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  • SciShow is supported by Brilliant.org.

  • [♪ INTRO]

  • It took nearly a decade of work and billions dollars for Neil Armstrong and

  • Buzz Aldrin to walk on the surface of the Moon.

  • But you know what happened after those first historic steps?

  • They went back inside the lander.

  • Only two and a half hours later.

  • And in that time, neither of them even walked more than 100 meters from the lunar lander.

  • To do more science, future astronauts would need to travel faster, go farther, and carry more.

  • And to do that, they needed to stop being moonwalkers and become moondrivers.

  • Fortunately, NASA had just the tool for them: the Moon buggy!

  • Okay, technically it was called the Lunar Roving Vehicle, but c'mon.

  • The Moon buggy helped astronauts on Apollos 15, 16, and 17

  • do more science and bring back more samples than earlier missions.

  • And along the way, we built a really cool car.

  • Engineers had actually been thinking about how to build a lunar rover since the

  • early 1960s, but those first concepts were totally different.

  • Some engineers imagined heavy duty, fully-enclosed vehicles

  • that also gave astronauts a place to sleep and work.

  • Which was nothing like the final design.

  • By the time the Saturn V rocket was actually flying,

  • it became clear that there would be almost no weight to spare,

  • so the plans had to be scaled down a bit.

  • In 1969, the final contract was approved by NASA.

  • Then, the rover was put together by Boeing and General Motors.

  • It was built of aluminum alloy, weighed just 210 kilograms,

  • about a sixth of a modern-day compact car,

  • and had to fold in half to fit beneath the lunar module.

  • But it was also sturdy, and could carry 490 kilograms,

  • more than twice its weight and enough for two astronauts, their tools, and a bunch of moon rocks.

  • It even had space for some nice amenities, like seat belts, an armrest, and fenders.

  • So it was no Rolls-Royce.

  • But considering that it was a car on the Moon, it was pretty impressive.

  • The first Apollo missions had shown that the Moon's soft,

  • powdery surface could make for uneven footing.

  • So the Moon buggy had not only four-wheel drive, but four engines, one for each wheel.

  • Each produced only about 190 Watts of power, or about a quarter horsepower,

  • but the Moon's low gravity meant that that was good enough for a top speed of about

  • 13 kilometers per hour.

  • The lunar roving vehicle also carried what might have be the world's first dashcam,

  • a TV camera controllable from Earth.

  • That not only enhanced the PR value of later missions, but allowed scientists at mission

  • control to look for interesting features as the astronauts drove around.

  • Still, even that wasn't the most impressive piece of equipment on board:

  • The Moon buggy also carried a revolutionary navigation computer.

  • Since the Moon doesn't have a magnetic field to move a compass needle,

  • and since surface maps didn't have much detail,

  • the astronauts were in real danger of getting lost.

  • And, let's be real: Everything on the Moon just kind of looks the same.

  • To overcome that, a first-of-its-kind computer combined data about the rover's orientation,

  • taken from an onboard gyroscope, with odometer readings from each wheel.

  • That let it track the vehicle's exact meter-by-meter progress across the surface

  • and plot a direct course back to home base.

  • And just in case that failed, each astronaut also had to learn to read

  • a special lunar sundial to determine their direction.

  • Single-use batteries powered everything, but power was never actually a problem.

  • Instead, the limiting factor was the rule that barred astronauts from driving

  • farther away from the lander than they had air left to walk back, a few kilometers or so.

  • That way, if the buggy broke down, they still had a way home!

  • All-told, the lunar roving vehicle seemed like a miracle machine,

  • and all that wizardry doesn't come cheap.

  • On average, each rover would cost about $60 million today.

  • Fortunately, we put them to good use.

  • Apollos 15, 16, and 17 each brought a rover,

  • and all were driven more than 25 kilometers over at least three hours.

  • With them, astronauts were able to bring back individual rocks with masses as much as

  • 11.7 kilograms, more than half the total picked up on Apollo 11.

  • Also, since the lunar landers had to touch down a safe distance from things like big craters,

  • the Moon buggy opened up those areas for closer study on all three missions.

  • On Apollo 16, it enabled John Young and Charlie Duke to drive more than 150 meters higher

  • than their landing site in search of samples of the area's unique geology.

  • And the crew of Apollo 17 used their rover to deploy literal bombs on the surface.

  • Just in case you needed another reason to think Apollo astronauts were cool.

  • When exploded, these bombs created tremors picked up by seismic sensors

  • and used those to understand the physics of the Moon's crust.

  • The experiment revealed that the top layer of the Moon's crust is about 1.4 kilometers thick.

  • It's also a lot more broken up than similar areas on Earth,

  • probably because of the constant impacts from space.

  • All together, the Moon buggies were quintessential Apollo.

  • They were ultimately designed in only months and did so much with so little,

  • relying on clever engineering and state-of-the-art computers to enable exploration.

  • Without them, we'd probably know a lot less about the Moon than we do today.

  • Which might make them a little cooler than, say, a Tesla.

  • And, hey, what's more American than a car on the Moon?

  • So, NASA scientists had to do A LOT of creative thinking and problem solving

  • to figure out how best to design and use the Moon buggies.

  • And that made me want to work out my own spatial problem solving skills.

  • That's one small step for man, and now I'm really tired.

  • Anybody got a moon buggy anywhere?

  • Brilliant.org has a ton of great spatial reasoning quizzes, and today I'll be taking the

  • 3D Geometry Puzzles Shortest Distance quiz.

  • [tires squealing]

  • It starts out a little like the story of the tortoise and the hare,

  • but it's an ant and a fly trying to make their way through a 3D cube.

  • They even put them there so you can visualize it, and I think they're pretty stinkin' cute!

  • In this case, the ant definitely has the longer distance to travel,

  • because it can't fly through the cube and has to walk along its edges.

  • As you get deeper into the quiz, it gets more complicated and

  • I almost wanted to make a 3D model to help me think through the distance.

  • [honking]

  • What's cool, is that I'm not alone in this.

  • When you view the solutions, Brilliant has created 3D to 2D models

  • to illustrate how to think through these problems.

  • So give them a try.

  • And right now, Brilliant.org is offering the first 77 SciShow Space viewers

  • that sign up at brilliant.org/scishowspace 20% off their annual premium subscription,

  • and you'll support SciShow Space, so thanks!

  • [♪ OUTRO]

SciShow is supported by Brilliant.org.

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B2 中高級

把汽車送上月球,我們學到了什麼? (What We Learned by Putting Cars on the Moon)

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    林宜悉 發佈於 2021 年 01 月 14 日
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