A still from NASA TV shows the moment when the space shuttle Atlantis jettisoned its external fuel tank shortly after launch on Friday. (Video: "Space Shuttle's Final Days.")
After Atlantis safely reached space, NASA commentator Rob Navias said from the Johnson Space Center in Houston: "For the last time, the shuttle's engines have fallen silent."
With the space shuttles out of commission, NASA will have to rely on Russian Soyuz vehicles to transport astronauts and supplies to the space station for the next several years. NASA Administrator Charles Bolden recently addressed concerns that the delay could threaten the U.S. space program.
"Some say that our final shuttle mission will mark the end of America's 50 years of dominance in human spaceflight," Bolden said in a NASA video.
"As a former astronaut and the current NASA administrator, I’m here to tell you that American leadership in space will continue for at least the next half century, because we have laid the foundation for success—and for NASA, failure is not an option."