The thunderclap from Russia’s asteroid explosion last Friday was still echoing across the internet when a United Nations panel took up—again—a suddenly urgent topic: how to keep a far more damaging space rock from hitting Earth. Although asteroids have been on the agenda of the U.N.’s Committee on the Peaceful Uses of Outer Space for a dozen years, no final international agreement is yet in force. But after last week’s meeting in Vienna, the committee is finally close to endorsing a plan for countries to share asteroid warnings and prepare realistic mission designs to deflect a rogue object. The ultimate goal is to ward off a catastrophe far more damaging than smashed-out office windows, or even a tsunami.
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Because asteroid impacts are extremely infrequent, the slow-moving U.N. process seems somehow appropriate when dealing with this particular threat. The Science and Technical Subcommittee’s Near-Earth Object Working Group and its expert panel, Action Team 14, have been debating the details of an international approach since 2001.
But last Friday in Vienna, heaven itself seemed to short-circuit that measured approach. Delegates knew that a city-killer-sized asteroid, 2012 DA14, discovered last March, would pass close to Earth that evening. Then the Chelyabinsk event shook things up far beyond the immediate and dramatic physical effects in Russia. The 55-foot-wide asteroid, weighing as much as 10,000 tons, blew up over the industrial city with a force of 500 kilotons of TNT. The shock waves of its passage blew in doors and shattered thousands of windows, sending hundreds cut by flying glass to the hospital. Initial examination of small meteorite fragments identified the projectile as an ordinary chondrite, the most common type of rock now falling on Earth.
At the Subcommittee’s session last Friday, experts from member states and interested observers, like my own Association of Space Explorers, realized the new urgency to moving forward on impact prevention. Gravity tractors, hyperkinetic bullets, and nuclear explosives, along with other more exotic alternatives, can in principle divert a rogue asteroid from a collision course. What’s needed now is a decision on how best to cooperate globally to prepare, then execute, such a deflection campaign (the series of robotic missions necessary to nudge an asteroid onto a comfortably safe trajectory).
Because asteroids can strike anywhere on Earth, and the damaging effects of a large impact will cross borders and oceans, most countries support an international approach to impact prevention. In practice, however, a global framework must resolve thorny questions: Will a U.N. framework affect a nation’s own right to defend itself from a predicted impact? Will an asteroid agreement expand the costly and sluggish U.N. bureaucracy? Who will decide what space agencies or military forces should execute a deflection campaign? Will nations mounting a deflection campaign in good faith be blamed financially if the effort fails and brings down an asteroid disaster on our heads? Who will pay for collecting accurate asteroid orbits, for predicting potential impacts, for issuing asteroid warnings to the public, and for a deflection campaign that could cost billions?
The Association of Space Explorers—all of whose members have traveled to space—has argued at the U.N. since 2008 that we need a credible, tested plan to deal with these questions, just as spaceflight controllers and astronaut crews rely on well-established flight rules to deal with emergencies in orbit. To ensure safety, all the arguing is done in advance, on the ground. Technology and procedures are tested in simulators, then in flight. The flight rules are adopted and published. When crisis comes, you don’t debate and dither. You open the book, and act.
In 2008, the Association’s expert panel submitted a draft plan to the U.N. Several of the ASE plan’s fundamental recommendations are in the final Near-Earth Object plan debated this week before the Science and Technical Subcommittee. Member states agreed that existing asteroid tracking and prediction work, now funded voluntarily by NASA, the European Space Agency, and others, should be shared through an International Asteroid Warning Group. The spacefaring nations would also collaborate in a U.N.-approved Space Mission Planning Advisory Group, to agree on research priorities and develop answers to questions like: Which are the best technologies for diverting small, medium, and large asteroids? How much will a credible deflection campaign cost? And what probability of impact is worrisome enough to trigger a decision to act?
In the awful event that a deflection mission should fail, or disagreements keep it from even getting off the ground, the plan discussed in Vienna calls for an International Disaster Planning Advisory Group. That body would use our all-too-grim experience with earthquakes, tsunamis, and hurricanes to tell those in the impact target zone how best to evacuate, and how to deal with injuries, property damage, and cleanup.
The proposal before the U.N. isn’t perfect, but the process has helped NASA, ESA, and the Japanese and Russian space agencies to engage in joint asteroid exploration planning. The European Union is funding the NEOShield project, investigating the best technologies for asteroid deflection. The agencies also are looking for ways to fund and mount a joint deflection demonstration mission. Such a mission would gather scientific information on asteroids and prove one or more deflection technologies, possibly before 2025.