USS Robert A. Heinlein

The USS Robert A. Heinlein was a Federation starship in the 23rd century, commanded by Hikaru Sulu. On stardate 1456.67, the ship went missing, and the Enterprise was sent to find it in the 140 Trianguli region. 

The Heinlein is the second known starship to bear the name, after a 22nd century Daedalus class starship of the same name, which participated in the Earth-Romulan War.