Deep space, deep thoughts

A few thoughts on the future of space exploration from a couple of deep thinkers:

• Lawrence Krauss, chair of the physics department at Case Western Reserve University, explains to Wired just why he's down on the whole notion of sending a manned expedition to Mars. Among other reasons, humans are "bulky, fragile, and expensive to maintain. Almost all of the cost of a manned mission goes into keeping the humans alive and getting them back to Earth."
• Science fiction writer Ben Bova, in his latest column for the Naples Daily News, reminds us of the incredible return on investment that this country -- and society at large -- has gotten from NASA so far. But, he thinks a big part of space exploration's future may be in the hands of private entrepreneurs. ("The frontier has always been a place of high risk and high rewards. Space is no different.")