Comprehensive planetary defense would have two basic purposes: to prevent catastrophe and, failing that, to salvage and restore a severely stricken planet. “Comprehensive” is the key concept; planetary defense would be a single program comprising several parts, some new and others already in place but in need of refinement, like programs of Earth observation.
Satellites in low orbit, such as the new, advanced Landsats, should be directed to make constant methodical observations of Earth in unprecedented detail. They could thus inventory resources and spot natural or man-made trouble in the early stages. Before a volcano erupts, for example, the ground begins to heave slightly and expand, like the crust of a frozen pie that is being heated. Satellite observation in conjunction with the use of seismometers on Earth’s surface could provide warnings for evacuation. Satellites are already monitoring the breakup of the Antarctic ice shelf and the shrinking of the Aral Sea, on the border of Kazakhstan. But global warming needs to be studied more intensively, both on and off the planet. We have the equipment in place, but the efforts are fragmented and incomplete. An international body should coordinate the analysis and recommendations for action.
Determining that a killer asteroid is on a collision course with Earth is worthless unless there is a way to ward it off before impact; likewise, no good effect can come from watching Earth unless nations are prepared to act in concert to ward off catastrophe. If the whole planet gets clobbered anyway, the species needs to be spread out to guarantee survival and restore what can be restored on Earth. That’s where the lifeboat comes in. We should settle a large and self-sustaining colony on the moon.
Eventually, after many generations, the colony would grow so much in size and sophistication that its members could organize and help direct recovery operations on Earth in the event of a planet-wide calamity that comes up short of exterminating everyone. If there were no one on Earth left to save, lunar colonists would be alive to preserve the species and its record. Such a level of capability and self-reliance will be attained only far in the future, but we can begin now by designing the spacecraft to transport us there and increasing current research on closed systems.
And we should establish a record or archive of Earth’s collective life and civilization, including cultural and scientific records and biological specimens, so they could be replicated in the event of widespread destruction anywhere on Earth. It would not be a time capsule—time capsules become increasingly useless as time passes—but a continually updated repository. Some of us have formed an organization, the Alliance to Rescue Civilization (or ARC, as in “archive”), to create and maintain such an extensive record. Chemistry professor Robert Shapiro, my colleague at New York University, conceived the idea, and the others designing it include Steven M. Wolfe, a space specialist who was an aide to the late Representative George Brown of California; Ray Erikson, an aerospace engineer who has participated in many NASA programs; Sean Hadley, a lawyer; and myself. The Space Frontier Foundation is providing initial support.
ARC would by definition be a highly cooperative international effort, perhaps run by a new, permanent agency of the United Nations. It would not, however, be controlled by government. Its essential funding would have to come from corporations and foundations—the private sector—so it could not be held hostage by changes in political administrations or even systems over the course of decades and centuries.
Planetary defense is an overwhelmingly compelling reason to send people to space. It is time to shed the notion that people from Earth will advance outward to our planetary neighbors because we have a genetic predisposition to explore. There is no public will to land on one or more of the planets as a political stunt and no cost-benefit analysis that supports plans to exploit other planets commercially. It is time for a space program that addresses the multiple perils faced by Earth.
William E. Burrows is a contributing editor to Air & Space/Smithsonian and the author of a number of books on space, including This New Ocean: The Story of the First Space Age.