Star Trek Expanded Universe

The Challenger-class cruiser was a type of starship on active duty in Starfleet during the late 24th century.

Apparently contemporary with the Galaxy-class explorer and the Nebula-class starship, Challengers had a primary hull similar to that of the two classes, but with one warp nacelle above the hull and another below.

The Challenger-class USS Buran was one of the ships lost during the Battle of Wolf 359. (TNG: "The Best of Both Worlds, Parts 1 and 2")

USS Marco Polo is designated Challenger class in a TNG comic story "Thin Ice" — but bears little resemblance to the Buran. There may have been another Challenger class extant earlier in the 24th century.

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