MURRIETA -- Everyone held their breath, both in the room and around the world.

"The intention was to go straight down and land," Lee Heinz said. "But when they got down to 400 feet, Armstrong looked out the window and saw boulders."

Forty years ago this week, the American astronauts of Apollo 11 first walked on the moon. Across the country, celebrations are planned to mark the event.

Heinz, of Murrieta, was a U.S. Air Force captain that day, July 20, 1969, working as a simulation coordinator at the NASA Space Center in Houston. His job, along with others, was to present scenarios to test both the Apollo astronauts and flight coordinators in Mission Control on the numerous things that could possibly go wrong on the mission to the moon.

"We created problems for them," Heinz said this week. "Then we worked with the crews and flight coordinators on how to solve them."

Boulders were not on the list.

"This was not simulated," he said. "This was unexpected."

Heinz heard shouts of "what's going on," and "what's he doing" around Mission Control as Armstrong looked for a place to land the module, called The Eagle, containing both him and Edwin "Buzz" Aldrin, along with the goal of a martyred president and hopes of a nation.

"We were all looking at our (computer) screens and could see the fuel was running low," Heinz said. "Finally, Charlie Duke, who was the Capcom (capsule communicator) and was speaking directly to Neil, told him 'You've got 60 seconds.'"

At 4:17 p.m. EDT, the landing pads of the lunar module touched down.

"Houston, Tranquility Base here. The Eagle has landed," Armstrong said.

"Roger, Tranquility," Duke replied. "We copy you on the ground. You got a bunch of guys about to turn blue. We're breathing again."

Among those finally able to catch a breath was Heinz, who had come to Houston in 1967 and worked on Apollo Missions II through XII.

"There was supposed to be a two-minute fuel reserve left on board when they landed," Heinz said. "They ended up with just 17 seconds' worth."

There was little celebration in Mission Control immediately after the landing.

"There was work to do and checklists to go over," he said. "But around the room, I did hear people praying."

Immediately after the landing, the words of President Kennedy, who in 1961 had set the goal of landing a man on the moon in the 1960s "and returning him safely to the Earth," were shown on a big screen at Mission Control.

"I remember thanking God for getting them down to the moon," Heinz said. "Then I asked him for help in getting them back up."

Several hours later the module hatched opened, Armstrong emerged and headed down a ladder toward the lunar surface.

"They were supposed to sleep for four hours after they landed," Heinz said. "Imagine thinking they'd possibly be able to sleep."

Armstrong's boot touched the surface at 10:56 p.m. EDT.

"That's one small step for man, one giant leap for mankind," he said, the sentence immediately etched in history.

"He made that up on the way to the moon," Heinz said with a laugh. "He didn't think about what he was going to say until he was on the way there."

Armstrong, Aldrin and the third astronaut, Michael Collins, returned to Earth on July 24, 1969, splashing down in the Pacific Ocean 812 nautical miles southwest of Hawaii. The trio was then transported by helicopter to the USS Hornet.

"When they got back to the carrier, that's when we finally celebrated (in Houston)," Heinz said. "We each got a cigar. I don't even smoke, but I did that day."

Heinz said some in Mission Control cried.

Everyone in the room was given an American flag to wave.

That flag, along with models of the Saturn V rocket, the lunar module and other memorabilia and books are proudly displayed in Heinz's home in the Greer Ranch neighborhood.

After a two-year stint at NASA, Heinz left Houston later in 1969.

"I had a great time when I was there, but then I went on to the next mission," he said.

Now 73, Heinz retired as a colonel after 28 years. He and his wife, Pam, moved to Murrieta in 2001.

On Monday, Heinz will be part of a 40th anniversary celebration of the lunar landing taking place at the Murrieta Public Library.

The program begins at 2 p.m.

At 3:30 p.m., Heinz will begin his presentation, entitled "The Moon Landing That Almost Wasn't," which includes pictures, videos and more stories of the race to the moon that captured the world's fascination four decades ago.

He and Pam plan on attending the 40th reunion of the people involved in the lunar landing, which will be held in Houston later this year.

"They don't hold them in July," he said. "It's too hot and humid in Houston in July."

This year's reunion takes place in November.

"This may be my last one," Heinz said. "But who knows? I'd really like to make it back for the 50th."

Call staff writer John Hunneman at 951-676-4315, ext. 2603.