The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between NASA and ISRO to co-develop and launch an Earth observation satellite (EOS) equipped with dual-frequency synthetic aperture radar (SAR) in 2025. It will be the first radar imaging [emphasis added] satellite to use dual frequencies.
Imaging radar is an application of radar which is used to create two-dimensional images, typically of landscapes. Imaging radar provides its light to illuminate an area on the ground and take a picture at radio wavelengths.
It is, in a literal sense, “spotting” the subsidence using visual techniques, albeit at a lower EM frequency than what humans can see.
https://en.wikipedia.org/wiki/NISAR_(satellite) :
https://en.wikipedia.org/wiki/Imaging_radar :
It is, in a literal sense, “spotting” the subsidence using visual techniques, albeit at a lower EM frequency than what humans can see.
Sigh.
If you are using a camera, what is doing the spotting (or more broadly observing)? You or the device?
Are you trying to suggest that there’s no such thing as “spotting” anything from a satellite unless a human astronaut is riding inside it?