PHOTO: NASA

The Explorer-I satellite rises from a launchpad at Cape Canaveral Air Force Station, in Florida, atop a Juno rocket late in the evening of 31 January 1958.

Fifty years ago, the United States became a space-faring nation. On 31 January 1958, the U.S. Army launched a civilian satellite into Earth’s orbit from a research facility at Cape Canaveral, in Florida. It was broadcast live by international television networks. It was the first time most of the world had ever witnessed a spaceflight. And it set into motion a series of events that history has said led to the greatest accomplishment the human race has ever achieved: the Apollo moon landing. Few of the players in this achievement remain to bear witness to its significance, but those who remember know that they accomplished a practical miracle.

The historic flight of Explorer-I was the result of missed opportunities by the U.S. government to put a scientific satellite into orbit during the first International Geophysical Year of 1957, to study conditions beyond the Earth’s atmosphere. The distinction of being first to do so fell to the Soviet Union with the launch of Sputnik I in October of that year. Months prior to Sputnik, U.S. President Dwight D. Eisenhower, acutely aware of international concern over the development of rockets capable of delivering nuclear weapons in the chilly days of the Cold War, insisted to his advisers that America’s initial foray into space be a civilian project.

While the nation’s military had multistage rockets capable of reaching space by the 1950s, interservice rivalries compounded the problem of which branch should take the lead in building the scientific project. Building the satellite meant much less to each branch than perfecting a thermonuclear missile with global capability as a weapon. Thus, the United States dithered as the Soviets marched ahead without compunction. The civilian job was turned over to the Navy in 1955, which dubbed it Project Vanguard, and the organization contracted out its full construction to private organizations. On its first test flight, two months after the launch of Sputnik I, the Vanguard rocket exploded on the launchpad as millions watched on live television. The malfunction was a public embarrassment for all concerned. Still, the project broke the military-civilian logjam.

In Huntsville, Ala., a group of engineers largely composed of German expatriates from the Nazi V-2 effort of World War II, were pressing ahead on advanced rocketry for the Army Ballistic Missile Agency (ABMA) under the leadership of Wernher von Braun. They had arrived in the United States as the war was ending via a secret plan known as Operation Paperclip. Their new task was to expand on their groundbreaking work, and to design and build iteratively more-powerful launch vehicles. Shuttled from Texas to Alabama in the 1950s, the group was so prized by the Army that they were given the lead in developing its long-range missiles. After the Vanguard disaster, the Eisenhower administration turned to them to proceed with von Braun’s plan to quickly assemble a three-stage hybrid rocket that could be fast-tracked to the launchpad, where it would power a small scientific satellite into orbit.

Operating within a time frame of weeks, rather than years, of preparation, the von Braun team coordinated efforts with the government’s Jet Propulsion Laboratory (JPL), in California, to swiftly and efficiently assemble a launch vehicle and payload. The ABMA manufactured a rocket based on its Jupiter-C intermediate-range ballistic missile; the JPL made a tiny rocket—Explorer—to sit on its tip, which would carry a built-in set of instruments (designed by famed scientists James Van Allen and George Ludwig) to measure radiation to orbital altitude. Both organizations met their hurried schedules. They called their joint creation the Juno I.

On 29 January 1958, the vehicle was readied on pad LC26 at Cape Canaveral, but weather prevented its launch for two days. At 10:46 p.m. (EST) on the 31st, though, conditions had cleared and the Juno’s main stage was ignited. The rocket ascended exactly as planned. Its radio signals checked in perfectly at first. Then its tracking stations lost communications. Explorer-I had either malfunctioned, or its trajectory had been miscalculated. Waiting in Washington, D.C., with other leaders of the project, von Braun grew anxious when the satellite’s signature could not be heard by the JPL team on the West Coast as predicted. After several long minutes passed, its beeping signal was detected in Pasadena. The delay had been caused, ironically, by a JPL math error. Explorer was circling the Earth. Its creators exulted. President Eisenhower delivered the news himself to a jubilant nation. And the Space Race was on.