Norway working with US to develop new imaging microsatellite #NorSat4 to watch for ships in its waters, even during the long winter nights.

This is in addition to #NorSat3 launching this year, which uses an innovative passive detector to spot civilian maritime navigation radars https://twitter.com/kystvakten/status/1300321002937671680

NorSat 1 and 2 were AIS receivers only. 3 and 4 will have that, too, but with the additional tools to corroborate any ships that have AIS off.

Note dramatically different approach compared to @csa_asc 's #RadarSatConstellation which uses active radar and AIS.

But wait, you say, #NorSat3 detects navigational radars? But don't they transmit horizontally? How do you catch them from spaaaaace?

Thankfully, the earth is round. Ergo: (pic from https://directory.eoportal.org/web/eoportal/satellite-missions/n/norsat-3-4)