“This fancy one here was given to me by Mohammed Ali by his people,” he says. “It has my name on it and his name on the other side.”

I examine it closer. The engraved words “world champion” also encircle the diamond above the boxer and the astronaut’s names. This ring makes the one on his pinkie, and the diamond-encrusted crescent-moon-and-star combination on his middle finger, look positively understated.

“Now this is a typical symbol not of Turkey or Islam,” he says, “but having gone to the Moon and written a story about travel between stars, it became quite appropriate to different parts of my past and history. But the star is really not as significant any more so I need to round that off and put a ruby in it for Mars.”

He smiles. “Symbolism is catchy. Now I’m working with Florida Tech and the Buzz Aldrin Space Institute so I may create my own Florida Tech-type ring.”

Mars holidays?

Aldrin is clearly something of a fan of bling. He’s also sporting space-themed lapel pins and numerous metal, ceramic and material bracelets on each wrist, including one with white cubes. Four of them spell out B-U-Z-Z in black lettering.

It’s an incongruous touch, but then Aldrin is full of surprises. In 2010 he recorded a rap song called Rocket Experience, produced by Snoop Dogg. In the summer he’s a holographic guide for a new virtual reality Mars exhibition that opens at Florida’s Kennedy Space Center. But away from these trappings of space celebrity he is serious about the ‘cycler’ orbits he has devised that will take people to Mars and back.

Aldrin’s plan involves using spacecraft like shuttle buses, in hyperbolic orbits back and forth between the Earth’s Moon and Phobos, Mars’ largest moon, and docking with smaller spacecraft while in orbit.