American FlagH—Digital Camera Power Button
Structural Drawing (Internal)
(Drawings not to scale; dimensions are relative; positions are generalized.)
A—Flight String TubeF—Camera 2
B—Geiger CounterG—Timing Circuit
C—BASIC StampH—12V Battery Pack
D—HOBO Data LoggerI—9V Battery
E—Camera 1J—Heating Unit
K—Interface Circuit
2.5 Functional Block Diagram
3.0 Management
3.1 Organizational Chart
Division of Tasks for Construction
Team Members / Task for ConstructionJacob Rivera and Drew Gottula / Structures – Including mounting of systems, batteries, and insulation
Dustin Martin and Ben Anderson / Geiger Counter System – Including all circuitry and wiring.
Adam Trevizo and Stefan Quan / Camera Systems – Including all circuitry and wiring.
3.2Schedule
EventDeadline Date
Design Document Revision AOctober 6, 2006
Acquire Secondary CameraOctober 9, 2006
Primary Camera Calibration CompleteOctober 10, 2006
Acquire Basic StampOctober 11, 2006
HOBO Calibration CompleteOctober 12, 2006
Secondary Camera Calibration CompleteOctober 12, 2006
Design Document Revision BOctober 13, 2006
Foam Core Construction CompleteOctober 13, 2006
Acquire Geiger CounterOctober 14, 2006
Geiger Counter Construction CompleteOctober 15, 2006
Basic Stamp Calibration CompleteOctober 16, 2006
Insulation and Tube ConstructionOctober 16, 2006
Prototype Design CompletedOctober 17, 2006
Physical Testing on PrototypeOctober 18, 2006
Integration of all ComponentsOctober 20, 2006
Cold TestOctober 23, 2006
Ordering of all Back Up ComponentsOctober 24, 2006
Full Testing of Mock Final DesignOctober 30, 2006
Design Document Revision CNovember 1, 2006
Completed Final DesignNovember 5, 2006
Final System Tests, Checks, and Double ChecksNovember 10, 2006
LaunchNovember 11, 2006
ReconstructionNovember 14, 2006
Design Document Revision DNovember 27, 2006
Design ExpoDecember 9, 2006
Limitations on time and other events that might interfere with the schedule set by Axiom are slow shipping times for ordered equipment (unlikely), malfunction of equipment (possible), integration problems (possible), or other unforeseen problems that the team will work to avoid in all instances.
4.0 Budget
4.1 MassBudget
Mass Budget Chart
4.2 MoneyBudget
Money Budget Chart
5.0 Test Plan
The BalloonSat will undergo a series of tests to ensure that it will survive the fight to near space and back, as well as to make sure the systems will function throughout the duration of the flight. The satellite will be tested in three main
areas: Structural, Environmental, and Functional.
5.1 Structural
In these series of tests, the structure of the satellite will be tested to see if can survive different parts of the flight. All systems need to survive to be able to retrieve data collected during the flight. Ideally, the prototype would be tested with all functional systems inside the structure to fully ensure quality design. However, due to budget and time restrictions the structure tests will be performed without the integrated systems. To make up for this weight during the tests other objects of similar weight will be place in the satellite.
5.1.1Whip Test
In the whip test, the system will experience the maximum G’s it will see on the flight. The satellite will be tied to the end of a string and swung as fast as possible and then slammed into something or whipped to simulate a sudden change in direction during flight. This will also test to see if the systems and structure can survive the increased gravity on the flight.
5.1.2Drop Test
The Satellite will descend from its maximum height very rapidly being slowed only by a parachute. The drop test takes place when the satellite is dropped from about 5 meters up onto solid concrete. This will make sure that the structure will survive the landing and that it will sufficiently protect the systems it will carry.
5.1.3Stair Pitch Test
The Satellite will descend from its maximum height very rapidly being slowed only by a parachute. The drop test takes place when the satellite is dropped from about 5 meters up onto solid concrete. This will make sure that the structure will survive the landing and that it will sufficiently protect the systems it will carry.
5.2Environmental
In near space the satellite will experience very extreme conditions that could affect the functionality of the systems. The BalloonSat will be tested in two main environmental tests that will simulate the environment of near space. This will also help determine if the insulation is sufficient as well as the internal atmosphere.
5.2.1Cooler Test
In near space, the satellite will experience extremely cold temperatures. This will test to ensure that the temperature inside the box is warm enough to support the electrical systems in the satellite. The full functioning system will be placed in a cooler with seven to ten pounds of dry ice for three hours. Then the satellite will be removed from the cooler and tested to see if it is still functioning.
5.2.2Vacuum Test
In near space, the satellite will also experience low gravity. If possible the satellite will be tested in a vacuum for functionality of the system in these conditions.
5.3Functional
The system will be tested from a distance for the full time of a flight. Typical launch time is 90 minutes up and 45 to 60 minutes down, for a total of about two and a half hours. All systems will be turned on and then the satellite will be left alone for the rest of the time. This test will show that the systems function properly for the allotted time. The batteries must last for the entire flight and the systems should take data for the entire flight. Also, this test will ensure that all systems work and function properly.
6.0Test Results
6.1Drop Test
This test was performed twice from about 5 meters high onto solid concrete. The structure preformed better than expectations. We placed several objects in the structure to simulate the actual weight of the final product with working systems. Some of these objects were electronic themselves. All objects inside survived without any minute amount of damage, while the structure itself only experienced a slightly dented corner from a direct impact on both tests. Overall, the structure passed the drop test.
6.2Whip Test
This test was performed for about two to three minutes. We swung the structure at the end of a two meter long string at high velocities. It was clear that the satellite would have no problem experiencing being whipped around. Also, the structure was whip at the end of the string to test and abrupt change in flight. Once, again the structure performed to expectations. The structure passed the whip test.
6.3Stair Pitch Test
The stair pitch test was performed three times total. For the first two tests, the structure was placed on the edge of a flight of stairs and kicked down. For the last test, the box was rolled down the stairs starting from about 2 meters back. The structure took minimal damage here, while maintaining the protection of all objects inside the box. The structure passed the stair pitch test.
6.4Cold Test
The cooler test was performed with around 14 lbs of dry ice in a Styrofoam cooler. Systems were turned on and then the satellite was placed in the cooler. We preformed this test for one hour. At the end of the hour the satellite was removed and systems were checked for functionality. We found that a timing circuit had broken, but due to data from the HOBO, we concluded that it was not due to freezing temperatures. The heating circuit passed the cooler test.
6.5Mission Life Test
With all systems in the box, everything was turned on and left for three hours to make sure the systems would work as long as expected. At the termination of three hours we checked the satellite and found everything in working condition and still recording data. The satellite passed the functional test.
7.0Expected Results
The data and photos that will be collected from the Axiom will be collected immediately after the Axiom BalloonSat is recovered. Measures will be taken to protect the data and prevent data corruption.
7.1 Digital Camera
The photos from the digital camera should number more than 200, and will show the surface of the Earth from the satellite as it ascends and also as it descends.
7.2Film Camera
The photos from the film camera will be far less in number, as the maximum number of photos that can be taken on a single roll of film totals only 25, and at one picture every 3 minutes; the film camera will only take pictures over a time period of 72 minutes. Thus, the film pictures will show only the Axiom BalloonSat’s ascent.
7.3Geiger Counter
The data from the Geiger counter, recorded in counts per minute, is expected to do several things. First of all, it is expected that the number of particles detected per minute will increase as altitude increases, in an exponential fashion. This is because the atmosphere scatters and absorbs incoming solar and primary cosmic radiation which forms secondary cosmic rays which continue down through the atmosphere, in an effect known as cascading. The more atmosphere that particle of secondary radiation has to pass through, the greater chance it has of being absorbed. Thus, more secondary radiation can be detected at higher altitudes than at lower altitudes:a trend that will be shown by our Geiger counter data. After a certain altitude is reached, the data is expected to show a decline in the number of counts per minute. This is the point where the number of secondary particles begins to decrease and where only primary cosmic rays are found. Thedata will show that there is a critical altitude that above which fewer energized particles exist, though they may be more energetic.