Life-Line

Heinlein, Robert A. "Life-Line." Astounding August 1939. Collected The Best of Robert Heinlein. London: Sidgwick & Jackson, 1973.

Heinlein's first published story.

Alec Nevala-Lee describes it as "a story about a machine that can predict when a person will die" (p. 111).

The Wikipedia entry gives bit more information, succinctly summarizing, "The protagonist, Professor Pinero, builds a machine that will predict how long a person will live. It does this by sending a signal along the world line of a person and detecting the echo from the far end. Professor Pinero's invention has a powerful impact on the life insurance industry, as well as on his own life."[1] The entry also notes collections not listed in the 1978 Contento Index:"The Worlds of Robert A. Heinlein (1966), Expanded Universe (1980), and in a Baen edition of The Man Who Sold The Moon (1987)."[2] And mentions a TV series using the premise: Lifeline (2017 TV series).[3]