question:  Why did Ben leave with two rings?
context: And yet, at the same time, to be filled with a terrible, gnawing fear—a fear locked in my mind during the day and bursting out like an evil jack-in-the-box at night. The Academy, with its great halls and classrooms and laboratories, lay hollow and silent, an exhausted thing at sleep after spawning its first-born. They're going to bring us the metals and minerals that we desperately need. And perhaps most important of all, they'll make other men think of the stars and look up at them and feel humility—for mankind needs humility." Let him leave Jupiter and the others alone! My parents had died in a strato-jet crash when I was four, so I hadn't needed many of those "You are cordially invited" cards. Just one, which I'd sent to Charlie Taggart. He was Chief Jetman now on the Lunar Lady , a commercial ore ship on a shuttle between Luna City and White Sands. I remembered how, as a kid, I'd pestered him in the Long Island Spaceport, tagging after him like a puppy, and how he'd grown to like me until he became father, mother, and buddy all in one to me. The Universe was mighty big, but with two of us to face it together, it would be only half as big. Though it was daytime, I saw the stars in my mind's vision, the great shining balls of silver, each like a voice crying out and pleading to be explored, to be touched by the sons of Earth. "You made it, boy," he chortled, "and by Jupiter, we'll celebrate tonight. And you, Laura, were with him. "Charlie has only twenty-four hours liberty. On our way to the 'copter parking field, Dean Dawson passed us. "Ben," he called, "don't forget that offer. A moment later Mickey said, frowning, "What was he talking about, Ben?
output:  to symbolize the life he's giving up
options:  to symbolize the life he's giving up  to represent his marriage to Luna  to remind him to come home and get married  to honor Stardust Charlie