and comets that threaten Earth, but colonizing free space, the Moon and Mars, researchers said at a recent conference at Princeton University. Their idea of an "insurance plan" to first protect and then proliferate humanity into the cosmos involves taking up residence in large 10,000-person habitats, positioned between Earth and the Moon at first, and later spreading out to other niches within our solar system.
But first, we must make sure that life is not wiped out by a passing space rock.
Mass driver work reactivated
Asteroids are worrisome intruders in near-Earth space, as well as vast storehouses of diverse materials, said Lee Valentine, executive vice president of Princeton University's
Work done by Gerard ONeill and teams of students to build a mass driver -- an electromagnetic accelerator -- is soon to be reactivated, said Valentine. Several versions of a mass driver were pursued in years past -- a concept originally developed at the Massachusetts Institute of Technology, under the direction of Henry Kolm and ONeill.
The workings of a mass driver (which are also known as "linear accelerators") are straightforward. A long track or tunnel is lined with electromagnets which are wired so they can be switched on and off like Christmas tree lights. A magnetic object placed at one end is then carried along on "waves" of magnetic force, created by switching the electromagnets on and off in the right rhythm. By accelerating the waves of magnetism the object can be accelerated almost endlessly. On a body with weak-enough gravity, objects can be easily accelerated to escape velocity -- without having to fire a single rocket.
The last, substantive work on a mass driver was done in 1983-84, Valentine said.
One duty for a mass driver, as first proposed, was to move raw lunar material efficiently and economically to high Earth orbit for processing. But the same type device can also be used as a reaction engine for pushing asteroids to useful locations.
"A mass driver is a satisfactory engine for moving asteroids or comets," Valentine said. Even better, for altering the trajectory of a rocky mini-world in the event its streaking toward Earth, he said.
Valentine said that SSI, in concert with the Robotics Institute at Carnegie Mellon University in Pittsburgh, Pennsylvania, will be looking into mass driver technology. Making such a device more rugged, upping its performance and demonstrating robotic excavation, loading and firing of a mass driver as a prototype planetary defense system are to be reviewed, he said.
Wait and watch
"You can convert a hit to a miss using the mass driver," said George Friedman, SSI board of directors member. Ostensibly, advance spotting of an impending Earth impactor would allow many years of preparatory time.
An expert on detection and deflection of potentially harmful bodies, Friedman said a mass driver would be built on an asteroid, which would also be covered with solar collectors that supply solar power to run the driver operations. Chunks of the asteroid would be electromagnetically catapulted out into space, nudging the giant piece of space flotsam in a non-nuclear way, he said.
"In a year or two, you can move the trajectory of something that would have hit the Earth," Friedman said.
At present, we know that there are about 1,000 asteroids roughly larger than a half mile (1 kilometer) in diameter whose orbits cross Earth's. These are large enough to inflict serious global consequences in a collision. Furthermore, upwards of 250,000 smaller space rocks are out there too. They are considered more on the city-buster side of terror from the sky.
Cataloging the "bigger guys" is coming along beautifully, said asteroid expert, said John Lewis of the
at the University of Arizona in Tucson. Radical new technology is needed to find the smaller objects, he added. Lewis said asteroid cataloging is necessary to help discern which objects should be treated more as a resource than as a threat. Also, once an asteroids orbit is nailed down, observers are needed to re-check an objects whereabouts from time to time.
"The idea is to nail the orbit well enough the first time around so that you will acquire it the next time around," Lewis said.
"Follow-up is cheap and easy compared to discovery," Lewis said.
Survival 101
The "pay-as-you-go" orbital flight of
was hailed as a signal that a market for human presence in space is evolving, said Lewis. "More power to him," he said.Lewis called Titos trek as a sign that "the monolithic, government-controlled monopoly on space is cracking."
But what the world really needs now is a life insurance policy, said J. Richard Gott III, astrophysicist at Princeton University. "This is a planet littered with the bones of extinct species showing us that such catastrophes on Earth happen to individual species on a routine basis," he said.
Gott said that we should be asking ourselves what space program can be undertaken in the next 40 years. He advocates a self-supporting colony in space as a goal that would change the course of history and help the prospects for our species to survive.
Gott struck a tone similar to that of John F. Kennedys circa-1960s quest to land a man on the Moon. "Space colonization is a challenge that this generation should be willing to accept and one that it should be unwilling to postpone," he said.
"I think we should care about our survival as a species," Gott told SPACE.com.
Spreading out via space colonies and a settlement on Mars increases our chances for survival. Being a multi-planet species not only lessens the chance of humans being wiped out by an Earth impacting asteroid, but also validates that Neil Armstrongs "one small step" on the Moon can be truly viewed as a history-changing event, he said.
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