Had a satellite crashed into a large sea or an empty desert on Saturday morning, this would be considered a minor setback in the pursuit of knowledge. But the explosion of the space shuttle Columbia yesterday contained the most precious cargo: people. Seven individuals who had devoted most of their lives to becoming astronauts perished. Six people from the United States and one from Israel trained to gather information from dozens of scientific experiments.

Every venture into space, for example, enhances understanding of the universe and how our lives on earth are linked with it directly or indirectly. What is learned today can serve humanity tomorrow.

But the tragedy, reminiscent of the Challenger explosion in the 1980s – reminds us that there are risks. No matter how well prepared astronauts and ground control may have be, and no matter how solid the craft, there are always going to be unforeseen factors that can so drastically affect a mission.

All involved acknowledge such possibilities, and still they venture upward and outward.

For a time we’ll celebrate the earthly lives of the seven and also mourn their absence. Tomorrow we’ll again reach for the stars.