The destruction of the space shuttle Columbia has precipitated another round in the long-standing debate over the wisdom of the US space program. Should America spend billions upon billions of dollars to send human beingssintosspace on perilous missions?

　　Some critics point out that the money could usefully be redirected to pressing problems here on earth. Other critics see the space program as a gigantic and never-ending waste of taxpayers' money: let scientists, they say, find someone else to pay for their toys and games.

　　Many people who support the objectives of the space pro-gram still wonder whether manned space flights are justified. Wouldn't it be better to concentrate on unmanned flights? This would eliminate the risk to human beings and be much cheaper. Scientists would get more bang from the taxpayers' buck, so to speak,and no one would die.

　　But those who call for continuing the drive to put astro-nauts on Mars argue that exploration is essential to the fulfill-ment of our humanity. Curiosity is one of the noblest human faculties and, allied with courage, drives us to transform our-selves. Exploration is in some sense the human calling, the engine of our mental evolution.

　　Tony Auth's cartoon weighs in on the side of the manned space program. It takes us back to the days 400 million years ago when lobe-finned fishes first began spending time on land. Auth imagines that not all the lobe-finned fish were pleased.

　　But those daring fish were the ancestors of all other land vertebrates, including us. Implication: onward to Mars!