Space shuttle Endeavour remains on the launch pad today after a series of weather delays nixed launch attempts Saturday, Sunday and Monday. Much of the country is balmy and dry this time of year but precipitation, wind and lightning are a mainstay along Florida's Atlantic coast, home to Kennedy Space Center.

Many satellite launches, including some for NASA, lift off from elsewhere in the U.S., namely Vandenberg Air Force Base in California. And the space agency utilizes other arid sites for shuttle operations, as well, landing the orbiter at Edwards Air Force Base in California when the weather over Kennedy is poor and even once easing it down at New Mexico's White Sands Space Harbor.

All of which begs the question: Why did NASA pick Cape Canaveral for its launch site, not only for the space shuttle program but also for the manned missions of the Mercury, Gemini and Apollo programs?

We contacted space historian Roger Launius, a senior curator at the Smithsonian National Air and Space Museum, to find out why NASA settled on lifting off from the Cape.

[An edited transcript of the interview follows.]

Why do we launch space shuttles from a place where the weather is such a constant source of trouble?
Well, is there any place where the weather is not an issue? You do it in the middle of the country and you get Tornado Alley. You do it in the South and you get hurricanes. On and on and on. There are always those issues.

Florida was chosen for several major reasons. One was, it's close to the equator. [The linear velocity of Earth's surface is greatest at the equator, much as a ceiling fan blade slices through the air faster at its tip than at its center hub, conferring a fuel-saving boost to spacecraft attempting to escape Earth's gravity.—Editor's Note]

The second reason was it had to be on the east coast, over the ocean, so you wouldn't fly over people that might get killed as stuff dropped off or blew up.

And the location that they chose in Florida had a lot to do with the fact that there wasn't anything there. You go there today and you don't see it, but Brevard County in the 1940s was a bunch of orchards and hardly anything else. And this island that they're on [Merritt Island] had good logistics, because there was a navy base and an army base not too far away. But there was no population density whatsoever. It was just a beach, essentially.

So you could build what you wanted, but it had decent roads because of the military, and that was important. This is one of the problems that [the Soviet Union] had with Baikonur [Cosmodrome in Kazakhstan], their launch site. I mean, it is in the middle of nowhere. They had to build a whole infrastructure to run rail out there, to build highways, to bring in all of the water and power and everything else that was necessary to make that place habitable.
You mention that it had to be on the east coast so the launch would climb over the ocean. Why do launches have to go east rather than, say, west from California?
When you launch headed east, you gain the rotation of the Earth in terms of acceleration. And so you don't have to have quite as powerful a rocket.
And that's a benefit related to the one conferred by being close to the equator.
That's right. The best place to launch is the spaceport that the European Space Agency has in French Guiana [five degrees north of the equator].

So why not launch from a U.S. territory that's even closer to the equator, such as Hawaii or Puerto Rico?
I think NASA viewed those as too far removed.
You mentioned Russia's launch site in Kazakhstan. How are they able to lift off from such a high latitude?
Well, they've got a big rocket. You have to have a larger booster that can muscle you into orbit.

[The U.S.S.R.] wanted their launch site in territory that they controlled. They didn't necessarily care perhaps in the same way about people that might be overflown, but that was a concern at some level. And they wanted to keep it very, very secret. That launch site was virtually unknown until the U.S. started tracking their satellites and figured out where it was located.

If you want a more equatorial orbit, you want to be farther south. And the [Soviets] would have liked that, I think, but they just didn't have a place to launch from.

So the space station is put in an orbit where Russia can reach it easily. And in fact, I would contend that that was the fatal decision that made the space station not really useful to us to go to the moon.
Why is the International Space Station a bad way station on the way to the moon?
Because its orbit is highly inclined [tilted with respect to the equator]. That high inclination means it goes very high to the north and very far to the south as it goes over the Earth. Which means that you lose a lot of the gain that you would have by launching from a space station to go to the moon. All of the scenarios that people had developed before the Space Age for going to the moon involved a reusable vehicle that goes to and from Earth orbit and a space station as a jumping-off place to go to the moon. It's the base camp at the bottom of the mountain.
So what orbit should the station be in?
In an orbit that was more equatorial, where you could maximize your fuel savings by launching from there. You can't use the station in that way very readily with the orbit that it's in now. And that decision was made when we brought the Russians into the program.
Does that inclination make the space station harder to reach from Kennedy Space Center?
Oh yeah. What you'll see whenever you see a launch with a shuttle going to the station is it gets up a few miles and then you see it turn to get into a high-inclination orbit. It basically drives up I-95.
With so much under review at NASA right now in terms of human spaceflight, are there any other sites on the table that are being looked at for launches?
I think Kennedy is it for the foreseeable future. The infrastructure that's in place there would be so expensive to replicate somewhere else. That's one important reason it's stayed there all this time.