[ExI] Asteroid on track for possible Mars hit

John K Clark jonkc at att.net
Tue Dec 25 05:34:53 UTC 2007

"spike" <spike66 at att.net>

> Hi John, I may be wrong about this, but it seems we still need chemical
> rockets to get our nuclear Orion stages into LEO,

The original idea was to use no chemical rockets at all, it would be pure
nuclear from the surface of the Earth to the outer solar system. I find I
wrote a post on this subject on June 16, 2000:

I've been reading a little about an incredible idea taken very seriously in
the late 50's and early 60's but today is almost completely forgotten, it
was called Project Orion. The idea was to make a spaceship big enough
for 150 people and all the equipment they could ever want and blast it
into space. They wanted to make it 135 feet in diameter and 160 feet
high and they wanted most of that space to be usable by people not
wasted on fuel. They figured weight would be no problem, if a crew
member wanted to bring along his antique bowling ball collection and
his own personal barber chair there would be no objection. The advocates
of this approach were not interested in low earth orbit or even the moon,
they were certain they could be on Mars by 1965 and Saturn by 1970, the
leader of the project was determined to visit Pluto. And they figured all
this would cost less than 10% what the Apollo moon project did.

You might think that these people must have been a bunch of crackpots,
but it's not so. Nobel Prize winners  Niels Bohr, Hans Bethe and Harold
Urey were all enthusiastic advocates of the idea. Freeman Dyson thought
the idea was so brilliant that he took a one year leave of absence from the
prestigious Institute of Advanced Study so he could work full time on the

Yes, there is a catch, Project Orion needed nuclear energy, even worse it
needed nuclear bombs. The Orion spacecraft would contain 2000 nuclear
bombs, most in the 20 kiloton range, the size of the bomb that destroyed
Nagasaki. A bomb in a tank of water would shoot out the back of the ship,
when it was 100 feet away it would explode, the water would hit a carefully
designed 75 ton pusher plate and accelerate the ship. Between the pusher
plate and  the ship were 50 foot long gas filled shock absorbers to even
out the jerk. They wanted everything to be as cheap as possible, so they
asked the Coca-Cola company for the blueprints of one of their vending
machines, then they scaled it up a little and planed to use it as the
mechanism to dispense the bombs.

The pusher plate was obviously the most important part of the design. If you
explode a powerful bomb near a circular plate of constant thickness it will
shatter because of the uneven stresses that build up, but it turns out that
if you carefully taper the plate and make certain that the explosion is dead
center, the plate will be extraordinary  resistant to damage. A layer on the
plate will be vaporized by the heat but if some heavy protective oil is
spayed on it before each use it would be good for 2000 blasts. This beast
was tough, if it was properly oriented the Orion Spacecraft could survive a
16 megaton H bomb blast from only two thousand feet away, a fact of
more than passing interest to the military. Orion needed lots of radiation
shielding to protect the crew, but weight was never an issue so this
was no problem.

Wernher von Braun though all this was a dumb idea, then he saw a movie of
the launch of a one meter working model of Orion that shot 6 carefully timed
high explosives chemical bombs out the back of the model, it rose 300 feet
into the air in stable controlled flight. Wernher von Braun became a vocal
supporter of project Orion.

They planed to launch Orion from atop eight 250 towers in Jackass Flats
Nevada. The first bomb would be tiny, just .1 kiloton (100 tons of TNT)
exploded 100 feet below craft and 150 feet above the ground, then a new and
slightly larger bomb would be spit out the back every second for 50 seconds,
the last bomb would be the largest, 20 kilotons, and by then the craft would
be out of the atmosphere, the total yield of the 50 bombs would be 200
kilotons. The launch would have been a spectacular sight!

Project Orion was lead by Ted Taylor, a mediocre physicist but a good
inventor. Taylor had one unique talent, he has been called by some the best
nuclear weapon engineer on planet Earth and the Leonardo da Vinci of nuclear
bomb design. Taylor is the man who figured out how a two foot long 200
pound bomb could be made as powerful as the 12 foot long 10 ton World War 2
Nagasaki bomb. The reason the Orion  spaceship was so much bigger and faster
than anything we have today is that pound for pound such bombs have about a
million times as much energy as any chemical rocket fuel.

Orion wasn't the only thing Taylor was interested in, he found a way to make
new type of nuclear bomb, one that would produce a highly directional blast.
He designed a little one kiloton bomb that could blast a 1000 foot tunnel
straight through solid rock, he wanted to build a cheap tunnel between
New York and San Francisco and have a supersonic subway 3000 miles long.

Considering the big controversy we had last year when a deep space probe was
launched with just a few pounds of non weapon grade Plutonium on it to power
the electronics it may seem incredible and irresponsible that anyone would
even consider something as environmentally unfriendly as Orion, but we live
in a very different world. At the time Orion was under serious study the USA
was blowing up one megaton bombs deep under the sea and 300 miles in
space and the USSR was blowing up 57 megaton bombs in the atmosphere,
Orion seemed and indeed was pretty benign compared to that.

It all came to nothing of course, in 1963 the test ban treaty was signed
stopping all nuclear explosions in space or the atmosphere making Orion
illegal. The project died, but to this day most say it would have worked
technologically if not politically.

  John K Clark

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