Answer: She wanted to visit her brother.
Explanation: In the Cold Equations by Tom Godwin, Marilyn, was a stowaway aboard the Emergency Dispatch Ship (EDS) which she boarded in a bid to go visit her brother, Gerry, who was on planet Woden. The ship eventually ran out of fuel and she was about to ejected into space, to enable the ship carry on with the other weights. She imagined she'd die in space and didn't want her family to imagine she died in agony, this she narrated to the pilot of the ship. So the original plan was to go see her brother, thus the first option is correct.