EO·Atlas
TechDemoSat-1 (TDS-1)
Compiled from public sources on 2026-06-11. Not independently verified by Surrey Satellite Technology Ltd.
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UK technology demonstration satellite launched July 2014 by SSTL; carried SGR-ReSI GNSS-R instrument from Surrey Space Centre; first spaceborne demonstration of GNSS-R for ocean wind speed retrieval at scale.
TechDemoSat-1 (TDS-1) was a UK technology demonstration satellite built and operated by Surrey Satellite Technology Ltd (SSTL), launched on 8 July 2014 into a sun-synchronous orbit at 635 km altitude. The mission ended in May 2019 following deployment of its de-orbit sail.[1][2]
The primary instrument relevant to Earth observation was the SGR-ReSI (Space GNSS Receiver Remote Sensing Instrument), developed by Surrey Space Centre. SGR-ReSI was a 24-channel GNSS reflectometry receiver capable of processing GPS L1 signals and designed for Galileo and GLONASS compatibility, with dual FPGAs enabling real-time delay-Doppler map (DDM) generation. TechDemoSat-1 demonstrated spaceborne GNSS-R ocean surface wind speed retrieval from a dedicated GNSS reflectometry instrument.[3][1]
The methods and hardware validated on TechDemoSat-1 directly informed the design of the CYGNSS constellation (launched 2016) and the SGR-ReSI-Z receiver carried by the HydroGNSS Scout mission (launched 2025). TDS-1 carried a total of fifteen technology demonstration payloads across communications, propulsion, and remote sensing domains.[2]
- [1]TechDemoSat-1 mission overview, eoPortalagency doc2026-06-11
- [2]TechDemoSat-1, SSTL space portfoliooperator marketing2026-06-11
- [3]Spaceborne GNSS-Reflectometry on TechDemoSat-1, Unwin et al. JSTARS 2016peer reviewed2026-06-11