Page Content (OCR)
375 of self-defense is a legal consequence of the right of freedom of will. What one species sees as self-defense may be seen by another as aggression. Harrison and Dick suggested that if we encounter civilizations that already have formed a Galactic Club, they may offer us an interstellar legal framework. Would we accept it? Establishing a metalegal order might require significant changes in our own laws, which, as Freitas noted, do not include nonhumans as legal persons.” If we continue to survive and if our technological civilization continues to advance, we will become progressively more capable of defending ourselves dann The threat of asteroid and comet impacts has provoked some humans to think in terms of planetary defense. Telescopes already scan the skies for Near-Earth Objects, some of which might intersect our planet’s path. We are extending our concept of security beyond individual nations to the entire Earth. Scientists and engineers have proposed technological means for dealing with any bodies that look threatening, ranging from propulsion systems that would deflect an asteroid or comet nucleus from a collision course to nuclear weapons that would demolish the threatening body. The European Space Agency’s Don Quijote mission, planned for 2011, would practice steering asteroids away from Earth. Maccone has even proposed stationing weapons in space that would deflect incoming asteroids; this might violate the Outer Space Treaty and arms control agreements.™ Current search efforts focus on large asteroids, although smaller ones could do serious damage to our civilization. A NASA committee con- cluded in 2003 that the search for smaller objects could be done for less than $400 million, but no funding agency has volunteered to pay. Asteroid hunting does not fulfill an obvious scientific mission, observed Grant Stokes of the MIT Lincoln Laboratory; it is more like a public service.™* As a Planetary Society fund-raising letter pointed out, there is still no concrete plan in place for humanity’s response if we discover an asteroid heading our way. Some analyses indicate that we can divert Earth-crossing asteroids and comets only if we reach them years before their projected impact. For an asteroid 200 meters in diameter, we would need roughly 20 years; for a larger asteroid, the lead time would be longer.** To starflight theorist Gregory Matloff, that meant building an infrastruc- ture in the outer solar system—at a minimum, the lookout posts that would watch for incoming bodies.* That capability also could give us the means for spotting other potentially dangerous intruders—the probes or Planetary Defense Planetary Defense against outsiders. —lIsaac Asimov, 1979