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Exploring Space: The Survival Imperative

by Tom Jones 

Amid these times of high unemployment, economic recession and soaring deficits spending, we heard a speech last Thursday from President Obama committing America to one day sending its astronauts to nearby asteroids, lunar orbit, the moons of Mars, and eventually the surface of the Red Planet itself. How can we contemplate those long-term ventures, far beyond the International Space Station, when we have so many domestic needs down here on terra firma?

I’ve certainly fielded this question many times, during my years as a NASA astronaut and now a scientist and consultant. My answer usually contains several elements, and this week one of them originates partly from the sky above our heads. On April 13, a bright fireball seared the night sky over parts of Wisconsin, Illinois and Michigan, accompanied by a thunderous boom. Over the weekend, a Wisconsin farmer found a peanut-sized fragment of the meteorite responsible for the light show, and more pieces may eventually turn up.

Earth orbits the sun in a cosmic shooting gallery. About a hundred tons of debris from asteroids and comets rains down on our planet every day. The farmer's stone was just a tiny sample of that daily deposit, courtesy of the solar system we inhabit.

Of course, sometimes the incoming debris is a bit larger. Every 300-500 years, a rock 30 meters across or so slams into our atmosphere, big enough to reach the surface in one piece or explode overhead with frightening effect. The resulting multi-megaton blast, like the one caused by an impactor over Tunguska, Siberia in 1908, could destroy a city. Larger cosmic impacts, like the one that wiped out the dinosaurs 65 million years ago, fundamentally changed the course of life on Earth.

Today we possess the telescope technology capable of finding most of the near-Earth objects, or NEOs, capable of causing widespread damage to our world. We’re building larger instruments that should help us find and predict asteroid orbits, and provide us with early warning of an impact. We also have the spaceflight expertise to head off a future collision, provided we have a decade or two of warning. What’s missing is an international agreement on deciding when and how to divert a potential cosmic catastrophe. But scientists and diplomats, via the U.N., are working on that problem, too.

The technical solutions to preventing an impact are almost in hand. We can fly a small spacecraft called a gravity tractor to hover close to an asteroid or extinct comet, tugging ever so subtly on it over the course of several months. The tiny velocity change from that tug can cause a rogue asteroid to miss its appointment with  Earth. 

The Deep Impact probe strikes comet Tempel 1 on July 4, 2005, excavating a crater that revealed details of the comet’s internal structure and composition. (NASA)

In 2005, we tested another asteroid diversion method by slamming a scientific probe at very high speed into the nucleus of Comet Tempel 1. Hitting a hazardous NEO with such hypervelocity bullets can change its velocity enough to nudge it from a future collision.

The Hollywood solution to asteroid deflection is, of course, a very big nuclear explosive. Fortunately for us, such drastic measures will probably never be needed before we develop much more elegant solutions. Nuclear energy will only be needed anyway for 1 or 2 percent of asteroids that might head our way.

I can tell you with certainty that if we do nothing, Earth will be struck in the future by a NEO capable of causing widespread damage and millions of casualties. I can also tell you that if we continue to explore our solar system, we will develop the skills needed to prevent such an impact from ever occurring again. Humanity is now capable of stopping a process of planetary bombardment that has been going on for 4.5 billion years. God has posed us a long-term problem, but He’s also given us the tools and intelligence to solve it. We humans cannot deny our compulsion to explore space, especially given the potential good – our very survival – that flows from our innate curiosity about our universe.

Tom Jones is a planetary scientist and former NASA astronaut. He currently works with NASA on plans for exploring near-Earth objects and preventing a future asteroid collision with Earth. www.AstronautTomJones.com

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(The views expressed in this column are those of the author and do not necessarily reflect the positions of Headline Bistro or the Knights of Columbus.)