Space segment

Efir’s space segment consists of a single 1U CubeSat placed in Low Earth Orbit (LEO). Efir will overfly southern Europe, most of Asia, all of Africa and Australia and all but the extreme southern tip of South America and most of North America. 

As a technology demonstration mission, the satellite will only perform basic experiments. Efir will be equipped with a small camera in the visible and infrared spectra, and a set of magnetometers. The data acquired on vegetation and the planetary magnetic field will be used to raise interest in natural sciences studies.

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Conceptual 3D render of Efir.

The primary payload consists of an imager developed in-house on a CubeSat-standard dimensions board. 

Its task is to generate coarse-resolution images in both visible and near-infrared (NIR) spectra for normalized difference vegetation index, or NDVI, observation. NDVI is a basic method of tracking the health of forests, crops and other green systems. 

The payload will be used to monitor crops in North America, rainforests in South America, Africa and Southeast Asia threatened by clearcutting and fires, and general observation of Bulgarian forests. 

A set of backup magnetometers on the board will be used to generate magnetic field data independently of the attitude determination subsystem.


The payload is supported by a standardized set of subsystems: power management, attitude determination and control, communications, an on-board computer and a structure with a thermal management system. 

Uplink-downlink will be carried out in the UHF and VHF bands, 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. Power will be supplied by solar panels and a set of batteries. 

Experience acquired during design, integration and testing will be thoroughly documented and provided to several Bulgarian universities to improve their engineering programs. Additionally, radio amateurs will be able to use the satellite throughout its operational life. 

Some tests on a prototype subsystem board similar to the ones we'll use for the Efir platform.

Ground segment

Sofia Tech Park hosts our primary ground segment infrastructure elements. Under a comprehensive cooperation agreement, the Initiative is to deploy equipment and actively take part in the dissemination of benefits from the mission to the Tech Park community. The Laboratory Complex hosts a VHF receiver used to run satellite downlink tests and train future operators in the basics of satellite communications. Some of the labs are equipped for non-destructive inspection tests of flight hardware, as well as rapid prototyping and manufacturing capabilities for different stages of the mission. Mission control and planning will be held at the Incubator, which will also host aerospace know-how exchange events with Bulgarian startups. 

The Plana Mountain region is one of the best possible locations for satellite communications in Europe. 

Its clear skies throughout most of the year and surrounding mountains shielding the area from radio interference make it ideal for both uplink and downlink. 

The UHF/VHF ground station for Efir and future missions is being built here.

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