Litter, litter, everywhere.
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TVTranscript
00:00 With every rocket we launch into the Earth's orbit,
00:08 we're trapping ourselves on our own planet.
00:12 How could sending rockets into space
00:14 put an end to space exploration?
00:16 And how dangerous would it be to get stuck here,
00:19 with all the space debris floating above our heads?
00:22 This is WHAT IF,
00:24 and here's what would happen
00:25 if we trashed Earth's orbit with space junk.
00:30 Almost everything that we've launched into space
00:32 ends up either falling down
00:34 and burning up in the atmosphere,
00:36 or getting caught in the Earth's lower orbit
00:38 for thousands of years.
00:40 The Earth's lower orbit is surrounded
00:42 by just 200 kg (1,000 lb)
00:43 of small, rocky debris in the form of meteoroids.
00:47 But it's also got a belt
00:49 of about 3 million kg (1,000,000 lb)
00:51 of space junk.
00:54 20,000 pieces of debris as large as a softball,
00:58 500,000 pieces larger than a marble,
01:01 and many millions of pieces of debris
01:03 too small to track
01:04 are orbiting the Earth.
01:07 What makes these floating parts of old satellites
01:09 and spent rocket bodies so dangerous?
01:12 It's the speed they move at.
01:15 This junk is hurtling through space
01:17 at a speed of 8 km/s (1.8 mi/s).
01:20 At that speed,
01:21 one small bolt
01:22 is enough to shatter a working satellite
01:24 into hundreds of pieces.
01:27 But it's what comes next
01:29 that could hold off our dreams
01:30 of building moon bases,
01:32 colonizing Mars,
01:33 and any space exploration whatsoever.
01:36 The more junk we leave uncontrolled
01:38 in the Earth's lower orbit,
01:40 the harder it is not to get hit by it.
01:44 Things are running into each other.
01:46 Fragments of debris are colliding and breaking up,
01:48 multiplying the number of items
01:50 flying through the space junkyard.
01:52 And they're hitting working spacecraft too.
01:56 One day, they could hit enough satellites
01:58 to initiate an unstoppable,
02:00 destructive chain reaction,
02:02 the Kessler syndrome.
02:04 The cascade of collisions
02:05 would make our lower orbit
02:07 so congested with man-made debris
02:09 that eventually,
02:10 there would be no active spacecraft left.
02:13 Everything in the Earth's orbit
02:14 would be turned into a deadly wall
02:16 of celestial scrap.
02:18 Near-Earth space would become unusable.
02:21 No rockets could be safely launched
02:22 until we cleaned up the orbit.
02:24 We'd have to put our space missions on pause,
02:27 and we'd be trapped on the planet
02:28 for generations.
02:31 What would it be like down here?
02:34 Well, the debris belt wouldn't rain down on Earth
02:36 and cause massive destruction.
02:38 Space rubbish would disintegrate in the atmosphere
02:41 before it reached our planet's surface.
02:43 But the collisions would produce a lot of dust.
02:46 That dust, illuminated by sunlight,
02:49 would cause an ever-present twilight on the planet.
02:52 With this kind of light pollution,
02:54 you'd forget what nights used to look like.
02:57 What's even more unpleasant,
02:58 all of our satellite networks would go down.
03:01 There'd be no satellite communications,
03:04 no GPS navigation,
03:05 no weather data,
03:06 and no way to do any science in the Earth's orbit.
03:09 You'd have to go back to paper maps
03:11 and get your cash out.
03:14 Welcome to the 1970s.
03:16 On a positive note,
03:17 science has already come up with a few ideas
03:19 for cleaning up our lower-orbit mess.
03:22 They're looking at capturing the space debris with a net,
03:25 or a harpoon,
03:27 or vaporizing the small bits of junk with lasers.
03:31 Whatever action we deploy,
03:33 we should act quick if we want to launch humanity
03:35 on far space missions,
03:37 and finally colonize that red planet.
03:39 But that's a story for another WHAT IF.
03:43 ♪ ♪