Fifty years ago, a group of scientists and engineers imagined building a space ship that could cross the interplanetary gulfs using the explosive force of nuclear bombs. The concept was called Orion and it has just as much potential today as it did in the old days before a single person ever ventured beyond the Earth's atmosphere.
One of the great problems of interplanetary travel is the time that it takes
to traverse the great distances between the Earth and various destinations in
the solar system. Using chemical rockets, a manned expedition to Mars, for
example, would take upwards of three years round trip, including the time spent
on the Martian surface. Voyage times to other destinations, such as the moons
of Jupiter or Saturn, could be measured in over a decade or longer, clearly
impossible for human crews to endure. Not only does prolonged exposure to micro
gravity present health problems, including the weakening of muscles and bones,
but exposure to interplanetary radiation could prove fatal.
Nuclear rockets could provide some reduction in the time it would take to
voyage to the planets. But, ironically, one solution was explored during the
late 1950s and early 1960s that might have allowed humans to bridge the
interplanetary gulfs decades ago. With some modifications, that solution might
still give humankind the solar system, now that interest in space exploration
has revived.
Ironically, the solution depended on the explosive force of nuclear bombs, a
technology that once threatened the annihilation of the human species. It was
called Orion.
How does Orion Work?
An Orion space craft consists of the ship itself, where the crew, equipment,
and fuel in the form of nuclear bombs are kept, and a push plate to the rear.
In order to propel itself, the Orion ship ejects a nuclear bomb every few
seconds to the rear, which explodes. The shock wave of the explosion acts upon
the pusher plate, which transmits the force to the ship via shock absorbers,
propelling the ship forward. Using this method of propulsion, an Orion space
craft can achieve speeds unobtainable by other methods, including nuclear.
The History of Orion
The idea of using nuclear bombs to propel a space craft was first proposed
by Stanislaw Ulam at Los Alamos in 1955. In 1958 Los
Alamos’s Ted Taylor and Dr. Freeman Dyson, then a theoretical
physicist then at the Institute for Advanced Study at Princeton,
began the serious work on an Orion propulsion system at General Atomics, a
company founded to explore the peaceful applications of nuclear power. Funding
was provided by ARPA (Advanced Research Projects Agency.) The team led by Taylor
and Dyson refined the Orion concept, packing the bombs with polyethylene to
provide a focused plasma to enhance the propulsion speed. They also developed a
method of “greasing” the pushing plate to inhibit it’s erosion by the heat of
the bomb explosions. The General Atomics team launched a series of test
articles, propelled by conventional explosions, the last in November of 1959 at
a height of a hundred meters.
The Orion ship conceived at this time would have been immense. It would have
been in the shape of a bullet, six stories high, weighing ten thousand tons,
most of which would have gone into Earth orbit. At a time when the Mercury
program was planning to launch a single astronaut in cramped conditions, this
version of Orion would have had a crew of a about a hundred and fifty in roomy
conditions. Orion would have been like a space going battleship, with no need
of the weight saving methods necessary for conventional space craft. Perhaps
half seriously, Dr. Dyson said that the motto of the Orion team was, “Mars by
1965, Saturn by 1970.”
The promise of Orion began to fall apart by the end of 1959. The new space
agency, NASA, got all of the civilian space projects and the Air Force got the
military ones. ARPA was left with Orion as a kind of orphan program. It was
later transferred to the Air Force, but the Air Force could never find a need
for a space going battleship. At this point, the idea of a “first generation”
Orion, to be launched into low Earth orbit by a Saturn V rocket, and only then
to use its nuclear bomb drive to send eight astronauts to Mars, was explored.
But the Nuclear Test Ban Treaty, which forbade the test explosions of nuclear
bombs in the atmosphere or space, put the final nail into Orion’s coffin. The
project was terminated in 1965.
Project Daedalus
A variant of Orion was explored by the British Interplanetary Society, known
as Daedalus, was explored in the 1970s. Daedalus was to be an unmanned
interstellar vehicle that would be propelled by “fusion pellets” consisting of
deuterium and helium 3, ignited by electron beams in a combustion chamber. This
method of propulsion was far more elegant and efficient than the brute force
method of Orion. The concept, of course, could be adapted for manned
interplanetary voyages.
Fallout Problems
One of the unsolved problems of Orion was that of fall out resulting from a
surface launch. It was estimated that between one and ten people would die a
premature death from cancer for every surface launch of an Orion ship. Also,
were an Orion to be launched in the present, the electromagnetic pulse (EMP) of
the nuclear explosives would fry modern communications and computers for
hundreds of miles away. The solution would seem to be to assemble an Orion ship
in a high, “nuclear safe” Earth orbit and launch it to interplanetary
destinations from there.
Orion in Science Fiction
Naturally the idea of an Orion ship has found its way into science fiction.
Jerry Pournelle and Larry Niven, in their novel Footfall, imagined the building
of an Orion ship as a means to stave off an alien invasion of the Earth. Poul
Anderson, in his novel Orion Shall Rise, also imagined an Orion ship. Even the
film Deep Impact depicted an Orion ship being used to deliver a crew to a rogue
comet that threatened to destroy the Earth.
Could Orion Be Revived?
With renewed interest in sending people on interplanetary voyages, the
thought has to occur that an Orion type space craft would fit the bill. The
1959 version would have resulted in two year round trips to Mars (including a
long sojourn on the Martian surface) or three year round trips to Jupiter or
Saturn. These trips would have carried a hundred and fifty space explorers in
relative comfort and safety to and back from these destinations.
Modern materials, nuclear bombs, radiation shielding, and other technologies
would surely enhance the capabilities of a modern Orion interplanetary ship.
The advantages of using Orion technology over even conventional nuclear
propulsion are obvious. More people in less time can be delivered to destinations
such as Mars. The dream of colonizing the planets would happen much sooner.
Plus, a fleet of Orion ships would provide a certain defense against the
possibility that an asteroid, such as the one that wiped out the dinosaurs
sixty five million years ago, would impact the Earth in the future, to wipe out
our species.
The only problem that seems to stand it the way of reviving Orion seems to
be political. The Partial Test Ban Treaty of 1963 and the Comprehensive Test
Ban Treaty of 1996 would seem to preclude the use of a propulsion system that
uses nuclear explosives. But it would seem to be the case that an amendment to
those treaties could be easily negotiated to allow for the use of nuclear bombs
as fuel for space craft.
Of course, the revival of the Orion project would cause great upset and
anger in certain quarters of the environmental movement. The launch of
planetary probes, such as Galileo and Cassini, using a relatively benign power
source based on the atomic decay of plutonium are the regular venue of
protests. Imagine what the reaction would be if nuclear bombs were being lofted
into Earth orbit to fuel an orbiting Orion ship.
Still, the promise of Orion as a means to open up the high frontier of space
may well overshadow short term political considerations and fears. Reviving
Orion could bring about a new age of interplanetary exploration during the
lifetimes of most people unimaginable without it.