Alberto Carrasco-CasadoResearcher, Space Communications Laboratory, Wireless Networks Research CenterAfter completing his Ph.D. in electric, electronic, and automation engineer-ing from Carlos III University of Madrid and Spanish National Research Council in 2015, he joined the Space Communi-cations Laboratory, at NICT. Currently engaged in several projects related to space optical communications, ranging from the development of terrestrial in-frastructure, aerial demonstrations us-ing drones and HAPS, to space missions using dierent kinds of platforms, from CubeSats to large geostationary satel-lites.Ultra-fast Laser Communications Will Open a New World of Possibilities for CubeSatsubeSat microsatellite technology has made great progress in the last de-cade. The cost of developing small satellites has become reasonable, which has signi-cantly increased the number of users, and this trend is expected to steadily continue in the future. Going forward, CubeSats will play an active role in a variety of scenarios, from short-term missions for university ed-ucational purposes to mega constellations that will support communications for mil-lions of people, and it is expected that ul-tra-large capacity optical-communication technology will open up a new world of possibilities for CubeSats.■CubeSat overviewCubeSats are microsatellites composed of basic units (1U) with 10 × 10 × 10 cm ex-ternal dimensions. Two basic units are called 2U, three basic units are called 3U, and so on. Approximately 80% of launched CubeSats are between 1U and 3U in size. The modular development of small-satellite technology has made it easier to access space, and over the last few years, more than 1,000 CubeSats have been launched, with this number increasing every year.CubeSats have reached a high level of technical maturity, and are now ready to be used not only for educational purposes and simple experiments, but also for full-scale missions. However, terrestrial and satellite communication still depends on radio fre-quency (RF) communication, which has data rates in the “Kbps” class and where spectrum is already congested, so it is difcult to meet the increasing demand for data transmission to the ground. Optical communication, a promis-ing technology to solve this problem, has the potential to improve transmission speeds by several orders of magnitude while keeping the size, mass, and power of onboard optical-com-munication terminals low.■Role of high-speed optical communication for CubeSatsAs mentioned above, the basic technology for communication between CubeSats and the ground is VHF/UHF, and typical transmission speed is around 10 Kbit/s. With large terrestrial antennas, the S-band can reach several Mbit/s and the X-band can reach hundreds of Mbit/s, but with CubeSat size, mass, and power con-straints, it is difcult to dramatically improve communication speeds via RF technologies. Furthermore, already congested spectrum is in a difcult position to support the huge number of satellites that will be launched in the com-ing years. Moreover, space optical communi-cations have a very-high potential, not only to increase communication speeds while reduc-ing size, mass, and power, but also with room for further improvement in the future.There is a very wide range of applications that can benet from the increased transmis-sion capacities of CubeSats and small sat-ellites, including communication networks, space observation, Earth monitoring, disaster prevention, deep-space exploration, Inter-net-of-things device connectivity, basic and applied research, education, etc. There are already plans to use CubeSats in all of these areas, but with the future availability of high-speed communications, it is possible to think of even more new applications. For example, mega constellations can be deployed at a frac-tion of their current cost, enabling high-speed communications in remote locations and signicantly reducing latency. The number of deep-space exploration missions, current-ly only accessible by space agencies, could also grow signicantly due to lower costs. Most importantly, communication speed is currently the most-important bottleneck for CubeSats, so expanding CubeSat capabilities and providing them to the general public may bring completely new applications that no one could have imagined. This is the true value of Special Issue for Space ICTCNICT NEWS 2021 No.110
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