Colorado Space Grant Consortium
GATEWAY TO SPACE
FALL 2011
DESIGN DOCUMENT
Team Poptarts
Written by:
Corinne Desroches
Saad Alqahtani
Kyle Skjerven
Joseph (Connor) Jacobsen
Alexa Warly
Matthew Busby
Charles MacCraiger
10/04/11
Revision A/B
Gateway to Space ASEN/ASTR 2500
Fall 2011
Table of Contents
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Mission Overview .............................................................................................................. 3
Requirements Flow Down ................................................................................................. 3
Design ................................................................................................................................ 4
Management ....................................................................................................................... 7
Budget .............................................................................................................................. 10
Test Plan and Results ....................................................................................................... 13
Expected Results .............................................................................................................. 13
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October 10, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
1.0 Mission Overview
Our mission that we have for our BalloonSat is to gather data on the wind speed at
different altitudes with an anemometer to find the optimal altitude for an airborne wind turbine
balloon, or an elevated wind turbine. We will determine this by finding which altitudes have the
highest wind speeds.
The anemometer will be built by the team using a spinning cup propeller and a bike
computer. The bike computer will measure the rotational velocity of the anemometer as the wind
propels it during the BalloonSat's ascent. This data will be stored on the bike computer and,
when recovered, it will be compared to the altitude measured by the bike computer. If the
altimeter fails during ascent, as we expect it to do, then altitude will be obtained by using the
temperature outside of the BalloonSat over time. The anemometer itself will be located on top of
the BalloonSat and will rotate around the connecting rope. This allows it to collect wind from
almost all directions while still being firmly attached to the satellite.
The purpose of this mission is to find the optimal position for airborne or elevated wind
turbines. Wind power is a clean renewable energy resource that we have available to us as a
means of powering the world. Unlike other resources such as coal or oil it emits no pollution and
will always be available. Unfortunately high wind speeds are not available at every location on
Earth, and they unpredictable and never constant (Jobyenergy.com). This means that there are
few locations that make wind an perfectly affordable and reliable resource for most of Earth's
population. Wind speeds are likely to be greater at higher altitudes. In addition, there are less
obstructions at heights (Magenn.com). Therefore, airborne wind turbines would be an effective
solution to power demand, especially if the best altitudes can be found.
2.0 Requirements Flow Down
Mission Statement
Wind power on the Earth’s surface is not as efficient as it could be. At higher altitudes there are
greater wind speeds that would make generating power more efficient then back on Earth. So for
our mission we are going to measure the wind speed on our satellites trip up to figure out exactly
where would be the optimal point to place a high altitude wind generator in the future.
Mission Objective
On the way up our satellite will encounter high wind velocities that we are hoping to record data
on that is analyzable. To do this we are making our own anemometer. An anemometer is a
device that measures wind speed. Instead of ordering one we are going to design and build our
own around a bike computer.
Level 0 Objective requirements
To accomplish our objective we are going to use the bike computers rpm counter that would
measure a bikes speed to measure wind speed instead. The bike computer comes with magnets
that you put on the spoke of your bike that counts the rpm of your tire and converts it to velocity.
We will put these magnets on top of our satellite to measure how fast our anemometer, that we
will make, is spinning. This will give us our data that we need. We also need to make sure that
the material we use for the anemometer is strong enough to handle the wind velocity. The whole
satellite must be under 850 g. Also, we will have a tube through the center of our satellite in
order to allow space for the rope which will connect us to other payloads and to the balloon.
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October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
Level 1System Requirements
1.1
To meet the objective requirements we need to fulfill some system requirements. To collect data
we will use the bike computer because it has an internal component that keeps track and stores
all info that is collected. The bike computer also comes with a USB hook up to our computer that
we can use to download the data and analyze it.
1.2
We will also need a heater to make sure all of our components are proper heated so that they will
not fail due to cold temperatures. This will help our bike computer run efficiently and collect
data adequately.
1.3
Also to make sure our anemometer will be able to spin correctly so we have to make sure that we
can correctly construct our anemometer around the string tube that will be running through our
satellite. Otherwise the string keeping our satellite can interfere with the anemometer.
Level 2 Subsystem Requirements
2.1
Our bike computer has and internal power source also. So we will need to make sure that it will
have enough power to stay on and collect data for the entire flight. Otherwise our data will be
incomplete.
2.2
To make sure our heater is working proper we will need a certain number of 9 volt batteries,
which we will calculate, that will power our heater. We need to make sure that we have enough
power to keep the heater going the entire flight so we do not risk the bike computer freezing and
getting damaged at any point.
2.3
Finally in order to make sure our anemometer works efficiently we will need to construct a
lightweight cage structure surrounded by mesh around our anemometer so that it will be
protected from small impacts and landing.
Page 4 of 13
October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
3.0 Design
The design of the satellite shall be a 15 cm cubical structure made of foam core provided
by the class. The top of the satellite will be the base for a rotating cup anemometer that will take
up a quarter of the top’s area. Connected squares will be cut out then folded to produce a box
shape. The connecting inside edges will be reinforced with hot glue and the outside edges with
aluminum tape as to provide stability to the structure.
Through the middle of the satellite a PVC pipe will be integrated to allow a string to be
passed through. This string will connect to the bottom and top of the cube through knots so the
satellite stays stable. Friction between the satellite and the string will be minimized as to ensure
the satellite does not rotate around its axis too readily. This is because the mission is to measure
wind speed using an anemometer’s rotational velocity without factoring in the rotation of the
satellite itself.
A bike computer, ordered online, will measure the number of reps the anemometer goes
through per given amount of time. Using rotational velocity equations, the velocity of the wind
will be found. Of course a calibration will have to be done using a wind tunnel to test the
efficiency of the anemometer. This will be done by comparing actual wind tunnel speeds to their
corresponding rotational velocity measures of the spinning cups. This will produce a better
picture of what the results obtained will actually mean.
A magnet will be attached to one of the arms of the anemometer. As it passes over the
point in its circular path where another magnet is placed (underneath the foam core,) the
computer will take a reading. The device will store this data parallel to altitude readings. Once
computer is retrieved, wind velocity as a function of height will be graphed.
Other components of the satellite will include a HOBO, heater, 9 V batteries, switches
and insulating foam. All of these materials are provided by the class. The HOBO will measure
internal and external temperatures; therefore the internal heat level will be monitored to know if
it was kept above the minimum temperature requirement. A heater will also be used to ensure
sufficient levels of heat. This device uses three 9V batteries. Switches will be used to power on
the heater, HOBO, camera, and Bike computer. All of these systems will work independently of
one another.
The integrity of the rotating cups as well as the functionality of the bike computer on this
small scale will need to be looked over. Tests will be carried out accordingly. A limitation with
the design will be the plane on which wind will be collected. Wind turbulence will be measured
on a horizontal plane only as a result of the stationary positioning of the anemometer. However,
wind energy is usually collected on a horizontal plane; therefore this limitation does not hinder
the mission objective of finding a maximum horizontal wind velocity.
Page 5 of 13
October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
Diagram 1
Components:




HOBO
Bike computer
Heater
Four 9V batteries
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October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
Diagram 2
Anemometer:


Rotating cups.
Protective mesh.
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October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
Diagram 3

Close up view of the magnet system.
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October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
Functional Block Diagram
Page 9 of 13
October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
4.0 Management
Corinne is the team leader, and will be in charge of distribution of tasks and oversight of
all the Satellite’s subsystems, making sure that requirements are met. Connor is the budget
manager, and is in charge of ordering parts and keeping track of our resources. Alexa will be the
Head of Testing, and will plan and oversee all tests of the satellite and the subsystems, although
she will not be doing the tests exclusively by herself. Everyone will contribute to the building of
the separate subsystems, as well as documentation of results and design revisions. In addition,
all designs will be based on team collaboration, though some may have greater input based on
their preference for designing. All design suggestions will be considered fairly by the entirety of
the team, and the decision for or against them will be a group decision. If consensus cannot be
reached, the decision falls on the shoulders of the team leader. Similarly, final decisions
regarding budget fall to Connor, and testing to Alexa.
Project Manager
Corinne
Structure
Kyle
Matt
Corinne
Saad
Budget Manager
Head of Testing
Connor
Alexa
Anemometer
Software and Electronics
Matt
Connor
Connor
Charles
Charles
Alexa
Page 10 of 13
October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
Date
Schedule
Tuesday 9/27
Sunday 10/02
TBD
Turn in Hardware Order Forms
Team Meeting
Receive Parts
Begin Building Anemometer/Cage
pCDR Presentations
DD Rev A/B and CDR Due at 7:00 am
Test anemometer effectiveness with wind tunnel
Build structure
Build and test heater
Team Meeting
Test electronics. Insert electronics into structure. Cold test, whip test,
etc.
HW #5 Due (Heater completed)
G2S Movie Night
Integrate anemometer with structure.
Team Meeting
Complete BalloonSat
Mid-semester team evaluations due
Testing
Team Meeting
Pre-Launch Inspection—Bring all Hardware to class
In-class mission simulation test
Team Meeting
Launch Readiness Review (LRR) Presentations
LRR and DD Rev C due at 7:00 am
Weigh/turn in BalloonSats by appt.
DLC 270A and LRR Cards due
LAUNCH
Bring raw flight data to class
HW #7 Due
Final Team Presentations and Reports due at 7:00 am
DD Rev D Due
Team videos due
Hardware Turn in
Final Exam
HW #8 Due
Tuesday 10/04
TBD
Sunday 10/09
Tuesday 10/11
Sunday 10/16
Tuesday 10/18
TBD
Sunday 10/23
Tuesday 10/25
Thursday 10/27
Sunday 10/30
Tuesday 11/01
Friday 11/04
Saturday 11/05
Tuesday 11/08
Thursday 11/17
Tuesday 11/29
Saturday 12/03
Tuesday 12/06
Thursday 12/08
Page 11 of 13
October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
5.0 Budget
BUDGET/Hardware
List
Materials
Foam Core
Desiccants
Insulation
Camera/memory card
HOBO
Heater System
Wires
Switches
Batteries
Bike computer
Cage/Mesh supports
Mesh
Dry Ice
Total
Cost
provided
$4
provided
provided
provided
provided
provided
provided
$10
$189.99
donated
$5
$10
$203.99
Source
Gateway
AGM Container
Gateway
Gateway
Gateway
Gateway
Gateway
Gateway
Safeway
Brands Cycle
Alexa
McGuckin Hardware
King Supers
Page 12 of 13
Estimated
Weight* (g)
20
10
10
220
30
100
10
20
20
250
150
5g
(10kg)
845
October 4, 2011
Rev A
Gateway to Space ASEN 2500
Fall 2011
6.0 Test Plan and Results
In order to make sure our design meets all our objectives we are going to do multiple
tests on both the individual subsystems and the completed project. We will do whip tests, drop
test, freeze tests, staircase test, condensation tests, and camera tests in order to make sure our
balloon sat can withstand the obstacles of the rise and fall of the payload. We will also need
to test the effectiveness of the anemometer in the wind tunnel.
We need to do the freeze test to make sure the payload can withstand internal
temperatures of about -10 degrees Celsius at 30 km high. This will be done by placing
the payload in a container with dry ice which will have similar effects on the payload as the
actually flight will have. The whip test, drop test, and stair case test will mimic the impact of the
rise and fall of the payload, the burst of the balloon, and crash of the payload. The whip test will
be done by attaching the payload to a firm string and whipping it in jerky back and forth motions
to simulate the effects of burst on the satellite. The drop test will see if the payload and
its internal subsystems can endure the impact of the fall. The staircase test will see if the satellite
can withstand the crash and rolling after the impact.
We will test the power and electrical circuits by constantly testing it until it does exactly
what is needed in the most effective way. The electrical aspects will be tested pre-flight in order
to make sure data will be properly recorded and that the on and off switch can consistently turn
on the hobo, the anemometer, and all electric battery-run subsystems. We will test the bicycle
computer multiple times beforehand to make sure data is properly collected at certain
time intervals. The camera will be tested to make sure the pictures come out well and can be
taken properly. Each sensor on the hobo will be tested for its function and we will make sure it
can be transferred to Corinne’s computer correctly.
7.0 Expected Results
For our BalloonSat experiment, we are trying to calculate the wind speed at different
altitudes throughout the flight. We are going to use a bike computer to help calculate the
rotations per minute of our propeller that we are going to build and also use the altitude
measurement feature on the bike computer. As far as our results go, we expect that for the most
part, the higher altitude our BalloonSat goes, the higher velocity of wind. The wind speed will
probably fluctuate some but primarily increase with the altitude. However, we also expect that
after a certain point, the wind will reach a max around 40,000 feet and then steadily decline,
possibly to zero because the atmospheric pressure will be so little at 100,000 feet. Since we are
using a device whose function is measuring the speed of a bicycle, we also expect that after some
time, the altitude component will stop working because it is impossible for somebody to bike at
altitudes that we will be reaching. If that is the case, then we will still be able to estimate our
wind speed vs. altitude graph using our temperature graph. We will be able to see how long the
flight goes from takeoff to burst, and then match up our wind speed graph with those times. Also,
we will be able to calculate the rate of ascension using what data we do get from the altitude
function of the bike computer. This will be able to give us a fairly accurate measurement of
altitude over the time of our flight.
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October 4, 2011
Rev A