What is happening on the ground at the exact moment in which astronaut Matt Kowalski dismisses the loss of “most” of Earth’s artificial satellites as a mere annoyance to social media users?

The physical likelihood of an instantaneous cascading debris crisis as presented in Gravity has been thoroughly challenged by scientists, astronauts, and even the film’s own science advisor. However, a different look at this unlikely scenario illustrates how much of our lives are tied to outer space—unseen and largely unexamined by most of us who use satellites on a daily basis.

If all the satellites circling the planet were to fall out of the sky in the span of minutes, as they do in Gravity, we’d have a much bigger problem than a Facebook outage on our hands.

The Omnipresence of GPS

Of the many satellites that enable modern global systems of commerce, communication, energy, and transit, we are particularly reliant on GPS satellites. A “constellation” of 32 radio transmitters 20,350 km away provides timing and location services free of cost, supporting countless technological practices big and small, local and international.

GPS doesn’t just feed your personal car navigation device. Everyday technologies that seem fully ground-based, such as ATMs and domestic cell phone networks, use GPS for time and location services. Large, geographically distributed information systems require exact timing for synchronized, rapid data exchange and prevention of fraud, misdirection, and gaps in service. Cell phone towers coordinate calls using GPS, and many ATMs timestamp withdrawal information using either onboard GPS devices or connections to GPS-enabled networks, allowing banks to keep tabs on the flow of cash. (Time must be disseminated.)

The nation’s energy network depends on GPS for precise time and position data in the distribution of power from plants to the grid. Transportation systems from passenger trains to ocean freighters make use of the same services to move people and goods across vast distances on strict timetables. Facilitated by GPS, these distribution networks have grown in reach and load, achieving precision on the order of nanoseconds in the coordinated movement of massive quantities of information and material.

Anyone who has taken a flight through a major airport has seen first-hand how satellites have helped some industries field larger and larger loads. GPS has been deeply embedded in civil aviation, beyond navigation alone. While pilots and controllers use point-to-point radio to communicate, GPS keeps the messages moving and organized at most large airports. With the next generation system of civil aviation (“NextGen”) currently rolling out, GPS will replace radar as the main mechanism by which pilots and controllers know where airplanes are, both in the air and on the ground.