Asteroids: Hazard or Opportunity?
(Image Credit: Atari, "Asteroids", 1979)
The planets, asteroids, comets, and dust that orbit the Sun are only about 0.2 % of the mass of the solar system. Looking at the millions of miles between orbiting bodies and the unfathomably large distance to the edge of the Oort cloud (a significant fraction of the distance to the next star system), it can make everything that isn't the Sun in the solar system seem very miniscule. It’s as if the planets and anything nearly relatable in size to the human experience is just the powdery residue on the inside of a cosmic beaker. A constant reminder of this residue is asteroids. The infinitesimally small dusty left overs that lie in between the planets are fairly insignificant on the stellar scale, yet to life on Earth asteroids are both bringers of apocalypse and potentially bringers of enormous wealth.
Asteroids, meteors and meteoroids have been a fact of life since the dawn of time. Ancient civilizations were well aware of 'falling stars', even if they didn't know exactly what they were. The extinction of the dinosaurs is a topic hotly debated, but it is very clear that during that time the Earth received a tremendous impact. Molten rock and ejecta were hurled into the upper atmosphere, tsunami’s rippled through the oceans and continents were shaken to their roots. This is the image that is often conjured when many think of an ‘asteroid impact’. The reality is usually much less extravagant. More often, asteroids meet the Earth in the form of small brilliant streaks in the sky, signaling the end of their 5 billion year exile in interplanetary space. These small shards of rock enter our atmosphere every day all over the world. Antarctic ice is peppered with small black rocks that have fallen into the ice, to say nothing of the hundreds of tons of dust that fall into the atmosphere every day.
Despite the relatively mundane daily collisions, every now and then a much more sinister object crosses our path. The Chelyabinsk meteor strike in February 2013 entered the atmosphere on a low trajectory, exploding in the upper troposphere with the force 0.44 megatons (the force of a high yield atomic bomb). The shock caused windows to shatter and roofs to collapse and many were injured by flying debris. The true impact of this event was felt globally, however. The fear that another, more dangerous impact was reinforced when on that same day another asteroid passed uncomfortably close to Earth. The economic, geopolitical and social ramifications of a deadly meteor strike would be felt universally. Dinner table conversations globally shifted to the topic of planetary defense. The public cried for action.
Asteroid defense is tricky. After all, whose responsibility is it to safeguard all life on Earth? Should the most capable, space faring nation lead the cause? Or should the responsibility be shared globally, considering that a catastrophic impact would affect all seven billion of us? Even trickier, could a private company be contracted to provide asteroid defense? These questions are only compounded when the exceedingly high costs of technological development, launches and space based infrastructure are considered. These are the questions that are being fiercely debated right now in the US Congress over NASA's proposed asteroid retrieval mission.
These questions don't stop Planetary Resources however. After all, every chunk of space rock is an opportunity as well as a threat. The hydrogen, oxygen, iron and silicon stored in asteroids can provide billions of dollars worth of materials that don't have to be flown into orbit. These materials can be used to construct spacecraft, harvested for fuel or even converted into drinkable water. The profit for anyone willing to undertake such a incredible endeavor could be extremely high. The untapped mineral wealth stored within asteroids is staggering. Over billions of years of tectonic plates emerging and sinking, many valuable and rare elements that were once abundant early Earth's crust have sunk into the core- far beyond our reach. But out in the asteroid belt, these elements have been sitting in pristine condition since the planets first coalesced.
The challenges in utilizing asteroids are numerous: dust from drilling, gripping the surface and just plain getting there are a few. But, because of their tiny gravity wells, the potential uses are limited only by the imagination: a base for hotels, fuel depots, repair stations and drydocks are prime examples. Many raise questions about who can 'own' an asteroid; but that topic can fill books, let alone a single blog post. Truthfully, this blog post only scrapes the surface of what may be a multi-trillion dollar industry one day.
It seems that the closer we get to mining, utilizing and fending off asteroids more questions are raised than answers. This is common in the space industry. As a species we will collectively need to decide a course of action to deal with these problematic little rocks. As we push forward technologically and continue to globalize, asteroids will become more and more relevant. I hope that in the near future they will be looked upon as an opportunity rather than a threat.