An Ensign Stone was a member of the Tombaugh's crew. Stone had studied at Starfleet Academy for four years, and had just completed their first week of active duty shortly before the assimilation. (VOY: "Infinite Regress")
According to the Star Trek Encyclopedia (4th ed., vol. 2, p. 403), the starship may possibly be named for the American astronomer Clyde Tombaugh (1906-1997) who discovered the planetoid Pluto in 1930. Some of Tombaugh's ashes were carried aboard the space probe New Horizons, the first to reach this distant world.