Connecting a jacket to space to save lives
The future of satellite-connected wearables is closer to becoming an everyday reality thanks to the world’s first-ever two-way S-band connectivity from a wearable antenna with a geostationary satellite. In autumn 2025, a team climbed mount Halti to test the antenna’s capabilities. Developed by Finnish company Stealthcase, with support from the European Space Agency (ESA) and in collaboration with Radientum, the innovative antenna was integrated into a jacket by outdoor clothing brand HALTI. The demonstration paves the way for reliable communication for emergency responders and people in remote areas without cellular network.
Incorporating antennas into different types of fabrics and surfaces has been a long-term challenge, with their delicate components traditionally being difficult to fold. Additionally, achieving this rapidly and cost-effectively proves to be even harder. Stealthcase overcame these obstacles by finding a low-cost and scalable method to imprint the antenna coating onto textile without compromising its conductivity. Once perfected, HALTI designed a jacket to integrate the antenna, putting the technology to the test in real-world conditions.
To trial the jacket, a team carried out a six-hour trek to the summit and back of Halti, Finland's highest mountain (although its peak lies over the border in Norway). The team divided in two groups; those hiking Halti’s peak and those staying at lower altitudes. Along the route, the first team paused at intervals to test connectivity by sending and receiving text messages with the second team. They demonstrated the two-way communication capabilities of the wearable antenna through a direct link to a satellite over 35 000 km away.
Remarkably, the satellite link held strong even in spots where the terrain was expected to block the signal. As Juha Lilja, founder of Stealthcase and one of the demonstration members, noted, “Every now and then we stopped to make connectivity tests, and the surprising thing was that the satellite link was working at the lake in Norway [Guolasjávri], even though we thought it was shadowed by Halti fell.”
The team had anticipated zones where the antenna-mediated connection would not work, especially at the low-altitude starting point deep in the mountain’s shadow. Yet, as Lilja recounted, “Even at the low-altitude starting point – deep in the mountain's shadow the satellite link worked fluently. It was a moment where even the most reserved Finnish engineer had to chuckle and say, ‘Not bad’.”
Stealthcase has a reputation for developing pioneering antennas, including glass antennas that maintain indoor connectivity despite modern energy-efficient glass that often blocks signals. The company’s founder has dedicated years to advancing wearable, satellite-linked antennas, including collaborations with emergency services to create gear resilient enough for ocean rescues.
Now, with the successful demonstration of robust, two-way satellite connectivity in a wearable form, Stealthcase and its partners have brought the promise of truly connected, resilient wearables one step closer to everyday reality.
This technology demonstrates innovative uses of space driven by Finnish companies, unlocking the potential of space for daily life. It was made possible through the project ‘Wirelessly Connected Textile Antennas for Smart Clothing’, with funding from ESA’s Industrial Competitiveness programme line, part of ESA’s Advanced Research in Telecommunications Systems (ARTES) programme.
“Turning clothes, life rafts, and more into antennas makes sure we can keep people connected when they need it the most,” said Hoda Nematollahi, Antenna Engineer at ESA. “Stealthcase’s work is a great example of the unexpected solutions and innovations that come out of ESA supported research to enable new businesses and applications.”