Often we don't realize how much we depend on the satellites that orbit the planet Earth. But what would it look like if we lost all contact with the satellites?

At a recent international conference on "space risks", I heard a number of speakers outlining the situation. It was a massive solar storm disrupting satellite communications, a cyber attack partially deactivating the GPS system, and debris colliding with satellites monitoring the Earth.

The threats to this space infrastructure are real, and governments around the world are beginning to think seriously about improving the resilience of the systems we rely on. To better imagine this problem, here is a possible scenario of what would happen if a day without Staelites suddenly occurred.

08:00

Nothing sudden happened. The planes did not begin to fall from the sky, the lights did not stop, and the water supply failed. At least for now. Some things stopped working suddenly, but for most people it was only a small inconvenience, nothing fundamental. The loss of television satellites meant that countless families missed the cheerful smiles of the morning presenters and were forced to talk to each other instead of routine routines. There was no foreign news on the radio, nor were the results of the latest international sports matches.

Externally, however, the loss of satellite communications posed a danger. In a bunker, somewhere in the United States, the pilot squadron lost contact with armed drones flying over the Middle East. The loss of secure satellite communications cut off soldiers, ships and the air force from command, leaving them defenseless against attack. Without satellites, it was almost impossible for world leaders to communicate with each other without spreading global tensions.

Meanwhile, across the Atlantic, thousands of calm passengers watched their films without perceiving the pilot's difficulty in communicating with air traffic control. Without satellite phones, cargo ships in the Arctic, fishermen in the China Sea, and medical workers in the Sahara found themselves isolated from the rest of the world.

It was difficult for employees of offices in Tokyo, Shanghai, Moscow, London and New York to contact their coworkers from other countries. E-mail and the Internet seemed to be fine, but many international calls failed. The fast communications systems that held the world together have crumbled. Instead of the appearance of the rapprochement of the world, it seemed that people were far farther than they were before.

11:00

There was a loss of GPS on the surface. Most of us GPS helped get from A to B without getting lost. It has changed the lives of delivery companies, helped emergency services to be faster on the scene, allowed aircraft to land on isolated runways, and allowed tracking, tracing, and tracking of trucks, trains, ships and cars. However, GPS has been shown to play a much larger role in our lives than many of us have realized.

GPS satellites are something like a high-precision atomic clock in space that sends a time signal back to Earth. Ground-based receivers (in your car or smartphone) pick up these time signals from three or more satellites. By comparing the time signal from space with the time in the receiver, the receiver is able to calculate how far it is from the satellite.

However, there are many other uses for these accurate time signals from space. As it turned out, our society is increasingly dependent on them. Our infrastructure holds together over time (from timestamps to financial transactions to protocols that hold the Internet together). Once data-to-computer synchronization stops working, the entire system crashes. Without precise time, every computer-controlled network is compromised. Which means almost everyone these days.

When GPS signals were interrupted, backup systems using accurate earth clocks were thrown. Within a few hours, however, the difference began to increase. A fraction of a second between Europe and the USA, a slight difference between India and Australia. The cloud began to fall apart, search engines were slower, and the Internet began to work halfway. The first major constraints came in the evening as transmission networks struggled to match demand. Computer-controlled water treatment has been switched by engineers to manual backup systems. In most cities, traffic has slowed down due to non-functioning traffic lights and train signals. The already chaotic telephone services, later in the afternoon, were completely dropped.

16:00

At this time, the aviation authorities reluctantly decided to stop air travel. Due to the loss of satellite communication and GPS, it was necessary to cancel most flights, but the last straw turned out to be the weather.

Despite meteorological balloons and ground or water observatories, which are very important, the weather forecast has become more dependent on satellites. Retailers used forecast data to order the right meal (buying outdoor barbecue supplies lost meaning if the forecast said cloudy). Farmers relied on the weather forecast for planting, watering and harvesting. In the aviation industry, weather forecasts were needed to make decisions that could affect the lives of passengers.

The planes are equipped with radar to detect bad weather or other sources of turbulence, but they are constantly gaining new information from the ground. These constant forecasts allow them to monitor weather developments and act accordingly. This is especially important when traveling over the oceans, where these observatories on ships are very scattered.

If passengers on the ocean flights had understood this, they would probably have changed their minds about boarding the plane. Without data from satellites that monitor the weather, no storm clouds were rapidly forming over the ocean and the plane flew directly into it. The turbulence injured several passengers and left the rest a traumatic experience. Eventually, however, they completed their journey. In the world, other passengers have been forced to stay thousands of miles from home.

22:00

Now the full range of what would be known as a "day without satellites" has come to light. Communications, transport, energy and computer systems have been severely disrupted. The world economy has collapsed and governments have struggled to make up for it. Politicians have been warned that food supply chains will soon fall apart. Concerned about public order, the government was forced to introduce emergency measures.

If this collision continued, it would bring new challenges every day. There would be no satellites to show the amount of crop, illegal logging into Amazon, or the polar ice sheet. The satellites used to create images and maps for rescuers heading to disaster areas would not exist, as would satellites producing long-term climate records. We took all this for granted until we lost the satellites.

Could all this really happen? Only if everything failed at once, and that is very unlikely. What is certain, however, is that the infrastructure we all rely on has become very dependent on space technology. Without satellites, Earth would be a completely different place.