Satellites are also a big use case.

A number of the sats I worked with are single point cameras .. the satellite spins about a major axis orientated in the direction of travel, the point camera rotates with the satellite and a series of points of data are written to a line of storage as the camera points at the earth and pans across as the sat also moves forward.

Data stops being written as the sat rotates the camera away from the planet and resumes once it has rolled over enough to again point at the earth.

It may seem like a pedantic difference; a "line scan camera" is stationary while mirrors inside it spin or another mechanism causes it to "scan" a complete vertical line - perhaps all at once, perhaps as the focal point moves Vs a camera in a satellite that has no moving parts that just records a single point directly in front of the instrument .. and the entire satellite spins and moves forwards.