Privately-owned companies that launch and operate their own satellites, have distributed many satellite images of the conflict zone.
The proliferation of these images means members of the public and military analysts alike can try to gauge the situation on the ground in Ukraine and the progress of Russia's invading armed forces from thousands of miles away.
So, what's changed? While government and intelligence agency satellites gather classified, secret information, commercial firms have long been able to sell their own, unclassified, imagery. And now, this material is being made easily accessible.