Satellites are in space because they can do things up there that are impossible from the ground. Orbiting above Earth’s atmosphere, they relay communications across continents, pinpoint your location, track storms, monitor the environment, peer deep into the universe, and support national defense. As of early 2025, roughly 14,200 functioning satellites circle the planet, with thousands more launched each year as demand for space-based services grows.
The Cold War Started It All
The first artificial satellite, Sputnik-1, launched on October 4, 1957. It weighed 184 pounds, transmitted a simple radio signal, and changed the world. The Soviet Union put it in orbit partly to fulfill a goal set by the International Council of Scientific Unions, which had called for satellite launches during 1957 and 1958. But the real fuel was geopolitical rivalry. The United States had expected to reach orbit first, and Sputnik’s success triggered widespread fear that American technology had fallen behind. The Soviets tested the first intercontinental ballistic missile that same year, compounding the alarm.
The result was a rapid acceleration of space and weapons programs on both sides. Within a few years, satellites evolved from symbolic Cold War trophies into genuinely useful tools, and every major application we rely on today traces back to that initial push.
Global Communications
One of the earliest practical uses for satellites was relaying signals. A satellite in geostationary orbit, about 22,236 miles above the equator, stays fixed over one spot on Earth. It receives a signal from a ground station on one frequency, then retransmits it on a different frequency to another station thousands of miles away. This “bent-pipe” relay makes it possible to send television broadcasts, phone calls, and data across oceans and between continents without running cables across every stretch of terrain.
Today, roughly 800 satellites occupy geostationary orbit. They serve broadcast television, maritime communications, aviation links, and emergency services in areas where ground infrastructure doesn’t reach. Without them, live international news coverage, transoceanic phone service, and connectivity for ships and aircraft would look very different.
Satellite Internet and the Digital Divide
Traditional internet satellites sit in geostationary orbit, which means signals travel a long round trip. That distance creates noticeable lag. Newer constellations operate in low Earth orbit (LEO), typically between a few hundred and 2,000 kilometers up. Because they’re so much closer, they can deliver speeds approaching fiber-optic connections with significantly lower latency.
LEO satellite internet became commercially available to consumers in recent years, and it holds particular promise for rural and remote communities where laying fiber or cable is prohibitively expensive. The majority of satellites now orbiting Earth sit in LEO: nearly 14,900 payloads occupy that region, many of them belonging to broadband constellations.
Navigation and GPS
Your phone’s ability to pinpoint your location relies on a constellation of 31 GPS satellites. Each one carries an atomic clock and continuously broadcasts a time-stamped signal. Your receiver picks up signals from at least four of these satellites simultaneously and calculates how far away each one is based on how long the signal took to arrive. From those four distances, it works out your latitude, longitude, altitude, and the exact time.
GPS underpins far more than turn-by-turn driving directions. It synchronizes financial transactions, coordinates emergency response, supports agriculture with precision planting, and keeps air traffic safely separated. Other countries operate their own navigation constellations for the same reasons.
Weather Forecasting
Weather satellites come in two main flavors. Geostationary weather satellites hover over one hemisphere and take continuous images, tracking storm development in near real time. Polar-orbiting satellites circle from pole to pole, scanning the entire Earth as it rotates beneath them. They collect temperature and moisture readings at different altitudes, providing the detailed atmospheric profiles that feed forecast models.
Together, these satellites supply data on cloud patterns, lightning activity, ocean surface temperatures, and atmospheric moisture. That information feeds into the forecasts you check on your phone and, more critically, powers the early warnings that give communities time to prepare for hurricanes, floods, and severe storms.
Monitoring the Environment
Since the first Earth-observation satellite launched in 1972, scientists have used orbiting sensors to map and measure the planet’s surface. Satellites now track deforestation, measure sea-level changes, map flood plains, monitor urban expansion, and assess crop health. Some estimate how much water crops need by comparing rainfall data with evaporation rates, providing early warning when growing conditions deteriorate.
This kind of monitoring is only practical from orbit. No network of ground stations could cover every forest, coastline, and farmland on Earth with the same consistency. Satellites provide a repeated, standardized view of the whole planet, making it possible to spot trends over months or decades that would be invisible from the surface.
Exploring the Universe
Earth’s atmosphere is essential for life, but it’s a problem for astronomy. Shifting pockets of air make stars twinkle and blur telescope images. The atmosphere also blocks entire wavelengths of light, including parts of the ultraviolet and infrared spectrum that carry valuable information about distant objects.
Orbiting 300 miles above the surface, the Hubble Space Telescope avoids all of this. It operates in a permanent, clear dark sky with no weather interference and no light pollution. The result is a telescope that can see objects 10 times fainter than the largest ground-based observatories and capture sharp images across ultraviolet, visible, and near-infrared wavelengths. The James Webb Space Telescope pushes even further into the infrared, observing galaxies that formed in the early universe. These observations simply cannot be made from the ground.
National Security
Military satellites perform functions that directly affect global stability. They provide secure communications for troops deployed worldwide, detect missile launches within seconds, deliver precise navigation and timing for operations, and collect intelligence through surveillance imaging. Environmental monitoring satellites also serve defense purposes, giving military planners detailed weather and terrain data.
Some of these roles carry enormous strategic weight. Missile-warning satellites, for instance, are considered so critical that interfering with them could be interpreted as a prelude to a nuclear strike. That norm dates back to the Cold War and remains a cornerstone of deterrence today.
What Happens When Satellites Stop Working
With nearly 17,000 payloads in orbit and thousands of defunct objects alongside them, space debris is a growing concern. International guidelines established through the United Nations call for satellites in low Earth orbit to be removed within 25 years of completing their mission, either by letting them gradually descend and burn up in the atmosphere or by boosting them into a “graveyard” orbit away from active satellites. In 2022, the FCC tightened this timeline to just five years after launch for satellites it licenses, and the World Economic Forum issued similar recommendations in 2023.
Satellites can deorbit passively, using drag sails or electromagnetic tethers that increase atmospheric resistance and pull them down naturally. Active methods use onboard thrusters to lower the orbit deliberately. Some orbits are naturally short-lived, decaying on their own within a few years. Managing this end-of-life process is becoming as important as the launches themselves, because a cluttered orbit threatens the very satellites everyone depends on.