SpaceBox STEP-1 Proposal - Docs | SpaceBox Laboratory

Transcription

SpaceBox STEP-1 Proposal - Docs | SpaceBox Laboratory
SPACEBOX
LABORATORY
Project Proposal, Proposed to Thaicom PCL
Project: SpaceBox STEP-1
Thailand’s First CubeSat
“Self-Sustainable Technology and Engineering Project”
Proposal written on April, 2015
Page 1
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
ABSTRACT
___________________________________
(Figure 1.2)
(Figure 1.1)
SpaceBox STEP-1 (Figure 1.1) is a CubeSat, a
standardized miniature satellite measuring 10 x
10 x 10 cm with about 1 kg in weight. Its
operation is in Low Earth Orbit (LEO): 150 – 600
km from Earth. At present, it is considered a
cost effective science and technology platform
for promoting science education and instigating
the development of innovative sensors and
other advance autonomous instruments.
Moreover it possesses a potential to make a
contribution on a politically attractive and
economically viable basis to the expansion of an
emerging nation’s intellectual capital.
Commercially, it possesses the potential to be a
disruptive technology in the space industry from
which many applications of larger conventional
satellites could be displaced in the near future.
Because of its significant benefits and
prospective potentials, many governmental
space and research agencies support the
technological developments on this platform: in
US from NASA and NSF, in Europe with ESA’s
Educational Office, in Japan with JAXA, or from
United Nation projects such as Disaster
Management Constellation (DMC).
SpaceBox STEP-1 shall performs 3 missions in
when it’s operate orbit.
1. Earth Imagery - “Satellite Imagery of Earth”
First image captured and transmitted to Earth
from SpaceBox STEP-1 shall mark the first step
of Thai toward becoming a Space Technology
Developer, not only a Consumer anymore.
SpaceBox STEP-1 shall be equipped with 2
cameras: Slow Scan TV (SSTV) and Digital
cameras.
The SSTV is responsible for taking and
broadcasting low resolution images of earth in
real time which would allow general publics to
share this wonderful experience from Space.
For the Digital camera, it will capture high
resolution image of earth and send it back to
Earth. Then the transmitted images shall be
open for public accesses under a free to use
license from our website (Figure 1.3).
SpaceBox STEP-1 shall be Thailand’s first
CubeSat designed, manufactured, and tested
by a group of THAI engineers as indicated in
Figure 1.2 and it is planned to be launched in
2016-2017.
(Figure 1.3)
Proposal written on April, 2015
Page 2
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
2. O-Space Textbook - “Education from space”
In Thailand, as an emerging and developing
nation, the real firsthand experience with Space
technology would be a great inspiration to
students or personnel in education or science
and technology and could become a first
milestone for the country’s big space education
and scientific research movements.
To achieve this ambitious purpose, in this
project, we will develop a SpaceBox Kit (SBK) to
be distributed, first, to rural schools in Thailand
so their students would be able to connect and
communicate with SpaceBox STEP-1 when it
travels past their schools. This would be a great
opportunity for the students to learn about
Space technology and for the teachers to
facilitate their leanings as, from the learning
theory, “Learning will take place Naturally when
the Learner has a reason to Learn”
Additionally we believe that any developed or
discovered knowledge should belong to
nations, not any individuals.
All the designs, developments and processes to
secure launch opportunities shall be
documented and made available to public in
order to encourage other interested people to
follow our footsteps (Figure 1.4 - 1.5).
(Figure 1.5)
3. Space Tracker - “Enhanced Capability”
Hotspots monitoring for wildfire prevention,
data gathering for studying the migration of
animals, or the climate change research are
examples of the applications or studies by
major space agencies conducted on the Picosatellite platform. CubeSat platform possesses a
great potential of its own to tackle real world
problems, not only promoting the advance in
science and technology.
This mission objective is to demonstrate this
CubeSat capability with the earth object
tracking selected as a sample experiment. We
will invent a small low-cost efficient tracking
device in such a way that it could be located by
and establish the data transmissions with the
SpaceBox STEP-1 for remote sensing. With such
device, we could demonstrate its use through
conducting experiments in wide range of
applications as shown in Figure 1.6: Ship
Tracking in Sea Transportation or Fishery, Car
Tracking for Traffic Management and Animal
Tracking for the Wildlife Preservation.
(Figure 1.4)
(Figure 1.6)
Proposal written on April, 2015
Page 3
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
From this experiment, the technical challenge is
a requirement that the invented tracking device
must possess sufficient radio transmission
power to establish a connection with SpaceBox
STEP-1.
SpaceBox STEP-1 project is currently in the
Preliminary Design Review and the proposal for
requesting a financial support is being drafted.
Upon the completion of the proposal, it shall be
reviewed by the experts in the field for the
project’s feasibility and its merits. SpaceBox
STEP-1 will be mainly, if not fully, funded by the
sponsor. At the moment, the overall budget of
the project is estimated to be approximately
USD 140,000.
SpaceBox STEP-1 is developed with a strategic
goal of “Self-Sustainable Technology and
Engineering Project”. From being the genuine
Thailand’s 1st CubeSat to accomplish these
specified missions in space, SpaceBox STEP-1
aims to create a societal impact to Thai science
education and technological development by
showing that “by being truly united, we could
bit by bit help strengthen our nation’s
intellectual capital and create a selfsustaining path to Thai future”.
“The People Who Are Crazy Enough to Think They Can Change The World,
Are the ones Who Do”
Apple, Inc.’s “Think Different” (1997)
Proposal written on April, 2015
Page 4
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
CONTENTS
___________________________________________________________________________
Overview
6
SpaceBox STEP-1’s Mission
8
Benefits to Thaicom
11
Benefits To Thai Education and Scientific Communities
12
Public Accessibility
13
Satellite Ground Station and Satellite Construction Laboratory
13
Sub-System Designs
16
Technical Risk Analysis and Management
23
System Testing
25
Launch Opportunity
27
Summary Budget Estimation
28
Development Timeline
29
Experience on CubeSat
30
Appendices
Appendix A: Mission Analysis
32
Appendix B: Estimation Budget Analysis
38
Appendix C: Team members information
43
Appendix D: CubeSat’s working temperature
49
Appendix E: References
Proposal written on April, 2015
50
Page 5
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
OVERVIEW
___________________________________________________________________________
“SpaceBox STEP-1 shall be one small STEP for THAI Space Maniacs, A giant leap for THAI Space
Education and Technological Development”
It is known that the business in Space Industry has high barriers to entry: Finite resource of GEO
orbital positions, heavily regulated business by the local authorities, high upfront CAPEX, and
requirements of high technology and expertise in operations including the hindrance forbidding
technology and knowledge transfers. Therefore the new comer in this industry needs an innovative
business idea to draw the investors’ attentions, a possession of necessary knowledge, technology and
connections for business initiations and a feasible business model to answer the uncovered or
invisibly new demands.
In Space Industry, one of the strategies to obtain a good business proposition is lowering Cost or
reducing the Risk in business operation. Several techniques could be used to achieve this goal such
as Deploying a large high capacity Satellite to provide large scale of services: KA-Sat or Opting to use
a high technology small Satellite to provide highly flexible services to current fluctuating demands:
Eutelsat-Quantum series. It could be seen from the trend that, either going for the larger, higher
capacity or smaller, more advance in technology satellite, the operator aims to either reducing the
Cost or the Risk in the business operation.
Besides the movements from the big companies in the industry in response to current Space Industry
market, many new players in the space industry entered the venue from another arena: applications
on Small, Pico-Satellite platform. Skybox Imaging, PlanetLabs, UrtherCast, ISS, PlanetiQ, Dauria
Aerospace, Vivisat are allrising stars in the Space Industry. All built their businesses on the Pico to
Micro-satellite platforms operating in LEO. Working with this small satellite, these companies gained
the reduced risks from lowering the satellite construction and launch costs. Furthermore their
business models chose to answer the unprecedented demands: High spatial and temporal resolution
Earth imaging, Medium resolution “Whole Earth” imaging, 24/7 high definition VDO of Earth for
environmental monitoring, Atmospheric Imaging for weather forecast, or Satellite’s mission extension
services.
Additionally in Satellite 2014 conference, it was commented from the experts in the Space Industry
that, in the next decade, it could be considered as the coming of the 2nd era of the Space
Technology and Exploration: an era that one would send a spacecraft to space for servicing another
operating spacecraft. To accomplish this purpose, the small Satellite platform would play a crucial role
due to its low cost and rapid construction and development. This fact could be noticed from an
increase in the number of the small Satellite recently launched either from academic institutions or
governmental agencies; the number of launches increased at least approximately 50% each year for
the past three years. A pico-satellite class, CubeSat is originally used for educational purposes or to
conduct technological or scientific researches due to its low construction and development cost.
Moreover it has been used by the government agencies in technology demonstrations such as a deep
space optical communication. However recently more real world applications are aimed to be solved
on this small satellite platform: High resolution data gathering for weather forecasting or Commercial
Satellite’s mission life extension either from refueling or graveyard orbit maneuvering. Furthermore
recently more attempts have been done to use CubeSat to establish High-Speed Communications
with the use of frequency bands ranging from S to Ka bands.
Proposal written on April, 2015
Page 6
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Because of this, it can be easily seen the potentials of the CubeSat in either the educational or
scientific purposes or commercial aspects; therefore, this project not only could bring Thai Space
technology studies to the international level, it also benefits Thaicom to gain necessary knowledge
and experience in this technology to be able to select the right technology to serve the customer
demands at the right time in the near future.
Do you know?
CubeSat won the Third place in Sir Richard Branson’s Virgin Media Business –
“3 NEW THINGS 2014” contest.
Proposal written on April, 2015
Page 7
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
SpaceBox STEP-1’s Missions
___________________________________________________________________________
SpaceBox Laboratory team has defined the missions for the STEP-1 as follows:
1. Earth Imagery - “Satellite Imagery of Earth”
SpaceBox STEP-1 will perform two satellite imaging task on orbit. The first one will be conducted with
the SSTV camera which will capture the Earth images and concurrently broadcast the data to Earth as
shown in Figure 3.1 A. The data transmission will be on the open-access policy; therefore, the
captured and broadcasted images will be open for access by general public.
Figure 3.1 A
While the images captured by SSTV camera are under the open and free access policy, the high
resolution images captured by another high resolution camera on board will be transferred to the
SpaceBox’s Ground Station first before opening for downloading from our website. As shown in
Figure 3.1 B, due to the high resolution image’s data size, the SpaceBox STEP-1 will need to only
capture the image and store it in the on-board memory first; upon the completion of the image
capturing process, the data transmission will then be initiated to send the captured image to the
Ground Station.
Figure 3.1 B
Proposal written on April, 2015
Page 8
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
2. O-Space Textbook - “Education from space”
The O-Space Textbook from Space mission will allow the general students and youths at any place in
Thailand to receive the wonderful experiences in interacting with the real, on-orbit Satellite through
our developing SpaceBox Kit (SBK) which will later be distributed to selected schools. As the STEP-1
communication policy is open to access, anyone who has a capability to establish a connection with
the STEP-1 can communicate with it. Our team thus takes this advantage to offer this similar
opportunity to Thai youths and students and wish that this could create a societal impact to the Thai
Space and Technology development and education to come back and support the Space Technology
development and education.
Additionally we believe that any developed or discovered knowledge should belong to nations, not
any individuals. All the designs, developments and processes to secure launch opportunities shall be
documented and made available to public in order to encourage other interested people to follow
our footsteps.
Figure 3.2
3. Space Tracker - “Enhanced Capability”
Hotspots monitoring for wildfire prevention, data gathering for studying the migration of animals, or
the climate change research are examples of the applications or studies by major space agencies
conducted on the Pico-satellite platform. CubeSat platform possesses a great potential of its own to
tackle real world problems, not only promoting the advance in science and technology.
This mission objective is to demonstrate this CubeSat capability with the earth object tracking
selected as a sample experiment. We will invent a small low-cost efficient tracking device in such a
way that it could be located by and establish the data transmissions with the SpaceBox STEP-1 for
remote sensing. With such device, we could demonstrate its use through conducting experiments in
wide range of applications: Ship Tracking in Sea Transportation or Fishery, Car Tracking for Traffic
Management and Animal Tracking for the Wildlife Preservation (Figure 3.3).
Proposal written on April, 2015
Page 9
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Figure 3.3
From this experiment, the technical challenge is a requirement that the invented tracking device must
possess sufficient radio transmission power to establish a connection with SpaceBox STEP-1.
SpaceBox STEP-1 shall perform only one of the defined missions at a time because of the limitation
of the available power supplied from the Electrical and Power Subsystem.
SpaceBox Laboratory team has experiences in CubeSat Technology and has been seriously working
for over half a year on researching and experimenting on the concepts or technologies designed for
the defined missions. There are certainly issues or questions for which the team could not answer at
present; however, the team shall put our best efforts to answer all questions and develop our
technical knowledge and skills on the small satellite design, development and construction
throughout the courses of this project.
Proposal written on April, 2015
Page 10
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
BENEFITS TO THAI EDUCATION AND SCIENTIFIC COMMUNITIES
___________________________________________________________________________
In Thailand, the government agency that is responsible to supporting the Space technology studies
and in diffusing the relevant knowledge and experiences to the science and education communities is
National Science and Technology Development Agency (NSTDA); however, it can rarely notice any
activities or campaigns which are meant to accomplish those goals.
In Asia-Pacific region, the Asia-Pacific Regional Space Agency Forum (APRSAF) was founded to
encourage regional or international co-operations among members and the supporting countries to
enhance space activities and the uses of the space technologies for the regional or global benefits.
The forum opens for participations from all members in Asia-Pacific countries; LAPAN from Indonesia
and ANGKASA from Malaysia have been quite active in coordinating the activities with JAXA for their
interests. However, for Thailand, NSTDA appeared only as a participant.
It can be clearly seen that even though Thai has plenty of opportunities to promote the development
and studies in Space Technology or to use the relating activities in strengthening Thai education or
the future STEM[2] workforce, without the real awakening event, no one would step up to seriously
champion the Space Technology research and study.
SpaceBox STEP-1 missions are designed to create a societal impact on the science and education
communities in such a way that it would instigate the movements in Space Technology education:
providing meaningful aerospace and science technology, engineering and mathematics educational
experience to Thai youths.
SpaceBox STEP-1 shall present our work in the 22nd APRSAF (The Asia-Pacific Regional Space
Agency Forum) at Bali, Indonesia in December 1-4, 2015
Proposal written on April, 2015
Page 12
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
PUBLIC ACCESSIBILITY
___________________________________________________________________________
SpaceBox STEP-1 shall document all processes in this project starting from the designing, COTS
selections and procurements, modules’ constructions and integration, securing launch opportunities
and operations and then the documentation and learning shall be published on an open website
(www.SpaceBox.in.th).
Our team gives much attention to knowledge and experience transfer to any educators or the
scientists; thus, all the failures and successes will be reported for the benefits in the future uses.
Ground Station and Satellite Construction Laboratory
___________________________________________________________________________
SpaceBox STEP-1’s Ground Station together with the Satellite Construction Laboratory (SpaceBox
LABORATORY) shall be established at Darunsikkhalai School of Innovative Learning (DSIL) with the
granted school’s permission. The main purpose of this Ground Station is to create the opportunities
for the youths and students to connect to the real, in-orbit Satellites (with open communication policy
similar to that of SpaceBox STEP-1) or even to the International Space Station. Moreover it shall act as
a command and control center of the SpaceBox STEP-1once in orbit and as an information
distribution center for the project.
All the purchased equipment and testing device together with the right to manage the Ground
Station after the end of project shall be transferred to DSIL for the future uses.
Ground Station
The design of the Ground Station system is shown in Figure 4.1 and with the following specifications:
•
Be able to communicate to LEO satellite in frequency band VHF and UHF. And can support
every communication standard pattern including communicated activities to International
Space station.
•
High Capability Antenna can provide at least -100dBm of communication power with which
the Ground Station could establish a connection to any visible Satellite.
•
Be able to be accessed and controlled from other remote stations
Proposal written in April and revised in June 2015
Page 13
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Figure 4.1
Satellite Station On Demand (SSOD)
SpaceBox STEP-1’s Ground Station provides in general a direct access for DSIL students to use its
facilities. Nevertheless to give similar opportunities to the youths and students from rural or other
remote areas, the SpaceBox team shall develop the web-based system through which anyone would
be able to join by registration and consequently obtain the right to connect online to our Ground
Station. Then they would similarly gain a wonderful hands-on experience from their direct contact
with On-orbit Satellites through various activities and lessons: Establishing a connection and Selecting
communicating frequencies with On-orbit Satellites.
Proposal written in April and revised in June 2015
Page 14
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Satellite Construction Laboratory
The design of satellite construction laboratory is shown in Figure 4.2 Satellite Construction Laboratory
shall have its specifications as follows:
• Laboratory shall have relevant electronic device and communication equipment:
spectroscope, oscilloscope and others.
•
Laboratory shall have facilities necessary for satellite’s electronic part construction: equipment
and tools for building electronic prototype board or print circuit board (PCB)
•
Laboratory shall have facilities for both functional and environmental tests e.g. Thermal
Vacuum chamber, power generation (present as a solar radiation source to earth), Thermal
camera for convection analysis as well as other equipment to support further analysis and
CubeSat design.
Figure 4.2
Proposal written in April and revised in June 2015
Page 15
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Sub-System Designs
___________________________________________________________________________
SpaceBox STEP-1 is designed to operate on 3 Primary and 1 Auxiliary missions. The Primary mission
includes Earth Imaging, LEO communication and Space Tracking. For Earth imaging mission, two
main systems were designed to perform two different image capturing functions: Digital system shall
capture high resolution image and transmit via digital FSK modulation while Slow Scan TV (SSTV) shall
capture low resolution image and transmit via analog FM modulation. For the space tracking mission,
SpaceBox STEP-1 shall act as a repeater which functions to repeat the received tracking data from
trackers to SpaceBox Laboratory’s Ground Station. All primary missions’ communications operate at
437 MHz radio frequency while the auxiliary mission transmits the telemetry by AX25 protocol at 145
MHz. The designed system is shown in Figure 4.3 A and 4.3 B.
Figure 4.3 A
LEO:LowEarthOrbit
Proposal written in April and revised in June 2015
Page 16
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
System Overview
Primary Mission
OBC
¼ lambda
@437MHz
Camera
FM Enable
5 PV
EPS
watchdog
OBC +
report
Camera
FM data
FSK Enable
COMM
437 FM/FSK
FSK data
FSK Module
FM Module
¼ lambdaRedundant
@145MHz
1 PV
Mission
EPS + OBC +
FM145 (AX25)
Figure 4.3 B
Proposal written in April and revised in June 2015
Page 17
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Photographing and On-Board Data Handling Subsystem (OBDH)
The designs of the Photographing and OBDH modules are shown in (Figure 4.4).
OBC + Camera
FM Enable
OV5642
parallel F
I
F
Camera Module
parallel
SPI
MCU
O
FM data
OBC
FSK Enable
FSK data
5V 1A
enable
5V 0.5A
Watch dog/report
Figure 4.4
Mission Statements:
- To take Photographs and transmit the processed images to Earth
- To coordinate and control other systems’ functions and act as the data bank of the SpaceBox
STEP-1
- To modulation signal both FSK and SSTV
- To control the power distributions and consumptions of the SpaceBox STEP-1’s subsystems
- To continue functioning under the critical conditions in which some of the subsystems unable to
perform their functions normally and able to separate the damaged systems from the rest for the
safety of the Satellite.
System Requirement:
- Shall be able to capture Images at resolutions ranging from 320 x 256 to 640 x 480 pixels
- Shall be able to modulate signal in FSK and SSTV type Robot36 and to communicate between
subsystems via SPI
- The power source of OBC shall be separated from that of the cameras to prevent the electrical
surge in case of the occurrence of an electrical short circuit
- OBC shall contain a Watch Dog system functioning to monitor other subsystems for its operations
in order to prevent any anomalies
Proposal written in April and revised in June 2015
Page 18
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
- OBC shall be able to control and manage the SpaceBox STEP-1’s power usages through the
manually switching on or off certain device or systems.
Electrical and Power Subsystem
Figure 4.5 shows the design of the Electrical and Power Subsystem of the SpaceBox STEP-1.
Figure 4.5
Mission Statements:
- To generate and supply the electrical power to SpaceBox STEP-1’s subsystems
- To store the electrical power for the uses of other subsystems during the Eclipse or under the
occasions that the electrical power cannot be generated
- To monitor the electrical system on the SpaceBox STEP-1 and perform and necessary actions to
prevent the damages to the on-board electronics due to any unexpected events.
Proposal written in April and revised in June 2015
Page 19
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
- To be able to still supply the electrical power to other subsystems even under a critical condition in
which the SpaceBox STEP-1’s Batteries receive some damages and cannot perform its normal
function
System Requirement:
1.Ability to regulate electrical power of 5 bus to full-fill power consumption of each system and
cut the power when something goes wrong.
a) OBC: 5V and cut the power when it exceed 0.5 A
b) Communication on 437 MHz and 145 MHz: 5V cut the power when it is exceed 1A
c) Camera: 5V and cut the power when it exceed 1A
d) Others sub-missions
2. MCU can read following voltage and current; then send data to OBC through I2C or serial:
a) Voltage of 5 PVs
b) Battery voltages
c) Current of charging from 5 PVs
d) Total current of CubeSat loads
3. Support 5 Photo Voltaic (Solar) Cells while each of PV can generate voltage 3 – 6 V. The system
can receive power of each PV separately and able to cut the failed PV from electrical power
system
4. Support 2 Lithium Cell Batteries connected in parallel and able to cut failure battery out of
system (Battery cut loss system)
5.MCU Shall use the time interval method as a Watch Dog for OBC
Communication Subsystem
Figure 4.6 shows the design of the Communication Subsystem of the SpaceBox STEP-1.
Communication
5V 1A
FSK Enable
FSK
FSK data
SPI
SPI
FM data
FM enable
437 MHz
¼ lambda
20-27 dBm
FM
437 MHz
5V 1A
Command Selection
Figure 4.6
Proposal written in April and revised in June 2015
Page 20
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Mission Statements:
- To establish communications with the SpaceBox’s Ground System to receive tele-commands and
send telemetry data through the uses of both FM and FSK systems
- To transmit the captured images to the Ground Station
- Able to communicate with OBC1 : Receiving the commands from and Sending the data to OBC
- Able to cope with the heat generated from the electronic devices during the communication
process
- Able to prevent and handle the EMI
- Able to continue functioning even if some parts of the subsystems receive some damages and
unable to perform the regular functions.
System Requirement:
- Communication subsystem shall be able to communicate (sending and receiving data packages)
with OBC through SPI
- Shall perform a signal transmission at 1.2 kbps – 115 kbps with FSK2 method and be able to
‑
readjust this speed from OBC
- Shall be able to switch between FM or FSK for data modulation and able to adjust power
transmission 20-27dBm and frequency of transmission by commanding from OBC
- Shall separately supply power for FM and FSK processes in order to protect short circuit
- Shall be able to control the generated heat by the radio wave transmission with 25% duty cycle
- Shall be designed and tested to prevent the EMI
FSK:Frequency-Shi7Keyingisafrequencymodula?onschemeusedindatatransmissionovertheradiowaves
orothermeans
EMI:Electro-Magne?cInterference
OBC:OnBoardComputer
Proposal written in April and revised in June 2015
Page 21
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Auxiliary System
SpaceBox STEP-1’s Auxiliary system is designed to operate independently from the rest of the
subsystems in order to reduce the risk of mission failures due to any unexpected reasons; under
critical situation in which the main system is unable to function, the SpaceBox team should still receive
the signal from the Auxiliary System to indicate its existence in Space. Figure 4.7 shows the designed
Auxiliary system of SpaceBox STEP-1.
Auxiliary Mission
Watch
Step up
dog
reset
v1
PV
v1
Step
up
DC
OBC
tmp
Batt cut
loss
v2
v2
¼ lambda
@145MHz
Ax.25
tmp
FM 145
27 dBm
Figure 4.7
Mission Statements:
- To act as a redundant system of the SpaceBox STEP-1’s main system; hence, the designed
Auxiliary system is Simple and Durable
- Being independent from other systems and able to function as a stand-alone system
- Able to demonstrate a remote sensing and communication with the VHF range radio frequency
System Requirement:
- Auxiliary system shall be able to manage its own power consumption
- Able to measure electrical power and temperature also, send gathered data to ground station
with frequency 145 MHz with Ax.25 using power 24-27 dBm
- Shall have a monitoring mechanism to ensure normal operations of its own system
Proposal written in April and revised in June 2015
Page 22
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
TECHNICAL RISK ANALYSIS AND MANAGEMENT
___________________________________________________________________________
Thermal Risk
In space the temperature can range from -269 ° C to over 400° C. at Low Earth Orbit has some
cooling/heating cycles as it is in and out of sunlight, and we can expect a floating object to
experience a range from -160 °C to 200 °C. By clever thermal design, a temperature range may vary
about -100 °C to 100°C. This is still outside the range most off-the-shelf electronics can handle. In
additional, every electronic device generate thermal when they’re operating and they can’t convect
under vacuum condition thus, they may cause a consequence of failure systems.
Risk Management:
- Design and stabilize the CubeSat’s temperature by considering thermal characteristic of
aluminum. This shall be done with using commercial engineering software to design the total
system.
- Analyze thermal energy generated from some electronic devices by operating subsystem in
vacuum condition and capturing the generated heat’s profiles on the components by thermal
camera. Then, design the heat relocation mechanism to maintain batteries’ operating
temperature from the excess heat occurred at other areas.
- Finally, CubeSat shall be tested in heating and cooling vacuum chamber: CubeSat shall be put in
heating vacuum chamber for 50 minutes (estimated half orbit period) with using a 1300 watts/
meters2 power capacity heat source.Then transfer to a cooling vacuum chamber for 50 minutes
(estimation duration of another half orbit)
Space Radiation Risk
Space weather - radiation and energetic particles emitted from an active sun can damage satellites.
At low earth orbit is partially protected from the worst effect of space weather by the Earth’s
Ionosphere. The primary source of damage due to solar activity is due to highly energetic electrons,
protons, and ions emitted by the Sun. There is also a dip near Brazil, called the South Atlantic
Anomaly (SAA) These particles can penetrate past the satellite’s skin and the surface of the electronics
and dump their energetic charge into the electronics itself. This can cause glitches—Single Event
Upsets (SEU), where the electronics briefly get a wrong signal value. It can also degrade or erode the
solar panels and other sensitive bits The SEU may effect to memories of satellite’s on board computing and that may cause a
consequence of failure of operating system or a deadlock system.
Risk Management:
Proposal written in April and revised in June 2015
Page 23
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
- Installing EMI absorber in electronic devices which may sensitive to EMI in order to protect
conductions circuit.
- Develop watch dog system to detect failure from SEU and be able to restart system.
- Design Aluminum frame to imitate a faraday cage.
- Finally, CubeSat shall be gone through EMC testing.
Collision Risk from Space Debris
Space Debris is space junk and it can be hazardous for spacecraft. However, the collisions between
the spacecraft and micrometer objects or debris are infrequent and our CubeSat’s short life makes it
even harder to have a chance of collusion; thus, for the nano-satellite in LEOm the collision risk is
normally considered as negligible.
Proposal written in April and revised in June 2015
Page 24
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
SYSTEM TESTING
___________________________________________________________________________
Space environment always poses as the biggest threat to the in-orbit operating spacecraft’s health;
thus, the designer and builder needs to be certain that the developing spacecraft is well prepared for
such harsh conditions, as discussed in Nakaya et al. [8].
In term of the spacecraft’s space environment test, there are various standards one could use as a
reference for designing and executing the tests. NASA’s CubeSat requirement document [7] is one of
those widely accepted references.
Among the space environment’s attributes, vacuum condition is one of the most important factors to
be considered in the satellite development. The developer must test the satellite components to
avoid outgassing flux from the electronic parts by putting such components in vacuum chamber to
imitate the space’s vacuum condition. Additionally testing the developing satellite in thermal vacuum
chamber also simulates the heat radiation dominated mode of heat transfer in space. To accomplish
this goal, the vacuum chamber must be able to produce the “high vacuum” condition, see [11] for
more discussion. SpaceBox STEP-1 shall be tested in the vacuum chamber’s high vacuum condition 1 x 10-4 Torr with the suggested testing procedure in the NASA standard [7].
Besides the vacuum in space, thermal condition is also an important factor required a special
attention from the satellite developer. As the CubeSat’s COT electronic parts only operate in a limited
range of operating temperatures, the developer must design the satellite’s thermal management
system in such as way that the temperature inside the CubeSat’s chassis shall stay in this operation
temperature at all times. It could be found in various sources, [8] and [11], that approximated
maximum working temperature of the CubeSat is 70 degree celsius, see appendix D for the
derivation, and the minimum is -15 to -20 degree celsius which came from the working temperature of
the batteries.
“high vacuum” condition - vacuum condition where the mean free path of the residual gases is longer than the
size of chamber or the object being tested.
COT - Commercial Off The shelf
Proposal written on April, 2015
Page 25
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
SpaceBox STEP-1 shall perform a series of tests according to the Launcher’s requirements: Vibration,
Thermal Vacuum, and shock tests. However, to survive CubeSat in LEO orbit, there is functional
testing and environmental testing series are needed as show on following flowchart (Figure 5.1).
Figure 5.1
Proposal written on April, 2015
Page 26
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
LAUNCH OPPORTUNITY
___________________________________________________________________________
In term of securing the best Launch opportunity for the project, SpaceBox Laboratory team had
researched through each member’s international connections and the available information on the
Internet for gathering as many options as possible for consideration.
In general, the CubeSat launch from the non-US or non-European team would be charged in the
different rate and that from US or countries in European unions from the private launch companies.
With the launch date set in Q3-Q4 of 2016 or Q1 of 2017, the collected information regarding the
launch service from private launchers is shown in Table 1.1
Launcher
Price (in Bath and USD)
NanoRacks LLC (www.nanoracks.com)
Bath 2.8M ($85K)
Innovative Solutions In Space
(ISIS, www.isispace.nl)
Bath 2.4M-3.2M ($75K-100K)
Tyvak nano-Satellite System INC (Tyvak.com)
Bath 2.7M ($90K)
Soyuz-Fregat Launcher
Bath 2.8M ($85K)
Table 1.1
In the moment, we are under a consideration if we would explore other possibilities through
establishing a connection with an international space agency : JAXA or the local organization : THAI
Air Force in order to obtain a better launch price.
Additionally, to seek a more viable launch solution, the team would like to make a contact to Space-X
which has a business relationship with Thaicom. Nevertheless, for appropriateness, we would like to
discuss with Thaicom first to ask for its suggestion of how to proceed to avoid any unexpected
misunderstandings which could affect Thaicom’s business and its connection with Space-X.
Proposal written on April, 2015
Page 27
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
DEVELOPMENT TIMELINE
Time month no.
Development Plan
Output
1 2 3 4 5 6 7 8 9
Procurement of Tools and
equipments
Tools and equipments for
cubesat and laboratory
Laboratory, station and testing
facilities setup
Laboratory and cubesat
station
Detail design and
implementation Electrical
Power System (EPS)
EPS board
Detail design and
implementation Imaging
system
Camera board
Implement SpaceBox Kit (SBK)
SpaceBox Kit (SBK)
Detail design and
implementation
Communication System
Digipeater and
trasmission system
Implementation tracking
device
Tracking devices
Detail design and
implementation On-Board
Computer (OBC)
Onboard computer and
software coding
Integration and Testing in
laboratory
Integrated cubesat
1st Testing cubesat with High
Altitude Balloon
• Cubesat is tested in
space condition
• Cubesat at near space
photo
Enhance cubesat system from
data collecting from testing
enhanced cubesat
2nd Testing cubesat with High
Altitude Balloon
Completed cubesat
Testing according to launcher
Certificated cubesat
ready to launch
1
0
1
1
1
2
Waiting for launcher
Proposal written on April, 2015
Page 29
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
EXPERIENCE ON CUBESAT
___________________________________________________________________________
Our team members have experiences in designing, building and testing an experimental CubeSat
model: SpaceBox STEP-0 , which had Satellite Imagery by SSTV and altitude sensing as its defined
missions and was awarded the 3rd place in GISTDA’ THASA contest.
After the completion of the CubeSat’s development and all necessary tests conducted in the
laboratory, to test its operations in a Space-Like condition, it was sent up to the sky with a High
altitude balloon and reached the maximum altitude at 35 kilometers before starting to descend. At
this altitude above a standard sea level, the CubeSat will encounter a Space-Like condition : 0.01 BAR
pressure (close to Vacuum), 1,300 Watt per square meter of the Solar power density, the extremely
high and low surrounding temperatures, and similar Radio signal attenuation as that faced by the
general communication Satellite. Therefore, HAP testing is commonly used in the technological
development phase or the later stage of the CubeSat development and construction.
In the HAP test, as shown in ,the SpaceBox STEP-0 was carried by the 1,200 gram Helium Balloon up
to the altitude at approximately 30 Km above the standard sea level, shown in Error! Reference source
not found., which was considered the operational altitude. At this level, SpaceBox STEP-0 functioned
normally by capturing the Earth and surrounding images with its SSTV camera and then broadcasting
back to Earth at every 120 seconds. The test was lasted for 3 hours with the goal to test the CubeSat’s
components for its functionalities under the extreme temperature and pressure at this altitude.
It was later shown from the results of this HAP test that the CubeSat and its components can perform
normally at this Space-Like condition and no damage or operational anomaly could be noticed.
However due to the inappropriate light condition at this altitude, the captured images didn’t come
out as good and sharp as expected.
Figure 10 shows the captured Images by SpaceBox STEP-0’s SSTV camera. As mentioned above,
SpaceBox STEP-0 was set to take photographs by its camera while flying at the designated altitude,
to ensure uninterrupted operations from the power shortage throughout the entire 3 hours of
CubeSat operations (at this stage the CubeSat’s power came only from the on-board Batteries, not
yet from Solar Panels), the SSTV camera was commanded to take pictures at every 120 seconds and
then to transmit the images with SSTV system to the ground. SSTV system is an Analog picture
transmission at an amateur radio frequency: 437 MHz. It starts by digitally capturing the 320 x 256
pixels image and then converts this image to the radio waves to be transmitted to the ground. This is
an open system from which any amateur radio operators could receive the broadcasting information
and hence, during our HAP test, there were amateur radio operators in Thailand who could receive
the SpaceBox STEP-0‘s broadcasting signals resulting in the pictures shown in Figure 10.
From previous HAP Balloon experimental we found that
1.In short time period, CubeSat could be used to Take pictures and then Transmit the captured
images from high altitude to ground without receiving any damages from the extreme environmental
Space-Like conditions
2. SSTV system could transmit the captured 320 x256 pixels resolution images at the speed of 2 Kbps
(or at 40 images per second picture transmission rate). The transmission from the CubeSat at 30 km
Proposal written on April, 2015
Page 30
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
altitude above the standard sea level was successful; however, the transmitted images was at low
quality due to the Analog transmission system and the interfering noise during the transmission.
3. Radio transmitted power of 0.5 - 1 watts have enough power to receive and transmitted data to
Cubesat in LEO atmosphere.
Proposal written on April, 2015
Page 31
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
APPENDICES
___________________________________________________________________________
Appendix A - Mission Analysis
A1) Power Generation & Consumption Analysis
The power source of CubeSat is from Solar Power which will be converted to electrical power by
PhotoVoltaic (PV) Cell and then stored in the batteries.
A1.1) Power Generation
A1.1.1 CubeSat Orbit
The velocity of Cubesat:
The angular velocity of Cubesat:
Time for 1 orbit:
A1.1.2 Illumination on CubeSat sides
Proposal written on April, 2015
Page 32
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Figure 11 Schematic Diagram of the CubeSat's Exposure to the Sun
From figure 11,
!
!
A1.1.3 Calculation of Power Generation
The parameters have defined as follows:
- Approximate altitude: 350km (LEO)
- Earth radius 6,366 km and mass 5.972 x 1024 kg
- Dimension of cubesat 0.1m x 0.1m x 0.1m and mass 1 kg
- The PV cell one side equal 0.0057 m2 ( 0.0755 m x 0.0755 m) with efficiency of 30%
- The incoming irradiation amounts to 1,353 W/m2
- Universal gravitational constant (G) = 66.7 x 10-12 Nm2kg2
- CubeSat consists of 6 sides. 5 sides with PV cells and one with camera. The available power then
equals
Proposal written on April, 2015
Page 33
! of 50
!
Project: SpaceBox STEP-1
when
SpaceBox Laboratory
A = area of PV 1 side
S = the irradiation
k(t) = determined by the number of sides illuminated
n = efficiency of PV
From all defined parameters, we can calculate approximate value of:
- Time travel for 1 orbit = 5400 s
- If we use PV triple junction type with an efficiency of 30%, power of one side of PV is 1.61 W
- The maximum power that cubesat can provide is 4.84 W
A1.1.4 Photovoltaic Cell
Figure 12 is an example of Photovoltaic Cell that we may use in this project. The triple junction
cell from AZURSPACE, Germany has 30% efficiency.
A1.2) Power Consumption
Subsystem
Power (Watt)
% Duty Cycle
Power per orbit
On Board Data Handling
0.1
100
0.1
Camera module
0.5
18
0.09
Transmission SSTV @437 MHz
2.5
18
0.45
Transmission Image FSK @437
2.5
5
0.125
1
3
0.03
Transmission TM @437 MHz
Proposal written on April, 2015
Page 34
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
OBDH
Camera
TX SSTV @437
TX Image @437
TX TM @437
Figure 13 SpaceBox STEP-1 : Power Consumption from each function
A1.3) Power Assumption
The following graph represents the battery power for 1 orbit start with illuminated side and then
eclipse.
Power Assumption
3
1.5
0
-1.5
-3
-4.5
-6
0
362 724 10861448 181021722534 289632583620 398243444706 506854305792
Proposal written on April, 2015
Page 35
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
A1.4) Conclusion
From its Solar Panels, CubeSat can minimally generate power at 1.65 Watt and maximally at 4.97
Watt. If considering the maximum power usage by the operating CubeSat at 0.765 Watt, total
available power is still sufficient for the designed missions.
A2) Link Budget Calculation
A2.1) Path Loss Calculation
Path loss or path attenuation can calculate in dB domain from the following equation:
When
d = distance to satellite at horizon
f = radio link frequency
To calculate path loss of cubesat, we need to calculate distance ‘d’ from satellite when it is at
geometrical horizon seen to the ground station. As we define cubesat altitude is 350 km (h =
350km) and assume that the earth is perfectly spherical with radius 6378 km (Re = 6378). Cubesat
is designed to transmit in 2 frequencies 145MHz and 437MHz. Path loss can calculate as following:
A2.2) Link Budget Calculation
Link Budget at 145 MHz
Transmission between ground and satellite at frequency 145 MHz is shown in following table:
From CubeSat to ground
From Ground to CubeSat
Satellite Power TX
+27 dB
Ground Power TX
+45 dB
Satellite Antenna
0 dBm
Ground Yagi 15E
+15 dB
Path loss at 2141.752 km
-142.29 dB
Path loss at 2141.752 km
-142.29 dB
Polarization Mismatch
-3 dB
Polarization Mismatch
-3 dB
Ground Yagi 15E
+15 dB
Satellite Antenna
0 dBm
-103.29 dB
Proposal written on April, 2015
-85.29 dB
Page 36
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Link Budget at 437 MHz
Transmission between ground and satellite at frequency 437 MHz is shown in following table:
From CubeSat to ground
From Ground to CubeSat
Satellite Power TX
+27 dB
Ground Power TX
+45 dB
Satellite Antenna
0 dBm
Ground Yagi 15E
+20 dB
Path loss at 2141.752 km
-151.87 dB
Path loss at 2141.752 km
-151.87 dB
Polarization Mismatch
-3 dB
Polarization Mismatch
-3 dB
Ground Yagi 20E
+20 dB
Satellite Antenna
0 dBm
-107.87 dB
Proposal written on April, 2015
-89.87 dB
Page 37
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Appendix C - Team Members
Mr. Thunpisit Amnuaikiatloet - Project Manager
Experience:
Third Place’s THASA Contest, GISTDA
First’s Robotics 2013 - Regional (Colorado, USA) First Runner-Up
Thaicom Foundation “Global Warming Project Challenge” - First Runner-Up
Education:
Undergraduate in Computer Engineering - King Mongkut’s University Technology Thonburi, Bangkok
High School - Darunsikkhalai School for Innovative Learning, Bangkok
Abroad High School - George Washington High School, Denver, CO, USA
Contact Information
Phone: +66-81-274-2111
Email: fluke_family@hotmail.com, fluke_family@me.com, thunpisit.am@gmail.com
__________________________________________________________________________________________
Dr. Tawan Tantikul - Attitude and Orbit Control Satellite Engineer
Experience:
Attitude and Orbit Control Satellite Engineer - Thaicom Public Company Limited, Bangkok
Facilitator - Darunsikkhalai School of the Innovative Learning, Bangkok, Thailand
Researcher - Technische Universität Graz TUG, Graz, Austria
Education:
Ph.D. in Aerospace Engineering - University of Southern California, Los Angeles, CA, USA
Master in Mechanical Engineering - King Mongkut’s University Technology Thonburi, Bangkok
Bachelor in Mechanical Engineering - Kasetsart University, Bangkok
Contact Information
Phone: +66-81-988-5930
Proposal written on April, 2015
Page 43
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Email: hkbtotw@gmail.com, tawanta@thaicom.net
__________________________________________________________________________________________
Ms. Pirada Techalertvijit - Embedded Engineer
Educations:
Master in Embedded System - ISAE, Toulouse, France
Bachelor in Computer Engineering - King Mongkut's Institute of Technology Ladkrabang, Bangkok
Experiences:
Geo-Informatics and Space Technology Development Agency (GISTDA)
Winner of “AXE APOLLO SPACE ACADEMY” going to space in 2016. Thailand’s First Person in Space.
Winner of “Fan Pan Thae - 2013” TV show in subject “Apollo program and related space program.”
Awarded honorary degree - 3AF (Association Aéronautique et Astronautique de France)
Contact Information
Phone: +66-86-7832220
Email: ptechavi@gmail.com
__________________________________________________________________________________________
Mr. Wasanchai Vongsantivanich - Satellite Engineer
Educations:
Master in Aerospace Engineering - ISAE, Toulouse, France
Bachelor in Mechanical Engineering - Kasetsart University, Bangkok
Experiences:
Geo-Informatics and Space Technology Development Agency (GISTDA)
Contact Information
Phone: +66-81911-4228
Email: wasanchaiv@gistda.or.th
__________________________________________________________________________________________
Proposal written on April, 2015
Page 44
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Mr. Phonkit Sukchalerm - Telecommunication & Electronic Engineer
Experiences:
Telecommunication engineer - Thailand Space Research (TSR)
TSR-THAI-1, High Altitude Platform Experiment
TSR-THAI-2, High Altitude Platform Experiment
TSR-THAI-3, High Altitude Platform Experiment
TSR-LABD, Zero pressure Balloon Experiment
CanSat Electronic Development, Defence Technology Institute (Public Organization)
Contact Information
Phone: +66-81-736-2168
Email: tery_haha@hotmail.com
__________________________________________________________________________________________
Mr. Natthapong Wongphuangfuthaworn - Electronics Engineers
Educations:
Bachelor in Computer Science - Bansomdejchaopraya Rajabhat University
Experiences:
Electronic & Embedded engineer - Thailand Space Research (TSR)
TSR-THAI-1, High Altitude Platform Experiment
TSR-THAI-2, High Altitude Platform Experiment
TSR-THAI-3, High Altitude Platform Experiment
TSR-LABD, Zero pressure Balloon Experiment
CanSat Electronic Development, Defence Technology Institute (Public Organization)
Conical Scanning Antenna System for rocket tracking, Defence Technology Institute (Public
Organization)
Contact Information
Proposal written on April, 2015
Page 45
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Phone: +66-83-730-0100
Email: natthapong@pinnovation.co.th
__________________________________________________________________________________________
Mr. Aniwat Plodphai - Telecommunication & Electronic Engineer
Educations:
Bachelor in Telecommunication Engineering - Mahanakorn University
Experiences:
Telecommunication engineer - Thailand Space Research (TSR)
245MHz Radio Jammer
144-146 Radio Jammer
TSR-LABD, Zero pressure Balloon Experiment
CanSat Electronic Development, Defence Technology Institute (Public Organization)
Conical Scanning Antenna System for rocket tracking, Defence Technology Institute (Public
Organization)
Contact Information
Phone: +66-83-645-5647
Email: hs8prf@hotmail.com
__________________________________________________________________________________________
Mr. Pondet Anachai - Public Relation
Experiences:
Intern - United Nations Environment Programme (UNEP)
Contact Information
Phone: +66-84-715-6848
Email: pd.ananchai@gmail.com
__________________________________________________________________________________________
Proposal written on April, 2015
Page 46
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Ms. Porntip Limpichaisopon - Public Relation
Experiences:
Public Relation - Darunsikkhalai School for Innovative Learning, Bangkok
Public Relation - Science Creation Company Limited, Bangkok
Educations:
Bachelor in Liberal Arts, Thammasat University, Bangkok
Master in Journalism and Mass Communication, Thammasat University, Bangkok
Contacts Information
Phone: +66-81-633-1707, +66-88-579-3394
Email: im.uddjang@gmail.com, dsil.pr2014@gmail.com
__________________________________________________________________________________________
Group Captain. Thagoon Kirdkao - Advisor
Experiences:
Installation of the telescope at Klai Kung Won Palace for His Majesty King Bhumibol Adulyadej.
Founder of Kirdkao Observatory in Kanchanaburi Province.
C-130 Pilot, Wing 6th, Squadron 601st.
Robotic Optical Transient Search Experiment (ROTSE), University of Michigan, USA.
Catalina Sky Survey (CSS), University of Arizona, USA.
Observatoire de Haute-Provence (OHP), France.
Junior Session of the Astronomical Society of Japan.
Japan Aerospace Exploration Agency (JAXA)
Educations:
Bachelor in Science, the Royal Thai Air Force Academy, Bangkok
Master in Science Education, Kanchanburi Rajabhat University, Bangkok
Master in Astronomy, University of Western Sydney, Australia.
Proposal written on April, 2015
Page 47
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Contacts Information
Phone: +66-81-701-5340
Email: thagoonk@gmail.com
__________________________________________________________________________________________
Proposal written on April, 2015
Page 48
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Appendix D - CubeSat working temperature
To estimate the working temperature of the CubeSat, one could use a simple heat radiation
calculation exercise to get an approximated number, as discussed in Modest [9].
It is well known that the sun produces the electromagnetic radiation with the flux density (solar
constant [11]) equal to 1. 361
kilowatts per square metre.
The P/A of the equation below
represents this flux density while is the emissivity indicating
material property’s effectiveness to emit the energy as thermal radiation. Assuming the CubeSat’s
Chassis is made of the Aluminum with emissivity equal 0.6, see [12], and use Stefan- Botzman
constant
equal
to 5.67 x 10-8 W.m-2.K-4 , one could prove that the approximated CubeSat
temperature, T, is
approximately equal to 69 degree celsius; thus, estimated 70 degree as
suggested in
NASA standard [7].
Proposal written on April, 2015
Page 49
! of 50
!
Project: SpaceBox STEP-1
SpaceBox Laboratory
Appendix E - References
[1] CubeSat Power System, Institute of Energy Technology Aalborg University
[2] www.control.auc.dk/~raf/Aerospace/CUBESAT.pdf
[3] DTU Satellite Systems and Design course CubeSat
[4] Communication, Flemming Hansen, MSCEE, PhD,
[5] www.dsri.dk/roemer/pub/CubeSat's
[6] Make: Technology on your time – 10 DO-IT-YOURSELF SPACE PROJECTS magazine, O’REILLY.
[7] Launch Services Program : Program Level Dispenser and CubeSat Requirement Document, NASA
Launch Service Program, LSP-REQ-317.01 Revision B
[8] Tokyo Tech CubeSat : CUTE I - Design & Development of Flight Model and Future Plan,
Nakaya K. et al., AIAA (2003)
[9] Radiative Heat Transfer, MODEST M.F., McGraw Hill (1993)
[10] Vacuum, https://en.wikipedia.org/?title=Vacuum
[11] Solar Constant, https://en.wikipedia.org/wiki/Solar_constant
[12] Emissivity, http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
Proposal written on April, 2015
Page 50
! of 50
!