Fri, 14 Feb 2025 Surrey Satellite Technology Limited (SSTL) has successfully concluded its DoT-1 satellite mission, marking another milestone in the company’s leadership in small satellite innovation. Launched from Vostochny, Russia, in 2019, the 17.5 kg technology demonstration satellite re-entered Earth’s atmosphere and burned up on February 4th, completing its mission objectives.

DoT-1 was designed to provide in-orbit validation for SSTL’s Core Data Handling System (CoreDHS), ensuring a robust foundation for future missions. In addition to its primary mission, the satellite carried secondary payloads, including a Raspberry Pi camera and a Radiation Monitor, developed in collaboration with the Surrey Space Centre. These payloads demonstrated SSTL’s ability to integrate diverse instruments into its platforms while collecting valuable data. (Pic below of the Mediterranean was taken by DoT-1’s Raspberry Pi Camera.)



One of the mission’s major technological achievements was the deployment of GNSS Reflectometry (GNSS-R), an advanced technique that repurposes GPS and Galileo signals to measure Earth’s surface properties. DoT-1’s GPS antennas captured reflected signals, allowing scientists to derive ocean wind speeds and other geophysical data. This achievement played a crucial role in proving the viability of this approach ahead of the European Space Agency’s (ESA) Scout mission, which consists of two satellites currently in the final stages of manufacturing and set for launch in late 2025.

SSTL has been at the forefront of GNSS-R research since its early experiments on the UK-DMC satellite in 2003. The technology was further refined with payloads on TechDemoSat-1 in 2014 and NASA’s CYGNSS constellation in 2016, which utilized SSTL-developed instruments to monitor cyclones at sea.

Dr. Martin Unwin of SSTL, Principal Investigator on the HydroGNSS mission, emphasized DoT-1’s role as a critical stepping stone in GNSS-R innovation. “DoT-1 was a rapidly developed prototype that proved essential in justifying and enabling the HydroGNSS mission,” he said. “We are immensely proud of the technological advancements achieved on this small satellite.”

As SSTL prepares for the launch of HydroGNSS, the lessons learned from DoT-1 will contribute to improved scientific and environmental insights from space, reinforcing the company’s position as a global leader in small satellite innovation.