Project Orion: The True Story of the Atomic Spaceship by George Dyson. Henry Holt, $26, 345 pages.
The News & Observer
July 7, 2002
The Rocket Boys
By Phillip Manning
I spent the summer of 1958 working at Los Alamos, where we did not worry about spilling radioactive uranium on the wooden floor because the rumor was that when the lab got too "hot" it would be bulldozed down and buried. I spent the following summer at Redstone Arsenal in Huntsville, Alabama, where the explosion of a rocket engine we were testing almost killed two men monitoring the test, completely demolished the test range, and destroyed a dozen or so cars in a parking lot. No heads rolled because of the accident. After all, we were trying to win the Cold War and beat the Russians to the moon. It was a time writes George Dyson in his fascinating, well-researched book "Project Orion" when "tail fins, not seat belts, were standard equipment in American cars."
It was this don't-be-overly-concerned-about-safety, let's-get-the-job-done atmosphere that opened the door to Project Orion, one of the most ambitious or bizarre (take your pick) programs in the history of American science. It's goal: A spaceship propelled not by a nuclear reactor but by the explosive power of nuclear bombs.
Dyson traces the history of the project's many twists and turns,
from its beginnings in 1957 as a government-funded project at
General Atomic (a division of General Dynamics located in La Jolla,
California) to its death in 1965, a victim of interagency squabbling
and the nuclear test ban treaty. He interviewed many of the scientists
and engineers who worked on Orion and quotes extensively from
the documents they wrote. Dyson had an inside
track in his research; his father is Freeman Dyson, the well-known physicist at the Institute for Advanced Studies in Princeton, who worked on Orion for two years.
The idea for an atomic-powered spaceship had been around since the first bomb spread its mushroom-shaped cloud over the desert in White Sands. Atomic power produces a million times more energy per unit of fuel than conventional power. Thus, since it would not have to carry as much fuel as an ordinary rocket, an atomic powered spaceship could deliver the large payloads needed for a manned trip to Mars or the moons of Jupiter.
Controlled nuclear power requires heavy shielding to contain the deadly radiation generated in the reactor. This presents no problem in nuclear power plants or in nuclear-powered ships and submarines, but in spaceships or airplanes - where weight is important - it is a stopper. The solution was suggested in 1946 by physicist Stanislaw Ulam, a Polish scientist who worked on the Manhattan Project at Los Alamos: Eliminate the need for shielding by keeping the nuclear reactions outside the rocket. The concept was unnervingly simple; Project Orion scientists would design a rocket propelled by atomic bombs that are ejected from a spaceship, explode behind it, and push it along.
The beginning of the story has an Alice in Wonderland quality about it. By the late 1950s the largest payload Americans had ever put in space weighed 31 pounds. The early designs of Project Orion specified a 4,000-ton rocket carrying a 1,000-ton payload (later dreamy schemes - reflective of this shoot-for-the-stars era - envisioned massive spaceships that could carry thousands of colonists to other stars). As originally designed, Orion would be manned by a crew of about four. Nuclear bombs would be exploded to boost the rocket off the launch pad. Scientists later estimated that about 10 civilians would die from the radioactive fallout from each mission; they also concluded that number would be unacceptable to the public, so they decided to launch the rocket with conventional explosives.
Once out of the Earth's atmosphere, the spaceship would deploy its arsenal of 1,000 or so atomic bombs, releasing them at the rate of about one per second. The bombs would be set to explode behind the craft, sending a 120,000-degree pulse of plasma toward the rocket's "pusher plate." Shock absorbers connected the pusher plate to the crew compartment to reduce the jolt of an atomic bomb exploding only a few hundred feet behind the ship. Once the astronauts reached their destination - some scientists thought they could get as far as Alpha Centauri, 4.3 light years away - they'd drop more bombs to get home. So, you have a bunch of scientists and engineers sitting in comfortable offices in La Jolla designing a spacecraft that has the crew sitting on top of enough explosives to destroy a small continent. The first thought that comes to mind is WHAT IS WRONG WITH THESE PEOPLE?
Then, as detail after detail of the Orion design is refined, Dyson slowly wins the reader over to the feasibility of the project. In the first place, these are reputable, experienced scientists, many of whom worked on the first atomic bomb. They just might know what they are doing. Ted Taylor, one of the principals in the project, came up with idea after idea for smaller bombs that would focus the blasts at the pusher plate, giving more thrust per bomb. Maybe Project Orion really could put a man on Mars or Europa. Unfortunately, we do not find out; the project never gets beyond testing a small-scale rocket using conventional explosives, which, after many failures, reaches an altitude of 185 feet.
Herbert York, one of the men who helped start Project Orion and helped kill it, said that the problem was that Orion could not evolve the way other projects could. "We arrived at successful technologies like airplanes or telephones by building millions or billions of units, and making modifications one at a time", writes Dyson. He then quotes York's epitaph. "Orion involved putting together simultaneously a number of novel technologies, most of which could not be meaningfully tested in isolation."
Was Project Orion just a pipe dream of eggheads? A fantasy
from an era when safety took a back seat to beating the Russians
to the moon, when tail fins were more important than seat belts?
Dyson doesn't think so. It was, he says "too ambitious a
leap in 1958. Nuclear pulse propulsion had to wait." But
Orion will be back, he predicts. And it will fly. Astronauts will
one day stand on Mars.