“Those Asteroids that hit this morning – those were nothing – the size of basketballs and Volkswagens. This new one we’re tracking is the size of Texas, Mr. President. It’s what we call a Global Killer… the end of mankind. Half the world will be incinerated by the heat blast… the rest will freeze to death in a nuclear winter…” This quote from the 1998 disaster movie Armageddon perfectly matched the simulation that was played as an exercise at the IAU Planetary Defense Conference in Italy a few weeks ago.
If the dinosaurs had a space program…
Where most people think of Earth-destroying asteroids as stuff of movie scripts, the scientists gathered in Rome take the collision risk of ‘Near Earth Objects’, or NEO’s in short, very seriously. Although the example of the asteroid that wiped out the dinosaurs about 66 million years ago is seen as the ultimate example, we only have to go back in time two years to realize the risk at hand. In February 2013 the 60-feet large Chelyabinsk Meteor entered the Earth’s atmosphere, causing considerable damage on the ground when it exploded. A very loud wake-up call, as the large meteor came completely undetected.
Anything larger than the Chelyabinsk Meteor has the power to wipe out cities, countries or indeed the entire planet. Protecting humanity against these rocks from space was the subject of the conference, bringing together our current planetary defense community. The real ‘Bruce Willis’, on average, is a young astrophysicist, in equal number male or female, working in a specialized university lab or specialized institute, at places like NASA, NOAA, ESA, the Minor Planet Center, the NEO Shield Team, the Sentinel Mission or the Emergency Asteroid Defence Project. All working on different parts of the defense system that we need if we want to avoid the same fate that hit the dinosaurs.
Knowing what might hit us
The first step in our defense strategy is detection. We need to understand the risk that rocks from outer space really poses. Serious mapping of asteroids only started relatively recently, roughly when the Armageddon and Deep Impact movies were released. In that time thousands of asteroids have been detected and registered. The list is growing by dozens of new objects that are discovered every day.
The second step is to characterize these objects. How big or small are they? Are they on a potential collision course with our planet? And if so, when might they hit and at which speed? The vast majority of these objects is totally harmless and unlikely to hit us in the next few million years. However, there is a small percentage that deserve keeping an eye on. Even worse are the objects that are too small to be detected – but still big enough to do serious harm – or are in an orbit where they cannot be detected, like coming from the direction of the Sun, like the Chelyabinsk Meteor.
Gravity Tractors, Kinetic Impactors and Laser Games
Knowing what might hit us is one thing. Making sure they don’t is the next. This is where is becomes interesting. Forget about Bruce Willis now, the more realistic methods are much crazier, yet less appealing to movie makers. An asteroid in an orbit several millions of miles away from us, with perhaps dozens of years before it may hit, literally only needs to be diverted by a few inches to move out of harm’s way. This can be achieved by something simple like a spacecraft flying near to it. The very small gravity of the spacecraft, applied during several years, is often enough to alter the asteroid course by a few inches. This is called a gravity tractor. A similar effect can be achieved by flying into the asteroid at high speed, moving it only slightly, but sufficiently. This is called a kinetic impactor. If the course isn’t altered enough, you could just hit once more.
An even more exotic method is to shoot at the asteroid with a strong laser, or a controlled light beam from the Sun. The focused light energy will cause material on the surface of the asteroid to boil away, creating a small ’jet’ of gases that works just like the exhaust from a rocket engine, slowly propelling the asteroid off course.
Emergency Asteroid Defense
Much of the conference focused on the question “But what if there is no time for those fancy but very slow methods?” What if we only have months, weeks or even hours to respond? The conference had two answers to that scenario: First of all, technically, as per 2015 there is no defense. There is only damage control by evacuating impact zones and making sure we “keep calm and carry on”. However “the chances of anything coming” are very slim and scientists agree that we have time to develop the badly needed emergency asteroid defense system. Consensus right now – despite moral and legal issues – is to revert to the nuclear blast ‘deflection’ method depicted in our movie scripts, although we can probably launch that bomb without needing to send Bruce Willis or Ben Affleck with it… “Hey Harry… The timer on that nine-foot nuclear bomb just started ticking.”
Emergency Asteroid Defense Project
While scientists and government agencies around the world are aware of the potential threat of asteroid collision, no major funding has yet been designated for a near-Earth object mitigation technology study.
The Emergency Asteroid Defence Project aims to change exactly that. Researchers led by Prof. Bong Wie at Iowa State University’s Asteroid Deflection Research Center in partnership with the Emergency Asteroid Defence Project have developed a plan that is currently the most effective way to deflect or dissipate asteroids in an emergency scenario. Through our Indiegogo campaign, we now plan to collect the funds necessary to start the development of a sustainable system that can protect our planet against imminent asteroid impacts.
Developing a very fast spacecraft
he HAIV (pronounced “hai-vee”, or Hypervelocity Asteroid Intercept Vehicle) is a two-body spacecraft that is capable of deflecting an asteroid using two separate collision scenarios. The fore body, or Leader, first hits the asteroid with a kinetic impact, producing a crater on the objects surface. The aft body, or Follower, then delivers an explosive device into the crater to break up the asteroid into small harmless pieces, eliminating the threat. If a nuclear explosive device is used as the second impactor, the double-impact strategy requires only 5% of the explosive force that would be necessary to shatter an asteroid with a direct nuclear impact alone.