Gateway to Space Spring 2006 Design Document

Transcription

1 Colorado Space Grant Consortium Gateway to Space Spring 2006 Design Document The Big Kahunas Solar Hog Written by: Wes Furuya Scott Tatum Vince Williams Noah Moore Mike Loptien March 02, 2006 Revision B 1

2 Table of Contents 1.0 Mission Overview Design 3 Figure 1: The Electromagnetic Spectrum 3 Figure 2: Block Diagram Subsystems and System Requirements Management 6 Figure 3: Team Structure Schedule 7 Prototype 7 Testing Final Design 7 Durability Test 8 Cold Test Budget 8 Figure 4: Budget Test Plan and Results Expected Results 9 Diagrams Figure 5: Foam Core (With Camera Slit) 11 Figure 6: Insulation (With Camera Slit) 12 Figure 7: Satellite Side 13 Figure 8: Satellite Top 14 Figure 9: Internal Parts 15 Figure 10: Finished Satellite 16 Revision Log Revision Description Date B Preliminary Design Review 3/23/06 C Critical Design Review 4/13/06 D Analysis and Final Report 5/2/06 2

3 1.0 Mission Overview Due to the chemical nature of ozone, light with shorter frequencies such as UV tend to be deflected into space, protecting the Earth s surface. We plan to determine how the ozone layer affects the penetration of electromagnetic radiation through our atmosphere and to the ground. Our balloon satellite will observe solar emissions in the infrared, visible, and ultra violet electromagnetic spectrum. We will then determine the interaction between light concentration and the ozone layer in the Earth s atmosphere as our satellite ascends to 30,480 meters. Using a HOBO Data Logger with attached spectrometer and solar cells, the balloon satellite will record the amount of infrared, visible light, and ultra-violet light that penetrates through the different layers of our atmosphere, as well as the voltage produced as the amount of harmful light frequencies increase. 2.0 Design Our experiment is to observe solar interaction with the atmosphere. We will accomplish this by using the solar panels and light spectrometers. The solar panels are not large enough to provide power to all systems in the satellite, but we will be running two different groups of solar panels. The first panel will be attached to the wall of the satellite and the voltage sensor on the HOBO will be used to measure its voltage. As an additional test we will fly a second group of panels that will be placed in parallel with the power supply for the heater. We will be able test how well these panels work by comparing the graph of the internal temperature during testing without the solar panels, to the actual flight data with the panels. To measure light intensity, we will use a HOBO light collector. This HOBO will be devoted to light intensity readings in the Ultraviolet range, and we will be using a filter to block all light wavelengths but those in the UV range. This HOBO can measure the electromagnetic spectrum from 200nm to 1200nm, but we will be focusing in 200 nm to 100 nm. The light spectrum is shown in Figure 1. Figure 1: The Electromagnetic Spectrum Batteries are very heavy for their size and we will need several of them, which makes up a majority of our weight. In an effort to make a more efficient satellite, the panels attached to the 3

4 heater should help increase the temperature produced while the batteries are still operational, and once the batteries die they should be able to provide a sufficient amount of power to our heater. In order to protect our sensitive equipment our satellite will need to maintain an internal temperature of at least 0 o C as well as survive the massive G-forces sustained after burst and during landing. To keep the satellite s internal temperature above our hardware limitation, we will use a self constructed heater that runs off three 9 volt batteries and an additional three solar panels mounted to the side. The heater was made from three 4 ohm resistors set in series. To provide structural integrity, the walls of our satellite will be made of foam core provided in class, and will be reinforced with aluminum tape to keep the satellite tightly sealed. We will be using foam core to construct our satellite because it is a very strong, light, and structurally sound material and it is much easier to use than aluminum because it is easy to cut and form. Aluminum is a much denser material, and thus is much more structurally sturdy, but also much heavier. Weight is a main concern, and with the tape reinforcements the structure should be strong enough for our purposes. The foam in the foam core material acts as a very good insulator to keep the satellite warm and the tape will help trap any stray radiation that might be released from our heater. In addition we will add insulation around the inside of the balloon satellite to help keep the inside warm. The equipment needed for our experiments can be collected very efficiently by the HOBO data logging systems. The provided HOBO will be used for internal and external temperature readings, as well as humidity and voltage readings. The provided HOBO weighs approximately 30 grams. To measure light intensity, the new HOBO systems must be obtained and each one will be devoted to light intensity readings. This HOBO weighs only 18 grams. Each HOBO (new and provided) contains its own power supply, memory, and computer communication port, so they will not have to be activated by our control switch on launch day, but can be placed in hibernation until they are needed. Our mission objective is to determine how the ozone layer affects light intensity. If the light intensity in the ultra violet spectrum is observed to be lower while in the ozone layer, and dramatically increase above, the amount of light absorbed by the ozone layer can be determined. The extra HOBO is the light meter that detects UV rays and can store the data that is collected on its own memory. Once these readings have been obtained, it will be possible to determine the amount of light that is absorbed and deflected by the ozone layer, and we will also be able to tell how much light would be striking the surface of the planet if the ozone was not there. Our mission will also be able to tell if the UV rays affect the energy produced by solar panels, and if the blocked frequencies have any affect on energy production. We will obtain ascent and descent rates by observing our temperature vs. time graph. We will observe the changes in the temperature graph, and use a temperature verse high altitude graph that NASA has provided on their web page. We will then take that time and the approximate height (30,480 meters) and divide distance over time to get the ascent speed. Likewise, we can take that same maximum height time and subtract it from the end time to get the fall time and divide the distance by this time to get the descent rate. 4

5 Our second goal is to image the horizon of the earth and testing will reveal if the camera will need to be tilted for the best possible exposure. Also, the external temperature cable will be strung from the provided HOBO to the outside of the satellite and then mounted on the outside. The hole that is cut in the side of the satellite will be filled with some insulator to block the outside cold from leaking into the satellite. Figure 2: Block Diagram The balloon flight string will be mounted through the satellite because it is much sturdier than a side mount. The forces that are put on the string and its mounting would be too great if it s mounted on the side. However, if it is mounted through the middle, it has all the sides to help support it so the stress will be much less on the mounting which reduces the threat of it breaking off. Washers will be used to line the mounting area because they will provide extra support to the walls of the satellite and are much less prone to bending and breaking. The HOBO that we are using for our experiment were provided by Space Grant and we won t need many spare parts because all of our experimental hardware is provided in the HOBOs. The spare parts that we will need are items such as wiring, batteries, and electrical tape, as well as the filter to block all the other light frequencies. Any other expenses for fabrication and spare parts are taken care of in the budget under Other Fabrication Materials. With these being our only expenses, we will have plenty of money left in our budget for anything that may come up during construction and testing. The total budget can be found in the budget section below. 5

6 We will put our contact information on the satellite in case it is lost. The information will fly along with a small American flag sticker to show that our satellite is not a threat to anyone who discovers it. We have a video camera and a very good video editor so we are planning on documenting the whole fabrication process on video to show after our final presentation. The detailed drawings are included later in the Design Document. The experiment we are conducting is safe for us here on the ground. Our HOBOs are doing all of the measurements and data storage and the only risk we are taking is while soldering. This risk can be lessened by wearing safety goggles while soldering and having burn medications nearby. Liquid metal always poses a burn threat but if we keep medication nearby, the risk of serious injury is greatly reduced. The rest of our experiment is rather safe because we are not using any power tools or heavy equipment or conducting a hazardous experiment. 2.1 Subsystems and System Requirements Thus far our satellite has four subsystems. The first system is structural, comprised of the foam core and the aluminum tape used to hold the box together. The structure is augmented by the insulation that is glued to the inside of the box. The structure subsystem needs to be finished and the internal systems need to be attached to the inside of the box. The second system is the heater system. This system is comprised of a home-made heater built from three heating resistors in series. This system requires the power subsystem to run. The third subsystem is the power system which contains all of the batteries and three of the solar panels. This system will power all of the internal systems (excluding the structure system). The fourth system is the science system which is comprised of the non mission-critical and data-collecting pieces of hardware. The science system includes the camera, the two HOBOs, and one of the solar panels. This system requires the power subsystem and the structures system for power and stability in flight. 3.0 Management Our team is divided into the different subsystems needed for the different parts of the satellite. While each person is listed under a specific subsystem each person will help the team for any and all of the general needs of the satellite. We will attempt to follow the schedule laid out below, in an attempt to complete the satellite on time. Thus far we have been ahead of schedule, and we plan to finish all of our mission critical tests before spring break. The only thing we have left to obtain is the UV filter for our light intensity HOBO. 6

7 Figure 3: Team Structure 3.1 Schedule 1. Prototype: Finish Date: 2/26/06. Before starting on the actual satellite we will confirm which of our designs will work best. Detailed sketches will be made and therefore a prototype can be fabricated to give us ideas for our finished product. We will use a CAD tool which can simulate how everything will fit together with exact measurements. Our Prototype will look exactly like the eventual satellite will look. 2. Building Start: Finish Date: 4/06 Begin building structure for satellite. We will have all dimensions planned out so that our satellite is as compact and durable as possible. The shell of our satellite will be the first part of the building process. Then selectively, each component will be placed securely into the satellite, and the additional external features will be added when acquired. 3. Testing Final Design: Completion Date: 4/13/06 Since the launch date is 4/22/06, we plan to have our final design built and ready to fly no later than 4/13/06. If there are any complications or anything that needs to be changed we will have time to do it before the launch. Also if our satellite fails to meet the requirements of the cold test or durability test, adjustments can be made. 7

8 4. Durability test: Test Date: 3/15/06. This will test the strength of our structure. It will be dropped down the stairs and dropped from the 4 th story of the DLC which will simulate the impact on landing and movement in space. This test will also be performed on a dummy satellite after our structure is finished. This test is completed, but we will need to test a second prototype for more accurate results. 5. Cold Test: Test Date: 3/20/06. We will be placing our satellite in a cooler with dry ice and collect data to make sure all our functions work, minus the external solar panels. Temperature will have an effect on the components inside the balloon satellite; if it gets too cold then everything in our satellite could stop working. The cold test will be performed immediately after the first prototype is complete, and the heater is installed. We have finished the cold test. 4.0 Budget Our satellite is under budget for both mass and money, and unless testing requires more parts, our total cost is under $60 and the mass is around 570 grams. In order to stay on budget, Scott will ensure that every purchase is necessary for our project and possible with the funds we have left. Our budget is shown in figure 4. (Included later in document) 5.0 Test Plan and Results Our test plan is currently laid out in the schedule, but the tests will be conducted on different prototypes that we will construct. We conducted our first test on March 15 th. For this test, we took our prototype box and filled it with 700g of rocks. Our satellite only weighs 570g. The reason for this extra weight in our prototype is to make sure that our box will support the weight we have. We dropped our prototype from the 4 th story of the DLC onto concrete to test how sturdy our box will be when it lands on the hardest surface and going at a speed far greater than the predicted terminal velocity when attached to the parachute. Our prototype held up through the first drop with only a cracked side wall and one rounded corners. However, when dropping it the second time, the crack busted open and our payload of rocks flew everywhere and the box became unsalvageable. This test shows us that our real satellite will hold up very well and that we could launch it more than once without worry. We have made several modifications to the heater circuit, as well as cutting several holes in the side of the satellite for the camera and some of the switches. Our cold test will determine if our box is capable of withstanding the temperature range that we need it to be capable of withstanding. We need to test the solar panels that will go on the outside of the box and redesign their connection to the heater. 8

9 6.0 Expected Results From our two HOBOs, we will be able to obtain the range of our satellite s internal temperature, the range of the external temperature, the humidity inside our satellite, the voltage range of one of our solar panels, and the light intensity from the sun. From the humidity, we can approximate the amount of atmosphere present inside of the satellite. The external temperature tells us our approximate altitude, as well as the relative difference between the internal temperature and the external temperature. The internal temperature tells us how well our heater worked with the batteries and the solar panels, and this data will be augmented by the voltage readings from one of the solar panels. Our main experiment is the light intensity, and this reading tells us how much the ozone layer absorbs and deflects UV radiation. We can use this value to determine both the amount of ozone and the intensity of UV radiation that would strike the earth without the protective layer. 9

10 Equipment Description Mass (g) Cost ($) Self-Assembled Regulates time between Camera pictures 10 g Provided Timing Circuit Ensures that the shots will not be all taken at once Cannon Elph LT Captures Still images using magnetic strips to record on solid Film Strip 140 g Provided Timing Circuit Three AA batteries that provide the power 70 g Provided Power Supply required for the timing circuit Self-Assembled Maintains internal temperature of at least 0 oc 60 g Provided Heating Pad Heat Pad Power Supply Provides power to the heating pad 120 g Provided Activation Turns on all systems in the Satellite and includes all 5 g Provided Switch necessary wiring for the complete circuit 4 channel Monitors external and internal 30 g Provided HOBO temperatures of Balloon Sat Aluminum Tape Aids the structure and helps maintain stability 2 g Provided Foam Core Structure of the Satellite, provides the mountings for 10 g Provided Material everything Payload - UV light Monitors levels of UV absorption in the Ozone layer 40 g Free Detection systems from Space Payload (extra) Wall Mounted Solar panels Aids in the collection of data in the spectral range, could be mounted to a voltmeter and data storage unit Grant 45 g Free from Space Grant Small Reinforces the structural support and allows the cable to pass 1 g 2 $ Washers through sat Electrical Connects the members of the circuit together 2 g 5 $ Wiring provides direct power Black Light Filter Filters out all wavelengths but the UV-A spectrum 5 g 33 $ Other Other resources needed to finish construction of the satellite 10 g 20 $ Fabrication Materials Totals: 570 g 60 $ Figure 4: Budget 10

11 Figure 5: Foam Core (With Camera Slit) 11

12 Figure 6: Insulation (With Camera Slit) 12

13 Figure 7: Satellite Side 13

14 Figure 8: Satellite Top 14

15 Figure 9: Internal Parts 15

16 Figure 10: Finished Satellite 16