A Galaxy-class Federation starship commanded by Captain Geordi La Forge in an alternate 2390, sent to stop Chakotay and Harry Kim from changing history.
The USS Challenger appears in the Voyager episode Timeless, in a future in which Voyager crashed on an ice planet in 2375 during a failed quantum slipstream flight and all but two of its crew died.
Fifteen years on, the survivors Harry Kim and Chakotay have stolen the Delta Flyer and a Borg temporal transmitter, intending to send corrected data back to Seven of Nine in the past. Starfleet sends the Challenger after them under Captain Geordi La Forge.
La Forge admits that in their place he might do the same, but he cannot let them erase fifteen years of history, and he opens fire when they refuse to give up. Kim sends the message as the Flyer's warp core breaches, and that future ceases to exist.