NTS meaning in Radio Science ?

The National Traffic System (NTS) is an organized network of amateur radio operators sponsored by the American Radio Relay League for the purpose of relaying messages throughout the U.S. and Canada.

During normal times, these messages are routine greetings ("Happy birthday Aunt Mary") and keep the system well oiled and the operators trained so that everything works when needed. When there is an emergency or disaster NTS works closely with the Amateur Radio Emergency Service to provide emergency communications. The most common type of disaster-related messages are "health and welfare" inquiries and notifications into and out of the area affected by the disaster.

In time of disaster, it is easy to expand the system by simply creating additional meeting times for the nets with high volume, or by setting up a specific "trunk line" between two points.