They will receive a transmission from the satellite and show that your distress call was received, That is exactly what the item (6) is in the diagram I showed a few posts earlier.
ITYM the purple link. #6 is when the helo lifts off. Hopefully nobody in the whole world has ever lost the call between the ground receiver and the launch pad, but it is theoretically possible. (That's what makes the two-army problem theoretically unsolvable.)