FINDING DOOMSDAY ASTEROIDS
New York Times Editorial
Published: April 3, 2007 How much effort should we expend to ward off the possibility that an asteroid might some day collide with Earth? Space experts attending a recent conference in Washington lamented the failure of the federal government - indeed, of the entire world - to take the threat seriously enough. The National Aeronautics and Space Administration, at virtually the same moment, advised Congress on steps that could be taken to find and divert threatening asteroids only to conclude that it couldn't afford them. That seems shortsighted. The risk is remote, but the consequences are potentially catastrophic. It would seem wise, at a minimum, to look harder for any death-dealing rocks that might menace us. The encouraging news is that the most horrendous hazards - asteroids like the one that wiped out the dinosaurs or even smaller objects whose impact could disrupt the global environment - have mostly been identified under a $4 million-a-year survey program. The space agency estimates that there are some 1,100 near-Earth objects whose diameters exceed six-tenths of a mile, big enough to destroy a medium-sized state and kick up enough dust to affect global climate and crop production. The survey has already identified more than 700 of them. None are on a path to collide with Earth. More troublesome is the threat of smaller asteroids, greater than 460 feet in diameter (about one-seventh the threshold of the really scary big ones), that could devastate a region but not the whole globe. NASA estimates that some 20,000 of these might be potentially hazardous; it has identified only a fraction of them. Two years ago Congress asked NASA to propose new search programs and to analyze ways to divert any asteroids on a collision course with Earth. The agency did that in a March report to Congress, but it balked at the notion of spending up to $1 billion or more to build search instruments or spacecraft. That is understandable. NASA is burdened with the need to finish the space station, build a successor to the shuttles, return to the moon and conduct wide-ranging research. It already has more jobs to perform than money to perform them. But finding asteroids that might threaten the planet, and studying their characteristics in the process, is probably more important than at least some of the other robotic missions mounted by NASA. Congress should either add funds to the agency's budget, or the agency should divert funds from other programs to accelerate the asteroid hunt. Developing ways to deflect asteroids is more problematic. NASA suggests that the best solution would be to explode a nuclear bomb next to an asteroid to deflect it off course, but international aversion to nuclear weapons in space would make that approach difficult without a global consensus. Other experts favor a high-speed ballistic impact or using the gravitational attraction of a hovering spacecraft to nudge the asteroid off course. Before plunging ahead with an asteroid-deflector, let's wait to see whether a real threat even exists. =================================== THE SKY IS FALLING. REALLY.
By Russell L. Schweickart
New York Times Op-Ed, March 16, 2007 AMERICANS who read the papers or watch Jay Leno have been aware for some time now that there is a slim but real possibility - about 1 in 45,000 - that an 850-foot-long asteroid called Apophis could strike Earth with catastrophic consequences on April 13, 2036. What few probably realize is that there are thousands of other space objects that could hit us in the next century that could cause severe damage, if not total destruction. Last week two events in Washington - a conference on "planetary defense" held by the American Institute of Aeronautics and Astronautics, and the release by NASA of a report titled "Near-Earth Object Survey and Deflection Analysis of Alternatives" - gave us good news and bad on this front. On the promising side, scientists have a good grasp of the risks of a cosmic fender-bender, and have several ideas that could potentially stave off disaster. Unfortunately, the government doesn't seem to have any clear plan to put this expertise into action. In 1998, Congress gave NASA's Spaceguard Survey program a mandate of "discovering, tracking, cataloging and characterizing" 90 percent of the near-Earth objects larger than one kilometer (3,200 feet) wide by 2008. An object that size could devastate a small country and would probably destroy civilization. The consensus at the conference was that the initial survey is doing fairly well although it will probably not quite meet the 2008 goal. Realizing that there are many smaller but still terribly destructive asteroids out there, Congress has modified the Spaceguard goal to identify 90 percent of even smaller objects - 460 feet and larger - by 2020. This revised survey, giving us decades of early warning, will go a long way toward protecting life on the planet in the future. The good news is that scientists feel we have the technology to intercept and deflect many asteroids headed toward Earth. Basically, if we have early enough warning, a robotic space mission could slightly change the orbit of a dangerous asteroid so that it would subsequently miss the planet. Two potential deflection techniques appear to work nicely together - first we would deflect the asteroid with kinetic impact from a missile (that is, running into it); then we would use the slight pull of a "gravity tractor" - a satellite that would hover near the asteroid - to fine-tune its new trajectory to our liking. (In the case of an extremely large object, probably one in 100, the missile might have to contain a nuclear warhead.) To be effective, however, such missions would have to be launched 15 or even 30 years before a calculated impact. The bad news? While this all looks fine on paper, scientists haven't had a chance to try it in practice. And this is where NASA's report was supposed to come in. Congress directed the agency in 2005 to come up with a program, a budget to support it and an array of alternatives for preventing an asteroid impact. But instead of coming up with a plan and budget to get the job done, the report bluntly stated that "due to current budget constraints, NASA cannot initiate a new program at this time." Representative Bart Gordon, Democrat of Tennessee, was right to say that "NASA's recommended approach isn't a credible plan" and that Congress expected "a more responsive approach" within the year. Why did the space agency drop the ball? Like all government departments, it fears the dreaded "unfunded mandate"; Congress has the habit of directing agencies to do something and then declining to give them the money to do so. This is understandable. But in this case, Congress not only directed NASA to provide it with a recommended program but also asked for the estimated budget to support it. It was a left-handed way for the Congress to say to NASA that this is our priority ... like it or not. But for some reason NASA seems to have opted for a federal form of civil disobedience. Another problem with the report was that, while it outlined other possibilities, it estimated that using a nuclear-armed missile to divert an asteroid would be "10 to 100 times more effective" than non-nuclear approaches. It is possible that in some cases - such as an asteroid greater than a third of a mile across - the nuclear option might be necessary. But for the overwhelming majority of potential deflection cases, using a nuclear warhead would be like a golfer swinging away with his driver to sink a three-foot putt; the bigger bang is not always better. Why the concern? First, even with good intentions, launching a nuclear-armed missile would violate the international agreements by which all weaponry is banned from space. Second, the laws of probability say we would be struck by such a large asteroid only once every 200,000 years - that's a long time to keep a standing arsenal of nuclear asteroid-blasters, and raises all sorts of possibilities of accidents or sabotage - the old "cure being worse than the disease" phenomenon. In the end, of course, this is not just America's problem, as an asteroid strike would be felt around the globe. The best course is international coordination on deflection technology, along with global agreements on what should be done if a collision looks likely. Along these lines, the Association of Space Explorers, a group of more than 300 people from 30 nations who have flown in space (of which I am a member), is beginning a series of meetings in cooperation with the United Nations to work out the outlines of such an agreement. Still, as with many global issues, little will be accomplished unless the United States takes the lead. With the entire planet in the cross hairs, NASA can't be allowed to dither. If Congress's mandates and budget requests aren't energizing the agency, perhaps public hearings would shame it into action. Russell L. Schweickart, a former Apollo astronaut, is the chairman of the B612 Foundation, which promotes efforts to alter the orbits of asteroids. ================================== NASA SAYS CAN FIND MOST KILLER ASTEROIDS BY 2020 BUT LACKS THE MONEY International Herald Tribune, 5 March 2007
The Associated Press WASHINGTON: NASA officials say the space agency is capable of finding almost every asteroid that might pose a devastating threat to Earth, but because it lacks the money to do it, the job will not get done. The cost to find at least 90 percent of the 20,000 potentially hazardous asteroids and comets by 2020 would be about $1 billion, according to a report NASA will release later this week. The report was previewed Monday at a Planetary Defense Conference in Washington. Congress asked NASA in 2005 to come up with a plan to track most killer asteroids and propose how to deflect the potentially catastrophic ones. "We know what to do; we just don't have the money," said Simon Worden, director of NASA's Ames Research Center. . . . The agency already is tracking larger objects, at least [1 km] in diameter, which could wipe out most life on Earth, much like what is theorized to have happened to dinosaurs 65 million years ago. Even that search, which has spotted 769 asteroids and comets - none on a course to hit Earth - is behind schedule. It is supposed to be completed by the end of next year. NASA needs to do more to locate other smaller, but still potentially dangerous space bodies. While an Italian observatory is doing some work, the United States is the only government with an asteroid-tracking program, NASA said. One solution would be to build a new ground telescope solely for the asteroid hunt, and piggyback that use with other agencies' telescopes for a total of $800 million. Another would be to launch a space infrared telescope that could do the job faster for $1.1 billion, but NASA program scientist Lindley Johnson said NASA and the White House called both those choices too costly. A cheaper option would be simply to piggyback on other agencies' telescopes, a cost of about $300 million, also rejected, Johnson said. "The decision of the agency is we just can't do anything about it right now," he added. Earth got a scare in 2004, when initial readings suggested an 885-foot asteroid called 99942 Apophis seemed to have had a chance of hitting Earth in 2029. But more observations showed that would not happen. Scientists say there is 1 chance in 45,000 that it could hit in 2036. They think it would be most likely strike the Pacific Ocean, which would cause a tsunami on the U.S. West Coast the size of the devastating 2004 Indian Ocean wave. John Logsdon, space policy director at George Washington University, said a stepped-up search for such asteroids is needed. "You can't deflect them if you can't find them," Logsdon said. "And we can't find things that can cause massive damage." ================================= BUDGET DODGES KILLER ASTEROIDS
National Public Radio, March 28, 2007 Robert Reich (former Secretary of Labor) According to a new report from the National Aeronautics and Space Administration, some 100,000 asteroids and comets routinely pass between the Sun and the Earth's orbit. About 20,000 of these orbit close enough to us that they could one day hit the Earth and destroy a major city. But the worrying news is NASA believes over 1,000 of these things are large enough - about a mile wide in diameter - and their orbits close enough to us, as to pose a real potential hazard of crashing into the Earth with such force as to end most life on this planet. Scientists believe this is what killed off the dinosaurs about 65 million years ago. Congress has given NASA a budget of a little over $4 million a year to track these killer asteroids, but NASA says it needs at least a billion dollars more to find all of them by the year 2020. This might involve building a special observatory for tracking them and launching a spacecraft to observe the space around Earth from Venus. The job could be finished sooner than 2020, says NASA, but that would probably require a deep space orbiting infrared observatory, at an additional cost of $700 million. All of which raises at least three pertinent questions. First, if we're spending over a billion dollars a day in Iraq, why can't we bring the troops home a few days earlier and use the savings to track killer asteroids that might end life on Earth? And since we're talking about the survival of most living things and not just Americans, why shouldn't we expect other nations to kick in some money, too - especially now that the dollar is dropping relative to the euro and the yen? And third, once NASA knows for sure that a killer asteroid is heading directly for us, how exactly are we supposed to get ourselves out of its way, or it out of our way - and how much should we be budgeting to accomplish this? |
