Orbiting Perspectives: The Evolution and Impact of Satellites | Full Documentary

We live in a world our ancestors would barely recognize. Around the globe, the impact of human ingenuity is now everywhere. We've pushed back the limits of our planet at speeds, depths, and heights that would have left our forebears breathless. Driving all these achievements is humankind's extraordinary gift for invention. Through genius and inspiration, we've created exceptional solutions to complex problems. From the everyday to the spectacular, some good and some not so good. This series celebrates the million ways our great inventions have transformed our world. That's one small step for a man, one giant leap for mankind. Among the great inventions to transform our world, one circles high above the rest. Born as a testbed to develop weapons of mass destruction. It showed that they could fire missiles all the way to the states. Our lives have come to depend on them. From global communication. They've made the world a smaller place. To transforming navigation. The GPS system means you can know where you are, no matter where you are on the globe. From watching to predicting the weather. We've gotten much better advanced weather warning systems, so they're literally saving lives. And international espionage. They were using them to spy on their rivals. Even exploring the vastness of the universe. From Earth to outer space, few things have transformed our lives like the satellite. Satellites have literally changed the way we look at our own world and the universe beyond it. 4th of October, 1957. On a remote military site in central Kazakhstan, Soviet scientists prepare an R-7 intercontinental ballistic missile for launch. The Kremlin are using its secret payload to send a message to the United States. As the 280-ton missile reaches an altitude of 223 kilometers, it deploys the classified cargo. 19 seconds later, Soviet scientists on the ground detect faint radio signals from the world's first artificial satellite. Sputnik. At 58 centimeters in diameter and weighing just over 80 kilograms, launching this small metallic sphere becomes one of humankind's greatest scientific achievements. Crucially, Sputnik has been designed with four radio antennas so it can be tracked from the ground. And its path intentionally takes it directly over the United States. You could hear through your radios these beeps. They're the iconic beeps of the space age. But what they served to do in America was to terrify the population. Here was this Soviet technology overflying them, out of reach. They could do nothing about it. The world listens in awe to the radio signals from this milestone scientific achievement. But the real purpose is to send the United States a military message. And the U.S. High Command receive it loud and clear. Sputnik was launched in the aftermath of the Second World War. And now the U.S. knows that the Soviet Union can launch payloads into orbit directly over their airspace. Twelve years earlier, America drops atomic bombs on the Japanese cities of Hiroshima and Nagasaki, ending the Second World War. The United States and the USSR emerge as competing post-war superpowers. The world descends into the Cold War. The United States is the first country to build the atomic bomb. But it isn't long before the USSR catches up. It kicks off a different course of human history here, because suddenly it changes the balance of power across the world. And there's only two so-called superpowers that have this technology, the United States of America and the Soviet Union. A full-blown arms race emerges between the East and West, but the United States has a major advantage. They have a fleet of sophisticated high-altitude bombers to deliver their nuclear arsenal. And they know the USSR lack the capability to strike back. The Soviet Union need a new kind of technology, something called the intercontinental ballistic missile, a rocket to carry bigger and bigger payloads, nuclear weapons, longer and longer distances. Soviet military scientists begin developing the R-7 rocket and plan to make sure that America knows that the balance of power has shifted. You have to remember, this is, you know, the Cold War. People are genuinely afraid nuclear bombs could mean the end of the world. Now, the thing that keeps them feeling safe is that the Soviets don't have a way of delivering this bomb, until, of course, they do. Sputnik announced that the Soviet Union had the means to strike back. And now we know that our biggest enemy has the means, the missiles, to do this. Alarm bells ring in the Pentagon. When they put Sputnik up there, you know, essentially being travelled on what is kind of a ballistic missile, it showed that they have the capability of going that high up. And that high up is also about how high up you need to go if you want to... You can see what I'm talking about here. They could fire missiles that would be able to travel all the way from the USSR to the States. At this point, the Americans feel that they need to react and react strongly when it comes to their own sort of satellite and missile program. Because, yeah, they both have the bomb. But now, you know, their archenemy has a very clear means of delivering it. And they've told them in no uncertain terms by launching Sputnik. The USA need to catch up. The space race has begun. And satellites will be on the front line. Keeping satellites in orbit isn't easy. It's a real challenge to get things into orbit, to put something in space and make sure it actually stays there. There are two factors. You've got speed and you've got gravity. Satellites actually stay in orbit by getting the balance right between the gravitational pull of the Earth and the speed at which the satellite is moving. Get that speed wrong and you could send a satellite just shooting out into space. Get it right and you could have a satellite that's orbiting the Earth constantly. Kind of like if you were to swing a ball on a piece of string around your head. The ball would fly off if the string disappeared. But the string is keeping it in, keeping it going in that circle. And that string is analogous to the force of gravity. So in exactly the same way that the planets orbit around the sun, the moon orbits around the Earth, the same laws determine exactly how satellites orbit our planet. The first stage is to find a reliable way to launch the satellites into space. In an unexpected move, they turn to the Navy, setting them the challenge of launching the United States' first satellite. 6th of December, 1957. In front of the world's press, the U.S. Navy prepares to launch their Vanguard rocket. It rises to an altitude of one meter, then the first stage loses thrust. The decision to ask the Navy to deliver the first satellite was an odd one. The U.S. already had a rocket program. Led by a man with far more expertise than the Soviet scientists. But his existence was a closely guarded secret. The U.S. missile program was led by the top Nazi rocket scientists. They weren't just using the technology that the Nazis developed in the V-2 rocket. They were actually using the very same scientists with Werner von Braun, who had been developing missiles for the Nazis only a decade before, now developing rocket engines for the U.S. They gave him just 60 days to work out how to turn one of his existing rockets into an orbit-class rocket that can launch the United States' first satellite. Designed with the U.S. Army, von Braun's four-stage Jupiter-C rocket is readied for launch. On board is Explorer 1, a satellite the U.S. hoped they can place into orbit. On the 31st of January, 1958, the U.S. Army fired the 29-ton rocket's engine. At 350 kilometers above the Earth, it successfully releases Explorer 1, the United States' first ever satellite. They finally managed to restore a bit of national pride. They showed the USSR that they're capable of developing a rocket powerful enough to put a satellite into orbit around the Earth. But even though Explorer 1 was launched by the military, it would transform our scientific understanding of the planet. One of the chief instruments on board was the cosmic ray detector, which had been put there on the advice of physicist James Van Allen. When they started getting the results back from this radiation detector, the results were shocking. The levels of radiation were a thousand times higher than anyone had predicted, completely unprecedented levels. Scientists were astonished. Just beyond the atmosphere, space is flooded with radiation. But then, at an altitude of 1,400 kilometers, something unexpected happens. Suddenly, this enormous level of radiation completely vanished. That would have been a huge discovery, completely unexpected at that point. It was baffling them at the time. Physicist James Van Allen had taken the very first reading of radiation captured by the Earth's magnetic field, the magnetosphere. This blanket of radiation covering the Earth will become known as the Van Allen Belt. Without it, life wouldn't exist. As well as light, the sun is giving out a constant stream of radiation, a stream of charged particles called the solar wind. The Earth's magnetic field takes these charged particles and it deflects them mainly away from the planet entirely. But those few that do make it to Earth are funneled down into two points or two sort of circles around the magnetic poles. That's where you get the aurora borealis and the aurora australis, these beautiful green lights you can see in the night sky. But as a result, it means that our atmosphere is safe. It isn't being stripped away by the force of the solar wind. With the discovery of the Van Allen Belt, scientists realize they need to explore more of the Earth's upper atmosphere. In 1960, the United States launched SOLRAD 1. It was trying to look at solar radiation, measuring X-rays, high energy photons in the upper atmosphere to really see that dynamic between how the sun affects the top parts of our atmosphere. SOLRAD 1 also had another mission. It was the US's first spy satellite. Since the start of the Cold War, the United States has been flying secret reconnaissance missions over the USSR. But it was dangerous work. Over 200 airmen were shot down. The US needed a way to avoid Soviet radar that was identifying the American pilots. Orbiting 800 kilometers above the Earth, SOLRAD 1 is directed over Soviet territory to probe for radar blind spots. They've realized that the radar beams they use on the ground, they actually go all the way into space. So when the SOLRAD 1 satellite passes over the USSR, it can pick up their radar beams, find out what bandwidth they're on and get that key information. SOLRAD 1's secret mission is a success. The United States begin designing more sophisticated spy satellites. But it soon becomes clear that satellites have potential beyond the military. Before satellites, the distance that radio and television signals could be broadcast was severely limited. Radio waves, the electromagnetic frequency that send broadcast signals, only travel in a straight line, so range is limited by the curvature of the Earth. To send signals over the horizon, you need a chain of relay antennas and receivers. But you can't build an antenna in the middle of the ocean. Satellites offer a unique way around the horizon problem. Scientists could use them as orbiting relay stations. The early experiments are remarkably low-tech. And one of the experiments they conducted was to launch Echo-1, which essentially was a giant reflective balloon. Echo-1 has no electronic components. It is simply a giant orbiting mirror bouncing radio signals over the horizon. On the 12th of August 1960, the giant mirror ball is launched into orbit aboard a 54-ton Thor-Delta rocket. At an altitude of 1,600 kilometres, it releases its payload. Once up in space, they inflated it using a chemical reaction and then they sent some radio waves which bounced off its reflective spherical surface and sent signals back down to Earth, proving that you could send and receive radio signals from Earth. This opened the doors for so much potential in communication. The proof of concept sees engineers develop electronic satellites that will allow them to receive and transmit radio signals from Earth. But for these pioneers, just keeping a satellite in orbit is an enormous challenge. The problem the early satellite designers were having to overcome was the fact that satellites that are orbiting pretty close to the Earth, they're not travelling through a perfect vacuum. It's almost a vacuum, but there are still a few sort of residual air molecules slowing down the satellite as it goes around the Earth. Over time, it's not able to counteract the continuous force of gravity and so eventually the satellite crashes back to Earth and burns up. If scientists could push the orbit further away from the upper atmosphere, the vacuum of space should dramatically reduce drag. On July 10, 1962, they test the idea. Telstar 1 is placed into a medium Earth orbit, permanently travelling around the Earth. Two days later, it makes history when it relays across the Atlantic Ocean the first ever live television images from a satellite. I understand that part of today's press conference is being relayed by the Telstar communications satellite to viewers across the Atlantic and this is another indication of the extraordinary world in which we live. Telstar 1 ushers in a new era of global satellite television communication. The opportunities seem endless. But not long after, Telstar falls victim to the Cold War. The U.S. military are looking for ways to shield America from nuclear attack. They know Soviet missiles would need to pass through the Van Allen radiation belt. If they can supercharge this region of space, the belt might become a defensive shield, frying the electronics of any incoming missiles. They test the theory by detonating nuclear bombs inside the Earth's magnetic belts. The theory works. The Van Allen belt becomes supercharged and it's thought Telstar becomes the first casualty as the radiation surge destroys its electronics. Telstar was a milestone in satellite technology. Space communication is now a reality. But communications satellites still have to get past a major problem. To overcome Earth's gravitational pull, they need to travel at over 21,000 kilometers per hour. This is much faster than the Earth turns. So receivers on the ground only see the satellite for a short 20-minute window. With communication satellites, what you want is ideally a constant line of sight out to it. You don't want it disappearing over the horizon all the time. Imagine you're trying to broadcast a major world event. You've only got a 20-minute window in order to get that message out before the satellite disappears and everyone's TV goes fuzzy. So can you actually have a bigger window or even an infinite window? If the satellite stays above the same spot on Earth at all times, that means you have 24-hour coverage from that satellite. It's known as geostationary orbit. Geostationary orbit is the right altitude to place a satellite so that its orbital period, the amount of time it takes to do a complete circle, is the same amount of time it takes the Earth to do a rotation around its axis. And it just so happens the sweet spot is somewhere around 36,000 kilometers above the surface of the Earth. As the Earth rotates every 24 hours, so does the satellite. It does a full orbit, and that means it stays above the same spot on Earth all the time. NASA start the SYNCOM program, short for synchronous communication, to put a satellite into geostationary orbit. Although the theory is sound, the execution requires absolute precision. If your calculations are just a little bit wrong, your satellite ends up either shooting off into space or crashing back to Earth, both of which are very bad outcomes. And disaster strikes NASA's first attempt when SYNCOM-1's motor misfires and they lose control of the satellite. But the astonishing benefits of geostationary orbit to global communication are too important. In August 1964, NASA launched and hit geostationary orbit. They got a satellite called SYNCOM-3 to successfully stay in geostationary orbit above one point in Earth. And this was a landmark moment in the history of communications technology. The dream of continuous global satellite communication and cooperation is real. The European Space Agency, China, Japan, and India will all start space programs. The number of satellites explodes. Communication satellites, Earth observatories, and international space stations all begin shaping our views and understanding of the world we live in. It opens up the doors for an unprecedented era. Satellites made the world a smaller place. You know, access to ideas and information and people all of a sudden became easy, became possible. Satellites have opened up a new world of scientific exploration, global communication, and television. And they are soon transforming our lives in unexpected ways. For most of history, humankind has been at the mercy of Mother Nature. Before the 1960s, predicting the weather was a crude science. For the early meteorologists, measuring temperature in the atmosphere was key. The first pictures of Earth from space were captured from Wernher von Braun's early rocket tests. As the rockets reached the edge of space, they captured a fleeting glimpse of the Earth. The view was too brief to be useful, but meteorologists saw the possibilities for satellites in permanent orbit. I can't imagine the feeling of what it must have been to be a meteorologist back then, seeing the Earth from space for the first time, seeing these weather patterns from a bird's-eye view or beyond a bird's-eye view, a god's-eye view. Weather is caused by the sun heating our atmosphere. If meteorologists could chart temperature changes, it could help predict the weather. But the early satellites could only see the weather, not the temperature. How do you measure temperature using a camera? NASA think they have a way. They turn to a cutting-edge piece of technology. Anything that's got a temperature has energy in its individual atoms and molecules. They're vibrating around, and as they vibrate around, they emit radiation. Now, if you get something hot enough, like if you get some red-hot molten iron, that can be vibrating hard enough to give off visible light that you can actually see. But most things around us in everyday life and in the Earth's atmosphere aren't that hot. So rather than radiating invisible light, they're radiating in what's called the infrared. If you can measure the amount of infrared radiation coming off something, you can work out how hot it is. In 1969, NASA launched a meteorological satellite, Nimbus 3, to trial the technology. On board is an infrared spectrometer to chart shifts in temperature within the Earth's atmosphere. When they pointed it back down at the Earth and took those infrared measurements, it worked. They were able to determine those temperatures, and it allowed them to start increasing the accuracy of weather predictions. Weather satellites use this principle with hundreds of thousands of soundings every day. In the case of natural disasters, this can be hugely important. Infrared spectrometers are literally life-saving devices. They allow us to predict the severity of storms long before they make landfall, so you can inform people as to whether to evacuate or batten down the hatches. And in the longer term, they allow us to watch how the global climate is changing and feed that data into models, which can tell us what's going to happen to weather patterns in future, and therefore save lives that way, too. Weather satellites have made all of our lives safer. But alongside the benefits of scientific satellites, the military continued to develop them for more sinister purposes. Since the birth of the space age, the United States and Soviet Union have both been developing satellites to spy on each other. Any insight into their rivals' missile programs could prove vital, and satellites provide an ideal eye in the sky. As early as 1960, the CIA launched their first photographic reconnaissance satellite, codenamed Corona. Orbiting at 160 kilometers above the Earth, the Corona satellite is directed over Soviet territory. With an array of precision camera lenses, the satellite photographs its journey over the USSR. But working with 1960s technology presents a unique set of challenges. The CIA devised novel solutions. They took these photos on film. So these early spy satellites would be sent up there with miles and miles of film, and they would just indiscriminately take photos of different parts of the Earth as they traveled across it. But then, how do you get that film back down to Earth? In an age before digital imaging, the CIA have no choice but to physically retrieve the film from space. If they drop it from the satellite, could an Air Force recovery plane catch it out of the air? So think about all the things that have to go right in order for that to actually happen successfully. It has to deploy at the right point in its orbit so that its trajectory enters the Earth's atmosphere at the right spot. Survive the incredibly violent re-entry into the Earth's atmosphere. The parachutes would then have to successfully deploy to slow it down enough. The airborne rescue team have to get up and deploy to the right zone as well. They've got spies on the plane with binoculars looking for it. To then scoop it out of the air, there's so many ways for it to go wrong. And even if everything did manage to go to plan, it would still be days or even weeks until those photos would be developed. By that point, who knows what might've changed behind the Iron Curtain. It kind of worked. Between 1960 and 1972, over 100 Corona missions are conducted. Remarkably, more than 800,000 photographs are returned to Earth. But by the time the Corona satellite images can be scrutinized, they are already weeks out of date. The Soviet Union also recognized the problem. Their solution was to replace orbiting cameras with spies. In the initial days of the space race, the USSR set the pace. In 1961, Yuri Gagarin becomes the first human to orbit the Earth. Now they aim to put cosmonauts into orbit for extended missions. They had had plans for space stations for decades and they had incredible amount of data on keeping cosmonauts, keeping humans alive beyond the Earth. This was something that they knew they could, again, beat the Americans at. In 1974, they launch a manned space station, Salyut 3. They claim it's an orbiting Earth observatory. They just wanted to have people up there observing the Earth and taking photos of how things change and weather patterns and so on. But in reality, it was a spy satellite. The Almaz spies are a major update on America's spy system. They were there to not only direct the camera as opposed to just snapping away indiscriminately, but also they had the added bonus of being able to relay what they were seeing in real time without having to wait for the images to be sent back to Earth. Almaz proves far more effective than the CIA's unmanned Corona satellite missions. But the Soviets worry that their cosmonaut spies are vulnerable to counterattack. The Russians were so paranoid about getting caught out that they thought it was necessary to arm their satellites with, get this, a space cannon. I mean, we're talking real James Bond stuff here. The 23-millimeter cannon designed for supersonic bombers is adapted to fit the Salyut space station. But firing a cannon in space presents unique problems. Newton's third law kind of gets in the way, this idea that for every force there is an equal and opposite reaction. You know, if you stand and point a gun, you'll feel the recoil, but ultimately your feet stuck to the ground will absorb most of that force. In space, you don't have that luxury. You know, they could have actually fired on an approaching enemy and shot themselves out of orbit and off into space. The Soviet Union had taken Cold War warriors into space. Now the USA was about to announce a jaw-dropping escalation. Since the dawn of the Cold War, the specter of nuclear apocalypse hung over both the East and West. But Armageddon is kept at bay by a balance of power known as mutually assured destruction. Both the USA and the USSR possess an enormous arsenal of nuclear warheads and the intercontinental ballistic missiles to deliver them. But both powers know that if one side ever pushed the nuclear button, the other could react in kind. Firing the first missile would effectively be nuclear suicide because once retaliatory missiles were airborne, the aggressor would also be doomed. They're able to see these missiles coming towards them, but they can't stop them. All they can do is wait. Ronald Reagan was not happy about this at all. Let me share with you a vision of the future which offers hope. What if we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies? In 1983, President Ronald Reagan sets America's best and brightest, the task of finding a way to render mutually assured destruction obsolete. The program will become known as the Strategic Defense Initiative. Reagan got together his best and brightest military minds to try and come up with ways to shoot down an intercontinental ballistic missile while it's in space. That was gonna mean they'd have to arm satellites. And the weaponry they imagined mounting on board the satellites comes straight out of science fiction. Reagan was thinking about putting laser beams on there, high energy kinetic projectiles, potentially even nukes. I mean, this was totally outlandish. And in fact, the people thought that at the time as well. That's why they nicknamed it Star Wars. This is such an incredibly difficult task. First, you've got to identify these missiles which are traveling really fast. You've gotta be able to target them effectively. Bear in mind as well, they're gonna be a ton of decoys. Once you've done all of that, then you go and try and shoot them down. And you've gotta be 100% sure that these incredibly complicated high-tech weapons are gonna work first time and every time. While the USA see the Strategic Defense Initiative as purely defensive, the USSR see it very differently. Actually, it shifts the balance in mutually assured destruction fundamentally. The Americans could launch a first strike and when the Russians try and retaliate, if a significant number of their warheads get intercepted, then that means that the Americans are gonna win a nuclear war. This meant that the Soviets were gonna have to produce their own equivalent of Star Wars. It wasn't long before the program ran out of money and eventually the whole country ran out of money with the Soviet Union collapsing just a few years later. Space again becomes the arena for exploration and research. And scientists look to turn satellites outwards to explore the vastness of the universe. Since Galileo first turned his telescope towards the night sky in 1610, astronomers have struggled for a clear view of the heavens. The Earth's atmosphere is like a big soup. There's a lot of material that distorts our view of space. In fact, you can see this with your own naked eye. When you look at a star that's low on the horizon, you can see it twinkling. That's the Earth's atmosphere affecting it. If we could somehow get a telescope on a satellite completely outside of the Earth's atmosphere, it would be an absolute breakthrough. NASA propose a program to do just that. In 1983, work begins on the Large Space Telescope. Placed high above the atmosphere, it should give astronomers their first unimpeded view of distant stars, solar systems, and galaxies. But to see objects billions of light years away requires the most advanced telescope ever built. NASA begin designing highly sophisticated sensors to detect both visible and invisible light. All needed to see further into space than ever before. But if engineers are to incorporate these instruments into a single satellite, the Large Space Telescope needs to be very large indeed. 13 meters long, 4 meters wide, and almost 11 tons in weight. But NASA's typical satellite deployment systems won't cut it. NASA needs an entirely new craft to get it into orbit. To get a satellite up into space of this size required a vehicle with a huge space for cargo. And that vehicle was the shuttle. In 1972, work begins on NASA's iconic Space Shuttle. Uniquely, the shuttle will be able to launch, repair, and even catch and return satellites. And it's designed to carry much larger payloads, almost 30 tons with each launch. Exactly what the Large Telescope will need to reach space. It's an incredible technological undertaking consisting of about two and a half million moving parts. Crucial to the shuttle's success is its heat shield. Not only does it have to survive re-entry into the Earth's atmosphere, traveling at over seven kilometers a second and generating temperatures of more than 1,600 degrees Celsius, each shuttle needs to do this many times over. Previous NASA craft used ablative heat shields, a protective coating of plastic resin that burned away during re-entry. But this type of disposable system won't work for the Space Shuttle, which is being designed for multiple missions. Instead, they line the underside with more than 25,000 ceramic composite tiles. To line the shuttle with ceramic tiles was an incredible stroke of genius because if any of them got damaged, they could be easily replaced. In 1981, the first Space Shuttle successfully launches and returns. NASA enters a new age of satellite delivery. Four years later, the Large Space Telescope is completed, the most sophisticated optical satellite ever built. It's destined to change the way we look at the universe. And in honor of acclaimed 1920s astronomer Edwin Hubble, NASA christened it the Hubble Space Telescope. Hubble is scheduled to launch aboard the Space Shuttle. But before it can, after 24 successful flights, disaster strikes. We have main engine start, four, three, two, one, and liftoff. Challenger, go at throttle up. The lives of all seven crew are lost. Obviously a major malfunction. It would have had a horrific, I think, effect on anyone watching. These are people who know the people who are going up in the shuttle. These are people that have worked with them. They would have taken it very personally because A, it was their life work. B, they knew the people involved. And C, it was a failure that would have been reverberated throughout the world. It was a very public failure. OK, are there any forces headed out there? Yes, sir. DOD also reports that all soft forces have been scrambled in the area. It will be two years before the shuttle program resumes. In 1990, the Space Shuttle Discovery is ready for launch. Eventually, the Hubble Space Telescope gets its turn. There would have been a huge amount of trepidation at the launch, right? Just kind of that nervous energy. Because you remember what happened, the Challenger was only a few years before. That would have been very fresh in their minds. We are go for main engine start. T minus six, five, four, three, two, one. And liftoff of the Space Shuttle Discovery with the Hubble Space Telescope. To give Hubble the clearest view possible, the Space Shuttle Discovery has to launch higher than any shuttle mission before or since. Guidance officer confirms a good roll maneuver. Four years after the Challenger disaster, it must have been such an incredible relief to finally launch that Hubble Space Telescope. Discover Houston. You have a go to open the doors. At 600 kilometers above the Earth, Hubble is released. One of the most sophisticated satellites ever launched. And Hubble starts to return the clearest views of the universe ever seen. But for astronomers, one of the most incredible moments comes over Christmas 1995. Astronomers decide to point the Hubble Space Telescope at what they think to be a completely empty patch of sky. We're talking like a tiny, tiny little fraction of the whole sky. They come back 10 days later to find 3,000 galaxies. I mean, just think about that. You know, they thought there'd be nothing there, very little. It's the best Christmas present ever. For the first time, a telescope observes the stars without interference from the Earth's atmosphere. The Hubble Space Telescope changes our understanding of the universe. The images sent back of distant constellations are staggering and allow astronomers to see over 13 billion light years into the past. Because the speed of light is constant, this means that the further away you look, the further back in time you're looking. We were able to see the earliest images of the universe. We're able to look back and actually understand our cosmological history for the first time. And it blew the lid off of everything that we thought we understood about the universe. Satellites are helping us to understand our place in the universe, even discover distant planets. But they're also able to help us navigate our own planet. 31 satellites circling over 20,000 kilometers above the Earth constantly transmit their positions. Receivers on the ground use this information to pinpoint their precise location, creating what we know as GPS, the Global Positioning System. The GPS system means you can know where you are to an accuracy of centimeters no matter where you are on the globe. The GPS system has also transformed shipping and air travel. It's made it so much safer because we can always keep track on where planes are, even if they're out in the middle of the ocean. Satellites have given us global navigation and soon even access to information anywhere on Earth. Access to broadband requires a huge physical infrastructure. It's near impossible for users in remote areas to connect to it. But it could be possible to provide uninterrupted internet access to the entire planet. Not with land-based networks, but satellites. Elon Musk's SpaceX company is aiming to do just that. But it requires a radical new approach to the way satellites are used. You might think, OK, well, why don't we use these geostationary satellites that can see large swathes of the planet at a given time? You've got to remember that geostationary orbit is really far away and it takes those signals time to travel to the satellite and back again. You don't want that with your broadband. Elon Musk's solution is just to build a gigantic constellation of satellites in low Earth orbit that are going to be swarming around the planet at all times. The project is called Starlink, a constellation of 12,000 satellites circling in low Earth orbit. In order to get thousands of satellites into low Earth orbit, you need to be able to launch every one of those satellites as cheaply as possible. We don't throw away planes. We reuse those, so why don't we do exactly the same for space? They're using rockets that, rather than just being used once, are reusable. If you want to get a rocket that you've launched into space to come all the way back down to the ground, then you've got a very, very difficult problem on your hands. Firstly, you need to slow the rocket down. You've got to be able to reignite that booster. As you descend down, you're going from a hypersonic regime to a supersonic and then transonic, and then you want to get it to at least terminal velocity. But that's not enough. What you need to be able to do is guide that rocket into the right spot so it can land on a particular pad. Inevitably, there were some teething problems. But eventually, they perfected the technology. SpaceX have been using grid fins to guide the airflow around the rocket to subtly manoeuvre it in order to bring it down and land it vertically on a landing pad. It's just mad. The Falcon 9 is the first ever orbital-class rocket capable of reflight. In 2019, the first 60 of the proposed 12,000 satellites were successfully delivered into low Earth orbit. It's the most ambitious satellite program ever undertaken. Once in orbit, the constellation of satellites will allow fast broadband access to anywhere on the surface of the Earth. And satellites will soon be a regular feature around other worlds. Since 1998, the International Space Station has circled our planet in low Earth orbit. Crewed by astronauts from many countries, it serves as a research lab, allowing experiments to be conducted in microgravity. But now, NASA are looking to push the scientific boundaries further afield with the Gateway satellite, a crewed space station that will orbit the Moon. Gateway will allow astronauts to access the lunar surface to conduct scientific experiments. But NASA also hope to use the space station as a test bed for new technologies and life support systems for their ultimate goal, sending astronauts to Mars. It's the furthest from home anyone has ever traveled, and it will be thanks to satellites. It's amazing to think within 60 years, we've gone from not being able to put things in space to having the first satellites, to now our lives being, you know, almost entirely reliant on them. They enable us to make more accurate predictions of the weather and the climate. With the GPS global positioning system, we can navigate much, much more safely and effectively. And by placing satellites in space, astronomers can get the clearest views of the known universe. Satellites have literally changed the way we look at our own world and the way that we look at the universe beyond it.