In today’s highly connected world it might seem apparent that pilots of the Solar Impulse aircraft are always accessible; but getting there was less than a piece of cake.

The Solar Impulse HB-SIA’s flair to amaze its supporters by taking flight without a drop of fuel was only made possible thanks to a qualified team of experts that skillfully calculated the perfect balance between weight, size, stored energy and power.

It is a unique and experimental airplane. For this reason, the Solar Impulse team predicted the need to develop a communication tool capable keeping the pilot in touch with the Mission Control Center, collecting data and measurements about the aircraft’s behavior during flights and providing the opportunity to the pilots to communicate with the world from the air.     

The data collection and measurements are particularly important given the experimental nature of the aircraft. They are essential to improve its performance as well as to better design its big brother, the HB-SIB, which is currently being built in Dübendorf (Switzerland). This is where Solar Impulse’s Official National Partner Swisscom, comes in.

In 2009, Swisscom brought together seven engineers to work on an innovative communications solution. The restrictions to create such a device were great, requiring a good mix of innovative spirit and imagination. For example, standard commercial airplanes are equipped with two communication devices: the VHF (very high frequency) radio, meant only for direct communication with the air traffic control tower up to a distance of 50km; and the HF (high frequency) radio, covering only voice and weighing over 20kg. Evidently such heavy technological devices are not fit for such an innovative aircraft.  

Another challenge was to design a device capable of withstanding extreme temperatures (ranging from +80°C to -40°C), consuming no more than 50W (equal to a bedpost lamp) and, because the HB-SIA’s cabin is not pressurized, a device able to endure a radical change in air pressure when flying above 8000m.

It took the Swisscom team of engineers one year to come up with the current communication solution. It’s an incredibly light device (5kg) designed to use as little energy as possible while simultaneously providing the pilot with uninterrupted communication with the ground via text messaging, videos and voice transmission. The device can also transmit more than 100 sets of measurements to the Mission Control Room keeping track of battery voltage, engine temperature and position of the plane. As a bonus, the system also allows the public to experience the flights real-time via the video stream and messaging on social networks.

The Swisscom communication solution is designed to allow the greatest independence of the pilot’s voice from text messaging and image transmissions.  This was especially built so that, in case of a malfunction of one part of the device, the other remains unaffected. However, in case of a total breakdown of the communication system, the cockpit is equipped with a satellite phone permitting the Mission Control Room to guide the pilot to the nearest airfield.