KENNEDY SPACE CENTER — The space shuttle Atlantis lifted off Friday morning on the final mission of America’s 30-year space-shuttle program, a thunderously poignant moment for fans and veterans of the space program.

Some of the thousands of people who gathered to watch the launch chanted “U.S.A.” Others shed tears as Atlantis roared aloft atop its powerful rockets on what a NASA commentator called a “sentimental journey into history.”

“Godspeed, Atlantis,” read a sign held up by a saluting member of the ground crew whose job it was to seal the shuttle’s doors for the last time.

The four-member crew blasted off on a 12-day mission just before 11:30 a.m. The four — all shuttle veterans — are on their way to deliver supplies to the International Space Station.

The possibility of storms had raised doubt about whether the launch would take place as planned, but NASA gave the shuttle a “go” for launch a few minutes before liftoff. With the countdown nearing the 30-second mark, the launch had to be delayed briefly to investigate whether a vent arm had properly retracted, which it had.

Almost a million people were expected to be on hand to witness the historic moment, including some who came to Kennedy Space Center three decades ago for the first shuttle lift off.

Linda Johnston fulfilled a lifelong dream to watch a launch, tearing up as the shuttle lifted off.

“I think it’s kind of a real shame it’s not going to be around anymore,” she said.

One onlooker flew in with a friend Thursday from New York. Unable to find a hotel, the men went to a Walmart and picked up a tent, air mattresses and some tortilla chips and camped out on a nearby spit of land to wait for the launch. Seeing the shuttle blast off, they said, will let them check an item off their  bucket list.

“It’s really the last opportunity to see something that’s a feat of mankind,” the man, who identified himself as Nate, said.

The launch came a day after violent storms hurled two lightning bolts at the launch facility, striking a water tower 515 feet from the launch pad and a nearby beach. The shuttle was not damaged, NASA said.

President Richard Nixon commissioned the space shuttle program in 1972, three years after the Apollo program put a man on the moon.

The first shuttle, Columbia, blasted off in April 1981. Since then, space shuttle crews have fixed satellites, performed scientific studies and ferried materials and people to International Space Station Alpha, a football field-sized construction project in orbit.

Retired astronaut Bob Crippen flew on that first mission.

“I am sad,” he said of the shuttles’ retirement. “I think it’s a great vehicle. Probably will not see anything like it in my lifetime.”

In 134 missions, the five space shuttles have ferried 355 astronauts half a billion miles in space, turning heroic feats into the routine.

“It’s an amazing vehicle, and its legacy will live on,” Atlantis’ final commander, Chris Ferguson, recently said.