D. Knapp was a Human Starfleet officer in the 22nd century.
In 2151, he was listed as an Imaging and Sensor Technologies officer on the dedication plaque of Enterprise NX-01. (ENT: "Broken Bow", dedication plaque)
In 2154, he was listed as a Propulsion Systems officer on the dedication plaque of the Columbia NX-02. (ENT: "Affliction", dedication plaque)
In January of 2155, he was listed as a Thermal Operations officer on the directory placards at Starfleet Command's Fleet Operations Center, Sol Sector. His office was located in room #1323. (ENT: "Demons", directories)
This character was only mentioned in writing.
He was named after director of photography Doug Knapp