Local officials estimate that more than 700,000 people will gather along the beaches and lakeshores nearby to watch the second-to-last shuttle flight.
Jeff Spaulding is the NASA test director and he says he knows exactly why those people are here.
"When you're outside and you can feel those shock waves coming and see as it's climbing up through the sky, that's really what it's all about, when you not only get to see it, but you get to feel it and hear it and hear the rumble shaking the ground. And it is really awe-inspiring."
NASA says there's a 70 percent chance that Endeavour will take off on time tomorrow, but they want to see what happens tonight.
Warren Woodworth is here from League City. He's the chief shuttle engineer for United Space Alliance, a NASA contractor.
"The vehicles are in good shape, ready to go, the only concern we have is the inclement weather, and there's a concern about potential for hail, and so if that's the case we may end up delaying the launch a day."
But that's still just a possibility. Kennedy buzzed with preparations all day. I spoke with Jerry Ross just after he met with the six astronauts in quarantine.
"They're relaxed, they're enjoying their quiet time."
Ross flew on seven shuttle missions himself and now works as chief of vehicle integration. That's a fancy way of saying the person that works with the crew. He's sort of like their coach, but also like their stage manager.
"We work with them, we go through training exercises in Houston where they get strapped into a mockup of the space shuttle and we work with them on how many pads they want inside their helmet, how many pads they want on the headrest of the seat, in what sequence do they want their checklist stacked into this little saddlebag that's attached to the side of the seat. It's all the details that they have thought about or worked through, and when they get into the vehicle, everything's the way they want it."
As always, Ross will help the astronauts suit up tomorrow and will ride halfway out to the launch pad with them. He says it's work that is now tinged with sadness.
"Right now there's a lot of frustration and confusion, it's just not a good sense, there's a lot of people that are losing their jobs."
Like the shuttle program, Ross will retire later this year. He spent 32 years at NASA.
From Kennedy Space Center in Florida, I'm KUHF health, science and technology reporter Carrie Feibel.