Jan 30, 2018

America's Debut in Space: Explorer 1

Sixty years ago, on January 31, 1958, the United States joined the "space race" with the successful launch of the Explorer 1 satellite. But the event was much more than a rocket launch. 


Geopolitically, it leveled the Cold War playing field with the Soviet Union, which had sent Sputnik into orbit four months earlier. Scientifically, the launch of Explorer 1 represented the first time humans sent instruments into space ― including a modified Geiger counter for tracking radiation ― to collect data and relay it back to Earth. And historically, it led us into an infinite new frontier that has yielded data, images, and wonders never before imagined.

University of Iowa physicist James Van Allen, who designed and ran the science experiment on Explorer 1 and experiments on myriad subsequent missions, called the event "one of the landmarks in the technical and scientific history of the human race." He continued: "Its instrumentation revealed the existence of radiation belts of the Earth and opened up a massive new field of scientific exploration in space. It inspired an entire generation of young men and women in the United States to higher achievement and propelled the Western world into the space age."

Jim Green, NASA's Planetary Science Director, was among those who were inspired, as a student and protégé of Van Allen's at Iowa. Green says, "Dr. Van Allen was a pioneer of the space age, and the results from his Explorer 1 instrument marked the birth of space science. The discovery of the radiation belts encircling the Earth was a game changer for space exploration. Space was no longer thought to be empty, and for that the man and the mission will long be remembered."

Spacecraft en route to Earth orbit or deep space must dash through the Van Allen belts, donut-shaped regions of charged particles trapped by Earth's magnetic field. The high-energy particles can batter spacecraft and even interfere with onboard instruments. To ensure the safety and health of astronauts and space science missions, scientists have been uncovering vital information about the radiation belts ever since Explorer 1 discovered them. 

In a speech at Cornell University on March 3, 1965, then-NASA Administrator James Webb explained the critical importance of success in the vast new horizon of space: "...the mastery of a new environment, or of a major new technology, or the combination of the two as we now see in space, has always in the past had the most profound effects on all nations and on all the peoples of the Earth. ...In the modern world, basic knowledge, applied through technology, is a source of national power." 

Former NASA Chief Historian Steven Dick summarized the impact of Explorer 1's launch: "One could hardly have known what this singular event would set off during the next 60 years. …. Like the railroad and the airplane, spaceflight has impacted society in ways even the visionaries could not have foreseen, and that we cannot fully fathom even today."

The drive for discovery that enabled the success of Explorer 1 endures today at NASA. The Agency's innovative spacecraft continue to find new ways to observe and understand the interconnected systems of our home planet as well as help us see beyond our solar system into worlds we can explore as one.

For more on amazing advancements in space science, visit