ИСТИНА

Constellations of the CubeSat format nano-satellites have recently found increasingly wide application for various scientific, educational and technological purposes. Unlike specialized "larger" spacecraft, they do not require separate launches, since they are launched into orbit as a by-pass payload, are relatively cheap and are characterized by short times required for the manufacturing and payload and onboard system ground testing. The problems and challenges associated with the fast development of CubeSats and their constellations include the fact that such spacecraft can make a significant contribution to the space debris. This report examines the experience, problems and prospects for the development of a cluster of CubeSat format nanosatellites, currently being deployed in orbit in the frame of the Moscow University space project Sozvezdie-270. To day, 20 spacecraft have been launched into orbit, 9 of which continue to function at present. Among the scientific problems solved with the help of this cluster of satellites, it is worth noting the monitoring of space radiation, observations of electromagnetic transients of various nature, i.e. atmospheric, solar and astrophysical, as well as experiments in the field of astrobiology. An essential aspect of the Sozvezdie-270 project is educational. It consists primarily of involving various categories of students, from schoolchildren to undergraduate and graduate students, in all stages of the preparation and implementation of space missions, including participation in the elaboration and creation of scientific instruments, processing and analysis of the received data. For this purpose, in addition to the orbital segment, the creation of a ground segment in the form of a network of antennas for receiving data from satellites and sending control commands to them has begun. Some of them are located directly in schools and, thus, schoolchildren have the opportunity of direct participation in space research. It should also be noted that technological experiments are being implemented and are planned for realization on some satellites of the Sozvezdie-270 constellation. Thus, equipment AZN-V for monitoring aircraft traffic was installed on the Avion satellite. Preparations are underway for the launch of a group (swarm) of spacecraft with the ability to practice inter-satellite communications, time synchronization of signals simultaneously recorded on different spacecraft, in particular, for localization by triangulation of gamma-ray burst sources. Work has begun on the creation of a specialized CubeSat satellite for conducting technological experiments on practicing quantum communications. The experience of the Moscow University CubeSat nano-satellite low-orbit cluster operating shows that the active life of such spacecraft can reach several years, while such nano-satellite constellation "self-cleans" due to the fact that satellites that have exhausted their resource leave the orbit naturally, burning up in the atmosphere, and, thus, do not become space debris. That is, it can be concluded that the cluster of CubeSat nano-satellites is an effective way of solving scientific, technological and educational tasks without significant environmental damage.