If Atlantis were lifting off on any other flight, its space station resupply mission would be considered routine at best, mundane at worst. No doubt, it would be given only cursory coverage by the mainstream media. But when the solid boosters ignite and STS 135 carries four astronauts into orbit (scheduled for July 8, 11:26 A.M. Eastern time), this mission will be anything but. Atlantis’s flight, the 135th of the 30-year shuttle program, will mark the culmination of a half century of almost continuous U.S. manned spaceflight that began in 1961, when Alan Shepard was lobbed into a 15-minute ballistic suborbital trajectory over the Atlantic.

This launch is important and historic because it marks the end, not the beginning, of an era of U.S. human space exploration. And a doleful finale it is, because an American space transportation system is being retired without a clear set of mission goals and programs, nor the political will, to make NASA once again an agency primarily dedicated to space exploration beyond Earth orbit.

FINAL FLING: With space shuttle Atlantis in the background, the STS 135 astronauts answer questions from the news media at Launch Pad 39A. They are, from left: Mission Specialists Rex Walheim and Sandy Magnus, Pilot Doug Hurley and Commander Chris Ferguson. Credit: NASA TV

Although the popularity of space exploration peaked in 1968 with the flight of Apollo 8 and declined precipitously after the first moon landing, many Americans have generally accepted the reality that humans must have access to orbit as a fact of modern life. But although the U.S. got five space shuttles and what will be 135 flights for around $195 billion, they have not been enthusiastic about putting more public treasure and human capital into manned exploration beyond low Earth orbit. It will be interesting to see how the new reality sets in after Atlantis touches down and is mothballed and mounted at the Kennedy Space Center. What will visitors think when they see the space plane, like its orbit-hardened sister ships Discovery and Endeavour, as a museum piece—a tribute to the past, rather than a harbinger of the future?

The shuttles hardly ventured into unexplored territory. Nevertheless, they ushered in great technological triumph, and twice saw human tragedy—all within 400 kilometers from home. Scientific American, which has chronicled human progress since 1845, will be covering this history-making mission from Kennedy Space Center.