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CanSat

Final Review

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May 3, 2002

The Department of Aerospace Engineering and Engineering Mechanics

The University of Texas at Austin

Austin, Texas 78712

Team CanSat

ASE 463Q

University of Texas at Austin

May 3, 2002

Dear Dr. Stearman,

The following paper is the final report for our CanSat project. Our main goal is to create a pico-satellite the size of a 12-ounce coke can with transmitting and receiving capabilities. Our team has divided our objectives into three main systems for our satellite: structure, data telemetry, and sensors. The work we have completed thus far in each of these subsystems is thoroughly discussed here, as well as the work to be completed in the future.

If you have any questions regarding this report or the CanSat project in general, please feel free to contact us in WRW 407, or at our individual email addresses listed below.

Sincerely,

David Dominguez

ddavid@mail.utexas.edu

Robert Harpold

q_kumber@mail.utexas.edu

Shaun Stewart

w.sam@mail.utexas.edu

Acknowledgments

The CanSat team would like to acknowledge the following people for their help with our project.

• Dr. Noel Clemens

• Dr. Takuji Ebinuma

• Dr. E. Glenn Lightsey

• Rick Maldonado

• Dr. Ronald O. Stearman

• Dr. Robert Twiggs

• Tom Rouse

Abstract

This report summarizes the progress of the CanSat project as the first satellite design initiative at the University of Texas Satellite Design Lab (UTSDL). The main objective of this project is to establish an ongoing satellite design program at the University of Texas by demonstrating that small, inexpensive satellites can be built, tested, and launched in the span of a year. A major obstacle in designing student-built satellite missions is aerospace engineers’ lack of experience with digital packet communications systems, which hinders their ability to implement a reliable, inexpensive data telemetry system for control and data relay communications. In order to allow for future students to easily improve on the CanSat design, a main priority of this project is to develop and document a small, inexpensive satellite data telemetry system that future groups can incorporate in improved satellite designs. A secondary objective, following the establishment of a functional telemetry system, is to outfit the satellite with robust command and control capabilities that will transmit to the Earth analog and digital measurements made on the satellite. This report summarizes the details of that design.

Table of Contents

Index of Tables………………………………………………………….………….…….ii

Index of Figures……………………………………………………….…………….……ii

1.0 Introduction……………………………………………………….…………….…….1

1.1 Problem Statement………………………………………….……….………..1

1.2 Project Background………………………………………..…………………1

1.3 Objectives………………………………………………….…………………3

1.4 Previous Missions………………………………………….…………………4

1.5 CanSat Group Assignments………………………………….……………….5

2.0 Background Theory……………………………………………….………………….6

2.1 Circuit Theory……………………………………………….……………….6

2.2 Communication System Design…………………………….………………..7

2.3 Amateur Radio Protocol……………………………………….……………..8

2.4 Signal Structure……………………………………………….……………...8

2.5 Analog vs. Digital Sensor Theory……………………………………………9

3.0 Current Progress and Future Goals……………………………….….………………10

3.1 Circuit Design…………………………………………….…….……………10

3.2 Sensor Testing………………………………………………….……………11

3.3 Structural Design…………………………………………….………………14

4.0 Cost Analysis………………………………………………………..….……………21

5.0 Project Schedule…………………………………………………….…….…………22

6.0 Conclusions………………………………………………………….………………24

7.0 References……………………………………………………………...……………25

List of Tables and Figures

Tables

4.1: Cost Analysis 21

5.1: Project Schedule 23

Figures

2.1: Communication System Schematic 7

3.1: MPX4115A (Pressure Sensor) 11

3.2: MPX4115A Pin Diagram 12

3.3: MPX4115A Output to Micro-controller 12

3.4: LM335Z (Temperature Sensor) 13

3.5: LM335Z Pin Diagram 13

3.6: LM335Z Output to micro-controller 14

3.7: Structure Dimensions in cm, 1:10 Scale 16

3.8: Alternate Structural Design 18

• 1.0 Introduction

This report presents the preliminary design results of the CanSat project. The design is a work in progress and is scheduled for completion and launch by August 2002. The design will be finalized and tested by a second design group preceding the launch date.

1.1 Problem Statement

Our goal is to begin an ongoing satellite design program at the University of Texas. The initial part of this goal is to design a small, soda can-sized satellite integrated with a basic packet radio communication system that will transmit basic analog and digital measurements (made on the satellite) to the Earth on request. The design should demonstrate command and control capability and should be as inexpensive and simple as possible.

1.2 University of Texas Satellite Design Laboratory (UTSDL)

The motivation for this project came from an initiative by Dr. Glenn Lightsey to create a satellite design lab at The University of Texas at Austin and to use student-built spacecraft to perform experiments in space. Once the CanSat project is underway, Dr. Lightsey plans to oversee the construction of a permanent ground station at the W. R. Woolrich Laboratories Building at the University of Texas at Austin. This ground station will include a steerable antenna array on the roof of the building with an observation station in the satellite design lab. Once an inexpensive, compact satellite design is built and tested, the systems developed can be extended to experiments for both the Shuttle Get-Away Special (GAS) program and the Cube-Sat program [1]. These programs allow students to conduct experiments in space and are discussed below.

The ultimate goal of UTSDL is to implement student-built spacecraft experiments in Earth orbit. However, a reliable and robust design is required before committing to the expense of launch into space. In order to successfully implement a satellite design in space, thermal control, attitude control, and power generation become major concerns. In all these cases, the spacecraft requires command and control capability for housekeeping purposes such as antenna and solar panel pointing, station-keeping, and power consumption control. Even if the expense associated with launch is subsidized, such as in the GAS program, it is imperative that the communication system onboard the satellite be reliable, robust, and tested so that these minimum control requirements are possible.

1 Earth-Orbiting Experiments

Get-Away Special

The University has had reserved, since the 1970’s, a canister on the Space Shuttle for experiments in space. The GAS canister gives the University an opportunity to run an experiment at 280 kilometers altitude. This program provides an opportunity for exposing potential satellite designs to the harsh environment of space before actually launching an Earth-orbiting satellite mission.

Cube-Sat

The Cube-Sat program allows university students to launch satellites with volumes of 10 cm3 into orbit. The cost of launching a single satellite through this program is $50,000. Currently, UT students have proposed Cube-Sat missions for formation flying and relative navigation experiments as well as experiments in Earth-moon orbits.

2 CanSat

The CanSat sounding rocket program has been chosen to test the individual subsystems for the above-mentioned eventual spacecraft missions, since the cost of launch is minimal ($600). This test will subject the electronics to loads similar to those for launch into space, and will allow for an extended test at high altitude.

The CanSat program was initiated in 1998 to give students hands-on experience in the design of spacecraft and to determine if small satellites can perform useful functions [2]. Several universities have participated in the project since its beginning, including Stanford, the University of Texas at Austin [3], the University of Tokyo, and Tokyo Institute of Technology [4].

The CanSat program allows university students to launch 12-ounce soda-can-sized satellites from a sounding rocket complex in New Mexico with minimal launch costs. This project allows for the design and testing of a compact, inexpensive data telemetry system under extreme launch loads and for conditions near 12,000 feet altitude. This project will provide the first project for UTSDL, but also a platform for the future design and implementation of Earth-orbiting spacecraft at the University of Texas.

2. Objectives

The CanSat mission objectives are listed below in order of significance:

• Collect and transmit data.

• Demonstrate command and control capability.

• Show that an inexpensive design will survive launch loads.

• Create prototype data telemetry system and signal design for future implementation and improvement.

The main objective of the initial CanSat project is to show that the design of a small, inexpensive data telemetry system is possible. The system will have both receiving and transmitting capabilities and will be incorporated with a complement of basic analog and possibly digital sensors. Although the sensor data is important for verification of the telemetry objectives, achieving individual sensor precision is not a primary goal of this CanSat. The success of this project at UT will hopefully pave the road for the funding of annual CanSat design projects with improved sensor packages and mission objectives.

1.4 Previous Missions

Several universities have completed CanSat projects in the past, each with different missions. The University of Tokyo’s project, Gekka-Bijin, consisted of three CanSats that attempted to rotate a satellite, gather temperature and pressure data, and to use a camera [4]. They have also designed a satellite to test systems that will later be used in a Cube-Sat project. Other universities such as Arizona State University [5] and Kyushu University [6] have designed satellites to test a tracking system and to collect temperature data.

Most of these projects are used simply to give students experience in a hands-on project. They must deal with ordering equipment, designing systems, making reports, and working in a group. This will give them an idea of what to expect when they enter the work force.

UTSDL has considered some of these previous designs when working on our own project. The structure for our satellite will closely resemble some of the other designs. We are also researching components that other projects have used to determine if any will be appropriate for our satellite design.

1.5 CanSat Group Task Assignments

To handle the workload required for this project, the responsibilities were split between the three group members. Shaun is in charge of programming the chips to work with each other, David is in charge of handling the components (such as the sensors and the circuit board), and Robert is in charge of the structure of the satellite. The members are not restricted to working only in their area, but they specialize in one area and are responsible for making sure that area meets its requirements.

The hardware integration and testing will be the responsibility of all group members. In addition, everyone contributes to the written and oral reports.

2.0 Background Theory

The main theoretical background required for the design of the CanSat involves circuit theory. A firm understanding of the relationship between current and voltage and the role of capacitors, resistors, and inductors in circuit design is imperative for the completion of this type of project. The task will also require knowledge of how to convert a radio frequency signal to digital data and programming microchips to carry out those conversions. Programming microchips to handle radio signals necessitates an understanding of how binary data is stored in data registers, the different types of registers, the implementation of interrupt logic, and amateur radio protocol for transmitting data. Most of these topics are more closely related to electrical engineering than aerospace engineering and are thus outside the bounds of an aerospace undergraduate preparation. A large learning curve has been associated with these topics; given below is a brief synopsis of those topics and recommendations as to what future CanSat groups may need to research before attempting to improve on this CanSat design.

2.1 Circuit Theory

It is assumed that any student working on the CanSat project has at least a minimal understanding of circuit theory. The circuitry for the satellite will involve inductors, capacitors, resistors, and op-amps, among other electronic components. Each of the sensors require 5 volts (V) to function properly, and therefore a step-down transformer will change the output of 9V batteries to provide the correct amount of voltage to each.

2.2 Communication System Design

Figure 2.1 shows a basic schematic of all the major components required for the data telemetry system. For simplicity, the interfacing resistors and capacitors have been omitted. The data sheets for each chip, as well as a complete circuit schematic, are provided in the Appendix. This telemetry system is much like the modem on a computer. The radio signal can be thought of as sound tones from a telephone port. Sound tones are transmitted from the ground and are received by the antenna on the satellite. A decoder chip (CM8870 in this case) converts the sound tones into four-bit binary numbers and sends them to the micro-controller. Pre-programmed definitions for the appropriate command signals will be continually compared against all incoming signals, so that errant signals on the appropriate frequency cannot switch off any of the satellite subsystems. The details of the signal structure will be discussed in the amateur radio protocol and signal structure sections.

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Figure 2.1: Communication System Schematic

After the micro-controller interprets the signal, it will begin taking sensor data (analog and digital in this case), convert the inputs to 8-bit binary numbers, and record them in a time tagged data string. Figure 2.2 is an example of the data string generated by the CanSat. The first column is a time tag in seconds. The second column is verification that the CanSat received and properly interpreted a command. The third and fourth columns correspond to output voltage from the temperature and pressure sensors. The 5-volt outputs from these sensors are scaled to output values ranging from 0 to 255. The remaining columns are reserved for additional sensors.

Figure 2.2: Telemetry String

This data string is represented in binary format on the micro-controller, and in order to transmit data via a radio frequency signal, the data must be transformed into a serial data format. Basically, this means that the data is mapped onto a sinusoidal signal with variable frequency corresponding to the 0 and 1 values of the data string. The signal switches between two frequencies which are directly interpreted as zeros and ones. The micro-controller converts the data string serial data format and then sends the sinusoidal signal to the encoder chip. The encoder chip converts the signal into a format that an amateur radio transmitter can recognize and then sends them for transmission to the ground station. Future CanSat projects may opt to store data on the CanSat itself in memory for analysis after recovery of the satellite. This design has reserved pin locations for that purpose even though data storage will not be an objective for this mission. Once the transmitted data reaches the Earth and is received by the ground station receiver, the data then needs to be decoded once again so that it can be interpreted on a PC. Depending on the quality of the receiver purchased, this may or may not require the design and programming of a second decoder chip.

2.3 Amateur Radio Protocol

In order for a commercially built receiver to receive and interpret RF data signals, amateur radio protocol, AX.25, must be followed. There is a predetermined manner in which AFSK (Audio Frequency Shift Keying) packet communications must be designed so that commercial amateur radio receivers and transmitters will recognize a signal. The TNC designed by Dr. Ebinuma assigns this protocol to the data string before it reaches the transmitter.

2.4 Signal Structure

There are 16 possible tones for RF communication. Each sound corresponds to a particular 4-bit number that can be used to compose words, much like the letters of the alphabet. The tones are the same as the 12 available on a telephone, except there are four extra: A, B, C, and D. Currently, we are planning to use three-tone command words. The commands will begin with ‘*’, [1 0 1 1], and end with ‘#’, [1 1 0 0]. If the satellite receives a 3-tone signal on the appropriate frequency starting with ‘*’ and ending with ‘#’, then the middle tone will be implemented as a command. This provides control safety in that stray RF signals, which may correspond to commands, will have to be validated in this manner before implementation. Future groups may expand on this design, but this is the minimum required to demonstrate command signal validation. Note, in Figure 2.2 above, the micro-controller verified that it received two commands:

‘ * 7 # ’ and ‘ * 2 # ’. So after the CanSat is launched, it will be possible to instantly determine if a command was correctly interpreted and if some stray signals were accidentally interpreted as commands.

2.5 Analog vs. Digital Sensor Theory

At this time, our CanSat only has analog sensors. Once these sensors have been integrated, we will consider employing digital sensors as well. The difference between these types of sensors is discussed below.

An analog sensor records data continuously, while a digital sensor defines data in several individual “steps”. The main advantage of an analog sensor is its ability to fully represent a continuous stream of information without eliminating any information. Digital sensors, on the other hand, are less affected by unwanted noise and interference, and therefore provide a clearer signal. These types of signals are often converted from one to the other. For example, this conversion occurs every time a signal is sent over a phone line. A transmitting (encoding) modem converts digital data from a computer to analog sounds and the receiving (decoding) modem then converts the analog signal back to the original digital data for analysis. Because of these characteristics, analog signals are used to transmit data over long distances and digital data is required for computer analysis.

3.0 Current Progress and Future Goals

Responsibilities for this project were split into three areas: the circuits, the sensors, and the structure. This section will detail our progress and work remaining in each of these areas.

3.1 Circuit Design

Currently, the micro-controller can receive analog commands and convert them into a digital format. It can interpret command strings from the receiver, output the data into a time-tagged data string, and convert the data into serial format for RF transmission. The TNC applies AX.25 encoding to the serial data necessary for communication with amateur radio wave hardware. Currently, the data telemetry string has been generated and verified from a com port on a computer; however, an “across the room” telemetry test remains to be carried out.

3.2 Sensor Testing

As stated, one of the main objectives of the CanSat project is to create a pico-satellite that can send and receive messages. In order to test the communication system, our satellite will conduct a basic environmental analysis by taking temperature and pressure measurements with analog sensors. The accuracy of the sensors is not a major concern, as our main objective is to establish a sound telemetry system. The data gathered will be used to show that the satellite telemetry system worked properly. In order to ensure that some data is collected, even in the case of command signal failure, one of the sensors may be configured to transmit data prior to launch. The sensors selected for this project are discussed below.

Pressure: MPX4115A

The Motorola MPX4115A (Figure 3.1) is an analog silicon pressure sensor capable of measuring pressure in the range of 15 to 115 kilo-Pascals (kPa). For a 5 volt input, the output voltage conversion factor to kPa is 0.04 volts per kPa, or

P(kPa) = 25*Vout (1)

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Figure 3.1 MPX4115A

This sensor can provide a measurement accuracy of (1.5 kPa and can operate in temperatures between –40 and 125 degrees Celsius ((C). It is ideally suited for microcontroller-based systems, and is therefore optimal for our project.

A basic pin diagram of the MPX4115A can be seen in Figure 3.2. Initially, the output from pin 1 was to lead to the micro-controller through the setup shown in Figure 3.3. The capacitors present in this schematic were to eliminate some of the noise picked up by the analog sensor and provide a cleaner signal. After consideration, however, these capacitors were connected to the power supply, as discussed in a later section.

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Figure 3.2 Pin Diagram MPX4115A [7]

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Figure 3.3 Initial Ouput to Micro-controller [7]

Since it is difficult to manually modify pressure, there is no simple way to calibrate a pressure sensor. The conversion chart for this sensor is in the Appendix. Pressure readings have been taken with this sensor at an altitude slightly above sea level, and a pressure 0.95 atmospheres (atm) was measured. Several readings have been taken at different locations to validate the accuracy of the sensor and the conversion chart.

Temperature: LM335Z

The LM335Z, seen in Figure 3.4, is an analog temperature sensor from National Semiconductor. The output voltage can be related to degrees Celsius with the following equation:

T((C) = (Vout*100)-273.15 (2)

The LM335Z has the ability to take measurements in the range of –40 to 100(C with an accuracy of ( 1(C. It is very small and easily integrated with a micro-controller, making it ideal for our objectives.

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Figure 3.4 LM335Z [8]

The pin diagram of the LM335Z is seen in Figure 3.5. Readings from the temperature sensor will be taken with the setup seen in Figure 3.6. The value of the resistor in this circuit is 1 k-ohm [8].

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Figure 3.5 Pin Diagram LM335Z [8]

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Figure 3.6 Output to Micro-controller [8]

Tests were conducted with the temperature sensor and the output was compared with temperature readings from an infrared thermometer. The data collected with the sensor was converted with [2] and was fairly close to the actual temperature.

Power Supply

As stated, the sensors mentioned above require five-volt inputs. A nine-volt battery will be converted to output five volts by a volt regulator as seen in Figure 3.7. As previously discussed, the capacitors in this circuit are to provide for a cleaner signal to and from the sensors.

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Figure 3.7 Power Supply Schematic

Soldering

The integration of the electronic components of the CanSat required the soldering of the appropriate circuits onto circuit boards small enough to fit inside the satellite. Lacking previous experience with soldering and knowing that a poorly assembled circuit could result in a failure of the satellite, our team practiced soldering smaller circuits before attempting to construct the actual prototype. Some of our preliminary work can be seen in Figure 3.8. Figure 3.9 shows the final product, with all electronic components included except for the pressure sensor. The circuits in the latter picture were created by Dr. Ebinuma for our group to use as an example.

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Figure 3.8 Preliminary Circuits

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Figure 3.9 Completed Circuit

3.3 Structural Design

Our group has a prototype structure built, though it may need to be lighter than anticipated and it does not provide enough room to hold the receiver and the circuit boards. A method for attaching the parachute will also need to be determined.

Requirements

In accordance with the rules for the CanSat project, the satellite must be able to fit inside a soft drink can and must weigh equal to or less than an unopened soft drink can filled with soda. This limits the dimensions to a maximum diameter of 6.604 cm and a height of 10.3 cm. The communications antenna can slightly exceed the dimension restrictions. The mass, including that of the components, is limited to 0.350 kg.

The structure must also be capable of withstanding the loads it will be subjected to during flight. A maximum load of 40 g’s will occur at parachute separation, so the structure must be designed to endure this acceleration. In addition to the dimension and load requirements, the structure must be able to hold the equipment necessary to complete the CanSat’s tasks: a transceiver, an antenna, a 9V battery, and a circuit board.

Material

Aluminum was chosen for the material because it is light (the density varies between 2600 and 2800 kg/m3), inexpensive, readily available, and has a relatively high yield strength (35-500 Mpa). While steel has a slightly higher yield strength (280-600 Mpa), it has a much greater density (7850 kg/m3) than aluminum, making it undesirable from a mass perspective. Other possible materials are much more expensive than aluminum and steel.

Current Design

A prototype structure (Fig. 3.10) has been built but, while the design will remain essentially the same, some changes will need to be made. The current model does not provide enough room for the receiver and the circuit boards and may be too heavy. While this model is less than 100 grams, the 9V battery that will be used as a power source was heavier than anticipated.

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Fig. 3.10 Prototype CanSat structure inside half of soda can.

The prototype cannot be altered to be compatible with our requirements, so a new structure will be built. As can be seen from Fig. 3.10, the four supports are attached by sliding them into holes in the top and bottom rings and then using horizontal pins. To reduce the weight and provide more room, the four supports will be much thinner and will be attached to the top rings by vertical screws. In addition, the top and bottom rings will be reduced in thickness.

One problem that this team has encountered and that future teams may encounter is the wait time for a structure to be prepared. The WRW machine shop has to complete orders for several people and CanSat would have to be put on a waiting list. To circumvent this difficulty, the team plans to go to the machine shop and learn how to operate the equipment over the summer. This will allow us to build the structure ourselves and to make minor modifications if necessary.

With the proposed modifications, the structure should meet all requirements. It will be able to hold the receiver and circuit boards, fit inside a soft drink can, and withstand 40 g’s.

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Figure 3.11 Final Structure Design

The transceiver used for this satellite has dimensions of 5.6 cm x 9.4 cm x 1.36 cm, disregarding protuberances. The main support has to be at least 9.6 cm tall to enclose the transceiver and its antenna. This constraint limits the thickness of the top and bottom portions to a maximum of 0.35 cm each.

For the final structure, the top and bottom disc thicknesses will be 0.125 cm, the supports’ diameters will be 0.3175 cm, and the supports’ heights will be 14.25 cm. From Fig. 3.11, it can be seen that the supports are not spaced equally around the rings. Two of the supports are offset to provide a better hold on the transceiver.

Preliminary calculations have been done to determine the lowest area that would be able to withstand the maximum stress. With a yield strength of 35 MPa and a maximum acceleration of 40 g’s, the following calculations were performed:

σy=[pic] (3)

where F is the force and A is the area.

F=ma= 0.35 g * 40 * 9.805 m/s2= 137.27 N

σy=35 MPa

A= F/ σy = 3.922e-6 m2 (4)

Our can has no points with an area lower than the calculated amount, so it should be able to withstand the highest stress. This was also a conservative calculation: we used the highest stress and the lowest yield strength, so we will actually be able to have a lower area and still not have structural failure.

Other Considerations

The satellite will use a parachute to land safely. As the outer shell of the soft drink can would not be able to withstand the force of the parachute separation and will not be used for structural support, the parachute must be attached directly to the structure. Two methods are under consideration for doing this. The parachute could just be tied to the top ring of the structure. A better method would be to drill a hole through the top of the structure and attach a small aluminum ring with a nut and bolt. This ring would protrude from the mouth hole of the can shell. If it is deemed infeasible to affix this ring for structural reasons, then the first method will be used to hold the parachute.

An antenna will also need to be attached to the satellite. The method for doing so has not yet been decided. The team is considering either wrapping the antenna around the structure or attaching it to the top disc.

Two methods for inserting the satellite into the can skin are being considered. A model has been constructed to test those methods and to determine the appropriateness of the current dimensions. The first method is to cut open the soft drink heightwise and put the satellite in through the side. The second method is to cut off the top of the can at its widest point and put the satellite in vertically. Some previous CanSat projects from other universities have taken off the can’s top altogether and just used an aluminum plate.

Once the design has been finalized, the group will either send an order to the WRW machine shop for the structure to be built or they will machine the parts themselves.

Antenna Choices

In order to communicate between the ground station and the satellite, antennas will be required. The satellite and ground station will most likely use different antenna types. As of yet, no final decisions have been made as to what type or brand to use, but some preliminary research has been conducted.

A variety of antennas are used for diverse applications. The main types under consideration are half-wavelength dipole, quarter-wavelength vertical, ground plane, whip antennas, and directional. Each one has advantages and disadvantages to separate it from the others.

Half-wavelength dipoles are composed of two equal parts, totaling half the wavelength of the signal. For radio frequencies, this size will be too long for the CanSat. This type of antenna generally depends on placing wires in the ground and so is probably not practical for our ground station, which will not be permanent.

Quarter-wavelength vertical antennas are relatively easy to build and inexpensive. As they are vertical, they have more powerful signals towards the horizon and are almost a manageable size. For a signal of 440 MHz, the length would be 17.5 cm, which is larger than the satellite. This might work if it were wrapped around the satellite, with only the antenna’s tip protruding from the can’s mouth hole [9].

Ground-plane antennas are good for mobile applications and are being considered for the ground station. They can be attached to a car roof and are omnidirectional.

Whip antennas are flexible and come in many sizes. Other CanSat projects have used whip antennas for their satellites. Since a whip antenna is flexible and is thus less susceptible to snapping, it might be a good choice for the CanSat.

Directional antennas direct most of their energy in one direction and have good gain for that direction. Some of the previous projects have used a common directional antenna, a Yagi, for ground stations [10].

The choice of antennas will be decided either by the summer design group.

4.0 Cost Analysis

One of the goals of the CanSat project is to make the satellite as inexpensive as possible. Table 4.1 shows a breakdown of the purchases made so far, and also includes those anticipated in the future. The cost to launch the satellite is the most expensive aspect of this project, at approximately $600.

Table 4.1 Cost Analysis

|Items Purchased |Cost |Items to be Purchased |Estimated Cost |

|Electrical components |$100 |CanSat Launch |$600 |

|AVR Testing Board |$80 |Ground Station |$500 |

|Sensors |$20 |Antenna |$20 |

|Power Supply |$10 |Parachute |$20 |

|Soldering Iron |$50 | | |

|Transceiver (in satellite) |$150 | | |

|Total Purchased |$410 |Total to be Purchased: |$1140 |

|Grand Total: |$1550 | | |

5.0 Project Schedule

Table 5.1 shows the proposed schedule for the remainder of the CanSat design. It should be noted that a summer group will complete the testing of the satellite and oversee the launch. All dates are subject to change.

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6.0 Conclusions

The CanSat program was developed to give students an opportunity to participate in the design of actual hardware for a real mission. Although we will have a working satellite that will take temperature and pressure readings during its flight in August, collecting data is not its main purpose; it is being built serve as an educational experience. In addition, our project will provide a starting point for future UTSDL CanSat projects.

Much work remains to be done on the project. So far, we have tested and calibrated the sensors, built our circuit boards, designed the main structure of the satellite, and finished programming the chips. Over the summer, the three current team members and the summer design team will integrate the parts of the satellite, test the telemetry system and structure, and prepare the satellite for launch in August.

7.0 References

[1] Lightsey, Glenn, Student Produced Atmospheric Research Cluster of Satellites (SPARCS), The University of Texas at Austin, September 2001.

[2] Twiggs, Dr. Robert (1998). CanSat-The Project for CanDo Students. CanSat Main Web Pages. (February 2002).

[3] The University of Texas at Austin CanSat Program. The UT Aerospace Engineering CanSat. (February 2002).

[4] University of Tokyo CanSat Website. CanSat Main Page. (February 2002).

[5] DATSat. CanSat2—Can 1. (February 2002).

[6] ARLISS 2000. TITECH ARLISS 2000. (February 2002).

[7] Motorola Semiconductor Technical Data. (February 2002).

[8] Precision Temperature Sensors. (February 2002).

[9] Burns, Jim. (January 2000). An antenna is an antenna, right? Home Theater Magazine Archives. (March 2002).

[10] Antenna Em. (March 2002).

Web sample:

Burka, L. P. (1993). A hypertext

    history of multi-user dimensions.

    MUD history.

    talent/ lpb/muddex/essay (2 Aug. 1996).

Appendix

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