Clue: Pull back, being a much-travelled character (8)
Answer: GULLIVER
Explanation: Definition: a much-travelled character
LUG reversed + LIVER (one who lives, a being). Gulliver is a proposed European mission to collect samples from the Martian moon Deimos, so called because *Gulliver's Travels* describes the scientists of Laputa knowing of two moons orbiting Mars, over a century before they were actually found