First GPS Satellite Launched
The US launched the first operational GPS satellite, beginning the global navigation system
February 22, 1978
Navigation Goes to Space
The Global Positioning System traces its origins to the late 1950s, when U.S. scientists tracking Sputnik realized they could determine its position precisely by measuring changes in its radio signal frequency. The U.S. military began developing a satellite-based navigation system in the 1970s. The first GPS satellite — Block I Satellite Vehicle 1 — was launched on February 22, 1978, from Vandenberg Air Force Base in California. It was the first step in building a constellation of satellites that would eventually give anyone on Earth the ability to determine their precise location at any time in any weather.
Building the Constellation
A fully operational GPS system requires at least 24 satellites in orbit to ensure coverage across the entire Earth at all times. Building the constellation took over a decade. The system was declared fully operational by the U.S. military in 1995. Initially, civilian GPS signals were intentionally degraded — a practice called Selective Availability — to prevent adversaries from using precise GPS for military purposes. In May 2000, President Clinton ordered Selective Availability turned off permanently, instantly improving civilian GPS accuracy from about 100 meters to roughly 10 meters or better.
A Technology That Changed Everything
GPS has transformed navigation, logistics, agriculture, surveying, finance, and military operations in ways its creators could not have fully imagined. Farmers use GPS-guided tractors that plant crops with centimeter precision. Shipping companies track fleets in real time. Smartphones navigate turn by turn. Financial networks use GPS timestamps to synchronize transactions globally. Emergency services locate callers to within meters. Today multiple satellite navigation systems exist — Europe's Galileo, Russia's GLONASS, and China's BeiDou — all building on the concept launched with that first GPS satellite in 1978. Use the countdown tool to mark GPS milestones.