SpaceShipOne's splendid achievments have me re-visiting the days of my youth, when the most remarkable video I had ever seen was the jerky footage taken from a modified V-2 rocket as it lifted off some time after the war -- Walter Kronkite used this footage as the introduction to the CBS documentary series 'Twentieth Century.' You would see the launching pad dwindling below, then the scrub desert not all that far from where SpaceShipOne flew, and as the flight progressed, just a glimpse of a stunningly curved horizon that told you how far into the unfathomable black you had traveled. How exciting the future looked in those days, as I followed the flights of the X-15, a rocket vehicle whose altitude record SpaceShipOne exceeded today. I began to puzzle over the question of nostalgia for a future that never happened, an odd notion that makes me think of all the dreams we as a culture have assigned to the future at different times in our history. Then along comes a fine essay called...

The continuing success of SpaceShipOne -- and other ventures suggestive of future commercial space activities like Richard Branson's Virgin Galactic and Robert Bigelow's Bigelow Aerospace -- bring me back to Freeman Dyson. It was in 1979, in his book Disturbing the Universe, that Dyson wrote about what he called the three 'romantic ages' of spaceflight. The first, beginning in 1927, was inaugurated by the Verein für Raumschiffahrt, Germany's Society for Space Travel, which met in Breslau that year. The VfR would include such luminaries as a young Wernher von Braun, and would make an enthusiastic contribution to early rocketry before its talents were hijacked by the German military. Dyson's second age was the era of Orion, Ted Taylor's nuclear spaceship. Working on an outrageous but theoretically plausible design that involved enormous shock absorbers cushioning nuclear blasts behind the vehicle, Orion's slogan was 'Saturn by 1970.' When in 1959 the decision was made not to use...