Astronaut Russell Schweikart was the speaker as the Silicon Valley Astronomy Lecture Series opened for the 2004-2005 year. As always, Andrew Fraknoi, the astronomy teacher at Foothill College welcomed the crowd to the lecture. Fears that the number of people would exceed the seating availability were unfounded but the free lecture on October 6th was well attended. Parking was a bit tricky because of the changes made to the lower level parking lots (Hint: take the Gagarin route - make a nearly complete orbit around the campus and turn into Parking Lot 7 - the lot is mostly empty, the exercise up the hill is good for you and the remodeled lot has parking voucher machines that take dollar bills.)
Russell (Rusty) Schweikart is the chairman of the board of the B612 Foundation. This is an organization trying to raise awareness of the problems posed by near earth asteroids and the methods for alleviating those problems. The big problem is that there are so many near earth asteroids, perhaps upwards from 200,000, that cross the earth's orbit or come close to it. These are asteroids that are at least 100 meters long. An asteroid of this size would have the same impact as two of the largest thermonuclear warheads ever developed. The immediate devastation plus the nuclear winter to follow could kill millions. Smaller impacts, say something on the order of the Tunguska event, is not of immediate concern but obviously such an event directly on a populated area would be enormous.
The audience gasped when Schweikart displayed a plot that showed how many known asteroids intersect the earth's orbit. Many of these objects have only been seen for part of one orbit so their exact location data is preliminary at best. The B612 Foundation web site says we will have a 90% inventory of 1 km sized objects by 2008 and perhaps the same for 100 m objects 10 years after that.
Despite all of this, the odds of a major event in the next 100 years is very low. But we all know that it will happen some time. And we all know that if we don't kill ourselves first, an asteroid will do unto us what it apparently did unto the dinosaurs 65 million years ago. So the B612 Foundation (B612 is the asteroid from Antoine de Saint Exupery's The Little Prince) wants to develop a solution that could be demonstrated to be effective by the year 2015. A "safe" asteroid that comes close to earth would be used to demonstrate the capability. After that, it isn't necessary to keep a fleet of rockets ready to fire - just don't loose the plans.
Here is the scenario that Schweikart presented. Imagine that a 100 meter asteroid is found with an orbit that is going to lead to an earth impact in 10 to 20 years. Most of these asteroids have rather elliptical orbits. A rocket would be attached to the asteroid (details on how to do that are to be determined) which would push the asteroid into a slightly larger orbit. How? First, you have to understand the kind of rocket envisioned. It turns out that the Jupiter Icy Moons Orbiter, an ion engine powered spacecraft, fills the bill. The thrust is shy of 10 pounds but it can run for a very long time. Second, the rocket would be attached as it came near the earth and would start firing near perihelion. In this scenario, the rocket pushes the asteroid forward starting about 100 days before perihelion and continues for 200 days. The result is that the asteroid shows up late for its date.
So if the problem is so clear and the solution conceptually designed, what's the problem? Mostly, funding is needed. The ion engine rocket, also known as the Prometheus project, has not added asteroid management to its to-do list. Letters to NASA or your congressperson are suggested.
One of the most interesting points that Schweikart made that night was why we don't want to use nuclear weapons to blow up an asteroid. More important than the fact that we don't know how an asteroid will react (a look at the craters on the asteroids demonstrates that they don't disintegrate easily) is that we don't want to keep nuclear weapons around forever just in the off chance that an asteroid heads this way. After all, it is nuclear weapons that could wipe us out before an asteroid ever gets a chance.
The B612 Foundation has an interesting website at http://www.b612foundation.org.
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