NPR logo

Trinity Scientist Recalls Building the A-Bomb

  • Download
  • <iframe src="https://www.npr.org/player/embed/4757424/4757425" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
Trinity Scientist Recalls Building the A-Bomb

Trinity Scientist Recalls Building the A-Bomb

Trinity Scientist Recalls Building the A-Bomb

  • Download
  • <iframe src="https://www.npr.org/player/embed/4757424/4757425" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Extended Audio from Don Hornig

  • <iframe src="https://www.npr.org/player/embed/4757424/4757470" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">

Eleven scientists who helped build the first atomic bomb gathered at the National Academy of Sciences this week to recall their experiences. Don Hornig, the youngest scientist to work on the project, tells his story.

JENNIFER LUDDEN, host:

Sixty years ago today, in a remote section of the New Mexico desert, scientists tested the first atomic bomb. The explosion turned darkness into daylight. Observers 10 miles away felt the heat. The world changed in that moment. This week, 11 scientists who worked on the project gathered on a stage at the National Academy of Sciences to share their memories of that moment. Their mentor and boss was the late Robert Oppenheimer, who died in 1967. The 11 men are old now; one used a cane, another brought a squeeze bottle of something lemony to help his voice. In the middle of the group sat Don Hornig. The 85-year-old scientist recalled his arrival at Los Alamos. Here's an excerpt of his story.

Dr. DON HORNIG (PhD, Atomic Scientist): Anyway, we arrived at an obscure office and were assigned to the last available bungalow and told how to get to a place called Los Alamos, which I hadn't heard of before, on top of a mesa in the Jemez Mountains. So off we went again until we reached a guardhouse, where we were admitted to a depressing olive-drab military base. I was settled in a dismal office. I learned that my job was to measure the characteristic of shock waves from a huge nuclear explosion in order to determine its size, and was shown a small pellet of plutonium. That was a real shock.

My qualification was that for my PhD thesis, I had measured the characteristics of a two-ton bomb. Now that was the biggest around then. This was going to be 20,000 tons. The only trouble was that there was no plutonium, the test site had not yet been built and no one knew how to carry out the implosion anyway.

(Soundbite of laughter)

Dr. HORNIG: It was very discouraging and I hated the thought of just sitting in my office planning. I was very depressed. Fortunately I attended Oppenheimer's staff meeting, at which the question of how to initiate the spherical implosion was discussed. At this point I had an idea and made a suggestion that was eventually my principal contribution to the success of the project. This was that we ought to be able to trigger a high-voltage spark gap within a fraction of a microsecond and use the switches then to fire the detonators, which would initiate a spherical implosion with adequate simultaneity. So we went back to work more furiously than ever, built a--to build a reliable firing unit which was later called the X-unit. And getting from there to Trinity was rough sledding.

But the worst came at Trinity itself. The test was scheduled for July 16th and we weren't ready. But President Truman was already meeting with Stalin and Churchill in Potsdam, so we had to be. On July 9th, during bad weather, the X unit fired prematurely. That made everyone very nervous.

(Soundbite of laughter)

Dr. HORNIG: Oppenheimer berated Chiskiakovsky(ph) for entrusting the job to an incompetent like me...

(Soundbite of laughter)

Dr. HORNIG: ...but we found the problem, which was a disconnected ground wire, and proceeded. On July 15th, the assembled bomb was placed to the top of a hundred-foot tower--there's a picture out here--on which it would be detonated. That same day, a spare X unit failed. There was panic, and I was in deep trouble again. The decision by the high command was to proceed, though the confidence level was lower now than ever before. On July 15th, the weather looked bad and was getting worse, but the orders from Potsdam were to go ahead.

Against this backdrop, Oppenheimer held a meeting at about 6 PM. He was terribly worried at the possibility of sabotage on top of all these other troubles, and decided that someone who understood the details should stay with the gadget until it was locked up for firing, and as the youngest, I had priority.

(Soundbite of laughter)

Dr. HORNIG: Thunder and lightning enveloped the site, but at 9 PM I climbed the 100-foot tower to the top, where I baby-sat the live bomb. It was a deeply philosophical experience...

(Soundbite of laughter)

Dr. HORNIG: ...to contemplate the monster beside me and what it was about to do to the world.

LUDDEN: Eighty-five-year-old Don Hornig. At age 25, sitting in the arming pit, he was the last person who could have stopped the atomic bomb test. Hornig spoke earlier this week at the National Academy of Sciences about the Trinity test, which took place 60 years ago today.

For more on the Trinity test, including a rare color photograph of the explosion, and an extended version of Don Hornig's recollections, you can go to our Web site, npr.org.

This is NPR News.

Copyright © 2005 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

We no longer support commenting on NPR.org stories, but you can find us every day on Facebook, Twitter, email, and many other platforms. Learn more or contact us.