The transporter malfunction during the hurried departure of the refitted Enterprise that killed the Vulcan science officer Commander Sonak and a second officer.
The accident occurs early in Star Trek: The Motion Picture. With V'Ger approaching Earth, Admiral Kirk takes over the refitted Enterprise and pushes for an immediate launch although her systems are untested. The Vulcan Commander Sonak, assigned as science officer, and another officer begin to beam up from Earth.
A fault develops in the transporter circuits. Janice Rand, at the controls, cannot hold the patterns, and Kirk and Scott rush to help. Two distorted figures form briefly on the pads before Starfleet pulls them back. Starfleet then reports that what it received did not live long.
The loss leaves the ship without a science officer until Spock arrives from Vulcan. It also gives McCoy, who is drafted back into service soon after, fresh reason to distrust the transporter.