On this day 60 years ago, America became the second country to send a human-made object into low-Earth orbit, with the successful launch of its first satellite – Explorer 1. The launch of Explorer 1 took place against the backdrop of the Cold War between the United States and its adversary, the Soviet Union, which had shocked the world by launching Sputnik 1 into orbit in October of 1957.
Space exploration has come a long way. Today, the exploration of the space environment is, at least in certain respects, considered to be an area of international cooperation, but it was once an arena of fierce technological competition, with the pride of entire nations hanging in the balance. The USSR had drawn first blood in the space race with the launch of the Sputnik 1 and Sputnik 2 orbiters. The US, fearing in part Russian dominance of space, responded less than four months after the initial Soviet success with the launch of Explorer 1, which was destined to be blasted into orbit atop a converted ballistic missile.
Personnel at NASA's Jet Propulsion Laboratory (JPL) working under the leadership of Dr. William H. Pickering built the Explorer 1 probe in less than three months, as the science payload was being developed by physicist Dr. James Van Allen, who was at the time working at the University of Iowa.
Explorer 1's main scientific instrument was a cosmic ray detector tasked with observing the radiation environment in near-Earth space. The satellite also played host to an array of temperature sensors, and equipment designed to record the number of collisions with tiny micrometeorites. This data was transmitted back to Earth with the help of four whip antennas that formed a single turnstile antenna, and a further two transmitters mounted on the body of the spacecraft.
In order to get the satellite into orbit, NASA relied on a Jupiter-C rocket. The Jupiter-C launcher was essentially a conversion of the Redstone ballistic missile – a direct descendent of the German V-2 rocket. Both the Redstone and its predecessor, the V-2, were the work of Dr. Wernher von Braun – the father of modern-day rocketry who had been brought over from Germany to the US in 1945 as part of Operation Paperclip.
At 10:48 p.m. EST on January 31, 1958, the 71 ft (22 m)-tall Jupiter-C rocket blasted off from Cape Canaveral, Florida, carrying Explorer 1, and America, into the space age.
The satellite traveled around Earth in a highly eccentric orbit, with its distance from Earth's surface ranging from 354 km (220 miles) to 2,515 km (1,563 miles). Explorer 1 made 12 full orbits of Earth every day at a rate of one per 114.8 minutes, and spun around its long axis 750 times per minute, forcing the whip-antenna to remain fully extended.
America's first space probe was soon joined by a second satellite, Explorer 3 (following the failed launch of Explorer 2). Together, the pair collected data that led to the ground-breaking discovery of the Van Allen Belts – two (and sometimes more) donut-shaped radiation belts formed from charged particles that emanated from the Sun, and were subsequently trapped by our planet's magnetic field.
The final transmission from Explorer 1 was received on May 23, 1958, after which the probe fell silent, its batteries depleted. On March 31, 1970, the third satellite to be launched into space burned up in Earth's atmosphere, having completed an impressive 58,376 laps of the blue marble.
Explorer 1 now has a place in history alongside the Sputnik orbiters (pictured above) as the starting point for an incredible journey that set humanity on a course to explore the solar system, and to better understand our place in the universe.
Since the advent of the space age just a little over six decades ago, humanity has set foot on the Moon, sent probes to orbit nearly every planet in the solar system, explored fascinating natural satellites, visited an asteroid, and set up a crewed habitat in low-Earth orbit, just to name a few highlights.
Along the way, the scientists and engineers that made space exploration a reality have invented incredible, revolutionary technologies that have transformed how we live our lives back on Earth. Once again, it has been just a little over six decades since our species went orbital. Who knows where we could be in another 60 years?
Scroll down to see a vintage, 1958 television report from the United States Army recounting the story of Explorer 1.
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