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  • About 100 days ago,

  • we landed a two-ton SUV

  • on the surface of another planet,

  • on the surface of Mars.

  • This is one of the first pictures we took there with our rover.

  • It's looking out at Mount Sharp.

  • To me, it's, I kind of cry a little bit,

  • choke up, when I see this picture.

  • Why Mars and why do we look at these other planets?

  • And part of it is to understand our own planet,

  • what's the context for us?

  • We live on this amazing planet,

  • but Mars is a lot like Earth.

  • It's similar in size.

  • During the day time,

  • it can get up to 70 degrees in the, uh, Fahrenheit.

  • So, it's so like Earth, but at the same time,

  • you know, this is a barren landscape,

  • you don't see any trees,

  • you don't see any cactuses growing

  • or anything like that.

  • So, today I'm going to tell you

  • about how we got from Earth to Mars

  • and why it's so cool.

  • So one of the things we start with is

  • a blank sheet of paper.

  • We knew from the previous missions in 2004,

  • Spirit and Opportunity,

  • there was water on Mars in the past,

  • but, you know, what's the next step?

  • We're looking for an even more fundamental level

  • of what does it take to have life survive?

  • And so, to have that kind of, you know,

  • knowledge and understanding,

  • we have to carry a mass amount of instruments.

  • We have to carry the kind of labs

  • that people actually have whole rooms devoted to on Earth

  • inside of essentially a small car.

  • And what we did was we shrunk it all down

  • to something that weighs about as much as I do,

  • and then put it inside of this rover

  • that weighs as much as your car does.

  • And that rover is now on the surface of Mars,

  • but it's so heavy,

  • and so it kind of takes a special challenge for us

  • to make it all work and come together.

  • So we look at our tool,

  • of like what do we have to land stuff on Mars?

  • And one of the options is airbags.

  • We've done it before.

  • Airbags are pretty cool,

  • they bounce around a lot.

  • You could never put a human inside of an airbag

  • because they would get squashed.

  • But, the problem with airbags is,

  • the airbags that you see here,

  • which landed the smaller rover,

  • it's like 400 pounds, the entire rover,

  • were about the size of this room.

  • So you can imagine the size of airbags

  • it would take to land a two-ton rover on Mars.

  • And then they'd have to be actually made out

  • of materials that don't even exist today,

  • so it'd be some kind of exotic material

  • that we have to develop and may or may not work.

  • So what about rockets?

  • And this is the way we've like,

  • you know, you see all the rocket ships landing

  • in movies and everything else,

  • all rockets on the bottom,

  • it's a cool idea.

  • It works when they are pretty light still,

  • but the problem is,

  • these rockets have to be pretty strong

  • to actually softly land you on Mars.

  • And so they would be so powerful,

  • they could actually dig holes into the ground

  • and then you would just end up inside of a hole

  • and not be able to drive out of it.

  • So, not the best design.

  • But what if I could take the rockets and move them up?

  • And that's kind of what we came up with.

  • It's actually a rocket-powered jet pack,

  • we call it the Sky Crane.

  • And basically what it does is,

  • this big rocket sits on top of our rover

  • and when we're ready to land,

  • the rocket is going to hover in place

  • and we slowly lower the rover to the ground.

  • And then we touch down,

  • we're actually on the wheels,

  • we're ready to drive day one.

  • But in addition to that,

  • you know, the scientists were like

  • well, we actually want to go somewhere interesting.

  • The last two missions, they were really cool,

  • but they basically landed in what was like

  • landing in the plains or desert,

  • not very exciting.

  • We all know, like, from the exciting places on Earth,

  • or like places like the Grand Canyon and things like that,

  • and those are, for the scientists, the most interesting

  • because you see that whole layer,

  • you see years and years of history all in one place.

  • The same thing is true for where we landed.

  • We wanted to land somewhere that was unique,

  • that had this crater wall

  • where things had been dug up for us,

  • where mountains were pushing things up.

  • But, the problem is, if you landed with the older systems,

  • you could have landed

  • on the side of that mountain and just tumbled off,

  • could have been the side of a cliff,

  • could have been on the crater wall,

  • or a large boulder.

  • So we needed the kind of technology

  • to help us land in a very small area,

  • and that was this little guided entry from Apollo.

  • We took it from the 1960s.

  • We flew over just like the manned vehicle

  • because they had to actually pick up men,

  • you can't just land all over the place,

  • and then we landed, like, spot-on in the middle.

  • And in fact, it was so spot-on

  • that when we did it,

  • we were able to basically, like a quarterback,

  • you know, launching towards Mars,

  • it was like a quarterback, though,

  • the quarterback was in Seattle

  • and throwing at a receiver

  • that was moving here in Giants Stadium.

  • That's how accurate we were,

  • it's kind of awesome.

  • But, you only get one shot,

  • and so we actually have to design a system

  • that we can build,

  • and test,

  • and operate,

  • and so it's not just about can we get it to Mars,

  • but then, if it's only one chance,

  • how do you make sure that one chance goes so well?

  • And so there's all these processes we have

  • to make sure that things are built properly.

  • And then we go out to the desert.

  • And we drive around, and we test it.

  • We fly things in F-18s

  • to make sure the radar systems work in high speeds.

  • And then, most importantly, we actually test the team

  • to make sure they know how to operate it.

  • We don't want to accidentally miss it

  • because we send the wrong command,

  • and now it's just going to be rebooting forever.

  • So, that guy, Fred, there, he did a lot of that.

  • And then we launched it on this rocket to Mars.

  • And, you know, the entire thing,

  • we landed 2,000 pounds on Mars,

  • but the entire thing actually weighed about 10,000 pounds

  • when we lifted off from Earth,

  • all the fuel and the solar rays

  • and everything else that we needed.

  • And again, we were so accurate

  • that we landed in this, like, little pin-point on Mars.

  • In the meantime, though, we had to design

  • a landing system that worked.

  • And I told you about the actual physics of it,

  • but here's the catch:

  • Mars is about fourteen minutes away from Earth in lightspeed,

  • which means that if I try to control it with a joy stick,

  • I would be always controlling

  • to fourteen minutes in advance, so it wouldn't work.

  • So we had to give it all the smarts

  • and all the knowledge that it needed

  • in order to make it happen.

  • And so what we did was,

  • we built in all these smarts and algorithms and everything

  • and we told it here's what you're going to have to do,

  • and it goes from basically the speed,

  • five times the speed of a speeding bullet

  • to about a baby's crawl

  • all within about seven minutes,

  • which is called the seven minutes of terror

  • because I was about to throw up.

  • But today we are on the surface of Mars,

  • and this was one of the panoramas that we took

  • a couple days after we landed,

  • and I think it's amazing to me

  • because look at this and you can see the Grand Canyon,

  • you can see your own planet,

  • you can imagine walking on the surface.

  • And so, what we're going to do

  • and what we're going to continue to do

  • is to understand why, what makes Mars so special,

  • and what makes Earth even more special

  • that we are all here together today.

  • And so we'll see where Curiosity takes us,

  • not just our rover,

  • but our sense of exploration.

  • Thank you.

About 100 days ago,

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B1 TED-Ed rover landed rocket earth land

【TED-Ed】How Curiosity got us to Mars - Bobak Ferdowsi

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    wikiHuang posted on 2014/01/04
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