NanoSatC-Br1 (Brazilian CubeSat Project-1)
NanoSatC-Br1 is the first CubeSat project of Brazil, developed at the Southern Regional Space Research Center (CRS/CCR/INPE-MCT) in collaboration with the Space Science Laboratory of the Federal University of Santa Maria (LACESM/CT - UFSM), Santa Maria, RS, Brazil. The INPE (Instituto de Pesquisas Espaciais) South Regional Center is in fact located on the campus of UFSM (Federal University of Santa Maria) and collaboration between the two institutions is of importance for mission success. The mission has three objectives in the fields of science, technology validation, and academic i.e., student involvement in all mission phases. 1) 2) 3) 4) 5)
The CubeSat project is considered to be a capacity building mission with the goal to involve a new generation of scientists and engineering students through a CubeSat program, providing hands-on training and learning dealing with aerospace technologies and space weather issues. The NanoSatC-BR project made it possible to involve Brazilian universities, such as UFSM (Federal University of Santa Maria), in the Brazilian Space Program with a collaboration of INPE. CRS acts as the NanoSatC-BR1 mission general manager and PI in collaboration with INPE.
The objective of the mission is to provide monitoring of Earth's magnetosphere by measuring the magnetic field over Brazil and to study the magnetic phenomena of the SAA (South Atlantic Anomaly) and the EEJ (Equatorial Electrojet). Note: This SAA is also referred to as SAMA (South Atlantic Magnetic Anomaly).
• One feature of particular interest is the South Atlantic Anomaly (SAA), an area where the radiation hazard from high proton fluxes and cosmic rays is high due to the relatively low shielding effect provided by the Earth’s magnetic field. In this area, for example, a significantly higher number of so-called SEUs (Single Event Upsets) occur in LEO (Low Earth Orbiting) satellites (Heirtzler, 2002, Figure 1).
• The EEJ (Equatorial Electrojet) is a narrow ribbon of current flowing eastward in the day time equatorial region of the Earth's ionosphere. The abnormally large amplitude of variations in the horizontal components measured at equatorial geomagnetic observatories, as a result of EEJ, was noticed as early as 1920 from ground observations. The EEJ phenomenon was first identified using geomagnetic data. The amplitude of the daily variation of the horizontal magnetic intensity (ΔH) measured at a geomagnetic observatory near the dip-equator is 3–5 fold higher than the variation of data from other regions of Earth. A typical diurnal equatorial observatory data show a peak of strength ~80 nT at 12:00 hours LT (Local Time), with respect to the night-time level.
EEJ studies from satellite data were initiated with the arrival of data from the POGO (Polar Orbiting Geophysical Observatories) series of satellite (1967–1970). The characteristic signature of the EEJ is a sharp negative V-shaped curve in the ΔH field, attaining its minimum within 0.5º of the magnetic dip equator. The magnetic data from satellite missions like Orsted (1999–present) and CHAMP (2000–2010) have vastly improved our knowledge of the EEJ (Figure 2). 6)
The NanoSatC-BR1 concept was developed to:
• monitor, in real-time the geospace, the particle precipitation and the disturbances at the Earth’s magnetosphere over the Brazilian territory
• determine their effects on regions such as the South Atlantic Magnetic Anomaly (SAMA).
Figure 2: Ionosphere Equatorial Electrojet representation (image credit: GFZ)
NanoSat-BR1 is a 1U CubeSat of size of 10 cm x 10 cm x 11.3 cm and a mass of 1.33 kg. A 1U CubeSat kit of ISIS (Innovative Solutions In Space BV, Delft, The Netherlands) was purchased while the local work has been concentrated in the development of the payload and in the students participation in activities such as mission analysis and design, integration, testing and operation, besides specific studies on the platform itself.
Figure 3: Illustration of the deployed CubeSat (image credit: CRS/CCR/INPE-MCT)
Figure 4: Engineering model of the NanoSatC-BR1 platform (image credit: CRS/CCR/INPE-MCT, UFSM)
RF communications: Use of an amateur UHF/VHF band radio transceiver for downlink and uplink communications. In addition, an S-band link is used. The S-band stations are located in Sao José dos Campos at ITA (Instituto Tecnológico de Aeronáutica), and at INPE South Regional Center in the southern part of Brazil.
Figure 5: Proposed operational test set up suggested by the vendor of the platform (image credit: ISIS)
Legend to Figure 5: Since INPE has a very large AIT (Assembly, Integration and Test) facility, called LIT, it is not clear yet which facility will be used for the system operational testing.
Launch: A launch as a secondary payload is planned for late 2013 on a Chinese vehicle.
Orbit: Sun-synchronous orbit, with a desired altitude in the range of 500 -600 km to meet the 25 year de-orbit rule.
Sensor complement: (FGM, ICs)
FGM (Fluxgate Magnetometer):
The science instrument is a XEN-1210 FGM from Xensor Integration BV, Delft, The Netherlands. The objective is to measure the intensity of Earth's magnetic field in the SAA (South Atlantic Anomaly) region and the EEJ (Equatorial Electrojet). 8)
A second magnetometer (XEN-1210) is used for attitude determination by the satellite attitude determination and control subsystem. The magnetometers chosen fit with the technical and scientific aspects of the satellite proposal.
The requirements for the magnetometer are listed below:
• Collect data in a frequency at least three frames per second
• Get information about the three components of the geomagnetic field
• The data must be available at least once daily
• The acceptable intensity resolution of the magnetic field must be 15nT.
The XEN-1210 FGM is a magnetic field sensor based on the Hall effect. It uses Xensor’s patented high performance Hall technology, with a resolution of 15nT and a magnetic field range of 63mT. The device is available in the SFN8 package (Figure 6). 9)
Figure 6: Various illustrations of the XEN-1210 FGM along with a 3D board of 3 XEN-1210 sensors mounted in 3 orientations (image credit: Xensor Integration)
Figure 7: Functional block diagram of the XEN-1210 device (image credit: Xensor Integration)
Table 1: Overview of the XEN-1210 parameters
ICs (Integrated Circuits) of technology payload
In addition to the science payload, two technological payloads are flown using different implementation techniques; the objectives are to test their radiation resistance in space. These are the first circuits designed in the country for space applications that will fly on a spacecraft (Ref. 5).
1) An industrial FPGA for which the Brazilian university,UFRGS (Universidade Federal do Rio Grande do Sul) developed a fault tolerant software in VHDL, in order to operate it in a radiation intense environment. A fault tolerant software was developed in order to provide radiation protection to a standard commercial FPGA.
Besides testing the FPGA behavior under radiation in space, this group is also developing the board where the three payloads will be placed (magnetometer, on/off driver and FPGA).
Figure 8: The payload board with the FPGA, magnetometer and on/off driver (image credit: UFRGS, INPE)
2) A driver IC designed by a Brazilian software house located on the campus of UFSM (Federal University of Santa Maria), also to be tested for radiation resistance.
Driver on/off IC: This circuit was designed by the Santa Maria Design House, located at UFSM using a library also developed in house for radiation hardening characteristics. The requirements were stated by INPE's Aerospace Electronic Division for a possible support of its future missions. The functional capability of the driver on/off IC is to receive on/off telecommands from the satellite bus and direct them to the various payload equipment destinations.
The prototype of the circuit was manufactured and is available (digital part) incorporating other functions of interest as well such as a transition set and shift registers to measure radiation dosages.
Figure 9: On/off integrated circuit for the Multimission Platform (image credit: INPE)
1) Rafael Lopes Costa, Petrônio Noronha de Souza, Nelson Jorge Schuch, Otávio Santos Cupertino Durao, Lucas Lopes Costa, Rubens Zolar Gehlen Bohrer, “NanoSat-BR - Energy Generation and Storage,” URL: http://mtc-m19.sid.inpe.br/.../COBEM2009%20Poster_Nanosat%20-%20Energy%20
2) W. N. Guareschi, N. J. Schuch, A. Petry, A. S. Charao, L. A. Tambara, “Analysis of field programmable gate array alternatives for use in nanosatellites,” Proceedings of the 61st IAC (International Astronautical Congress), Prague, Czech Republic, Sept. 27-Oct. 1, 2010, IAC-10.B4.6B.12
3) Nelson Jorge Schuch, Otavio S. C. Durao, Geilson Loureiro, Pawel Rozenfeld, Odim Mendes Junior, Nalin Babulau Trivedi, Severino L. Guimaraes Dutra, Alisson Dal Lago, Clezio Marcos Denardini, Antonio Claret Palerosi, Natanael Rodrigues Gomes, Joao Baptista dos Santos Martins, Ricardo Augusto da Luz Reis, Cassio Espindola Antunes, Tardelli Ronan Coelho Stekel, William do Nascimento Guareschi, Lucas Lopes Costa, Eduardo Escobar Burger, Rubens Zolar Gehlen Bohrer, Lucas Lorencena Caldas Franke, Fernando Landerdahl Alves, Andirlei Claudir da Silva, Jose Paulo Marchezi, Talis Piovesan, Dimas Irion Alves, Andrei Campanogara, Mauricio Rosa Souza, Bruno Knevitz Hammerschmitt, “Progress in the NanoSatC-BR Cubesat Development,” Proceedings of IAC 2011 (62nd International Astronautical Congress), Cape Town, South Africa, Oct. 3-7, 2011, paper: IAC-11.B4.1.5
4) Nelson Jorge Schuch, Otavio S. C. Durao, Geilson Loureiro, Alexandre Alvares Pimenta, Odim Mendes Junior, Nalin Babulau Trivedi, Natanael Rodrigues Gomes, Joao Baptista dos Santos Martins, Tardelli Ronan Coelho Stekel, Lucas Lopes Costa, Eduardo Escobar Burger, Rubens Zolar Gehlen Bohrer, “Progress in the Brazilian INPE-UFSM NANOSATC-BR Cubesat Program,” Proceedings of the 63rd IAC (International Astronautical Congress), Naples, Italy, Oct. 1-5, 2012, paper: IAC-12.B4.1.5
5) Otavio Durao, Nelson Schuch, Alexandre Pimenta, Jeroen Rotteveel, Manoel de Carvalho, Geílson Loureiro, “A cube/nanosat program based on national and international cooperation,” Proceedings of the UN/Japan Workshop and The 4th Nanosatellite Symposium (NSS), Nagoya, Japan, Oct. 10-13, 2012, paper: NSS-04-0311
6) H. Lühr, S. Maus, M. Rother, “Noon-time equatorial electrojet: Its spatial features as determined by the CHAMP satellite,” Journal of Geophysical Research, Vol. 109, 2004, A01306, doi:10.1029/2002JA009656, URL: http://www.geomag.us/info/Smaus/Doc/eej.pdf
7) J. R. Heirtzler, “The Future of the South Atlantic Anomaly and implications for radiation damage in space,”. Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 64, Issue 16, November 2002, pp.1701-1708, doi:10.1016/S1364-6826(02)00120-7
8) J.P. Marchezi, O. Mendes Jr., C.M. Denardini, N. B. Trivedi, O. Cupertino Durao, N. J. Schuch, “The NANOSATC-BR1 Scientific Payload: Magnetometer System,” Proceedings of the 2nd IAA Conference on University Satellite Missions and CubeSat Workshop, IAA Book Series , Vol. 2, No 2, Editors: Filippo Graziani, Chantal Cappelletti, Rome, Italy, Feb. 3-9, 2013, paper: IAA-CU-13-03-01
9) “Magnet Sensor XEN-1210,” data sheet of Xensor Integration, May 26, 2011, URL: http://www.google.de/url?sa=t&rct=j&q=magnetic%20sensor%20xen-1210%20data%20sheet&source=web&cd=1&cad=rja&sqi=2&ved=0CDkQFjAA&
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates.