Space segment

Efir’s space segment consists of a single 1U CubeSat placed in Low Earth Orbit (LEO) at an altitude of 400 kilometers and an inclination of 51.6 degrees. With this orbit, Efir will stay in LEO for a little more than a year, overflying southern Europe, most of Asia, all of Africa and Australia, all but the extreme southern tip of South America and most of North America.

Using its camera, Efir will supply us with imagery for basic Earth observation and atmospheric studies. Measurements of the Earth`s magnetic field will be taken using the magnetometers of the attitude determination and control system (ADCS). The experiments are mostly basic and serve to provide a basis for more advanced studies on later satellites.

Conceptual 3D model of Efir

The payload will be supported by a standardized set of subsystems, including power management, attitude determination and control, communications, a navigation sensor, an on-board computer and a structure with a thermal management system. Uplink-downlink will be carried out in the UHF band, allowing amateur radio operators across the world to receive data packets and imagery. A set of magnetometers and magnetorquers will provide 3-axis attitude determination and control, respectively. Like all CubeSats, power will be supplied by solar panels and a set of batteries.

Ground segment

The ground segment consists of a transceiver station, a data processing facility and a mission control and operations center. The ground segment will be a multi-use facility that will receive data from other satellites, and will be built with future, more complex missions in mind.

Three possible sites are being studied to situate the station:
Sofia, preferably a university campus site, allowing easy access for both Initiative operators and student trainees and good infrastructural availability.
Plana region, where Bulgaria’s principal satellite communications facility is currently located. Surrounded by low mountains, Plana is isolated from stray emissions and radio interference from cities, while having the least rainfall in the country. It is generally an excellent location to send and receive satellite transmissions.
Kondofrey, a small village some 60 km southwest of Sofia. Kondofrey bears the same geographic benefits as Plana, however it was a secondary location for the satellite communications center and thus it never hosted a large installation.


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