It has been 12 months of triumph and tragedy for NASA and, by extension, for all of us. The space agency suffered a great loss a year ago today, as the Columbia space shuttle, the oldest in the fleet, broke up upon re-entry to the earth’s atmosphere, killing all seven astronauts aboard in an accident eerily reminiscent of the shuttle Challenger accident 18 years ago last week.

In the wake of the Columbia tragedy, as investigators looked at what had physically gone wrong with the spacecraft, officials also began to look at what was wrong with NASA’s culture &045;&045; and found an agency whose safety measures had been severely compromised after decades of successes.

NASA, in humility and grief, pledged changes. In the months since, the shuttle program remains grounded, although the next crew is waiting in the wings. The International Space Station crew remains on board its craft, aided by missions sent by the Russian space program.

But despite the tragedy, the last month has been one of great triumph for NASA &045;&045; and for all of us interested in scientific discoveries. The space agency has landed two rovers on Mars, and the craft have sent back amazing images of the surface of the Red Planet. Even a major computer malfunction on the first rover has been all but corrected; officials expect to pronounce it &uot;healed&uot; today.

President Bush last month declared his intention to seek new funding for major new goals for the space program: return to the moon and, much later, land astronauts on Mars.

It is a bold goal, but it is one which, we believe, the lost Columbia astronauts would applaud. They surely understood the rewards and risks of space travel. They gave their lives for scientific exploration.

Our tribute to them should be a renewed pledge to support NASA &045;&045; and a renewed pledge by NASA to continue improving its culture of safety. We will return to human exploration of space.