When the GPS signals stopped, back-up systems (employing accurate clocks on the ground) kicked in. But, within a few hours, time had started to slip. A fraction of a second in Europe, compared to the US; a tiny difference between India and Australia. The cloud began to fail, web searches became slower, the internet started to grind to a halt. The first power cuts came later in the evening, as transmission networks struggled to balance demand. At computerised water treatment works, engineers switched to manual back-up systems. In major cities, traffic lights and railway signals defaulted to red, bringing transport to a standstill. Mobile phone services, already patchy, finally failed in the late afternoon.
By this time, aviation authorities reluctantly decided to ground commercial aircraft. The loss of satellite communications and GPS had already seen a majority of flights cancelled, but it was a more mundane failure that proved to be the final straw: the weather.
Although meteorological balloons, ground and ship observations were still important, forecasting had become increasingly reliable and reliant on satellites. Retailers used weather data to order the right foods – no point in stocking up on meats for the barbeque if the outlook was gloomy. Farmers relied on forecasts for planting, spraying and harvesting. The aviation industry needed forecasts to make decisions that would affect the lives of passengers.
Aircraft are fitted with radar to detect bad weather or other sources of turbulence, but they take note of constant updates from the ground. These “nowcasts” allow them to keep track of weather patterns developing and act accordingly. These are particularly important over the oceans, where observations from ships are sparse.
If passengers on trans-Atlantic flights had known this, then they would have thought twice before boarding. Without weather satellite data, a storm system developing rapidly over the ocean was missed and the aircraft flew straight into it. The severe turbulence experienced by passengers left several injured and the remainder badly traumatised by the experience. But at least they got to complete their journey. Around the world, other travellers were stranded thousands of miles from home.
By now, the full impact of what would become known as “the day without satellites” had become apparent. Communications, transport, power and computer systems had been severely disrupted. Global business had ground to a halt and governments were struggling to cope. Politicians were warned that food supply chains would soon break down. With fears of a breakdown in public order, governments introduced emergency measures.
If the disruption continued then each day would bring new challenges. There would be no more satellite data showing the health of crops, illegal logging in the Amazon or Arctic ice cover. Satellites used to produce images and maps for rescue workers responding to disasters would be missed, as would the satellites producing long-term records of climate. It was a tribute to the space industry that we could take all this for granted, but it was only when the satellites were lost that anyone noticed…
So, could all this happen? Only if everything failed at once, and that is unlikely. What is certain is that the infrastructure we all rely on has become increasingly dependent on space technology. And that without satellites, the world would be a very different place.