Modern operations lean heavily on satellites: for communications (SATCOM), imagery (ISR), warning and navigation (GNSS, GNSS and navigation warfare). That dependence makes space a target — and its electromagnetic part is the EW specialist's terrain.
Counterspace is the umbrella term for attacking space capabilities. It ranges from kinetic (physically destroying a satellite) to non-kinetic. EW provides the reversible, non-kinetic part: jamming, spoofing and dazzling — effects you can switch on and off without creating space debris, which makes them politically and operationally attractive.