KENNEDY SPACE CENTER–I’d said I’d be back, and here I was after a day and night of travel that had included three airports, two flights, one border crossing and 120 miles of Florida highways.

But those nine hours aren’t important. What happened next is.

Launch day had begun with my waking up after maybe 45 minutes of fitful, futile sleep, then showering, getting dressed and heading over to the Kennedy Space Center.

Even at the dead hour of 3:30 in the morning, KSC showed no signs of slumber, with the pad and Endeavour bathed in floodlights, countdown announcements echoing off the pavement and the Vehicle Assembly Building and helicopters flying overhead.

Unlike the first attempt at launch, there was no comfortable tent for myself and the other attendees of the Tweetup NASA organized for the launch. Instead, we shivered on a set of increasingly damp metal bleachers with occasional breaks to share snacks and position tripods.

A few minutes after 5, our vigil was punctuated by the arrival of the “Astrovan” carrying the crew to the pad. This time, there was no U-turn signaling a scrub (gratifying the Tweetup attendees who brought handmade signs advising against going anywhere but the pad). After a retreat to a nearby press auditorium for a presentation about a planned test of an automated docking system–a somewhat difficult thing to focus on with the monitors next to the podium showing Endeavour’s crew getting strapped into the cabin–the sky lightened.

Layers of clouds moved in and out over the next two hours, giving the anxious among us–meaning all of us–reasons to worry about yet another scrub. But the decision from NASA at each time was the same: Go.

The last scheduled hold ended with nine minutes left, the countdown clock resumed ticking, and my heart promptly leapt higher in my throat than I would have thought possible. I walked over to my tripod and verified for the 20th time that I had the shuttle in frame and in focus.

That spot, on the nearest edge of the KSC press site to Pad 39A–only about three miles away–provided the closest view. But it also offered the least context. I could no longer see the countdown clock (though the photographer to my right had a countdown app on his phone) or hear the announcements.

With less than two minutes left, I observed through binoculars that NASA had retracted the “beanie cap” vent hood that covers the top of the external tank. But it wasn’t until the last 20 seconds were ticking away that everyone nearby began counting down aloud, and it all became even more gut-churningly real.

Ten… nine… eight… seven… six… somebody yelled “main engine start!”, and we knew the shuttle’s three engines had lit from the cloud of steam that erupted at the pad… five… four… three… two… one… an intense white light, bright as the hazy sun, shot through from the shuttle’s solid rocket boosters and Endeavour sprang off the pad.

For the first few seconds, the soundtrack was all human: cheers, whoops, applause. I did my part by shouting my fool head off–“Go, Endeavour!”–as I mashed the camera’s shutter button.

Then the noise of Endeavour’s launch assaulted us–a relentless, thunderous crackling, rumbling across the sky and through our shirts–while that white-hot glow from her boosters shot her upward, faster and faster.

On television, where the camera pans to follow the shuttle, this machine may appear to be soaring. From the ground, it looked more like it was getting thrown straight into the sky. There is a primal, visceral immediacy to its escape from gravity: The shuttle wants to fly, now.

It took no more than 20 seconds for Endeavour to punch a hole through a thin layer of clouds, leaving only the continuing racket of her ascent and a pillar of orange-tinged smoke. And an enormous grin welded to my face.

(Edits, 6/3: Gave this a slight rewrite and added a gallery of my photos after the jump. 6/27: Looked up some of my original tweets and embedded them in the post for a bit of a Storify treatment.)