Icy first light of shoebox-sized PRETTY CubeSat

A shoebox-sized satellite looking far to the horizon picked up a strong signal reflection from hundreds of kilometres below it, beside a lonely polar island in the Canadian Arctic. ESA’s PRETTY CubeSat mission team could not be quite certain of what its instrument first light was showing until cross-checking it against a Sentinel-1 radar map of the same location, to find a precise correlation with a stretch of offshore sea ice.