Preserving the Lord's Tempel

Back in January, I wrote about the NASA space probe Deep Impact on the occasion of its launch. Now its time is drawing near. On July 4, while its companion looks on, the 820 lb. copper-cored Deep Impact should collide with comet Tempel-1 at over 23,000 mph. Scientists hope this unique effort in experimental astronomy will blast a stadium-sized hole in the comet and reveal the interior of a comet to us for the first time.

As a scientist, I find the mission exciting, and there is something sinfully satisfying about finally getting to smash one o' them suckers around to find out what's inside. And it also pleases me to celebrate the Fourth of July with some American-made celestial fireworks. Yet I cannot help thinking that this well-intentioned mission is nonetheless an act of vandalism that will forever damage comet Tempel-1. We are so ignorant of cometary structure that, for all we know, Deep Impact could shatter the comet entirely, or ruin a beautiful crystalline formation, or perhaps destroy some unknown wonder that future astronauts now will never have the chance to see. And suppose it were Halley's comet instead? Would we really wish to risk destroying that once-in-a-lifetime spectacle?

We do not have a good record in protecting any of the Space we have been able to get our hands on. According to NASA's own Orbital Debris Program Office, there are over 10,000 pieces of space junk bigger than a softball littering near-Earth orbit, over 100,000 larger than a pea, and "tens of millions" of pieces of man-made space debris scattered up there as grains of sand. And now we have also now deposited plastic and metal debris on Mars, Venus, Moon, Titan, and at least one asteroid.

I am glad to report that NASA now at least sterilizes its spacecraft before launch, but there is no international treaty requiring that emerging Space powers do the same. It is sobering to realize that biocontamination is a very real possibility in our solar system--even on airless worlds. In 1967, the (unsterilized) space probe Surveyor 3 landed on the Moon, and a piece of it was later recovered by the Apollo 12 crew and returned to Earth. Stunningly, some 50-100 bacteria (Streptococci) were found still alive. These hardy bacteria had managed to survive the launch, Space vacuum, three years of radiation and deep-freeze (~20 degrees above absolute zero), not to mention a complete lack of nutrients and water. They were placed in a petri dish and they thrived.

Yes, there are billions of comets out there and I believe this mission is well worth the price. But before we give another heavenly body the equivalent of an anal probe, perhaps we should begin discussing "environmental preservation" as a wider concept than just protecting biodiversity, or even protecting our Mother Earth. We can't argue for preserving the pristine landscape of Mars or Titan to save the spotted owl--but are there then no limits to our right to alter it as we will? Has man been given dominion over the heavens as well as the Earth? What does it mean for humankind to be a good steward of the Universe?

Oh, some will say the rest of the Solar System is empty, lifeless, and dead. But what is lifeless is not dead. What is lifeless can never die.