Friday marked the 45th anniversary of a launchpad fire that killed three NASA astronauts during testing of the then-new Apollo capsule. Reviews found many flaws in the craft’s early design. Among other problems, engineers saved weight by filling the capsule with pure, low-pressure oxygen instead of air, which is 80 percent inert nitrogen.

Faulty wiring probably sparked the blaze that killed Roger Chaffee, Virgil “Gus” Grissom and Ed White, according to NASA and congressional investigations. The fire spread quickly in the pure-oxygen environment.

The tragedy is still etched on the space agency’s collective psyche. The agency held its annual day of remembrance last week. NASA Administrator Charles Bolden laid a wreath at Arlington National Cemetery, and a ceremony at the Kennedy Space Center visitors center honored the three Apollo heroes and the 14 astronauts who later died in space shuttle disasters.

When the 1967 tragedy happened, NASA’s first news director, Jack King, was in the blockhouse, the heavy concrete launch room near the pad. He’s got a sharp memory and can still rattle off figures for how many pounds of thrust each of the early NASA rockets delivered. A former Associated Press reporter, King was on site the day of the fire to type up the news of a successful test and get it out to reporters: another small step toward the moon, welcome fodder for a press corps eager to trumpet the nation’s triumphs in the accelerating quest to beat the Soviets to the moon.

King, now 80, took a reporter out to the site of the tragedy, Space Launch Complex 34. It’s on Cape Canaveral, on Air Force land, a quick jog up from the beach. A weathered four-legged concrete stand — which supported the Saturn IB rocket — sits surrounded by grass and weeds. The blockhouse is still there, a squat, heavy mound of tan concrete a hundred yards or so west of the launch stand.

When asked what he remembered about that day in 1967, King lighted a cigarette and wiped the corner of his eye under his glasses. “It’s something you never forget,” he said.

There were a lot of problems with the early Apollo capsule, King said. Before the test, Grissom had been complaining about communications issues between the capsule and the blockhouse. King recalled Grissom saying, “How could we go to the moon if we can’t even talk to each other?”

King stopped talking. He stood in the sun and stared at the blockhouse. “I was locked in there for 10 hours,” he said.

Donald “Deke” Slayton was the chief astronaut at the time. Slayton left the blockhouse and climbed up to the capsule to confirm what everyone feared. The trio was dead. “Deke opened the hatch and it was just black everywhere inside,” King said.

Slayton then made a deal with King: King was not to transmit one word of the tragedy until the three widows were informed. Lockdown was in effect. During the next 10 hours, King fretted and smoked. “Thank goodness there was a cigarette machine in there,” he said. He puffed through three packs.

When King finally sent word to reporters, some of them — many his good friends — savaged him for delaying the news. “But if Betty had heard it from me or from the news it would’ve been horrible,” King said, referring to Grissom’s wife.

The fire still resonates for one of NASA’s launchpad-safety veterans, too. For 70-some space shuttle launches, Travis Thompson strapped in the astronauts and closed the hatch, then sent them on their way. As leader of the “close-out crew,” Thompson made astronaut safety his first priority.

Thompson now works on the next space race — the struggle by four U.S. companies to hoist astronauts back into space from U.S. soil. And he’s worried that the companies have not absorbed the prime lesson of Apollo 1 — that bad design begets tragedy.

“Commercial crew is all dollar-driven,” Thompson said. “It’s all about doing it cheaper than NASA.”

Thompson is pushing the four companies to make their new vehicles easy to exit on the launchpad.

“They think they can design the vehicle to be so safe that we won’t have to ever get the crew out,” Thompson said. But, he added, these are early days; the companies still have time to adopt a more conservative model of launchpad safety.