The USS Challenger (NCC-2032) was a Federation starship operating in the 23rd century.
In 2293 the Challenger conducted a deep space exploration mission near Klingon territory. It was among the task force that would have been assembled for the abandoned assault code-named Operation Retrieve, which would have rescued Captain James Kirk and Doctor Leonard McCoy from Qo'noS in 2293. (Star Trek VI: The Undiscovered Country)
Background
The icon representing the Challenger on the barely-visible chart in the Federation President's office was a Constitution-class starship, according to Michael Okuda. However, all ships on that chart save the USS Excelsior had the same icon, so its very unlikely that the Challenger 's class can be determined. This ship is not related to the Challenger-class of starships, which were employed during the 2360s.
In the non-canon board game Star Fleet Battles, USS Challenger is a Byrd-class Galactic Survey Cruiser, a modification of the Constitution-class which replaces the photon torpedoes with special scientific sensor equipment. As a tribute to the space shuttle Challenger, USS Challenger is never to be used in any story or scenario where it could possibly be destroyed.