Sign in to comment!


Air & Space

Will a Space Cannon Fuel the Next Moon Landing?

Space Cannon

A conceptual drawing of the space cannon shows how the device will accelerate its payload at speeds of up to 11km per second from underwater. (John Hopkins/Quicklaunch)

It was at a cocktail party that Dr. John Hunter, a fast-talking 54-year-old physicist who once worked at Lawrence Livermore National Lab, had a crazy idea.

As sometimes happens over a third martini, a colleague suggested that gas-powered guns are much more powerful than conventional guns: When ignited, a gas gun can shoot a projectile at insane speeds of over 11 kilometers per second -- or roughly 25,000 miles per hour. 

And that got Hunter to thinking . . .

What if he could build a massive, 1-kilometer-long cannon powered by hydrogen that could be housed below the surface of the ocean? The sort of device Jules Verne wrote about in 1865 in his novel "From the Earth to the Moon"?

And what if it turned out not to be a such crazy idea, after all?

Such a cannon could solve a nagging problem at NASA: how to send manned missions to the moon and Mars at a lower fuel price. Currently, it costs thousands of dollars per pound of fuel to launch stuff into space. Hunter' cannon could reduce that price to a few hundred dollars per pound.

And that savings could be very lucrative to the person who made it happen, which is why Hunter created and is drumming up support for Quicklaunch Inc., which he hopes will launch payloads into space within the next five years.

How would a space cannon work? 

The basic concept behind a space cannon is simple: A hydrogen explosion shoots the payload -- Hunter is concentrating on delivering rocket fuel at first -- up the lengthy tube. The tube's mouth sits just above the surface of the water, and when the payload emerges, it's aimed directly into outer space. 

Re-positioning an underwater cannon would be easier than moving one on land, and the sonic boom would be nearly eliminated due to a concept called impedance mismatch, which predicts that over 90 percent of the explosion's ear-deafening sound would be reflected into the atmosphere.

"It's a very simple idea in principal," Hunter told "Hydrogen has a low molecular weight, so it can launch things much faster than ordinary guns can."

Translation: highly packed gas makes a bigger bang than gunpowder or an electrical current.

"It takes 100,000 pounds of propellant per person to land on the moon from low-Earth orbit," Hunter says. Today, it costs $5,000 - $10,000 per pound to launch those propellants. The space cannon would allow NASA and other space agencies to send fuel for future space missions directly into space, where spacecraft could fuel up at dramatically lower costs. In the future, Hunter says, colonization of the moon might mean sending 100 people at a time or more.

"I think the space cannon idea could be developed into a reliable and low-cost method of placing small payloads into orbit," science-fiction author Ben Bova told "The major problem that I see is that it would take a fairly considerable effort of time and money to make it viable, and it's in competition with existing rocket launchers. People tend to go with what's already available and demonstrably reliable, rather than investing in new technology, whatever the long-range benefits might be." 

But there is already a history to the cannon. Hunter built a massive gas gun, called the SHARP (Super High Altitude Research Project), while working at Lawrence Livermore National Lab. While the project was a functional proof of concept, Hunter never found the funding to proceed with his work. The new cannon, he says, will kick-start the comatose space program, which he says has faltered since the last manned mission to the moon.

"There has been nothing significant since Apollo," he says. "I know the astronauts are going to come after me for this, but fortunately they are all elderly so they won't be able to catch me."

Quicklaunch reality check

Representatives at NASA, who declined to comment for this story, have already done the numbers on future missions to the moon and Mars. The trips will be exceedingly expensive. The Orion vehicle currently being tested as a reusable spacecraft is designed to keep costs as low as possible. In 2007, Boeing proposed fuel depots at low-Earth orbit to help make rocket propellants easier to manage.

"The question with a system like this is how long will it take to build," says Chuck Gannon, a professor at St. Bonaventure University and a space advisor to the Discovery Channel and Homeland Security. "I may be wrong, but I think a ground-based version is going to be a lot easier to construct, repair and learn from than a sea-based portable version." 

"The challenges of a mobile, kilometer-long, submerged launching tube system that has to bear the stresses of the depths, and thermal gradients and currents while maintaining an absolute ramrod straight tube...." Gannon mused, trailing off. "well, let's say I think you could do it but I'll bet you've got a decade or two of trials and kinks to work out of that system." 

With the Quicklaunch cannon, there are also questions about the physics of the actual payload rocket, possible weaponization and the environmental impact of a space cannon.

In a widely-circulated talk Hunter gave at Google headquarters, the physicist explained away many of the chief concerns -- that a two-stage rocket would be used to attain speed and altitude, that payloads would be heavily insulated to withstand atmospheric pressure and drag and so on.

Possible weaponization is an interesting topic. Hunter says the cannon would be too long and too obvious to be used as a weapon -- it would be an easy target. That said, Saddam Hussein had developed a space cannon concept during the first war with Iraq. Hunter himself was involved with the "Star Wars" missile defense program under Ronald Reagan and has a background in weapons.

Quicklaunch is currently in a phase-one stage, looking for funding. The next stage is to use the cannon to obtain a world altitude record for a payload launch. Then the company plans to launch a two-pound satellite into orbit before shooting the first rocket propellant into space by 2015.

"Technically, building a cannon over a kilometer long is feasible," says Barrett S. Caldwell, PhD, an associate professor of Industrial Engineering and Aeronautics and Astronautics and the director of the Indiana Space Grant Consortium at Purdue University. 

"I'm not sure where in the world's oceans you'd put it so that the cannon remains aligned," he mused. "Remember, at the exit speeds described, extreme precision of alignment is required, in a variety of wind and water conditions. This would be a very large target, and if placed in international waters -- where you need at least 700-800 meter depth, given the angle of the cannon -- ownership and guardianship is questionable."

Speaking of the ocean, environmental impact is a non-issue, says Hunter. A typical shuttle launch releases an enormous amount of acid rain, and Quicklaunch's cannon is much safer. And the sonic boom would quickly dissipate in the depths, he notes.

"We have no plans to infringe on the whales or the pinnipeds or the crustaceans," Hunter says with a chuckle, discounting the green-tech issue. "We love them all equally."