What is the furthest man has travled into space?

From Cape Canaveral, around the moon, and back to earth.

Greatest distance from earth during the trip = about 240,000 miles, or roughly

-- 0.0056 of the shortest possible distance to Mars,

-- 0.0026 of the distance to the sun,

-- 0.00000004 of the distance to the nearest star outside the solar system.