Yikes, this was clearly harder than I intended it to be!
"Destination Moon", page 51, we see Tintin, Captain Haddock and Professor Calculus in Mr. Baxter's office, having a debrief. Tintin's coveralls are buttoned all the way up, and his collar is turned up. Up until then, we have always seen his trademark blue sweater and white shirt collar peeking out of his coveralls. At no other point in the entire story arc do we see him without his sweater (except for when he's wearing PJs), and there is nothing in the previous pages that would indicate that his regular clothes have been shredded or otherwise rendered unfit to wear.
So, the most logical conclusion I come to is that it's laundry day, his regular clothes are being washed, and he is wearing is coveralls to...well...cover all.
Sorry if this proved too confusing! |