FinalReport_Wyoming - Colorado Space Grant Consortium
WYO GALACTIC 2009-2010
Wyo Galactic Final Report
Final Draft
Charles Galey;Nicholas Roder;Peter J. Jay;William Ryan
4/29/2010
Abstract
Colorado Space Grant Consortium (COSGC) and NASA offer Universities in the United States affordable access to sub-orbital space flights. Wyo Galactic, composed of four Mechanical Engineering students, will continue UW involvement for a second year. The goal of Wyo Galactic was to develop technologies and components for future UW experimenters to use as part of their test packages. These experiment sub-systems included, a rotationally stabilized camera plate, GPS tracking and logging of flight data, wireless recovery of test data.
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Table of Contents
I.
INTRODUCTION
II.
DESIGN
F i n a l D e s i g n R e p o r t | ii
III. FABRICATION
IV. TESTING
V. MANAGEMENT
VI. CONCLUSION
VII. APPENDICIES
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F i n a l D e s i g n R e p o r t | 1
I.
Introduction
BACKGROUND
The purpose of the RockSat program is to provide a low cost means for student and university access to space. RockSat rocket and payload requirements were designed specifically to make this process as straightforward and simple as possible. The inaugural year of the RockSat program was 2008. Students from universities across the country designed payloads that were launched June 26, 2009. A Terrier
Improved-Orion rocket catapulted four RockSat customer canisters with 10 experiments from Wallops
Flight Facility (WFF) to an altitude of over 75 miles.
In ’08-‘09, two teams from the University of Wyoming successfully designed, built, and flew two experiments. The projects were designed in conjunction with the University of Minnesota, who shared a canister with UW. Experiments flown by UW included testing effects of extreme G-forces upon crystal oscillators (in excess of 20 G), a multi-sensor package including: temperature, humidity, and an extensive processing and data storage system for payloads. This system was developed by the Electrical
Engineering team members and contains an open ended operating system, which was designed to be easy to use, and offer a streamlined approach to integrating a variety of experiments.
Great importance was placed on developing systems which may be used for future projects. This would enable future design teams to place more of an emphasis on developing actual experiments as all of the acceleration recording, power, processing, and data storage systems will have already been developed.
All of these systems are essential for any successful experiment. With this in mind Wyo Galactic developed a payload that would provide a solid, easy to integrate base to future group projects.
Wyo Galactic was committed to creating flexible, task oriented, and advanced payload subsystems for future teams who require high quality products for their forward-thinking applications. We accomplished this by: Creating a payload providing a stabilized platform which will be utilized to deliver images for analysis by University of Wyoming and the new University of Minnesota team (MinnSpec);
Tracking the flight of the rocket using a GPS module; Wirelessly retrieving payload data post flight before obtaining the physical payload; While ensuring all systems are easy to use, understand and integrate into any future payload system or application.
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PROJECT DESCRIPTION
Overview
UW RockSat team, Wyo Galactic, designed, built, and will test a rocket payload for the NASA RockSat
Program. NASA requires that the payload fit inside the NASA designed RockSat canister. Wyo Galactic will split the canister with a University of Minnesota based payload group, MinnSpec. RockSat canisters must meet stringent requirements to be qualified for launch in June 2010. NASA’s criteria are discussed below in the Engineering Specification section. The first goal of the group was therefore, to design a payload that will meet or exceed each of these requirements. To achieve this goal Wyo Galactic designed a robust package that also met several experimental objectives. The payload will address 6 major areas of interest identified by the design group:
Experimental Instrumentation
GPS Tracking
Data Storage/Processing
Data Transmission
Rotationally Stable Platform
High Quality Photography
Goals
There were several goals that Wyo Galactic set in addition to the completion of each system. The payload was to properly integrate with the experiment developed by UW partner group MinnSpec.
Experiment needed to meet COSGC and NASA provided deadline requirements. The payload was selected for flight on the June 24 th launch date, and must survive the flight, and provide retrievable data.
UW also hopes to analyze the data before returning home from WFF.
ENGINEERING SPECIFICATIONS
Terrier-Improved Orion Rocket
The RockSat payload canister has specific dimensions, weight, center of gravity and ports. The summary of key constraints can be viewed in Table 1 as seen below. An important consideration when viewing the constraints is Wyo Galactic’s fraction of original values (half) due to sharing a canister with MinnSpec.
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Table 1: Summary of Key Constraints
Type
Physical Envelope
Mass
Center of Gravity
Ports
Quantitative Constraint
Cylindrical:
Diameter: 9.3 inches
Height: 4.75 inches
UW Payload = 6.5 lbm
Canister + Payloads = 20 ± 0.2 lbm
Lies within a 1x1x1 inch envelope of the RockSat payload canister’s geometric centroid.
Customer shall provide drop down tubing for atmospheric plumbing.
Plumbing must terminate with a male ¼” NPT connector.
Additionally, the customer shall design in a redundant valve to protect the payload at splash down.
(Source: RockSat Payload Canister User’s Guide 2010)
Electrical specifications for the rocket payload include the payload access window and wire-way, optical and atmospheric ports, power, telemetry tracking and control, finally harassing and stacking. The window alongside the canister has dimensions of 3.5 inches wide by 4.5 inches tall, and MinnSpec has agreed to give Wyo Galactic access to the whole window. Each payload must be completely selfcontained with a hookup for an early activation relay so that Wallops has complete control of payload current at all times. It is highly recommended that experiments have rechargeable batteries, but the use of rechargeable lithium ion batteries is prohibited.
All data must be stored on internal memory as experiments will not be allowed to transmit data while the rocket is in flight. All payloads shall harness wires with a nylon lacing tape or the equivalent. It is also recommended that all connectors and IC sockets be tied and staked in place using aerospace grade RTV.
Table 2: Key Performance Parameters
Key Performance Parameter
Altitude (km)
Spin Rate (Hz)
Value
≈115 km
≈1.3 Hz at Terrier burn out;
≈4.8 Hz at Orion burn out
Maximum Ascent G-Load
Rocket Sequence (Burn Timing)
25 G
5.2 s Terrier burn—9.8 s
Chute Deploy (seconds)
Splash Down (seconds) coast—25.4 s Orion burn
489.2 s
933 s
(Source: RockSat Payload Canister User’s Guide 2010)
Wyo Galactic’s canister will undergo tests to verify its ability to withstand G-load requirements (Table 2).
As one of the biggest environmental conditions to account for is the G-load the payload will undergo.
During the flight the specifications the payload has to be able to withstand 25 G’s of quasi-static loading thrust axis, a possible 35 G impulse in along the thrust axis and 10 G’s in horizontal axes. The payload
F i n a l D e s i g n R e p o r t | 4 must pass three vibrations tests, centroid verification and two Day in the Life (DITL) tests before it will be cleared for launch.
Stabilized Plate
A plate will be spun via electric stepper motor which must have the capability to spin the platform at a maximum rotation of 288 rpm (to match the rocket’s maximum spin rate). The motor must also have enough torque to accelerate the plate and experiments at the maximum spin rotation acceleration of the rocket, which is not yet known.
The plate itself must withstand the gravitational forces (35 G’s max) created by the rocket on both the plate and the attached cameras. To support the plate a shaft has been designed which will withstand all torsion forces created by the motor and rocket. A bending force will also be placed on the shaft when the rocket becomes parallel to the surface of the earth, and when any centrifugal forces are places on the assembly. This shaft will be supported by a steel ball bearings which must withstand all forces, both axial and radial created by the system.
Instrumentation / Experiments
Accelerometers are the only analog devices that will be flown. Two accelerometers will be used to measure both the spin rate and lateral movement of the rocket. Along the rocket thrust axis, a single axis accelerometer should be able to measure up to 35 G’s and surface mount for easy integration. To measure rotational accelerations requires a single axis accelerometer capable of less than 2 G’s. The third accelerometer needs to be dual-axis with a measuring capability greater than 10 G’s.
Wireless Data Transmission
The wireless system must transmit the stored data within a reasonable time frame and distance.
Representatives of the COSGC have advised that there will be access to the rocket as it is returned to
WFF. We should be able to get within 50 ft. of the rocket. Therefore, the range of the wireless system does not need to be too large. It has been determined that there will be 5.5MB of data to retrieve (see
Table 5 on page 15). The wireless connection will provide a transfer rate of at least 250kb/s at a range of
100ft.
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II.
Design
MORPHOLOGY
In previous versions of the design this morphology took the reader from inception to selection of parts.
Since then Wyo Galactic’s design evolved to reflect the practicalities and requirements of real world design. This section will discuss the original parts from last semester and how they have evolved to Wyo
Galactic’s final design.
GPS Tracking
The first GPS unit that was selected from the 8 design specifications stated in Appendix A. That device was the Copernicus DIP Module from sparkfun.com. This particular GPS model has a cold startup time of
39 seconds which was longer than desired. The update rate for this particular model was 1Hz and includes an onboard RAM memory. The cost of this specific GPS module was $74.95 excluding shipping and handling.
However, shortly before our ordering process began the Copernicus became out of stock and backorders were not allowed. As a result a new module had to be selected as close to the previous spec’s as possible. The new selection was called the Micro-Mini which meets and exceeds the capabilities of the Copernicus. The cost of the new GPS module was $79.95 excluding shipping and handling. The refresh rate is the same (1 Hz) with an SMA Antenna port. Additional benefits included much faster start times and a smaller form factor.
Substructure
For the most part Wyo Galactic utilized the substructure which was designed last year. Some changes were made, such as material, mounting holes and other modifications to accommodate the stabilized plate. Further modifications are detailed in lower sections.
The substructure will be tested for structural soundness via calculations and through utilization of finite element programs.
Power System
Several options were considered for powering the payload from batteries to nuclear fusion. While fusion would have been a good option lack of ability to enrich uranium was a significant drawback. A power generation system was planned the full morphology of which can be found in Appendix B. The generation system has been discarded so, experiments will be powered by a system which will consist of standard batteries.
Batteries
Originally, Wyo Galactic wanted to utilize the high efficiency of lithium-ion batteries; however, the use of these batteries is strictly prohibited by NASA. This has led to choosing standard alkaline batteries.
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There are many benefits to using these batteries including cost, ease of use, and can be purchased at virtually any store. These batteries are very reliable; they do not have a chance of exploding after prolonged use, and will be able to sustain our power needs under the flight constraints. The batteries must have enough capacity to power the wireless transmission several hours after launch.
Plate Stabilization
Plate Assembly
After determining that the power system would not function as intended the group chose to build a system which would provide a stabilized mounting platform for future experiments. This system entails a plate mounted to a freely spinning shaft. The shaft is supported by two bearings which provide support in both radial and thrust directions. The shaft and plate are spun by a stepper motor which is controlled by the main CPU. The CPU takes inputs from the accelerometer packages and spins the motor and therefore the plate at a rate and direction to counter act any spinning done by the rocket. A mockup assembly can be seen in Figure 4.
Figure 4: Stabilized Plate Mockup
Motor– A JAMECO 237490 NEMA 17 stepper motor was selected to drive the camera plate. Using the masses, geometries of the camera plate and the components mounted on it was determined that the motor would need to provide 7.2 oz-in of torque. The motor selected will provide 25 ozin at 5 volts and is capable of the precise speed control needed for the plate to remain still relative to the rocket. The motor can easily travel at 288 rpm and provides enough torque to properly accelerate our plate and experiment.
Shaft – The shaft for this system must withstand two major forces;
1. The forces exerted by the plate and experiment under a maximum G load of 25 G’s.
2. The forces created by tension in the belt and the components under the tangential acceleration of the spinning plate. This component was made of mild carbon steel.
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Plate– The plate must withstand all torsion forces created by the mass moment of inertia of the experiment & plate, and the torque created by the motor. The plate must support our experiment and the weight of the plate under maximum G loads of 25 G’s. These components will be made of Aluminum.
Bearings-
The bearings must withstand both radial and thrust forces for this experiment. Radial forces will include the forces created by the rocket during flight, and the forces created by the motor, connecting belts, and pulleys. Instrument ball bearings will be used.
Platters Substructure platters must be modified to incorporate this system. This will include changing the spacing of the platters to accommodate for the plate, experiment, and stepper motor. In addition to this holes will be drilled in the platters to accommodate bearings, and serve as motor mounts.
Instrumentation and Experiments
Full details of each experiment that was rejected (not included in the final payload) due to feasibility and other reasons can be found in Appendix C.
Camera
The plan at the end of last semester was to purchase a camera from a big box store and disassemble it until only the circuitry and other necessary components were left. After several cameras failed to meet requirements an alternative was found from the security community. The DVR623V 5M DSC/DV module is simply a barebones circuit board with a bonus, a detached lens allowing significant changes to the plate and space requirements. Where the old plan required the circuit board with lens attached to stand tall at almost 4 inches the new lens allowed a height of less than 2 in. Decreased weight on the edge of the plate and associated geometry changes reduced torque requirements from 23 oz-in to less than 8 oz-in.
Accelerometers
Wyo Galactic was originally planning to have two accelerometers, determining the acceleration and spin of the rocket. The accelerometer that was designed for was a 3-Axis VTI: SCA3000-E05 from digikey.com.
Further design this semester revealed that this accelerometer would not measure high enough g-forces in a single plane. Thus the sensor package was redesigned with a single axis accelerometer measuring up to 35 G’s recording in the thrust direction. Two additional 2-axis accelerometers placed at the edge of the payload with resolutions of up to 18 G’s will record rotational and horizontal G-forces.
Wireless Transmission
Wyo Galactic wants to obtain information wirelessly once the rocket is back at Wallops. This will allow
Wyo Galactic to obtain and analyze the data without having to wait six hours to retrieve the data manually, which is exactly what last year’s RockSat group had to do. To determine which wireless system was to be used several options were researched details of each of the other formats can be found in Appendix D. Originally the final format selected was IEEE 802.11 more commonly known as Wi-
Fi. It has a range of approximately 300 ft with a high data transmission rate of 200 Mbps. Further
F i n a l D e s i g n R e p o r t | 8 research led the group to discover that a Bluetooth system would be easier to configure and transmit at a higher data rate than Wi-Fi so that format was selected.
FINAL DESIGN
Wyo Galactic broke the system down into five categories to better characterize each subsystem. The five subsystems are:
Structural Support
Drive Train
Sensors and Visual Components
Power
Command and Control
Structural Support
The structure inside the payload must withstand some severe conditions while in flight. As mentioned above, payloads will undergo upwards of 25 G’s in the longitudinal axis and +/-10 G’s in the lateral axis.
To maintain the integrity of the payload Wyo Galactic is utilizing a four pillar structure for the payload
(Figure5).
Figure 5: Structural support inside the canister. (Clear plates used to represent UM’s experiments)
The mounting plates and stabilized plate are constructed out of 6061 T6 aluminum alloy. The mounting plates and camera plate are 1/8” in thickness. See Appendix F for detailed dimensions of the complete assembly. Wyo Galactic’s support and power transmission shaft is constructed out of 12L14 carbon
F i n a l D e s i g n R e p o r t | 9 steel. In a bending stress analysis under expected loads the shaft has a factor of safety of 16. Standoffs are made out of 5/16” hex bar 6061 T6 aluminum. These are drilled and tapped in the ends to support the joints. Steel ball bearings have been employed to support the spinning shaft and plate. Bearings selected have the capability of supporting up to 243 pounds in the radial direction and fifty pounds in the axial direction, which greatly exceeds anticipated loads. These bearing were selected for their strength, size, and cost. All of these materials will suffice for both our strength and weight requirements.
The lower gray portion of Figure 5 will be Wyo Galactic’s payload while the upper half will be occupied by MinnSpec. Based on the loads that are expected an initial structural analysis was conducted on the structure using Solidworks Simulation Express (Figure 6).
Figure 6: Solidworks initial stress analysis at 25 G’s
The deformation scale is not user definable and Solidworks has set it to 110, in an actual test the structure would only deflect 0.2 mm at the worst case.
Drive Train
The platform is stabilized longitudinally by a stepper motor attached to a pulley system. Pulleys are attached to the shaft with set screws and will provide a gear ratio of 1:1. Wyo Galactic has also chosen to use a timing belt configuration to avoid any slippage of the pulley and belt during flight. The timing belt is rated at 10 oz-in of torque, which gives a factor of safety of 1.4. This works well with the JAMECO
F i n a l D e s i g n R e p o r t | 10 stepper motor, which due to component changes, was specified for many times the torque needed to accelerate the plate and camera from dead stop to the maximum spin rate of the rocket. The Terrier-
Orion rocket will reach a maximum of 288 rpm so the motor must be able to compensate to ensure a stable surface. To accomplish stability a negative feedback control system will be implemented using data from the accelerometers to adjust the speed of the motor. A full description of this process will be detailed in the Command and Control section. See Appendix H for detailed part numbers.
Command and Control
The code and data processing is conducted by a new custom control board manufactured by Wyo
Galactic. At the heart of this main board is a powerful ATMEL ATMega 1284p AVR Microcontroller. The chip is programmed using the C programming language. The board itself also contains accelerometers, voltage regulators, the MicroMini GPS module, Bluetooth unit, stepper motor controller, and SD logger circuit for removable data storage. Two peripheral boards are employed to hold both the external accelerometer, which is placed along the periphery of the canister, and camera control, which is located on the stabilized platform. A block diagram showing the functional block diagram of the circuitry can be found below (Figure 7). Detailed electrical schematics can be found in Appendix E.
Color Key
Data
Power
Data +
Power
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Voltage Regulator
Main Processing Board
RBF PIN/ Early
Activation Relay
Power Source
( Battery)
SD Data Logger
ATMega 1284P
Bluetooth module
2- Axis
Accelerometer
Interface to Peripheral Boards
1- Axis
Accelerometer
2- Axis
Accelerometer
( for side of can)
Interface to Main
Board
GPS
Interface to Main
Board
Antenna
Stepper Motor
Controller
Stepper Motor G - Switch Power Source
Interface to Main
Board
PIC Controller Camera
Switch Data Storage
Figure 7: Block diagram of the electrical system.
To facilitate communication between the main board and the peripheral devices Input/output (I/O) and
Serial Peripheral Interface (SPI) communication methods are used. These interfaces are very simple and easily accommodate all of Wyo Galactic’s data transmission needs.
On the main board itself data storage is completed by a SD logger circuit. While originally the SD card was planned to be attached directly to the processor, further research revealed that task to be a Sr.
Design project by itself. So a separate circuit was obtained to facilitate that communication. As
F i n a l D e s i g n R e p o r t | 12 mentioned above the main board also houses a Bluetooth RF module capable of transmitting the recorded data. This RF transmitter will be broadcasting at 2.4 GHz and is capable of transmission rates of up to 1.2 Mb/s.
The photography suite will not be included in the main board or stored there since it is already facilitated on the camera selected and a slip ring was determined not to be feasible. The RF module also would be unable to handle the amount of data stored by the cameras in a timely manner.
Main Board
To facilitate the instruction and control of all of these components an ATMEL ATMega 1284P microcontroller has been selected. The programming of this chip is done by a SDK-500 serial programmer provided to us by UW’s Electrical Engineering Department. Generally, an Atmel chip accepts commands from a C Language compiler. Serving as the coding and debugging environment was
Atmel’s AVRStudio 4 interface development environment (IDE). To compile the code Wyo Galactic will use the WinAVR compiler which is available free to the public under the GNU General Public License. All of the equipment and software has been tested and is compatible with each other.
The first step of the programming project was to generate a flow chart for each of the processes that will be required. As the programming is a new task for Wyo Galactic the plan was to break the system up into stages of decreasing priority:
1.
Motor Control (2-Axis Accelerometer, Motor Controller)
2.
SD Storage (Serial Interface)
3.
Additional components (GPS, other Accelerometers)
4.
Communication (Bluetooth)
This ensured that should a program fail to be completed, beyond stage 1, the payload could still function as intended.
Before any code was typed into a computer two key “pre-writing” tasks needed to be completed, a process diagram and flow-chart. The process diagram was intended to outline the various components of the system and how they interact with each other. In this case how they interface with the Atmel processor (see Appendix G). From this document a flowchart was created outlining the path of the program and how each action will be undertaken. An example of an early flow chart for stage 1 can be found in Figure 8 below.
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Initialize ATMEL
Processor
Set Mission Clock
Initalize ADC
Read ADC
Yes
Log n cycles
Convert to Velocity
Send to SD Logger
Same as Before?
No
Add to previous
Velocity
Yes Acceleration No
Subtract from previous velocity
Convert to PWM
Set PWM
Send STEP to Motor
Controller
No
Mission Clock
> 40 min?
Yes
Decelerate
Set STEP to Zero
Send System to
Standby
Figure 8: Flowchart for motor control programming
Note that in the image above most of the processes are green in color and one block is yellow. The yellow block indicates that it is part of a different stage of programming; in this case the yellow code has to do with stage 2, the SD Data logger. A chart diagramming the basic outline of the whole project including stages 2-4 can be found in Appendix G.
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As mentioned above the system was broken into 4 stages. The first of which was the motor control system. This system was labeled the most critical because the spinning platform. Also, if it was the only system coded the payload would still be able to function in a barebones state. To accomplish the spinning of the plate 3 systems in the Processer were employed:
Analog Digital Conversion (ADC)
Timer
First, data would be read into the system by the accelerometer via the ADC system that voltage would be converted into a binary coded decimal that could then be used to find the velocity. The ADC value is a
10 bit number so approx. 1024 total divisions. This is cut in half since the accelerometer sets zero at half the reference voltage, in this case 5V. The accelerometer has a resolution of up to 18G’s and there are
32.2 ft/s2 per G. Using this unit conversion the processor now has a usable acceleration value. Next the processor needed to convert the incoming voltage from acceleration to velocity. To accomplish this Wyo
Galactic decided to employ the trapezoid rule collecting 2 points of data,
This facilitates the conversion to velocity and ensures that the controller is outputting correct data. The
CPU takes data from the accelerometer approximately once every 8ms. so with only 2 points of data stored the system has an extremely fast response time to changes in spin rate. Once a velocity has been obtained it can easily be converted to pulses per second. The stepper motor rotates 1.8 degrees per step so from a velocity and a little geometry (Figure 9). x
R
1.8
Figure 9: Diagram of plate rotation w.r.t. stepper motor pulses 𝑝𝑢𝑙𝑠𝑒 𝑠𝑒𝑐
=
𝑉 𝑥
=
𝑉
R ∗ tan(1.8)
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From this timer 1 on the CPU is set to deliver to the motor that number of pulses per second until told otherwise. This programming is key because it would be disastrous if the chip were to stop sending pulses since the stepper motor would lockup and likely damage components. Further plans to introduce a negative feedback system were considered but discarded as beyond the scope of this project.
Programming stage 2 involved updating the software to implement the Universal Serial Asynchronous
Receiver/Transmitter (USART) functionality of the ATmega 1284P. To do this Wyo Galactic first obtained a logic level conversion chip to allow the processor and components to directly communicate with the programming PC. This allowed for each device to be tested and checked for functionality. This device also allowed for viewing of the communication between the devices to ensure they were sending intended signals. A certain amount of tweaking ensued to ensure communication. Once the cable arrived the processor needed to be set to a certain communication frequency or ‘baud rate’ to ensure proper communication between devices. This speed is set by the manufacturer of each of the various components and code for interacting with each of those devices needed to be tailored to that number.
Thankfully those settings are given by this equation from Atmel.
𝑈𝐵𝑅𝑅𝑛 = 𝑓 𝑜𝑠𝑐
16 ∗ 𝐵𝑈𝐴𝐷
− 1
In the equation above UBRR is the register where the baud rate is set in the processor’s unstable memory. With the baud rate set, first on the block to be linked was the SD card. This was important to assist in the final calibration of the Stage 1 code and would allow determination of the outputs from the accelerometers. Critical tasks since the plate and stepper control were not operating as expected.
The logger itself required very little hands on programming. A firmware update was required to enable latest functionality changes by the manufacturer. This task was completed using the afore mentioned cable.
At the time of this final report stages 1-3 are in the final phases of testing and implementation (See
Appendix G). Stage 4 (Bluetooth) is in the planning process but is scheduled for completion by early
May.
Camera Control System
The purpose of the camera control system is to trigger the camera at the appropriate time to take a picture through the optical port of the rocket, and to control the frequency of the pictures being taken.
The camera control systems will utilize one Microchip PIC microcontroller. The controller will be programmed via picBASIC pro. The controller will communicate with the camera and two photo gates.
The frequency of the photos taken will be regulated as to provide pictures of the entire flight. Also, as the triggering times will not remain constant (the rocket is spinning at different rates) this controller will recalcuate trigger times vased on data from the two photogates. Conversion values will be hardcoded into the pic for these conversions. For a detailed schematic see Appendix E
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Sensors
There are four different sensors on this payload. Two 2-axis accelerometers will be placed at the periphery of the canister located 180 o apart from one another. They will be attached to satellite boards to measure the rotation and horizontal motion of the rocket. This configuration was chosen to reduce external forces (gravity, lateral motion of the rocket) effect on the calculation of the rocket’s spinrate.
This allows the system to know how fast the rocket is spinning and send data to the plate to compensate. A third single axis accelerometer is also included, and is oriented to record data along the thrust axis. To further characterize the flight of the rocket a GPS unit is attached to the main board along with a SMA antenna to capture the signal from the satellites. The fourth sensor is a camera on the longitudinal axis. Each component has been carefully selected to interface properly with the processor via serial interface.
Power
The power system is driven by 8 AA Alkaline batteries. These in series will provide the necessary voltage to meet the requirements of the electrical circuitry and the motor. The electrical circuitry will require 2 voltage rails 12V, 5V. To comply with Wallops flight center requirements two fail safes will be built into the power system leads for the 1.SYS.2 early activation module for the main circuitry and a G switch to activate the camera system upon launch. A schematic of these systems can be found in Appendix E.
BROADER SOCIATAL IMPACT
As part of the ongoing effort in the world of engineering to take a step back and reflect on all of our actions. Wyo Galactic was asked produce this societal impact statement about the benefits and drawbacks of the payload and the overall impact the project might have.
This effort affects society in broad ways. The first impact is the vital importance of space exploration.
Space travel has brought to society many benefits that would not otherwise exist. From satellite communication that makes the world safer to GPS that makes it easier to navigate. It also provides the only hope for human survival, as our population explodes beyond earth capacity. Philosophers and scientists have long noted that earth is soon to reach its saturation point. Without a means of exiting near earth orbit and traveling to the broader universe the human race is doomed to sink into chaos and eventual extinction. The process will be slow; at first mild measures will be instigated to reduce birthrates. When this fails draconian china style solutions will be instituted ripping apart the fabric of freedom and democracy worldwide. This will result in a war on a global scale coupled with people fighting for fewer and fewer resources. Until the few survivors too dejected by the state of humanity to rebuild civilization move to the mountains and the race will finally die out. Without the small and vital contribution of Wyo Galactic, the world could very well sink into chaos
On a more focused scale there are some drawbacks. There are emissions from every rocket launch. In 1999 a Space Shuttle launch used an equivalent amount of fuel as was burned in two minutes of nationwide automotive use. However, most of the hazardous emissions come from the liquid fuel engines that combine purified kerosene and liquid oxygen. The solid rocket boosters provide about 70% of the thrust for shuttle launch and the byproducts, potassium chloride and aluminum oxide are not hazardous to the
F i n a l D e s i g n R e p o r t | 17 environment. RockSat’s Terrier-Orion rocket has solid-propellant motors also, so the environmental impact of the launch is low. The payload is small which doesn’t require a lot of resources. All of the major components will be made of recyclable aluminum. Also, the payload is intended for reuse which will reduce the amount of effort required of future teams of engineers. The spinning platform could very well become the basis of many future projects, such as artificial gravity, or a stabilized platform for a plane based laser, the possibilities are endless.
NASA has a Technical and Standards Program which publishes standards for everything from “Computer-
Aided Design Interoperability” to a “Handbook for Limiting Orbital Debris”. This program is run by the
Colorado Space Grant Consortium who publishes, “The RockSat 2010 Payload Canister User’s Guide”, which also contains design and build standards. There are numerous required safety features such as the
“no volt” requirement that forbids the supply of power to RockSat experiments prior to launch to reduce the likelihood of an accidental launch.
To ensure public safety commercial rocket launches are regulated by the Federal Aviation Administration
(FAA) through the Office of Commercial Space Transportation (AST). Permits and licenses for orbital and sub-orbital rocket flights are granted after an application addressing all aspects of the craft, flight, company ownership and a hazard analysis, as outlined by the AST. The RockSat/RockOn! program falls under the authority of NASA’s Wallops Flight Facility. NASA may or may not be required to comply with these regulations as NASA was given its authority in 1958 by the National Aeronautics and Space Act.
However, it is expected that NASA flight rules are comparable to those of AST. The most obvious safety requirement is that a reasonable distance from the launch pad must be kept by spectators. Also, AST requires that commercial, private launch sites cannot be within 5 miles of airport, cannot be within 1500 feet of the property boundary with an unrelated (private) property cannot launch if the sky is too cloudy
(5/10 coverage), and the restrictions go on and on.
F i n a l D e s i g n R e p o r t | 18
III.
Fabrication
Several custom components were fabricated for the payload and experiments. These components, their associated subsystems, and fabrication techniques are detailed below. These include:
Substructure
Support/Power Transmission Shaft
Substructure
Three components of the sub structure required custom fabrication. These include:
Standoffs
Support/Experiment Platters
Standoffs
The standoffs provide structural support and proper spacing for the bulkheads and platters. The standoffs were constructed out of 5/16” aluminum hex bar and cut to length, then drilled and tapped for a #8-32 thread.
Support Platters/Experiment Platters/Rotating Plate
These platters provide support for all of the experimental equipment, and provide support for the substructure. They are machined out of 1/8” T-6061 aluminum plate via the water jet, which uses an abrasive accelerated with high pressure water to cut the material. This is a CNC unit which directly interprets a DXF file. This enabled import of SolidWorks drawings directly into the water jet for fabrication. Using the water jet to machine these pieces greatly shortened the lead time of part production.
Support/Power Transmission Shaft
The shaft provides support for the rotating plate, and facilitates power transmission between the stepper motor and rotating plate. It is machined out of 12L14 Steel round bar on a lathe. This device spins the work piece while holding tooling stationary. This allowed for the shaft to be cut to specific diameters appropriate for the application.
F i n a l D e s i g n R e p o r t | 19
IV.
Testing
TESTING
Various types of testing took place through-out the production process. AVRStudio 4 IDE is a MS
Windows based development environment for programming microcontrollers (MCU) has been used simulate the operation of a piece of code on any Atmel CPU. This allowed development of the code to run the experiment before the electrical components even arrived. It also has an emulator that runs the code in real-time with break points and register checks.
The structural design has been and will continue to be modeled and tested in SolidWorks. Final testing will be conducted using an Instron or MTS load frame. The completed payload will be loaded into the machine and a one dimensional shake test will take place. Vibrations data from a previous flight will be used to generate a test cycle that will simulate the entire flight. This will test the electrical connections, structure and allow determination of the natural frequency of the assembly. The CG of the assembly will be determined by using a pendulum method, and through statics calculations in conjunction wilth load cells. The hope is to complete the final testing by the end of May.
The functionality of the experiment will be tested with a minimum of two Day in the Life (DITL) tests.
During the DITLs the experiment will run during the vibration tests. The canister will be placed in a lathe or mill and spun at rotational speed of the rocket during flight to test the camera plate control. This will be accomplished by the construction of a specialized test frame designed by Wyo Galactic. A mockup of this frame can be found in Figure 10 below. The data collected will be downloaded wirelessly and compared to the flight vibrations data used to design the test.
Figure 10: Design drawings for fixture to test payload on Mill
F i n a l D e s i g n R e p o r t | 20
V.
Management
BUDGET
The total estimated cost for this project was $12,900.00. This amount included materials cost, canister cost, and travel. The materials cost was $669.26 which included both the budget from the Mechanical
Engineering and Physics/Wyo Space Grant Departments. The ME department granted $154.00 and the
Physics department allowed $498.07 to be spent. Figure 11 shows the amount of money spent on each specified component for the canister. The canister cost was $7,000.00 because Wyo Galactic split the canister into two equal parts thus dividing the original canister cost ($14,000.00) in half. The travel budget is still undergoing investigation, but the approximate amount ranges from $3,250.00-$5,250.00.
The reason for this high range is due to the amount of participants from Wyo Galactic who will be traveling to Wallops. Currently 3 out of the 4 members will be attending the launch at Wallops so the cost is currently $3,250.00.
Camera
GPS
Wi-Fi
Accelerometers
Processor
Mechanical
Electronic
Figure 11: The amount of money spent on each component for the payload.
The estimated labor cost for this project was approximately $206,483.15. This cost includes four engineers at $30/hr, three consultants at $45/hr and the fringe benefits involved in this project. The amount of hours placed into this project for this spring semester is roughly 800 hours working approximately 20 hour weeks for 38 weeks. These numbers set a total project cost of $530,300.00. This total amount of project dollars does not include the cost of splitting the canister with MinnSpec
(University of Minnesota) and does not include the future summer work Wyo Galactic will have to accomplish prior to mission launch. An estimated amount of time invested in this project from May 8 to
June 24 will approximately be 140 extra hours. This will add to the project budget approximately
F i n a l D e s i g n R e p o r t | 21
$36,620.80 thus increasing the total budget to $566,620.00. Appendix H displays the current up-to-date spreadsheet of Wyo Galactic’s Budget.
SCHEDULE
The approximate times required to accomplish second semester’s mile stones are listed below:
Complete electrical components and send out PCB design-
Manufacture plates and supports-
Testing the fixture-
3 weeks
3 weeks
2 weeks
Programming the payload’s electrical systems- 8 weeks
Assembly of the physical structure, electrical components and finalize the program- 5 weeks
Test the camera plate and have a vibrations test of the payload-
Adjustments to modify the design-
2 weeks
2 weeks
Retest the camera plate and vibration testing of the payload after any modifications- 2 weeks
Finalize the design/payload at Wallops- 1 week
These were the relevant times over the spring semester. Most if not all the tasks overlapped each other which was designed to increase productivity and allow the project to be completed earlier than expected. The main tasks which overlapped one another were the programming, bread boarding, manufacturing the plates, testing the individual electrical components, and testing the spinning plate.
Unfortunately due to debugging and programming problems most of the tasks were set back a month or two. The other “bump in the road” deals greatly with the lack of cooperation from the University of
Minnesota. This lack of communication set Wyo Galactic back several weeks for more details see
Collaboration and Logistics below. The tasks that have been completed to date are manufacturing the plates, testing the individual electronic modules, testing the rotating plate, PCB design and fabrication, and testing the camera plate system.
Since this project proceeds through the month of June and does not have to be finished until June 17 th
Wyo Galactic has a set schedule until the team travels to Wallops. The set schedule over the summer after this spring semester is as follows:
F i n a l D e s i g n R e p o r t | 22
Present Research and Project
Rough Draft of the Post Flight Final Wallops Report
Final Flight Simulation
Full Mission Simulation Test Report
Presentation of Full Mission Simulation Test
Travel to Wallops
Launch Rocket at 6:00 AM
Analyze Data Received from Launch
April 24
May 7
Final Report due for Wallops July 14
Wyo Galactic will work periodically on the canister or the first and second week of May since finals and summer break begins. Wyo Galactic’s plan is to be complete with the programming and debugging along with the full assembly of the payload by May 12 so the team can run a full simulation test on the canister. After the full mission simulation presentation to NASA the team will proceed with any modifications needed for the canister and will complete the payload before June 17 th so the canister will be “flight ready.”
May 8
May 12
May 14
June 17
June 24
June 24
COLLABORATION AND LOGISTICS
One of the greatest challenges faced by Wyo Galactic this semester was the interaction with Minnesota.
As a group almost every design decision or scheduling change came as a result of this collaborative effort. Our first communication with Minnesota came before the project had really begun. They contacted us looking to find out how much of the can Wyo Galactic was going to use. This gave us the impression (wrong) that this relationship would flourish and proceed quickly.
The first hurdle came about three months into the project when Minnesota informed us that they would be using both the atmospheric and part of the optical port already claimed by Wyo Galactic. A certain amount of back and forth occurred and a compromise seemed to have been reached. Wyo Galactic would take the whole optical port and share its data with Minnesota.
Several months later Minnesota began inquiring about the camera dimensions. Wyo Galactic assumed that they were concerned about height of the stabilized plate. In fact Minnesota was unaware of Wyo
Galactic’s longitudinally stabilized platform and had assumed the camera would be placed on their payload. Requiring Wyo Galactic to send them a video made in solid works so that they would understand what the project was attempting to accomplish.
Further confusion occurred when Wyo Galactic agreed to machine all of Minnesota’s plates. This was to ensure proper payload integration. However, a month later Minnesota came back and informed Wyo
F i n a l D e s i g n R e p o r t | 23
Galactic that they had plans to make their own plates. A month after that they returned again asking for
Wyo Galactic’s assistance to machine them. This confusion resulted in over a month in manufacturing delays.
As of last week Minnesota returned informing Wyo Galactic that they intended on exceeding their volume limit that had been set almost 12 months ago. They informed Wyo Galactic that their power supply was now over two inches tall (keeping in mind the total height for the whole canister is 9.5 inches) rather than the one inch they had budgeted.
Wyo Galactic has learned a lot from this experience. Each member now has an acute understanding of the benefits and risks of a collaborative effort. Much like what NASA learned from the mars polar rover;
Wyo Galactic has learned communication is key to a successful collaborative effort. Future groups would do well to initiate contact early as was done here, but also to continue constant contact thereafter through weekly emails and frequent teleconferences.
VI.
Conclusion
The Colorado Space Grant Consortium and NASA have offered a fantastic opportunity to university students to explore Earth’s upper atmosphere. The Wyo Galactic team saw a need and took the opportunity to develop tools for future RockSat experimenters. By providing GPS derived flight data, wireless data recovery and a stabilized plate, Wyo Galactic built on the foundations of previous UW teams and hopes future groups will do the same.
In a perfect world Wyo Galactic would like to see a group possibly made up of Astronomy and Physics majors develop additional functionality for the payload. Some of the ideas for expansion include, using the data collected to predict the location of stars and take pictures of specific locations in the sky during flight. The camera certainly could be upgraded to take higher resolution photos, the data could be further streamlined and the accuracy and functionality of the longitudinally stabilized plate improved.
Again Wyo Galactic hopes that this can be the beginning of a great opportunity for a future group to expand and do something unique.
F i n a l D e s i g n R e p o r t | 24
VII.
APPENDICIES
Appendix A: Detailed GPS Morphology
Size -
An important consideration for the entire project, so the GPS is no exception. With technology evolving as it is, GPS units have been getting smaller and lighter. The devices researched so far could fit practically anywhere. The size of the GPS unit in particular is important because it determines whether or not RockSat will need to mount the GPS on a separate platter or on the existing board.
Startup time One of the design specifications that stood out most during initial research was that each
GPS had a significantly different time to ‘boot up’ and time to signal acquisition. Obviously this is directly a result of the signal the antenna but it also has to do with the board’s ability to process signals. Since the RockSat payload will be only given power at launch a quick ‘hot’ startup will be essential to getting complete flight data.
Update Rate This determines the frequency with which the GPS updates its position from the satellites.
Initially most GPS units updated at 1 Hz, or once per second. Automobiles with a navigational GPS will not drive fast enough to require a refresh more than that often. However, aircraft and other applications at higher speed will require a more frequent update thus 5 Hz and 10 Hz models have begun to appear.
Due to the high speed of the rocket a GPS obtained by RockSat will likely want the higher refresh rate.
The tradeoff being that a faster refresh will draw extra power.
Cost – GPS units have come down significantly in price since the early 2000’s. Almost all of the GPS units suitable for this project ranged in price from $50-$100. This relatively low amount means that RockSat will be able to obtain the required specification it needs without undue concern for costs.
Antenna From experiences gleaned from last year’s launch RockSat has determined that a GPS signal may be difficult to acquire inside the rocket. Thus a GPS system will either require NASA to provide an external antenna channel in the outside body of the rocket or careful placement of the receiver to allow satellite acquisition. This means that the group will need to locate a GPS receiver that has either a powerful integrated antenna or a connection to allow an external antenna to be attached. Both options are troubling since they will both require significant amounts of power.
Power-
Is the number one concern when it comes to the GPS module, it will need to be operational and producing data anywhere from 1-10 times a second. This specification will require a lot of extra power to the module. According to research the modules that fit requirements will draw approx 31mA at 3.3V.
An antenna like the one that will be needed for the module will require at least another 30mA.
Accuracy – the accuracy of the system is important in order to obtain usable data. More specifically, can the receiver handle the speed and altitude at which the rocket will be traveling? Most of the receivers looked at so far had a speed limit of some kind above which it either produces gibberish or less. A
F i n a l D e s i g n R e p o r t | 25 receiver for this payload will thusly need to be able to keep up with the speed of the rocket. Several of the receivers researched have also been used in “high” altitude experiments although none as high as
RockSat will be traveling.
Data Output –
A GPS bought for the RockSat will also need to output data in a form that is either compatible with the board that is used or stores the data on its own which will be later retrieved. Both options are acceptable but a transmitter that interfaces with the board would ensure that the data collected by the GPS is retrieved by the wireless transmitter.
F i n a l D e s i g n R e p o r t | 26
Appendix B: Power Generation System
While most of the theory behind this system was sound, some was not, and it was ultimately decided that this system would not work as intended. Many of the design features for this system were later utilized when we chose to build our system for stabilizing a plate in the rocket (see below).
The goal of the power generation unit was to supply supplemental power to our experiment only to prolong battery life. The power system will be considered effective if the following energy balance is obtained and the energy out is a positive value, see Figure 1.
Energy In from Rocket
(mechanical)
Power Generation
(converts mechanical energy to electrical energy)
Energy Required for generator to operate
(friction, control system)
Energy Out
(electrical)
Figure 1: Energy Balance for Power Generation Unit
After further exploration of this system, it was found that the energy in from the rocket would equal the energy required for operation, therefore the energy out would be zero and this system was discarded.
Both proposals for power generation revolve around the concept of inductance. This is the concept that when current is passed through a wire, an electromotive force is generated. Our generators will use this concept backwards using permanent earth magnets, or electromagnets which will be passed by a coil of wires which will induce a current through the wire. Passing the magnets by the coil of wire may be done in one of two ways:
Rotational
This method involves magnetic core and a coil of wires which is placed perpendicular to the rotation of the magnets, see Figure 2. Ideally either the core or the coil must remain stationary while the other rotates due to mechanical work entering the system. To produce energy we will only need a difference in spin rates of the core and the coil. This mechanical work will come from the engine of the rocket. While in flight, the rocket’s engine produces a spin effect on the fuselage of the rocket. The goal of this device would be to take the spinning effect of the fuselage and convert it to electrical energy.
F i n a l D e s i g n R e p o r t | 27
Figure 2: Rotational Power Generation System.
Magnets- There are two options for magnet usage for this system. We can use permanent earth magnets and a brush system, as shown in Figure 2. This system is fairly simple to construct but will have a few drawbacks. First, the system cannot be turned off. The electromotive forces and the frictional forces of the brushes will always exist, which makes creating different spin rates between the core and the coil significantly challenging. The other solution is to utilize a setup much like a stepper motor. This will utilize electro magnets which can have their polarity reversed at any time, do not have brushes to cause excess friction. This system will need a control unit to time the proper polarity of the magnets as the coil passes by. Different commercial solutions for both the magnet and coil configurations are being explored to maximize efficiency. While this setup may be more efficient further research will have to be put forth toward the power requirements of the electromagnets and the control unit.
Spin Rate To create a difference in spin rates the core of the device will either have to be suspended by some fashion or it will have to contain a very high mass moment of inertia, which will resist the induced electromotive force. Suggestions have been posted as to how we will suspend the core. One solution for suspending the core may to be to attach a gyroscope, a device for maintaining orientation based on the principles of angular momentum, to the core to maintain its orientation. The forces exerted by the gyroscope must equal the electromotive forces generated by the generator itself. The gyroscope would consist of a dense wheel attached to a bearing. The wheel would be spun at a certain velocity via an electric motor to maintain its angular momentum. This method would provide a very high difference in spin rates, but would leech energy from the generator to spin the gyroscope via electric motor.
Alternative means of spinning the gyroscope have been mentioned, such as a small spring and clutch which would be preloaded externally, pre flight, or spinning the gyroscope to a very high speed via external power during pre-flight. This would allow the high spin rate difference of a gyroscope without the leaching effect. However, it is not currently known how much energy could be stored in such a system, or how long it could sustain the angular momentum of the gyroscope.
Alternatively we can generate a difference of spin rates simply with a large mass moment of inertia of the core. This will be done by either making the core very dense, as size constrictions on this project limit our ability to change the geometry of the core, or by adding weight to the
F i n a l D e s i g n R e p o r t | 28 core. By using the brushless electromagnet method we could wait to turn on the power generator until the rocket has reached its maximum spin rate (maximum difference in spin rates) and simply let the forces generated by the large mass moment of inertia of the core generate a difference in spin rates. However, it is not known how long this difference would occur, and how much power may be generated using this method.
Linear
This method involves a magnetic core being passed through a coil in a linear motion; much like a
Faraday flashlight, see Figure 3. A system like this would utilize the vibration of the rocket’s engine and the rocket itself during flight. Linear paths of motion would be constructed in different orientations, as we do not fully know the vibrational behavior of the rocket during flight. The goal of this device would be to take the vibrational energy from the rocket and convert it to electrical energy. This system would be very cheap to get parts for, and would be relatively easy to build.
Figure 3: Linear Power Generation System.
Magnets-
As this system will require a free floating magnetic core; the only option is the utilization of permanent earth magnets. These will enable us to use a magnetic force while keeping frictional forces between the sliding core and its housing to a minimum.
F i n a l D e s i g n R e p o r t | 29
Appendix C: Detailed Instrumentation Morphology
Atmospheric Science
One of the main ideas for experimentation involves the Atmospheric Science Department. A few experiments which were considered are ozonesondes and infrared spectroscopes. An ozonesonde is a device that retrieves atmospheric particles during the rocket’s decent towards Earth. The idea would be to gather data in the mesosphere down to the troposphere analyze the data and present the results to the Atmospheric Science Department. This project will present data in the mesosphere which is important since “no data has not been collected from the mesosphere and analyzed,” quoted Patrick
Campbell from the Atmospheric Science Department. Form this, the RockSat team wanted to be the first to present this kind of data so it can be analyzed and used for future reference. Unfortunately according to Patrick Campbell, “ozonesondes would not be feasible for our particular project”. As it turns out there are many difficult complications in integrating measurements onto the rocket, and the available science we might gain may not be worth the significant unfunded effort. In fact, “people have spent their careers trying to measure just the temperature at 75 km”. Also, the technician said “data telemetry may be impossible because of line-of-site issues, and that there is no way to store data onboard using ozonesondes.” Since this experiment cannot be feasible the group decided to scrap this experiment.
The next type of atmospheric experimentation dealt with infrared spectroscopy. This project was thought after to obtain absorption spectra of compounds that are a unique reflection of their molecular structure in the atmosphere. The problem with this project deals with the money factor. According to caeonline.com for an API 3000 LC/MS/MS System it would cost $99,900.00. Since this type of spectroscope is obviously beyond the project budget, the group has to look for another means of receiving a laser infrared spectroscope. A positive outlook on the instrument is there is a company in
Laramie that deals with laser infrared spectroscopy. Unfortunately the company did not allow the team to obtain any type of instrumentation, so this particular project will be scrapped.
Composite Materials
A composite material analysis was one of the first experiments thought after. The original idea was to test the ductility and durability of many different kinds of composites in our rocket payload as it travels into space. The main reason why this experiment was exempt from our design is because no new information would be obtained from this experiment. The reason why becomes a question of “what can we do with/to these composites on a rocket that we cannot do here on Earth?” After coming up with no feasible answers the experiment was scrapped.
Relativity
Since the GPS experiment will be placed on our payload a project to which came to mind was to test the theory of relativity. In order to test the theory of relativity we needed a GPS which can transmit reliable data and a significant amount of power. The problem with this experiment involved the pre-flight power restriction. For this relativity experiment to work clocks need to be synchronized. Since the clocks on board the rocket can not start until after lift-off, the relativity experiment would not be feasible.
F i n a l D e s i g n R e p o r t | 30
Crystal Oscillator
A great idea for an experiment was to have a crystal oscillator design implemented on the payload. This experiment would be a great idea to view how effective the oscillator would work while under the rocket’s conditions. An immediate problem in regards to this experiment is last year’s RockSat group had already fabricated an experiment involving crystal oscillators and we do not want to repeat last year’s experiment.
Biological Experimentation
Other than mechanical experimentations the group looked toward biological experimentations for our design project. A few ideas that came to mind with this type of project regard plant life, animals and insects. The problems with having any type of animal or insect life in the rocket is that the animal/insect will not be able to withstand the 25 G’s trip into space and back to Earth. Since the animal will not be able to survive the trip, we do not want to put a specimen’s life in danger or kill it. Plus we do not want to have Animals’ Rights Activists on our case for placing specimens in a rocket. Another problem with having any type of biological experiments is that if we want the experiment to have any interaction with the outside atmosphere we need an external port, and NASA only has a limit number of port holes available. To obtain any of these external ports the design group had to request one earlier during the earlier stages of the design process. Unfortunately we did not request a port hole, however since the first NASA design project proposal arriving soon, we could state a request for one. A positive outcome to having a biological experiment is we can construct a sub-experiment involving the interactions of the atmospheric particles with the biological life in the payload. Again due to complications this type of project will not be feasible for our design.
F i n a l D e s i g n R e p o r t | 31
Appendix D: Detailed Wireless Transmission Morphology
This is a portion of the original research into the Wireless data transmission system.
Satellite Modem
This option has the largest range and is the most expensive. Satellite phone companies claim to provide service to the entire world. Therefore, theoretically, the range is infinite. The data could be retrieved from the rocket immediately after splash down. However, antenna for marine specific applications are quite large. The transmission rate is 9-20 kbps, which is a low rate. The satellite modem would be integrated by adding the appropriate port to the circuit board and plugging in the modem. The modems are configured to work with MS Windows systems. However, the circuit board developed last year uses a proprietary operating system. The estimated price for this option is $1000 - $3000.
Infrared (IrDA)
The most common use of this method is remote controls for audio/visual equipment. It has a narrow light cone, short range and cannot pass through solid objects. Therefore, it is essentially a line-of-sight transmission method. The use of IrDA will require an alignment and range that may be difficult to achieve. Cost is unknown, but should be in the same range as Wi-Fi.
Other Wireless Methods
There are several other methods available that have not been explored yet. Other options include: IEEE specifications, 802.15.4 (ZigBee) and 802.16 (WiMAX), Radio Frequency Identification (RFID), HiperLAN,
HIPERMAN, Wireless USB, Bluetooth, Ultra WideBand. All methods have approximately the same level of difficulty. All will require the integration of hardware, which is relatively easy. The difficulty will come in the coding of the software to operate the transmitter. Table (D1) on next page, retrieved from on
10/01/2009, shows a comparison of several wireless technologies. Note that the satellite option is not completely filled in and that not all options listed have been researched yet. More research must be done before a decision on a preferred method is made.
F i n a l D e s i g n R e p o r t | 32
Table D1: Comparison of wireless transmission methods.
802.1
5.4
Bluetooth
802.1
1b
802.1
1g
802.1
1a 802.11n
Ultra Wide
Band
Throughput
Mbps 0.03 1-3 11 54 54 200
Max range ft
Sweet spot Mbps-ft
Service bps-ft2
75
.03@7
5
530
30
1-
3@10
314M
200
2@20
0
251G
200
2@20
0
251G
150
36@1
00
1.13T
150
100@10
0
3.14T
Power mW 30 100 750 1000 1500 2000
BW
Spectral efficiency
Power efficiency1
Power efficiency2
TTGB
Price
MHz b/Hz mW/M bps mAh/G
B
0.6
0.05
1000
1
1
100
22
0.5
68
20
2.7
19
20
2.7
27
40
5
10
200
30
200@10
62G
400
500
0.4
2
2211 67
3.1 day 2.2 hr
46
12 min
12
2.5 min
18 7
2.5 min 40 sec
1.3 time 40 sec
US$ 2 3 5 9 12 20 7
(Source: http://www.bluetooth.com/Bluetooth/Technology/Works/Compare/Technical/)
Sat.
Phone
.09-.2 infinite high
Appendix E: Full Electrical Schematics
Main Board
F i n a l D e s i g n R e p o r t | 33
Camera
Accelerometer
F i n a l D e s i g n R e p o r t | 34
F i n a l D e s i g n R e p o r t | 35
Power
Appendix F: Technical Drawings
F i n a l D e s i g n R e p o r t | 36
F i n a l D e s i g n R e p o r t | 37
F i n a l D e s i g n R e p o r t | 38
Appendix G: Flow Chart and Process Diagram
F i n a l D e s i g n R e p o r t | 39
F i n a l D e s i g n R e p o r t | 40
F i n a l D e s i g n R e p o r t | 41
Appendix H: Budget
Budget for Senior Design Salaries
Budget for Senior Design
Salaries
Engineers:
Consultants:
Sub Total:
Fringe Benefits
41%
Entry Fee
(Canister)
Indirect Costs
41%
Total Project
Charles Galey
Peter Jay
Nick Roder
Will Ryan
Dr. Johnson
Dr. Walrath
Per Hour
$30.00
$30.00
$30.00
$30.00
$45.00
$45.00
Hours a
Week
40.00
40.00
40.00
40.00
1.00
4.00
Weeks
52
52
52
52
52
52
Per Year
$62,400.00
$62,400.00
$62,400.00
$62,400.00
$2,340.00
$9,360.00
$261,300.00
$107,133.00
$7,000.00
$154,201.93
$530,304.19
Budget Senior Design
Salaries
Engineers:
Consultants:
Sub Total:
Fringe Benefits
41%
Entry Fee
(Canister)
Indirect Costs
41%
Total Project
Charles Galey
Peter Jay
Nick Roder
Will Ryan
Dr. Johnson
Dr. Barrett
Dr. Walrath
Per Hour
$30.00
$30.00
$30.00
$30.00
$45.00
$45.00
$45.00
Hours a
Week
20.00
20.00
20.00
20.00
1.00
3.00
2.00
Weeks
38
38
38
38
38
19
38
Per Year
$22,800.00
$22,800.00
$22,800.00
$22,800.00
$1,710.00
$2,565.00
$3,420.00
$98,895.00
$40,546.95
$7,000.00
$60,041.20
$206,483.15
F i n a l D e s i g n R e p o r t | 42
Parts List
Parts
PCB
Part Number
Advanced Assembly, Aurora, Co
Batteries AA (Rechargable) Best Buy #DC1500B4
Accelerometer
Bearings
Battery Holder
Stepper Motor
Shaft
Pulleys
Belt
Aluminum Hex Bar
Aluminum Sheet
Main Processor
Optical Switches
Voltage Regulator
Digi-Key # AD22279-A-R2CT-ND
Grainger Item # 1ZEJ7
Jameco # 216152
Jameco # 237535
McMaster Carr # 1346K31
McMaster Carr # 1375K53
McMaster Carr # 1679K617
McMaster Carr # 88705K22
McMaster Carr # 89015K18
Rabbit BL1800
Spark Fun # SEN-09299
Spark Fun # COM-00527
A/D Converters
GPS
SD Card Holder
Spark Fun # COM-08636
Spark Fun # GPS-07951
Spark Fun # PRT-00136
Dual-Axis Accelerometer Spark Fun # SEN-00847
Wi-Fi
Motor Controller
Camera
Spark Fun # WRL-00691
SRI EDE1200P
SD Card
Misc. Elect. Hardware
Wal-Mart
Wal-Mart Kingston SD/2GB-2P
2GB
Misc. Mech. Hardware
Sub Total
Sponsored Item total
Shipping/Handling
Price
$100.00
$3.75
$11.80
$5.86
$1.15
$17.95
$10.22
$14.00
$3.00
$16.00
$26.00
$139.00
$1.95
$4.38
$2.30
$51.95
$3.95
$29.95
$19.95
$14.00
$69.88
Quantity Cost
1 $100.00
8 $30.00
1 $11.80
2 $11.72
2 $2.30
1 $17.95
1 $10.22
2 $28.00
1 $3.00
1 $16.00
3 $78.00
1 $139.00
2 $3.90
3 $13.14
2 $4.60
1 $51.95
1 $3.95
2 $59.90
1 $19.95
1 $14.00
1 $69.88
$12.00
$20.00
$25.00
2 $24.00
1 $20.00
1 $25.00
$758.26
-
$139.00
$50.00
