EPFL antennas chosen by ESA for nano-satellites

An important factor in these new, small-scale satellites is their system of communication: bearing in mind the small surface available, finding the right solution is a real challenge. Following an international competition launched by the ESA, EPFL was chosen for its innovative antenna solutions.

These antennas, which will equip the new generation of nano-satellites, are the result of a three-way cooperation between the Laboratory of Electromagnetics and Acoustics (LEMA, Juan R. Mosig and Gabriele Rosati), the JAST company located in the EPFL Science Park (Stefano Vaccaro and Jose Padilla), and the EPFL Space Center (Anton Ivanov). “For this type of research, it’s not unusual to have international cooperation, but in this case it’s a 100% Swiss consortium”, enthuses Juan R.Mosig of LEMA, a specialist in antennas and telecommunication.

As always with technology, the current trend for satellites is towards miniaturization. We have seen the development of real “monsters” of more than 1000 kilos that were so costly to develop and launch that only governments could afford them. Now, smaller and lighter alternatives can be considered, known respectively as micro-satellites (between 10 and 100 kilos), nano-satellites (between 1 and 10 kilos), and pico-satellites (1 kilo or less).

The ESA project concerns new-generation nano-satellites, weighing about 10 kilos and in the shape of a cube whose edge measures 25 centimeters. It’s a daunting challenge: to find an antenna with a frequency ensuring a satisfactory output (2 to 3 Ghz) on a small-scale satellite that can commutate between omnidirectional emitting mode (distress-beacon type) and directive emitting mode. EPFL’s solution – chosen by the ESA – is a flat antenna, integrated into the surface of the satellite. By avoiding any protruding parts, the satellite is very compact and easy to manipulate during the launch phase.

After one-and-a-half years’ work, the LEMA solution of, JAST and the EPFL Space Center was to use the four sides of a cube-form satellite. Commutation between sectorial and omnidirectional modes can thus be easily achieved. The antennas were initially simulated by computer by LEMA, and then developed and manufactured by JAST. Finally, the behavior of the antennas in space was validated, using the anechoic chamber at LEMA – a place with no echoes, partitioned off, and with a perfect absorption of the waves.

The ESA sees a big market for medium-size satellites like the nano-satellites. With their reduced weight, the cost of launching is reduced, and they can serve many purposes. They are of a suitable size for staying close to the Earth and performing observations of our planet (ocean currents, temperature variations, concentration of pollutants etc.). They can be deployed in groups for telecommunications, or focused on a celestial body to study exoplanets, for example. This kind of satellite can even be envisioned for Deep Space Missions to Mars or beyond.