The IS system was "co-orbital", approaching its target over time and then exploding a shrapnel warhead close enough to kill it. The missile was launched when a target satellite's ground track rises above the launch site. Once the satellite is detected, the missile is launched into orbit close to the targeted satellite. It takes 90 to 200 minutes (or one to two orbits) for the missile interceptor to get close enough to its target. The missile is guided by an on-board radar. The interceptor, which weighs , may be effective up to one kilometre from a target.