Guenter Wendt, 86, a driven and disciplined German-born engineer who ran operations at the launchpad before some of America’s most celebrated space missions, died May 3 at his home in Merritt Island, Fla. He had congestive heart failure and complications from a stroke.

From the first suborbital flight through the moon landings, Wendt held one of the key positions in one of the most closely followed of American ventures.

Beginning half a century ago, he was in charge at the launching pad in Cape Canaveral in the tense moments as Mercury, Gemini and Apollo astronauts prepared to carry the nation’s hopes into space.

As the man responsible for launch preparations, he was given the title of “pad leader.”

The historic July 16, 1969, Apollo 11 launch allowed Wendt little opportunity for reflection.

“You are not thinking they are going to the moon,” he said. Instead, he said he was thinking, “I got 148 items that must be completed. They must be completed on time.

“You’re worried about everything,” he said. “Do we have all the right tools? Do we have the right holders? Do we have the right fittings? Do we connect everything correctly? Don’t make a mistake when you hook up a line.”

When John Glenn’s wife, Annie, asked if he could guarantee a safe return, all he could guarantee, he told her, “is that at the time when I say ‘Let’s go,’ there is nothing that I know that could be detrimental to a safe return.”

Wendt worked not for NASA but for its contractors.

A change in contractors kept him away when Apollo 1 caught fire in 1967, killing three astronauts.