[rademacher]

SAR has been around since the 70s and works using the same principles as CT scans (projection slice theorem). Think about observing an image by rotating it and projecting it orthogonally to the rotated direction. Take a bunch of these measurements (basically a radon transform) and then you can invert the process using the back projection algorithm.

The resolution of the image is proportional to the bandwidth of the waveform and the distance traversed by the satellite during the collection process.

This article is a bit of an exaggeration and Capella is certainly not the first or only SAR service.