A Rocket Scientist Recalls the First U.S. Spaceflight

A pioneer of the U.S. space program looks back at its first success 50 years ago

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.

A Rocket Man Remembers

Among those cheering hardest was a member of von Braun’s original team of rocket scientists, Konrad Dannenberg, a specialist in propulsion systems. Dannenberg, now 95, had grown up with a passion for engineering in the city of Hannover, Germany, where he studied at its historic university. His first research focused on fuel-injection engines. In his spare time, he participated in one of the amateur rocketry clubs that had sprung up across the country in the 1930s. When war broke out in 1939, he was drafted for combat and took part in the Battle of France. His background, though, soon led to his transfer to the German Army’s Research Center at Peenemünde as a civilian adviser on the infamous V-2 missile program.

Photo: Konrad Dannenberg

Konrad Dannenberg served as a senior manager on the Jupiter missile project for the Army Ballistic Missile Agency. His rocket powered the Explorer-I satellite into space.

Dannenberg was a member of the Operation Paperclip detachment by war’s end. Before long, the U.S. military had employed him as a research scientist and had granted him citizenship with full top-secret clearance to work on its most advanced weapon systems. When Explorer-I lifted off in 1958, Dannenberg was a principal intermediary between von Braun’s team at the ABMA and contracted companies working on components for one of the nation’s first intercontinental ballistic missiles (ICBMs).

With the success of Explorer and Juno , Dannenberg’s responsibilities grew. He became a pioneering leader of the National Aeronautics and Space Administration (NASA), where he was named deputy manager of the Saturn rocket project in 1960. Under his leadership, the new Marshall Space Flight Center in Huntsville designed and built the rockets that first sent Americans into space and eventually took them to the moon.

He retired from NASA in 1973 and accepted a teaching position in aerospace engineering at the University of Tennessee Space Institute. An honored alumnus of the U.S. space program, Dannenberg is one of today’s most sought after commentators on rocketry and space exploration, especially in regard to their formative years.

This publication caught up with him last week on the eve of the 50th anniversary of the Explorer-I launch. Here is what he had to say.

Spectrum: What was the reaction at the ABMA in Huntsville after Sputnik and the failure of Vanguard in late 1957?

Dannenberg: Disappointment. We were, from the beginning, convinced that our proposal was better than Vanguard, because throughout we were using existing hardware. We used the Redstone rocket for the first stage. We used JPL-tested upper stages with solid propellant. And combining the two was only a minor job. The Vanguard was a completely brand-new, untested vehicle. And from our own experience, we thought its developers would not be able to launch it successfully in their first attempts. So we were not too surprised when the initial Vanguard test cost us the first U.S. satellite, but we were a little bit sad about it. The main reaction we had was sadness.

Spectrum: After that, Wernher von Braun was given the green light to pursue a satellite project on a crash-course basis. Meanwhile, he had been holding back a Super Redstone rocket, known as Number 29, set aside for so-called research purposes, in anticipation of getting just such approval to proceed. And it was the first launch vehicle.

Dannenberg: Correct, but you should refer to it as a Jupiter-C. We eventually built a total of 12 of them. One was the old Number 29 unit. We had to take it out of storage and make a few modifications to it. Then, of course, we shipped it to the Cape to get it ready for launch.

Spectrum: What was your role on the Explorer project?

Dannenberg: At that time, I was in charge of the Jupiter system. It was one of the first two intermediate-range ballistic missiles, along with the Air Force’s Thor. I was also working on the first ICBM assignment.

Spectrum: Where were you when Explorer launched on 31 January?

Dannenberg: I was not present at Cape Canaveral, because I was working on the Jupiter. But I was monitoring the launch from our ABMA facility in Huntsville on TV. As you may know, it took a long time for the satellite to make its first orbit around the Earth—longer than planned. Therefore, many people were afraid that it would also be a flop, that it might have fallen somewhere in the ocean.

Spectrum: What was the mood like when Explorer was finally detected in orbit by the Pasadena tracking station?

Dannenberg: Everyone was very enthused. We had finally done what the Russians had done a little while before. And we all felt pretty good. I would also like to point out that for the von Braun rocket team, this was really very important. It was the first time we could work on a peaceful payload. You probably know that in Germany, the A-4 vehicle we built in Peenemünde, eventually called the V-2, was a military system. And even in this country, after the war, we again had to do all our efforts for the Army. This was the very first time we could really do all the work, the design and the calculations, for a peaceful project. From this, many other significant civilian developments followed, such as the establishment of NASA.

Spectrum: How did the Huntsville rocket team celebrate the first orbit?

Dannenberg: There was, of course, a big celebration. Automobiles honked their horns. There were a lot of people still out after midnight. It was a pretty late launch. The rocket team was greatly pleased.

Spectrum: What did Explorer-I do for the U.S. space program?

Dannenberg: It helped us catch up with the Russians. But more important, we did it very publicly. The Russians always shrouded their launches in secrecy. With Explorer , the entire world could see it. It was a big step ahead for American rocketry. It led to the manned space program and the flights of Alan Shepard and Gus Grissom and, eventually, years later, to the Apollo project and all that it entailed. It’s what we’re gathered here this week to remember. The daughter of Sergei Korolev, Natalia, is here right now. It’s too bad that the old man [von Braun] and Korolev aren’t here to join in the celebration. They are with us in spirit, though.

Spectrum: How should Americans today remember the launch of Explorer-I ?

Dannenberg: I’ll summarize my opinion. It was really the turning point for America’s scientists to do many more intricate and sophisticated things than just launch small satellites. It helped change the world.

[ Editor’s Note: The original intent of this report was to interview two of the von Braun team leaders at the ABMA about their recollections of Explorer-I ; however, the second participant, Ernst Stuhlinger, age 96, who unfortunately has been hospitalized recently, was unavailable for comment at this time. Please seeRemembering Sputnik: Ernst Stuhlinger, from our October 2007 issue online for more on Stuhlinger and his participation in the U.S. space program.]

About the Author

Kieron Murphy is a contributing editor to IEEE Spectrum, as well as a freelance writer based in New York City.

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