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Understanding nano-satellites in eight points
May 3, 2022 in Telecom
1-The nano satellites that have appeared for 20 years, have attracted the attention of scientists because of their low cost compared to the importance of their usual space missions launched by large powerful countries.
2-A nanosatellite is a small satellite weighing 1 to 10kg. The nanosatellites developed by the university space centers (CSU) are of the CubeSat type, they have the shape of a small cube. A CubeSat embeds a scientific experiment, called a "payload". All the rest of the satellite that allows it to operate is called "the platform". The first university nano-satellite projects were carried out on the campuses of the major American universities Stanford and Polytech California. The CubeSat standard was designed by professors Jordi Puig-Suari and Bob Twiggs of California Polytechnic State University (CalPoly) and Stanford University. CubeSats have appeared since 1999 at the University of California. A CubeSat is a Satellite weighing less than 1.33 kg and measuring 10×10×10 cm.
3-Most of these nanosatellites are launched at a height between 400 km and 500 km above the Earth surface.
4-The challenge of spatial miniaturizationThe miniaturization of spacecraft and the reduction of their mass facilitate access to space at a reduced cost. Therefore, they are classified according to their mass:• Femtosatellite: mass < 100 g• Picosatellite: mass < 1 kg• Nanosatellite: mass < 1–50 kg• Microsatellite: mass < 100–150 kg (NASA < 100 kg)• Minisatellite: mass < 500 kg (NASA smallsatellite < 180 kg)
© Source: NASA, National Centre for Space Studies (CNES), Universitat Politècnica de Catalunya, KTH Royal Institute of Technology, École polytechnique fédérale de Lausanne, MIT [34 (https://www.mdpi.com/2072-4292/12/16/2546/htm#B34-remotesensing-12-02546)].
5-Rockets today are designed to launch dozens of small satellites. SpaceX breaks the record for the most satellites launched in one mission. A Falcon 9 rocket from Elon Musk's company took off on Sunday January 24 with 143 satellites on board, reports the American channel CNN. Prior to that, India had sent 104 satellites into orbit with a single rocket in 2017.
6- Elon Musk is far from the only one interested in this type of satellite. We can cite other private actors, such as Amazon. Jeff Bezos' company plans to launch a constellation of more than 3,200 satellites into low orbit to provide broadband services to customers, businesses and even governments. New players such as SpaceX or OneWeb are taking advantage of the reduction in launch costs to go for the supply of the Internet by satellites or more precisely by CubeSats.
7-In 2018, the National School of Computer Science and Systems Analysis (ENSIAS) in Morocco launched in partnership with the British foundation "KSF Space" and the National Autonomous University of Mexico, its first microsatellite. In CubeSat form, this device was aimed at studying the ozone layer. It was launched on February 28, 2018 from Mexico. This microsatellite was developed at ENSIAS in Rabat by Master students on the "Internet of Things" program, with the supervision of the startup "Heliantha Robotics".
8-Frequencies: For communications with cubesats, universities sometimes use the frequencies allocated to the amateur satellite service (see Articles 1.56 and 1.57 and 25 of the ITU Radiocommunications Regulations). Below are some examples of those:144-146 MHz frequencies, allocated on a primary basis in the three Regions of the International Telecommunications Union ( ITU );435-438 MHz frequencies allocated in Region 2 and 3 on a secondary basis. However, this amateur satellite service should not be used by commercial new space operators. These operators are required to use the frequency bands of the space operation service for remote control and telemetry of the satellites, as well as other radiocommunication services for the transmission of data between the satellite and the Earth.The 2019 World Radiocommunication Conference ( WRC -19) directed the use of telecommands and telemetry for small satellites to the bands 137-138 MHz (transmissions from satellites) and 148-149.9 MHz (reception from satellites).
(*): René Serres: Telecom and ITC consultant By René Serres (*)