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  • NASA's most important rocket launchesthe Mercury program, the Moon missions, and the

  • space shuttleslifted off from the Kennedy Space Center in Cape Canaveral, Florida.

  • But why there?

  • Florida doesn't seem to have a lot going for it.

  • The state gets hit by lightning more than anywhere else in the U.S., plus there's

  • monster hurricanes that blow through almost every year.

  • It's not impossible to launch rockets from somewhere else, but NASA has a need for speed.

  • And because of Florida's latitude, rockets get a big speed boost from the Earth's rotation.

  • Let's say you want to get up to the International Space Station.

  • It's in low-Earth orbit, about 400 kilometers up.

  • Distance-wise, that's not so bad.

  • Like, the Moon is over 350,000 kilometers away when it's closest to us, and we've

  • been there too!

  • The real problem is that the ISS is orbiting the Earth at speeds of over 27,000 kilometers

  • per hour.

  • So to get your flight to the ISS, you have to match its altitude and its speed.

  • By launching rockets from places on Earth that are close to the equator, like in Florida,

  • you'll get an extra speed boost.

  • All thanks to our planet's rotation.

  • See, imagine a flat, spinning disc, like a record, or a CD.

  • The whole disc finishes one rotation at the same time.

  • But a point on the edge is actually moving faster than a point near the center, because

  • it has farther to go.

  • A rotating sphere works the same way, and we're pretty much just a rotating sphere!

  • This means a point near one of the poles on Earth travels along a much smaller circle

  • than a point at the equator.

  • So the closer to the equator you areor the lower your latitudethe faster you're

  • moving.

  • But you can't really feel how fast you're moving when you're standing on Earth's

  • surface, because you're rotating with the planet.

  • Someone right on the equator in Ecuador, for example, is moving at around 1,670 kilometers

  • per hour.

  • So when your rocket lifts off in Cape Canaveral, Florida, at around 28 degrees north, your

  • speedometer is already reading 1,470 kilometers per hour.

  • Even though it's only a fraction of the speed you need, that extra oomph is energy

  • you don't have to spend in fuel.

  • And if you spend a little less fuel speeding your rocket up, you could bring along some

  • heavier experiments or satellites.

  • So speed was a big factor, but not the only one, when the US government picked Cape Canaveral

  • as a rocket launch site.

  • In the late 1940s, a team of engineers, scientists, and military analysts that would eventually

  • become part of NASA was test firing rockets and missiles in the New Mexico desert.

  • And they were running out of room.

  • Their rockets were going faster and higher than ever before, and they were landing farther

  • away.

  • They needed a new launch siteone that was big enough to handle more powerful rockets

  • that could enter space, and far enough away from people in case something went wrong.

  • Enter Cape Canaveral, Florida.

  • The area was pretty empty except for the Banana River Naval Aviation Station, which was already

  • owned by the US government.

  • This meant there were already roads to the rest of civilization, and they didn't have

  • to worry as much about the costs of making the site livable for everyone working on the

  • rockets.

  • Plus, to take advantage of the speed boost from Earth's rotation, rockets need to be

  • launched toward the east.

  • And the only thing that's east of Florida?

  • Thousands of kilometers of the Atlantic Ocean.

  • So there's much less danger of a wayward rocket or a spent first stage landing in a

  • densely packed city, like there was in the New Mexico desert.

  • And while Florida's weather might not be perfect, other parts of the country have their

  • storms too.

  • Now, this isn't to say you can't launch a rocket safely somewhere else, or at a higher

  • latitudeit just means you'll need more fuel, or a smaller payload.

  • The Soyuz space capsules that ferry astronauts up to the ISS, for example, have been launched

  • for decades from the Baikonur Cosmodrome in Kazakhstan.

  • It's at about 46 degrees north, near the same latitude as us here in Missoula, Montana.

  • Now, with the retirement of the space shuttle in 2011, NASA isn't launching astronauts

  • from Florida anymore.

  • But lots of unmanned rockets, carrying important satellites and spacecraft, are still launched

  • there regularly.

  • Even private companies like SpaceX are using Cape Canaveral launch pads to test their rockets,

  • and will probably continue when they start having manned missions.

  • So even as rocket technology keeps improving, many of them still depend on that speed boost

  • from the Earth's rotation, as they fly to low Earth orbit and beyond.

  • Thanks for watching this episode of SciShow Space, and especially to our patrons on Patreon.

  • If you'd like to support more content like this, just go to Patreon dot com slash SciShow.

  • And don't forget to go to YouTube dot com slash SciShow Space and subscribe!

NASA's most important rocket launchesthe Mercury program, the Moon missions, and the

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为什么火箭要在佛罗里达发射?(Why Are Rockets Launched in Florida?)

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    joey joey 發佈於 2021 年 04 月 18 日
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