After a four-day delay due to conditions at McMurdo, today we were optimistic… checked out of the hotel, went to the Antarctic Center, got weighed as well as my bags, dropped off the rental car, waited, boarded a bus, waited, then filed on board a C-130. Strategically waiting until last to board, in order to get a seat with no cargo encroachment. We took off, were an hour outbound towards the Ice… then the loadmaster told us we'd be returning to Christchurch due to an engine problem. Once back, they couldn't fix it in time for us to make another attempt today, so we will try again early tomorrow. Meanwhile, I had to scramble to rebook a hotel room and get a rental car for overnight, after earlier relinquishing these.