By Kenneth ChangThe New York Times

Oct 7, 2018 at 5:00 AM

DALLAS — In the summer of 1969, Rick Armstrong was 12 and whacking a baseball in the Houston-area Little League.

He was selected to play in the All-Star Game — but he had to skip it, because he was at Cape Canaveral in Florida to watch his father, Ohio native Neil A. Armstrong, blast off to the moon.

“I wasn‘t happy about that,” said Rick, now 61.

Rick and his brother Mark, 55, are auctioning about 3,000 items from their father, who died in 2012. In the process, they are revisiting their childhoods and the enduring legacy of their father as the first person to walk on the moon.

“I intellectually get it,” Rick said. “But internally I‘m not sure I will ever get it. It’s sort of just my dad.”

The auction is drawing lots of interest, with the 50th anniversary of Apollo 11 approaching and a movie about Armstrong, “First Man” starring Ryan Gosling, coming out this week.

The items to be auctioned include flags, medallions, stamped envelopes and other memorabilia that made the trip to the moon and back when the Apollo 11 lunar lander set down on July 20, 1969. Others come from earlier years, such as a letter that Neil Armstrong wrote as a boy growing up in Ohio to the Easter Bunny.

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Most of the material had been sitting in basements and storage lockers for decades.

“We felt like we should embark on the process of making sure we keep things in good condition and where possible conserve them,” Mark said.

They could have donated everything to a museum or a university, but then items might have sat in boxes. In an auction, each item is researched so that buyers know what they are getting. Photographs of every item will remain online.

“That means that item‘s history is preserved for anyone to see and for research later on,” Mark said.

The first batch of about 800 items will be sold soon — Nov. 1-2 in Dallas. Interested buyers have been able to see some of the items online at Heritage Auctions in Dallas.

Many NASA astronauts have auctioned off items over the decades, but “Neil Armstrong never did that,” said Michael Riley, director of the space-exploration department at Heritage Auctions. “Nobody ever realized what he had, what he kept — whether he kept anything.”

Mark admitted it was not an easy decision to sell his father‘s belongings. “It‘s something we struggled with,” he said. “Would Dad approve? Let‘s see what positive things we can do with the proceeds.”

Even though astronauts were national celebrities in the 1960s, Rick recalled his life was “just normal growing up in the suburbs. It did not seem particularly extraordinary or anything.”

Their mother, Janet Armstrong, taught synchronized swimming. They would have dinner usually at the same time every evening. Sometimes their father would get home on time. Sometimes he was away for NASA business. There was always an emphasis on doing well in school.

Neil Armstrong‘s first space mission, Gemini 8, almost ended in disaster. It was the first time American astronauts successfully docked with another spacecraft in orbit. But one of the thrusters aboard Gemini 8 malfunctioned, and the spacecraft spun faster and faster.

With the astronauts on the verge of losing consciousness, Armstrong shut off the thrusters and slowed the spin with the backup system. Only years later did Rick and Mark learn how close their father was to dying that day.

“We didn‘t understand the risk,” Rick said. “We didn‘t understand the complexity of what they were trying to do.”

For Apollo 11, the media attention increased. That included a writer for Life magazine following the Armstrong family for a few months.

On July 20, 1969, “There were more people in the house that day than the previous days,’’ said Mark, who was 6 then. He remembered that his father and Buzz Aldrin landed on the moon late in the afternoon.

“I had something to eat, and it got to be 9 o‘clock or so,” he said, adding that he then went to bed. His mother woke him late that night to watch the moon walk.

The most famous flag on Apollo 11 was the one that Neil Armstrong planted on the surface of the moon.

But the astronauts also took many smaller flags, part of a multitude of memorabilia packed for the trip. In the November auction, one of those American flags, a silk one measuring 17 3/4 by 11 1/2 inches, is expected to draw the highest bids, perhaps selling for $300,000 or more.

Perhaps the most unusual artifacts that went to the moon and remained in Neil Armstrong’s possession were parts of the original Wright brothers’ airplane that made the first powered flight in 1903. Armstrong was able to keep some of pieces of fabric from the plane’s wing and wood from its propeller. Those are in the auction, too.

One day after landing, the astronauts left the moon and started the journey home.

After splashing down in the Pacific, the astronauts spent several weeks in quarantine, to make sure that they had not brought back anything dangerous from the moon.

The quarantine facility — a modified camper — was flown in a C-141 cargo plane to Houston, where Mark and Rick could go see their father. Rick said he did not remember him talking much about the moon. “It was more: What had we been doing? Are you helping your mom? Are you mowing the grass?” he said.

Rick said the attention to the family became ‘‘pretty overwhelming.’’ They moved to Bethesda, Maryland, after Neil Armstrong took a leadership role at NASA headquarters. Then the family moved to Ohio — Armstrong was from Wapakoneta in Auglaize County in western Ohio — and Neil Armstrong became a professor at the University of Cincinnati. They bought a farm where they could get a measure of privacy.

The sons eventually followed their own paths. Mark became a software developer. Rick studied marine biology and became an animal trainer before shifting gears and joining his brother at a software start-up.

In later years, Neil Armstrong largely withdrew from public life, but his sons dispute perceptions of him as a recluse. “He was a funny guy,” Rick said.

Mark recalled being at a talk that his father was giving at the Sydney Opera House around 1977. Neil Armstrong, the program said, did not exercise because he thought everyone has a set number of heartbeats and he did not want to waste any — something he had said in jest in 1969 to Life magazine.

Mark said his father walked onstage and said, “Before I get started, I want to clear one thing up.” Armstrong took off his jacket, dropped to do about 20 push-ups, got up, put his jacket on and began his talk.

“I was more proud of him after those push-ups than after he went to the moon,” Mark said.