The students decided that detection was the first and most important step in preventing the collision of an asteroid with the Earth. If a threatening asteroid could be spotted many years before it hit the Earth, then a rocket could travel to that asteroid when it was far from the Sun. By giving it a modest push, the rocket would change the asteroid’s orbit ever so slightly – but that would be enough to cause it to miss the Earth.
The students understood that it was too late to divert Icarus using this method. By the time spacecraft could be dispatched to the asteroid, Icarus would be bearing down on Earth at over 100,000 kilometers per hour. One possibility was to destroy the asteroid with a hydrogen bomb. The students estimated that a bomb with a yield of one billion tons of TNT might suffice, but that was about 50 times more powerful than the largest bomb in the US arsenal. There seemed to be no way of manufacturing a bomb of such power at short notice. Worse, a powerful bomb might simply break up Icarus into fragments that would, collectively, still cause global devastation. The only option was therefore to redirect or deflect Icarus near the Earth, but that too would require enormous force.
By the end of the semester, the students worked out a plan. Six Saturn V Moon rockets would carry hydrogen bombs that each had a yield of 100 million tons of TNT. Guided by radar, the first bomb would detonate some 100 feet from the asteroid, far enough to minimize the risk of fragmentation. Radiation from the bomb would vaporize the surface of the asteroid, imparting momentum that would nudge the asteroid off course. Subsequent bombs would keep pushing the bomb if it was still heading for Earth, or destroy any Earthbound fragments.
Since each rocket could fail, and because the asteroid might disintegrate into fragments too small to destroy, the plan wasn’t foolproof. But the students calculated that “Project Icarus” had a roughly 71% chance of deflecting doomsday. And it would require no more than 1% of America’s GDP to complete.
In May, the students presented their complete plan in MIT’s Kresge Auditorium. With “tremendous enthusiasm,” as they put it, they followed the release of articles that described their project in “at least 30 newspapers from coast to coast.” Yet after Icarus sailed safely by the Earth in 1968, public interest in the impact risk declined. Governments had made no effort to fund detection programs – let alone systems that could, someday, intercept and deflect an inbound asteroid.