Lieutenant John Kelly was the commander of the Ares IV mission to Mars in 2032. He disappeared on October 19, along with the command module in which he was orbiting the planet, while the other two crew members were on the planets' surface.
USS Voyager subsequently discovered the command module, along with Kelly's body, inside a graviton ellipse in the Delta Quadrant in 2376. Kelly was given a full military funeral aboard Voyager, and is widely regarded as one of the true pioneers of manned space exploration.