Techn Session XX: TECHNICAL SESSION NAME
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IAA-XX-14-0S-0P
NanosatC-Br1 – The First Brazilian Cubesat
Otavio Durão*, Nelson Jorge Schuch**, Thales Ramos Mânica***, Leonardo
Zavareze da Costa***, Pietro Fernando Moro***.
Brasil has launched its first cubesat, NanosatC-Br1, a 1U, in June 19th this
year from Yasny launch base in Russia, with a DNEPR launch. The project
is a cooperation between The Brazilian Institute for Space Research – INPE
and The University of Santa Maria – UFSM, in which campus is located
INPE South Regional Center - CRS, who has managed the project. This
cooperation includes the participation of undergraduate students from UFSM
at the different phases of the project – analysis, development, software,
integration, testing, launching and operation, as well as the location of the
main ground station of the project. An average of 10 students per year have
been envolved in these activities throughtout the project. This student
participation covers one of the three objectives of NanosatC-Br1, which is
academic and hands on experience. The other two are scientific and
technological. As such, the satellite carries three experiments, one scientific
and two technological. The first one is a magnetometer to measure the Earth
magnetic field mainly over the South Atlantic Magnetic Anomaly – SAMA.
The other two are the first two integrated circuits designed in the country, by
two different methods, one by design and the other by embeded fault
tolerance software, for application in space with radiation resistance. The
paper aims to show the authors experience with the project since its
conception, development strategy, funding, management, payloads, AIT,
launching and operation, reporting lessons learned for future projects and
perspectives. And also to show the first scientific and technologic data
obtainded with it for respectively the Earth magnetic field at AMAS and at
least one of the payload integrated circuits.
*
The Brazilian Institute for Space Research - INPE, Brasil, otavio.durao@inpe.br
The Brazilian Institute for Space Research, South Regional Center – INPE/CRS,
Brasil, njschuch@lacesm.ufsm.br
***
Federal University of Santa Maria – UFSM, Brasil, thales-rm@hotmail.com, leonardozavareze@gmail.com, pietrojomoro@gmail.com
**
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Conception
NanosatC-Br1 was conceived to be a platform to be offered to the Brazilian
scientific and technologic community so they were able to place its experiments in space at a very low cost. Therefore there was no concern with the
development of this platform, with this phase being delayed to further projects or other projects in parallel that could use the NanosatC-Br1 platform
documentation and its engineering model (EM) to their subsystem developments. As such availability time and reliability were two critical factors for
the platform purchased through an international bid with these two conditions included. The winning company to provide the platform was the Dutch
company ISIS Innovative Solutions in Space BV which was located at the
Technological Park in the city of Delft, at the campus of the Technical University of Delft.
The payloads were proposed by INPE scientists, at its head quarter, and university professors that have had previous contacts with INPE South Regional
Center – CRS. Due to the pioneering mission with a cubesat in Brazil no announcement of opportunity was issued at that time.
The ground station was also purchased from ISIS and installed at CRS which
is located in the campus of the Federal University of Santa Maria – UFSM.
The student involvement therefore was in the analysis of the different models of the cubesat (structural, thermal, power etc), in the integration of the
payloads to the platform performed at INPE Integration and Testing Laboratory – LIT, tests and the same facility, launching and operation (there are
two stations both operated by students). Local developments were the technological payloads, the mission ground software, integration and tests and
operation.
1. Objectives
NanosatC-Br1 has three different objectives combining academic practical training, space science and technology
Academic
To offer practical training to students in all the phases of a sapce mission,
since its conception through its development, integration and testing, launching, operation and data analysis.
Scientific
To be a mean of generating in situ scientific data from space that can be
used for further non real time analysis on the ground.
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Technological
To be a test bench in space for technical experiments developed by Brazilian universities and/or research institutes.
Payloads
NanosatC-Br1 has three different payloads. They were all placed in one
board with the cubesat standards; this board also had to include the board
that came with the platform for communication among the different platform
subsystems and known as Breake out Board – BoB.
1. Magnetometer
The magnetometer was purchased and is a very low cost XEN 1210 model
from the company XI Sensor Integration[1]. It is based on the Hall effect with
a resolution of 15nT. Each axis and its electronics is mounted in a 2x2x2.4
mm. surface. At first there was a great concern on the measurement capability of the magnetometer due to its internal position and the possible electromagnetic interference from the platform subsystems.
2. On-off driver
This is the first integrated circuit designed in the country to be radiation resistant for use in space. This demand came from INPE Aerospace Electronic
Division – DEA. It is an on-off driver to be used onboard larger satellites to
receive commands from the ground and select the payload to be turned on.
The Chinese Brazilian Earth Remote Sense Satellite series – CBERS (2 ton.
satellites) does not use this as an IC, and the DEA engineers would like to
have it for the multi mission platform presently being developed at INPE to
missions using up to 500 kg. satellites. The design of the IC was done by the
Santa Maria Design House – SMDH, located in UFSM and the manufacture
of was made in a German foundry.
3. FPGA
This is a PROASIC3 A3PE1500-PQ208 FPGA with industrial standards. An
embedded fault tolerant software was developed to make it more resistant to
radiation for further use in space. This software was developed by the Institute of Informatics of the Federal University of Rio Grande do Sul –
UFRGS. So this is a different method than the one used for the on-off driver.
While that is radiation resistant by design, the FPGA is by its embedded
software. Still are the first two ICs designed in the country to be used in
space
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The same group also designed the payload board with the three experiments
and the BoB. Fig. 1 shows the payload board.
Fig. 1. – NanosatC-Br1 payload board with magnetometer, driver (SMDH chip), FPGA and BOB
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Integration and testing
Payload integration in the platform and tests were permormed at INPE´s Integration and Testing Laboratory – LIT. Tests were performed in the smallest infrastructure available at LIT for thermo vacuum and vibration. Equipment chambers and shakers were used and a balance of mass was also performed which measured 0.965 kg. for the complete satellite.
The proto flight test philosophy was used and only vibration tests were required by the launcher, although thermal and thermal vacuum tests were performed during the test campaign. NanosatC-Br1 pass all tests without need
to rework.
Calibration tests in the payload magnetometer were also performed in the
ground at ISIS facilities in Delft.
Launch
NanosatC-Br1 was launched on June 19th. With a DNEPR launcher from
Yasny Launch Center, in Russia, about 20 km. North of Kazakhstan. This
was the world record holder for simultaneous launch, with 36 satellites being
launched. Figure 2 shows part of these satellites and the sequence of their
launch. NanosatC-Br1 is in the second row above one of the QB50 precursors.
Fig. 2. – NanosatC-Br1 launch sequence
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Operation
NanosatC-Br1 has its main ground station located in Santa Maria, RS in
INPE/CRS at the UFSM campus. At first this was the only station able to
send telecomands to the satellite. An identical station, purchased from the
same company was placed in São José dos Campos, SP, at the Air Force
Technologic Institute – ITA. This station was also able to send commands to
NanosatC-Br1 after a few months of the launch. Both stations operate in S
band and VHF/UHF frequencies, although the satellite does not have an S
band transceiver. Both stations are fully operated respectively by UFSM and
ITA students.
Since the satellite operates in amateur radio frequencies, the support from
amateur radio stations, here in Brazil and abroad, was very important, both
for the capture of the first orbits as well as for the regular operation of the
satellite later on.
There are two ways data is received at the station. Through the nominal beacon which contains 165 bytes of information, both from the platform and the
payloads, and through the download of specific on board log files requested
by telecomands for a specific payload or platform subsystem. There are
more than 200 telecomands and about 30 types of different telemetries to
operate the satellite.
Platform and payload data are exported from the Santa Maria and ITA stations into a data basis in a server located at INPE headquarter. PIs, project
engineers, students and other scientists have access to these data through a
log in procedure in the project site (www.inpe.br/crs/nanosat/).
NanosatC-Br1 performance
The satellite has performed nominally for the first 100 days in orbit. After
that the power subsystem started to show a decline in the battery voltage.
Through operation procedures the ground team was able to elevate this voltage on board again and the satellite has operated well for another 2 or 3
weeks approximately. Presently these procedures are not being effective and
payload data can´t be reliably obtained at the present voltage level of the batteries. All the other subsystems are operation nominally. Fig. 3 shows the
decay of the battery voltage along the frame of data received over time with
the beacon in nominal mode.
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8.4
8.2
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7.8
7.6
7.4
Series1
7.2
7
6.8
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17
33
49
65
81
97
113
129
145
161
177
193
209
225
241
257
273
289
6.6
Fig. 3. – NanosatC-Br1 battery performance
The most probable reason at this point for this behavior is a lower than expected current generation from the solar panels after a certain time. This irreversible state may have been caused by a severe solar storm as those occurred during this period and indicated by EMBRACE service from INPE
(www2.inpe.br/climaespacial/portal/) that issues alert bulletins on those
days. At those days NanosatC-Br1 entered safe mode by “unknowns reason”
as indicated by the Morse code beacon transmitted while in safe mode and in
the region of the South America Magnetic Anomaly – AMAS. But this needs
further quantitative investigation with the combined data available.
An extension of the NanosatC-Br1 life is been sought with operation and
technologic experiments through the amateur radio community, combined
with using it as an educational tool to the classroom for some practical examples in some basic space physics concepts.
Results
Besides being the first Brazilian cubesat, NanosatC-Br1 is also the first Brazilian scientific satellite that has generated in situ science data from space to
be used by Brazilian space scientists. It has shown in practice to Brazilian
space authorities, engineers and scientists, the feasibility of using cubesats to
perform science and technology missions generating useful data and results.
It has also paved the way for the development of other cubesats by other
Brazilian institutions in a cooperative and helpful manner. It has generated
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so far more than 1,500 orbits of data both from every platform subsystem
and each one of its three payloads.
The three objectives of the project have already been achieved.
1. Academic
More than 30 undergraduate and graduate students from UFSM have participated in different phases of the project, since its conception through its different design analysis, integration, tests, launch, operation (at this phase both
UFSM and ITA students) and data analysis. This was done with the supervision of INPE´s engineers and scientists, undergraduate research scholarships,
local visits and training at INPE and local industries, and also through industrial and university periods abroad with hands on experience with cubesats.
Two of these students were hired by INPE after their graduation and after an
open and very competitive national process. Others are doing their graduate
work either at INPE or in others renown foreign universities in space related
fields and participating in other cubesat projects.
2. Scientific
NanosatC-Br1 has generated data from the Earth magnetic field which is
now being compared with existent models. The preliminary results of this
analysis are very encouraging[2,3] with values that confirm the AMAS over
the Brazilian territory and close to those given by the International Geomagnetic Reference Field – IGRF of the International Association of Geomagnetism and Aeronomy – IAGA. Further analysis is being carried out considering the entire set of orbits available, statistics and precise orbit determination. Specific articles are expected to be published in the near future with
these complete results.
The results so far are only for the magnitude of the Earth magnetic field at
the points of the orbits were readings were taken for the x, y and z axis of the
payload magnetometer. It doesn´t consider the direction of the field vector at
those points, although the attitude of the cubesat can be retrieved at the
measurements points with the values given by the attitude sensor magnetometer, located at the on board computer, and the solar sensor of the platform.
3. Technological
On-off driver
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The results obtained with this experiment so far are also very positive[4].
Combined with the data available for the solar activity during this period,
and the effects in terms of Single Event Effects – SEE detected in the circuit,
it shows that the SMDH design and its own software library have provided
significant protection against the radiation effects.
FPGA
This experiment has not yet reported significant results. An error, now
fixed, in the decoding process to store its data from the modulated signal into
engineering values in the payload data basis has delayed this analysis.
Conclusions
The results obtained so far with NanosatC-Br1 are beyond the most optimistic expectations at its beginning. Is has had a capability to generate new uses
for its data and operation that have been freely proposed and done by different people that has been somehow involved or interfaced with the project.
The perspective to use the data obtained so far by the technological experiments, combined with those obtained by the scientific experiment and the
solar activity data available through INPE/EMBRACE may provide very
valuable space science information. Comparing this perspective with the total cost of the project, including launch and operation, NanosatC-Br1 is
proving that cubesats may be indeed a brake through tool for valuable space
missions
Acknowledgments
The authors are deeply thankful to the Brazilian Space Agency – AEB for its
support throughout the whole project, moreover to its conclusion and launching. We are also thankful to the Brazilian amateur radio community for the
support in the NanosatC-Br1 capture and operation, providing valuable information used to important operational decisions.
References
[1] Data sheet XEN 1210; www.xensor.nl; Oct. 18, 2011.
[2]
Nelson Jorge Schuch, Marlos Rockenbach da Silva, Otavio Santos Cupertino
Durão et AL: NanosatC-Br Cubesat Development & Capacity Building Programs: NanosatC-Br1 & NanosatC-Br2, 2014, 1st IAA Latin American CubeSat Workshop, Brasilia, DF, Brasil.
[3]
http://www.inpe.br/noticias/noticia.php?Cod_Noticia=3769
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[4] Leonardo Medeiros, Carlos Alberto Zaffari, Jorge Johanny Sáenz Noval, Lucas
Teixeira, João Baptista dos Santos Martins: Using the NANOSATC-BR1 to
evaluate the effects of space radiation incidence on a radiation hardned ASIC,
2014, 1st IAA Latin American CubeSat Workshop, Brasilia, DF, Brazil