The emergence of the first fish that flopped out of the ocean and managed to survive on dry land would have played poorly on live TV. Those fish, Crossopterygii, destined to become the first amphibians were unphotogenic. With their beady heads and slick, polished, sloped heads, they looked like vacuum cleaners with teeth. They lived four hundred million years ago, during the Devonian -- a hardscrabble party's over period when the seas were receding and fish were dying everywhere as tide pools dried up. The few who subsisted by gulping dry air were obliged to make a living in an alien environment, violently hot and bright by day and cold and dark by night.

The story of the crossopterygii came to mind as I watched the live television coverage of the space shuttle mission to repair the Hubble Space Telescope, and again, a month later, when the first photographs taken by a refurbished Hubble were released. The mission was wreathed in historical significance - NASA's tattered reputation at stake, brave astronauts obliged to put their lives on the line to repair bureaucratic bungles and open human eyes to the far reaches of the universe - but watching it was at first about as exciting as hanging around the garage while a team of mechanics overhauls the transmission on your Subaru.

After about twenty hours of steady viewing, though, this stuff became hypnotic, then essential. Gradually, one began to sense what it's like to live in space. Most evident were the insistent oddities of weightlessness. Empty spacesuits bobbed in the spaceship's changing room, their bloated fingers groping like those of floating corpses. The astronaut Jeff Hoffman ate a banana in the shuttle cabin, the peel drifting up to enclose the banana after each bite. Out in space, Hoffman and Story Musgrave toiled painstakingly over a single bolt, the hydralike straps and wires on their tool kits writhing furiously in the vacuum, more animate than the living beings they served.

"We are in a strange place that we're still getting to know." Story Musgrave said. Fifty-eight years old and a veteran of more than eight hundred hours in space, Musgrave sports what approaches a parody of an astronaut's overachieving resume. In addition to his medical degrees he holds bachelor's degrees in statistics and chemistry and master's degrees in business administration, biophysics, and literature. He is the author of twenty-five scientific papers, the father of five children. He is also a mystic, who reads Teilhard de Chardin and has speculated about encountering an alien life-form while in orbit. With his shaved head and cold blue eyes he looks rather like an extra-terrestrial himself - a vision of evolution gone off on a tangent, a high IQ salamander.

Musgrave was interviewed from orbit for "Nightline." Pumped up for the mission, he spoke so rapidly -in his flat Kentuckian jet-jockey accent, with his words tripping over one another - that it was hard to understand him. But to listen carefully was to hear the voice of the Crossopterygii.

"I love space for all kinds of reasons," Musgrave said. "Zero g is kind of magical, because we have evolved, and we have been designed, by having that force between us and gravity, and so now, in an evolutionary sense, here we are kind of floating around, and we really weren't designed to be floating around, so that gives it a really kind of mystical, magical environment."

Ted Koppel asked him the "why" question: Why go to the trouble of exploring space when it's so dangerous and expensive? "We have no choice, sir," Musgrave replied. "It's the nature of humanity. It's the nature of life … And maybe I'm not just a human up here, you know. Now life is leaping off the planet. It's heading for other parts of the solar system, other parts in the universe … It isn't simply politics. It isn't simply technology. It's really not just the essence of humanity, but it's sort of also -- You could look at it as maybe the essence of life."

Thirty-one days after the shuttle landed, the first photographs taken through the repaired Hubble telescope were released. They showed a jewel-box star cluster in a galaxy called the Large Magellanic Cloud, and a gorgeous spiral galaxy -- it's coral pink inner spiral going to dove-gray along the dusty disk -- that lies fifty million light-years away in Virgo. To one accustomed to scrutinizing photographs of galaxies, the improvement in clarity was startling. It was like emerging from the ocean to see, for the first time, through lucid air.