NEW YORK (Reuters Life!) - Astronaut Buzz Aldrin has no regrets about being the second man to walk on the moon but admits that at the time he had made a strong case for why he should have been the one to take history’s “giant leap for mankind.”

In his latest book, “Magnificent Desolation,” Aldrin reminisces about the Apollo 11 mission ahead of the 40th anniversary next month and details his battles with depression, alcoholism and adjustment to post-Apollo life.

“People say, ‘Didn’t you want to be first on the moon?’,” Aldrin told Reuters in an interview.

“Yes, from a professional point of view, I wanted to take advantage of every opportunity and project discussions about the commander, who had many responsibilities, and maybe some of those things that include things outside and going out first should be done by the other guy,” he said.

Apollo 11 Commander Neil Armstrong and Aldrin made the first manned landing on the moon on July 20, 1969.

In the lead up to the flight, Aldrin said he assumed that in keeping with previous NASA extravehicular activities like spacewalks, as the junior crew member he would be first down the ladder to take mankind’s first steps in the lunar dust.

“One guy will stay inside, probably the commander,” he said.

“Then they realized, ‘No, we’ll send two out.’ There was a lot of uncertainty in the planning people. But all that newspaper stuff about a civilian versus a member of the military was just cooked up as a possible reason for hesitation on the part of NASA.”

Armstrong had been a U.S. Navy combat pilot but was a civilian aboard Apollo 11. Aldrin was still in the Air Force.

In the end the decision came down to logistics. The lunar landing craft’s hatch was located on Armstrong’s side. It would have too cumbersome, and perhaps even dangerous, for Aldrin to have climbed over his mission mate, so Armstrong went first.

DIFFICULT RE-ENTRY

Aldrin, Armstrong and Command Module pilot Michael Collins were arguably the most famous men in the world when they returned. On a worldwide tour they were feted with parades, medals and ceremonies by heads of state in over 20 countries.

But when the cheering subsided and after achieving his life’s goal he contemplated what to do next.

“It’s an unstructured, wondering, ‘Who do I look to, where is my schedule, what is going to happen?,’” Aldrin said. “Being kind of unstructured and a little uncertain doesn’t give you confidence.”

After his appointment as commandant of the U.S. Air Force Test Pilot School, Aldrin began to suffer bouts of depression and was eventually hospitalized for a month.

When he retired from the military the following year, he did consulting, endorsement and design work but the depression returned and he turned to alcohol.

“People in the military know how to be disciplined, and know how to relax. It’s what eases the unease of the situation,” he said of his earlier, problem-free drinking.

“But once you don’t have these other commitments, you begin to make decisions that are not the wisest, and if you’re a little uncomfortable in the morning, a drink really fixes it,” he said. “The ‘hair of the dog’ is the sign of addiction.”

After several attempts to quit drinking, Aldrin eventually turned the corner and recently celebrated his 30th anniversary of sobriety. He married his third wife, Lois, in 1988.

He champions the potential of space exploration and believes the United States has lost valuable ground in the next phase of “the space race” and should set its sights beyond returning to the moon.

“I know in my own mind that the Russians want to beat us to Mars,” he said. “They’re doing everything that you’d expect them to do to be first to Mars, and that’s not going to be good for America 20 or 30 years from now.”