As the lunar module pilot for Apollo 11, Buzz Aldrin remains the most well-known figure in the aerospace industry today and a consistent advocate for human exploration of Mars. He has long pushed for the concept of a "cycler," a semi-permanent spacecraft in orbit around the Sun that would carry cargo and crew between Earth and Mars periodically.
But in recent years Aldrin has begun to embrace the world that made him famous—the Moon—as a critical waypoint on the road to Mars. This involves the collection of lunar ice, believed to be accessible at the poles, for use as propellant to send astronauts deeper into space.
As we inch closer to the 50th anniversary of the Apollo 11 landing, momentum appears to be building behind this idea. Several officials with the Trump administration have indicated their preference for lunar landings before attempting to send astronauts to Mars, and after six years of promoting the "Journey to Mars," NASA has also begun considering a human return to the Moon.