The H-46 was the designation of a Sovereign-type escape pod assigned to the USS Enterprise-E. This pod was the first in a chain of pods that ended with H-926 on the port side of the primary hull, aft of the bridge. When leaving the Enterprise-E, this pod and H-48 were the first and second pods to be launched in their chain.
When the ship traveled back in time from 2373 to 2063 to stop the Borg from altering Earth's history, the ship was boarded by the Borg, forcing Captain Jean-Luc Picard to set the Enterprise to self-destruct. As a result, all crew were ordered to abandon the ship in escape pods, one of which was the H-46. The pods landed at Gravett Island on 21st century Earth, where Picard hoped the crew would "stay out of history's way." Fortunately, the Borg were defeated without the need to destroy the Enterprise, and the crew, along with all the escape pods, were returned to the ship before it returned to the 24th century. (Star Trek: First Contact)
An escape pod with the number 046 was seen launching from the Enterprise-E.