Off-ship vehicle carried in and deployed from the hangar decks of Federation
starships. The heavy shuttlecraft is larger than the Galileo shuttlecraft and was better suited
to travel though turbulent atmospheres and space-born energy disturbances such as ion storms.
In 2269 on stardate 4978.5, Harcourt Fenton Mudd abducted Nurse Chapel and stole a heavy shuttlecraft
(Registry number NCC-1701/12) in order to escape incarceration on board the
Mudd took Chapel and the vehicle to a rocky class-M world. Shortly after landing, a huge
rock-like creature smashed the craft. ("Mudd's Passion").
This type of craft was referred to simply as a shuttlecraft in the episode, but it is termed a "Heavy" Shuttlecraft here, due to its size and bulky design and for lack of a definitive name.