Today, the nation paid respects to the seven men and women who perished in the Space Shuttle " Columbia " tragedy. It is hard to overestimate the collective sorrow their deaths brought to us. It is a small measure of comfort that they spent the last sixteen days of their young lives doing the thing they loved most—exploring what lies beyond Earth's thin layer of atmosphere.

While suffering setbacks, it's worth noting some of NASA's successes. We put the first humans on the moon, and returned them safely. That was 33 years ago. With the two Voyager probes, we obtained the first close-up pictures of the outer planets. Those two little machines became the first man-made objects ever to leave the Solar System into true outer space. We soft-landed a rocket on Mars—millions of miles distant—that beamed back the first pictures from the surface of another planet. That was like hitting a dime with a .22 caliber rifle—shoulder-held—from five miles away! Those were both more than a quarter-century ago.

The loss of the Challenger, and the Columbia , the capsule with its three astronauts on the test launch pad , and the near-loss of Apollo 13 on its return from the Moon, remind us that we are still babes in the immense vastness of space. Exploring is inherently dangerous, but we've always considered it not only opportunity, but duty.