تدريب Shadowing: You Are Alive to Watch the Space Station Fall From the Sky - تعلم التحدث بالإنجليزية عبر الفيديو

The greatest technological achievement in human history is speeding overhead at 8 kilometers per second.

And in as few as five years, it'll be rubble at the bottom of the ocean.

The International Space Station is coming home in the greatest fireworks show that you'll ever see in your life.

It's the most expensive object ever made.

We're lucky enough to be able to look up

and see it with the naked eye as it tracks across the night sky.

There's even an app that will alert you to when it's passing overhead.

And humans have been living on it since the year 2000, a continuous human presence in space for nearly 30 years.

And we'll be alive to see the International Space Station's complete

and total destruction as it crashes back to Earth in a spectacular shower of fire.

As this technological marvel breaks apart and burns up in the atmosphere, it'll signal a fiery end for an era of science,

space exploration, and human cooperation in space.

Billions of dollars in investment and countless hours of collective effort will be vaporized by temperatures up to 1650 degrees Celsius.

And we will be witnesses to the tragic loss of humankind's greatest collective global effort.

Will this be the end of human science collaboration in space?

Will all this really be lost forever?

However, to say that the International Space Station is one of the greatest collective human achievements is an understatement.

Most of us know about the ISS from videos of astronauts playing with floating water balls or having crazy static hair,

but real science happens up there too.

So what exactly is the ISS?

Well, in addition to its massive thermal radiators and solar panels, the ISS has 16 pressurized modules,

including multiple labs, six bedrooms, two bathrooms, and a workout gym.

It spans an area roughly the size of a football field, and it weighs 430 ,000 kilograms.

That's 950 ,000 pounds.

The ISS is the largest human object in space, and I said this before, but it's traveling at 8 kilometers per second.

Think about the fact that a football field is traveling the length of America every 10 minutes.

To think of it in another way, a person who's standing in the middle of a flat grassland looking from horizon to horizon can see about 8 kilometers.

So if you were to experience the ISS flying past you at ground level, well, you'd blink and it'd be at your face, and you'd blink and it'd be gone again.

Horizon to horizon would take about one second.

Yeah.

So how did this astro bullet train ever come to exist?

Well, there's no way it could have been built on Earth and then moved into place.

It's just too massive and complex.

The ISS orbits at 415 kilometers above the surface of Earth in what's called low Earth orbit.

It might be in low orbit, but when you're fighting gravity, it's still a long way up.

Every single kilogram of equipment or supplies requires enormous energy to deliver.

To achieve what seemed impossible,

scientists and engineers from across the globe had to come together to share both technical expertise and resources.

The ISS took over a decade to build, and involved the collaboration of five space agencies,

representing 15 countries, making it not just a technological triumph, but also an unprecedented moment of geopolitical cooperation.

Booking a spaceflight to the ISS is an historic marvel,

And it's a marvel rivaled only by the enormity of how horrific the passenger flight booking system is currently.

But thankfully there's a fix for that that's much simpler than the cross -coordination of multiple countries to build a space station.

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Okay, now back to the history of the ISS.

Ironically, it was the end of the space race between the Soviet Union

and the United States that opened the door to imagining and building the ISS as a truly international effort.

It would never have happened if it wasn't for two historical coincidences.

The first was the collapse of the Soviet Union, which left Roscosmos, the Russian space agency, open to international cooperation.

And the second was the slashing of NASA budgets as pressure to beat the Russians evaporated.

At an estimated cost between $100 and $150 billion,

the ISS holds the Guinness World Record for the most expensive man -made object ever built.

The enormous cost of building space stations made collaboration an economic necessity.

Now, despite the historically antagonistic relationship between the old Soviet Union and the U .S., this wasn't the first time they collaborated.

The US and Russia had experimented with space cooperation before.

After decades of leapfrogging each other during the Cold War, there was a brief scientific thaw in the icy relationship.

Yeah, in 1975, the Soviet and American modules joined in orbit during the Apollo -Soyuz mission.

Astronauts from the two ideological rivals ate and worked together for two whole days before going their separate ways.

20 years later, in 1995, after the collapse of the Soviet Union,

NASA's space shuttle docked with the Russian space station Mir for a series of collaborative missions.

The Russians already had extensive experience building space stations.

At this point, Mir had been operating for over 15 years.

Mir was the template of the modular space station, but ISS was much more ambitious.

Even with an unprecedented budget and unparalleled international team, it would still take a decade to build the ISS.

Individual pieces were built in separate participating countries over several years, even before the assembly began.

It took 42 separate launches to ferry the individual parts and the crews to build it into space.

Assembly started in November of 1998, when the Russians placed the first piece, Zarya, which means sunrise, into orbit.

Zarya was a propulsion and control module system to keep the station in place, essentially the foundational anchor.

Two weeks later, Space Shuttle Endeavour arrived with Unity, a node module that other modules could connect to,

plus a six -person assembly crew to start building the station.

It took until July of 2000 for the third building block to arrive,

another Russian module, Zvezda, containing living accommodations and communications.

And on November 2nd, 2000, the first expedition crew finally arrived and began the era of continuous habitation.

Ever since then, there have been humans living in space.

Core construction was officially completed in July of 2011, over a decade after it began.

In the U .S segment alone, more than 1 .5 million lines of flight software code run on 44 different computers.

They handle signals for 350 ,000 sensors, measuring pressure, temperature, valve positions, and other critical data.

There have been over 280 spacewalks on the ISS since 1998,

and of course, each one of those was planned and executed meticulously.

Every time these astronauts step outside, they're adding to our collective knowledge of space exploration.

And that's the ISS's real purpose, the advancement of science and our understanding of living in space.

Now, what makes the ISS an experimental

and research powerhouse is its microgravity environment the curious thing is

that even at 400 kilometers away gravity is still 89 percent

of what you would experience on the ground on earth

so how is it a microgravity environment well the weird reality is

that the iss is in a perpetual free fall toward earth but

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because it's also traveling sideways at eight kilometers a second it

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never gets closer to earth By the time it's fallen one meter, well, Earth is now also one meter farther away.

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So it's constantly falling, but always missing Earth.

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Now, as strange as this sounds, this is what orbit is.

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But most importantly, the experience on board is weightlessness.

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We don't think about gravity all the time

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because it's just there every second of the day but Earth's gravitational pull has an effect on everything.

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So getting away from the constant force of gravity

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and operating in a microgravity environment enables research into specialized molecular and chemical processes.

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Experiments like crystallizing proteins in microgravity are part of efforts to develop artificial blood for animals.

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I mean, obviously, vets don't have access to large blood banks for animals, so artificial blood could be a game -changer for animal health.

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And growing stem cells.

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Stem cells are used in many life -saving procedures, but are especially crucial for treating patients with cancer, like leukemia.

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But creating stem cells, a process called expansion, can be difficult on Earth.

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Growing them in a microgravity environment on the ISS helps them stay in a high -quality state longer and reduces rejection.

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Other experiments have led to the development of small X -ray sources to improve CT scan technology,

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testing manufacturing technology in space to produce artificial retinas using processes that lay down 200 layers of film,

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Proving out robotic technology and creating an industrial -strength robotic glove to help astronauts and autoworkers in their jobs.

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Innovations in battery tech to improve the efficiency of power systems.

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Microgravity studies into how compounds burn.

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Research that leads to more efficient fuel use and advances in firefighting technology.

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Improving cancer treatment by developing high -quality crystalline suspensions can't be made on Earth.

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And aside from direct experimentation, there have been a whole host of secondary benefits and spin -offs from the ISS.

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In many cases, the tech developed specifically to solve the complex problems of sustaining human life in space

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and running a space station can be applied to problems back on Earth.

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Just like the original Apollo missions led to major advancements in microchip technology

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and the development of cordless power tools we all use today, and the invention of foil space blankets, which are now standard equipment in emergency kits.

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They've even tested remote robotic surgery on the ISS, proving that precise robotic procedures can be done in space or on a future moon base,

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or just across the country.

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But the benefits go way beyond these innovations.

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Over the last 20 years, scientists connected with the ISS have produced over 5 ,000 scientific publications,

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carried out over 4 ,000 experiments, and have been cited in scientific journals more than 100 ,000 times.

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The ISS has become a symbol of progress.

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It's a literal shining example in our night sky of how nations can overcome their differences.

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And all this, every success, every bit of history, will soon come crashing down in the end of an era.

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You know, the Great Pyramids were left unattended for thousands of years.

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And aside from some wear from the elements and some tear from human activity, they stayed put.

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Even now, they stand as a testament to the people who built them.

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But the ISS won't be around to be visited or studied as an antiquity in the future.

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An orbiting space station needs constant maintenance and reboosting to remain in orbit.

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NASA has committed to fully use and safely operate the station through 2030, but after that, it's scheduled for destruction.

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But why would the agencies involved allow this precious science lab,

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lifted into orbit at an astronomical cost to be discarded so casually?

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Why can't we save it?

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Well, science fiction movies have given us a false sense of.. ships in space that can last forever,

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but the films rarely ever pause the action long enough to feature the daily details of maintenance and metal fatigue.

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There's massive wear and tear in space.

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The ISS's structure experiences significant stress as heavy spacecraft dock and undock,

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and it undergoes constantly changing heating and cooling cycles as it orbits.

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So the station's structure has a finite lifespan.

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So why doesn't NASA just return the station to Earth?

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It's got enormous historic value and deserves a museum of its own.

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Well, it wasn't built to come apart.

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Assembly took over a decade and hundreds of spacewalks using a space shuttle cargo bay that no longer exists.

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Taking it apart?

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That would need the same work, but in reverse.

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Plus, the space shuttle with its roomy cargo bay has long been retired.

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There's nothing like it out there to do the same job again.

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NASA has been working with the Smithsonian Air and Space Museum to preserve small parts of the station,

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but it's just not practical to return any of the bigger pieces to Earth.

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Then why not just let it stay where it is?

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Well, even at 400 kilometers above Earth's surface, there are trace amounts of atmosphere, which create drag on the station.

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So it needs periodic booster lifts to keep it from slowly falling to Earth.

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And those boosts are costly to deliver.

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These days it costs a staggering 4 .1 billion dollars a year just to keep the lights on.

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So then why not push the ISS into a higher orbit where it could remain parked for multiple hundreds of years,

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awaiting some future use.

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Well, the first problem would be the amount of energy needed to push the station into a significantly higher orbit.

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There currently isn't a rocket that can do that.

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And any big booster mission has to consider the station's structural integrity during thrust.

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And even if we could push it high enough, there's another issue.

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All the delivery systems and vehicles that currently service the station are specifically designed to operate in low Earth orbit.

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At a higher orbit, there'd be no ability to regularly reach and crew the station.

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Without a crew, everything would degrade and become unstable quite quickly.

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NASA has calculated that if the ISS were lifted to an orbit of about 800 km,

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it would have a potential lifetime of 700 years.

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But there, the probability of a catastrophic impact breaking the station apart increases dramatically.

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The likelihood of an impact event, which is roughly estimated at 51 years at its current altitude,

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would drop to around four years at a higher altitude.

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Any gain in lifespan from pushing the ISS into a higher

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orbit would be cancelled out by the extreme risk of being struck by orbital debris, which could lead to complete fragmentation.

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And worse, all those smashed and disintegrating components could form a debris field that would compromise our safety in low Earth orbit,

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or even prevent access to it altogether.

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Then why not just let it fall to Earth?

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This seems like the cheap and easy solution.

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Left alone and depending on solar events, it could take between one to two years to slow down enough to fall back down to Earth.

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But did you know there's a safe re -entry requirement?

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The US government states that uncontrolled re -entering spacecraft must meet

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or exceed a 1 in 10 ,000 likelihood of public risk due to debris.

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Space junk is falling to Earth almost every day, but most of it we don't notice.

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An object the size of the ISS?

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Yeah, that would be noticeable.

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In 1979, the skies over Western Australia lit up with massive fireballs.

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Sonic booms were heard across the outback.

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Skylab was returning to Earth in an uncontrolled re -entry.

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At a whopping 76 ,000 kg, it was the largest human -made object ever to fall to Earth at that point.

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Launched in 1973, Skylab was NASA's first space station.

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It was planned to last a decade, but the unexpected happened.

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Higher -than -predicted solar activity heated Earth's atmosphere, expanding it and the increased drag on Skylab was dramatically shortening its life.

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Then, a planned visit to keep the station in orbit never materialized.

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A delay in the shuttle program meant there was no last -minute rescue for the doomed station.

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NASA did what it could to direct its fall, but ultimately couldn't control its re -entry.

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It broke up a mere 16 kilometers above Earth.

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The debris footprint stretched for an incredible 4 ,000 kilometers.

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Whole pieces of the station survived the heat of re -entry.

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The biggest was an oxygen tank, 2 .4 meters long.

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It would have weighed 1 ,270 kilograms before it hit Earth and broke in two.

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The town of Esperance, Australia jokingly fined NASA for littering, but the risk to human life was serious.

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NASA paid close attention to that failure and doesn't want to make the same mistake twice.

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The $843 million contract with the demolition crew has been signed.

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The de -orbit vehicle has already been ordered.

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Sometime soon after 2030, the ISS will be propelled back to Earth in a spectacular human -made meteor shower

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and it'll be the most extravagant and expensive fireworks show of all time.

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NASA hasn't set a date or a specific splash point yet, but the ISS will obviously be aimed at a spot least likely to cause harm.

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Death.

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Most likely a remote spot somewhere in the ocean.

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The most remote place in the world is known as Point Nemo, and it's in the middle of the South Pacific,

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roughly 3 ,000 kilometers from uninhabited land.

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The date is unknown, but tickets may soon be available to view the light show.

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In March of 2001, it was reported

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that people had paid an average of $6 ,500 for seats

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on flights from the island of Fiji across the Pacific Ocean to witness the re -entry of the Russian Mir space station.

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That was back before Instagram and the full effect the internet has on mob events. By 2030,

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there will be a line -up of thrill -seeking influencers lining up to try and get into the ISS burn zone.

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It feels like we're losing something irreplaceable.

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The ISS has been responsible for scientific advances in medical research, improving drug designs for cancer, diabetes and other diseases.

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The knowledge gift to the human race from this one space station is almost immeasurable.

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Every single day, we are answering big questions about Earth and about space, about where we came from and about where we're going.

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But the other thing that we're doing is we're learning more questions to ask.

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It serves as a testament to the fact that we can

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and will work together as citizens of Earth when the goal is worthy.

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But the ISS is not the end.

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Its destruction is more of a beginning.

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The ISS was never meant to be permanent, and with the winding down of the ISS, commercial ventures will take its place,

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building their own space stations because NASA is putting all its resources and energy toward the next steps.

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And those next steps are giant leaps for mankind.

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NASA's already completed mission 2 of its Artemis project.

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Built on the science and experience gained from the ISS, the Artemis mission is to return to the Moon and build a permanent base there.

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And after the moon base is established, infrastructure for manned exploration of Mars will be built.

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But that's a story for another What If.

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What was your favorite experiment on the International Space Station?

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Toby, great question.

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My favorite experiment was the one that I got to eat.

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It was us growing hatched chili peppers in our plant habitat.

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Station Huntsville on two.

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We have video in node one.

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Look at the chili peppers.

ما هي تقنية التظليل الصوتي؟

التظليل الصوتي (Shadowing) تقنية تعلم لغة مدعومة علمياً، طُورت أصلاً لتدريب المترجمين الفوريين المحترفين. الطريقة بسيطة لكنها قوية: تستمع لصوت إنجليزي أصلي وتكرره فوراً بصوت عالٍ — كظل يتبع المتحدث بتأخير 1-2 ثانية. تُظهر الأبحاث تحسناً كبيراً في دقة النطق والتنغيم والإيقاع وربط الأصوات والاستماع والطلاقة.

تدريب Shadowing: You Are Alive to Watch the Space Station Fall From the Sky - تعلم التحدث بالإنجليزية عبر الفيديو

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