How will we get so many people to outer space? Lasers? Elevators? Atomic bombs are out, Freeman Dyson says.
Speaking at Flight School, an offshoot of the PC Forum conference taking place here this week, the Princeton University Institute for Advanced Study professor emeritus sketched out a possible future, in which humans colonize asteroids and genetically engineer potatoes that can grow on Mars. (PC Forum is run by News.com publisher CNET Networks.)
Part of the motive to go into space will be dictated by the need for more room on Earth and an unpolluted environment. But there will be more mundane motives, too, Dyson said.
"You'll have people who go who dislike the tax collector or dislike their mother-in-law. The primary reason is that it hasn't been done," he said.
In the more immediate future, the United States will likely reinvigorate its manned spaceflight programs over the next 15 years because the Chinese have set their sights on the moon.
"It is an international sporting event. It is fun. The public likes the Olympics, and it likes football, and the public likes manned space exploration," Dyson said.
Getting there, however, will require some technological breakthroughs in propulsion. "What you need is a launch system that stays on the ground," he said.
One option is laser propulsion. Researchers at Rensselaer Polytechnic Institute have shown that they can propel an object weighing 5 ounces 300 feet into the air with a laser. A real-life version that could launch people in a vehicle "about the size of a Volkswagen" would require a 1,000-megawatt laser located on top of a mountain, he said.
Technically, that can be accomplished, but to make it commercially viable, a vehicle would have to be launched once every five minutes, which comes out to 100,000 vehicles a year.
Another option is the Slingotron. "It is a huge slingshot affair that accelerates your payload on a spiral track and then, zoom--off to outer space," he said. It would kill humans but could be used for cargo.
A third option is the space elevator, a large structure made of customized molecules that could spring people into outer space, according to proponents.
"I am on record in saying that it won't work, but I love to be proven wrong," Dyson said, noting that the elastic energy would have to be equal to the chemical energy required to send a rocket to space. "If it tears in one place, it is likely to be a disaster."
Dyson himself worked on Orion, a project to land people on Mars, in the 1950s and 1960s. Orion, which would have been built by a submarine company in Connecticut, would have literally been a spaceship.
"We were going to walk on Mars with our notebooks and draw pictures of everything. It would have been true 19th century exploring," he laughed.
To propel it out of orbit, however, would have required exploding 3,000 atomic bombs, one every two seconds. The bombs would have been tossed out of a hole in the plate in the ship, delivered by "essentially what was a glorified coke machine," he said.
Engineering prototypes and simulations showed that the project would work, and it would have cost far less than Apollo. The original plan was to get to Mars by 1965 and the moons of Saturn by 1970.
"The fatal flaw of this scenario, of course, was radioactive fallout," he said, the ill-effects of which were being discovered at the time. "Technically, it worked very well, but it was political death."