Humanity has always looked to the skies and wondered what lays beyond. Some believed that the gods resided there, while ancient astronomers observed the movement of the stars. The human need to explore the Sun, moon, planets and stars is evident in ancient civilizations like the Mayans and Ancient Egyptians. The Sun has been central in human history, and has played a major role not only in religious practices of indigenous people, but also art, culture and more.
The secrets of space have always fascinated us and sparked the imaginations of many, from authors to scientists and casual observers. Dreams of leaving our small planet and establishing our presence across the Solar System, meeting extraterrestrial life and learning the secrets of our universe are set in the mind of humanity.
Space travel is the most exciting and challenging adventure that we have ever embarked on. However, as irony would have it, the more we go into space may soon become the very reason why we cannot venture into the depths of space. Every rocket we launch and every satellite we deploy, we are creating a trap that becomes more dangerous and deadlier every year. Getting to space is already an expensive and difficult ordeal, but if the trap were to be triggered, the Space Age as we know it may be over for decades ahead, or even centuries.
Getting Stuff to Space is Hard
Officially you enter space at 100 km (≈ 62 mi) above the earth’s surface. The gases that make up the atmosphere, which keeps us safe from the dangers of space, thin rapidly the higher you go. At a height of 11 km (≈ 7 mi) you would have passed 77.5 percent of the Earth’s atmosphere and at 31 km (≈ 19 mi), 99 percent is behind you. This presents one of the challenges because a lot of energy is needed to overcome the air resistance that our atmosphere provides.
Getting something into space is also made incredibly hard because of Earth’s gravity. Even at a height of 1,000 km (≈ 621 mi) an item with a mass of 10 kg (≈ 22 lbs) only loses a quarter of its value.
Image Credit: NASA/Bill Ingalls
Both air resistance and gravity require the rockets that we use to get into space to go very fast. For example, to reach the International Space Station, which orbits Earth at a height of 360 km (≈ 224 mi), rockets need to reach a speed of 28,000 km/h (≈ 17,400 mph). To escape our planets gravity and travel to the moon or other planets, rockets need to reach a much higher speed of 40,000 km/h (≈ 25,000 mph).
So getting to space first requires you to move very fast, at first straight up to leave the atmosphere. Then, your spaceship tilts sideways, to begin a sort of circling around the earth. At this stage you are falling towards our planet, but at such an angle that you miss the planet and enter a Low Earth orbit.
The cost of getting a kilogram to space varies between private companies like SpaceX and government agencies like NASA, because of special mission requirements. It costs NASA on average $23,750 per kilogram (≈ 2.2 lbs), where SpaceX’s price per kilogram is around $6,078, with prices in the private space travel sector expected to fall further.
Once in orbit it’s very difficult to break from it, and unless you have energy to spare, you are locked in the fate of constantly falling around the planet for a very long time. This is extremely useful for things that we want to stay up there, like the ISS and satellites. Low Earth orbit holds the majority of our space infrastructure — just a few hundred kilometers above the surface. A height, in which the atmosphere is thin enough to keep things there for centuries, before air resistance can slow them down enough to bring them back to Earth.
The Source of our Deadly Trap
Rockets are just huge metal cylinders that keep big parts of fuel in place. Whenever a portion of the fuel has been spent, the empty tanks are dropped to make the rocket lighter — thanks gravity. Some parts fall down to earth or burn up in our atmosphere. However, a lot of the now completely useless rocket parts stay up and start their eternal dance of missing the earth.
For decades we have been sending rockets in space, which have littered Low Earth orbit with vast amounts of spent boosters, broken satellites and millions of pieces of shrapnel from missile tests and explosions, turning it into a junkyard.
As you are reading this, there are currently around 2,600 defunct satellites, 10,000 objects that are bigger than a computer screen, 20,000 that are the size of an apple, half a million the size of a marble and at least 100 million parts that are so small that they cannot be tracked. All of these debris are moving at speeds of up to 30,000 km/h (≈ 18,000 mph), circling around our planet, criss crossing orbits multiple times daily.
The ridiculously high speeds at which each of these pieces of junk are hurling around the earth, mean that being hit by a piece the size of a pea is similar to being shot by a plasma gun. On impact the debris vaporizes and releases enough energy to punch holes straight through solid metal. Even tiny flecks of paint can cause significant damage when traveling at these speeds.
— Tim Peake (@astro_timpeake) 12 май 2016 г.
Astronaut Time Peak tweeted an image in 2016 in which a 7mm-diameter circular chip was gouged out by the impact from a tiny piece of space debris. The European Space Agency said that it was “possibly a paint flake or small metal fragment no bigger than a few thousandths of a millimetre across.”
Through our decades of space flight we have covered the space around our planet with millions of deadly pieces of destruction that put our trillion dollar global infrastructure network in a dangerous position. We rely on it to perform many essential duties of our modern world — from global communication, GPS and navigation, collecting weather data, looking for asteroids and all types of scientific discoveries. All things we have come to love and rely on, which we will miss dearly if they suddenly went away (just ask your parents about having to use physical maps when on a road trip).
However, if even one pea sized bullet hits one of our active 1,957 working satellites, it will be destroyed instantly.
“The space junk problem has been getting worse every year,” Ben Greene, head of Australia’s Space Environment Research Centre in Canberra, told AFP.
“We’re losing three or four satellites a year now to space debris collision. We’re very close, NASA estimates, of within five to 10 years of losing everything,” said Greene.
As the number of satellites and the amount of junk we are creating in orbit is expected to grow tenfold over the coming decade, we are approaching a tipping point. The worst thing in space aren’t the tiny pieces of junk, but as Greene puts it “a catastrophic avalanche of collisions which could quickly destroy all orbiting satellites is now possible.”
If two satellites collide with each other, they won’t stop and fall out of the sky. Orbital speeds are so high that solid pieces spray right through each other, transforming the two satellites into clouds of thousands of small debris, still moving at a speed high enough to destroy more satellites. This could trigger the slowest and most destructive game of domino. As a shotgun spray, each collision will create more bullets, and what was a single tiny target that was unlikely to hit anything, grows into a wall of destruction that snowballs around the earth. With more satellites being consumed by this cloud of debris, the destruction will accelerate exponentially. Eventually it will consume everything that we have in orbit.
Because space if very empty, the first few collisions can take a long time and by the time we realize what’s happening, it will be too late. It could be one year we lose one satellite and that won’t be a big deal. The next we could lose five, and the year after it could be 50, until there is nothing left.
The situation around our planet is worsening and it might be possible that we are already past the point of no return. In the coming decades, the space around Earth may no longer be viable for long term satellites or rockets.
The worst case scenario is horrifying, as a debris field of hundreds of millions of pieces, many too small to track, moving at high speeds could create a deadly barrier around earth that may be too dangerous for us to cross. Our dreams of creating moon bases, colonizing Mars or space travel can be set back decades, if not centuries. If our space infrastructure is destroyed, some of our technology, on which we rely daily, can be sent back to the 1970s.
However, it might not be too late to clean up our mess. Although, the space industry has become better at avoiding space junk, and reusable rockets like SpaceX’s Falcon 9 limit the amount of debris we are creating, the industry is rapidly expanding and occasional weapon tests limit the reduction.
Seriously Wild Sci-Fi Solutions
There have been a couple of crazy, but serious suggestions on how we can quickly remove as much of the deadly junk in space as possible, without creating more in the process.
A lot of ideas are being considered, but some of the most seriously looked at involve capture and return missions, which are currently being tested.
One of the methods proposed is meeting a piece of junk in orbit with a small satellite that is loaded with a net. Once caught a small rocket could be used to bring it down towards Earth. In September 2018, a British satellite developed at the Surrey Space Centre, known as the RemoveDEBRIS satellite, successfully ensnared a simulated piece of junk in orbit using a big net. It deployed its onboard net, which then captured a nearby target probe that the vehicle had released a few seconds earlier. The success shows that the simple idea can be an effective way to clean up the junk orbiting our planet.
If the targeted material is too big for a net, it might instead be caught with a harpoon on a tether, and instead of using rockets to bring it down to Earth, it would deploy a large sail to produce atmospheric drag and accelerate orbital decay. The RemoveDEBRIS satellite will also be testing this sometime in the near future. The harpoon tether approach is also being tested by Airbus.
There are also other sci-fi sounding proposals too. One is the use of giant electromagnets, which will work by pushing on the magnetic components inside the satellites, which they use to stabilize and orientate themselves in Earth’s magnetic field. This may be safer and more reliable than nets and harpoons, because there is no direct contact with the junk that is being handled. So the risk of accidentally breaking up the target into more junk is nonexistent.
For the smallest pieces of junk, lasers could be used to vaporize them entirely. Satellites with lasers wouldn’t need to visit their targets and can shoot them from far away, lowering the risk of creating more debris.
Although large objects can’t exactly be shot down, lasers can be used to burn tiny amounts of material off to push the junk to a safer orbit, or one that will bring it down to Earth.
The laser idea is being explored by an international research project from Japan and Australia. They proposed an ion beam shepherd (IBS), a still-hypothetical contactless approach that was originally designed for asteroid deflection.
“If the debris removal can be performed by a single high-power propulsion system, it will be of significant use for future space activity,” said Kazunori Takahashi, Associate Professor from Tohoku University in Japan, in a press release.
Whatever technology we use in the end doesn’t matter unless we start doing something soon. Space won’t wait for us and in the blink of an eye a 100 million debris can become a trillion and the trap will be set. If we don’t act our space adventure will end before it has even began, and our dreams of colonizing the universe will remain just that — dreams.
Originally published at perfectly-plain.com on February 25, 2019.