From its first launch 30 years ago to its final launch scheduled for next Friday, NASA's Space Shuttle program has seen moments of dizzying inspiration and of crushing disappointment. When next week's launch is complete, the program will have sent up 135 missions, ferrying more than 350 humans and thousands of tons of material and equipment into low Earth orbit. Fourteen astronauts have lost their lives along the way -- the missions have always been risky, the engineering complex, the hazards extreme. As we near the end of the program, I'd like to look back at the past few decades of shuttle development and missions as we await the next steps toward human space flight. Space Shuttle Columbia lifts off from Kennedy Space Center, on April 12, 1981. Commander John Young and pilot Robert Crippen were onboard STS-1, the first orbital flight of the Space Shuttle program. The space shuttle twin solid rocket boosters separate from the orbiter and external tank at an altitude of approximately 24 miles. They descend on parachutes and land in the Atlantic Ocean off the Florida coast, where they are recovered by ships, returned to land, and refurbished for reuse. A technician works on sensors installed in the back end of a scale model of the Space Shuttle in NASA's 10X10 foot wind tunnel, on February 15, 1977.