Explorer ship

From Memory Alpha, the free Star Trek reference

In starship classification, an explorer ship is a type of spacecraft designed for exploring unknown regions of space.

The 21st century NASA ship Charybdis was classified as an "explorer ship". It was Earth's third manned attempt to travel beyond the Sol system. (TNG: "The Royale")

[edit] Background

The "Explorer" type is derived from the original designs, graphics and technical drawings of the USS Enterprise-D by Andrew Probert, Rick Sternbach and Michael Okuda.

More information about the explorer designation exists in the Star Trek: The Next Generation Technical Manual. This designation was mentioned in the script of TNG: "Yesterday's Enterprise", noting that the alternate timeline Enterprise-D differed from the familiar explorer-type ship.