NASA Administrator Charles Bolden (right) and pilot Doug Hurley speak while walking under space shuttle Atlantis after it landed at the Kennedy Space Center at Cape Canaveral, Fla., on Thursday, July 21, 2011. The landing of the spacecraft marks the end of NASA's 30-year shuttle program. (AP Photo/Scott Audette, Pool)
This image provided by NASA shows a view of Space Shuttle Atlantis while still docked with the International Space Station taken by crew member Mike Fossum aboard the station Monday. The robotic arm on the shuttle appears to be saluting "goodbye." Earth's airglow is seen as a thin line above Earth's horizon.
This panoramic view provided by NASA was photographed from the International Space Station, looking toward Earth past the cargo bay of the docked space shuttle Atlantis and part of the station, including a solar array panel, on Thursday, July 14, 2011, as the complex passed over the Southern Hemisphere. The Aurora Australis, or Southern Lights, can be seen on Earth's horizon, and a number of stars also are visible. (AP Photo/NASA)
July 17 NASA / ART: 50 Years of Exploration at National Air and Space
Through October 9 at the National Air and Space Museum, Independence Ave. and 6th St. SW, 202.633.1000, http://www.si.edu/Museums/air-and-space-museum
Astronauts Ronald Garan Jr. (top) and Michael Fossum work outside the International Space Station during the last spacewalk of NASA's space- shuttle era on Tuesday. They retrieved a broken ammonia pump.
BARBARA L. SALISBURY/THE WASHINGTON TIMES
NASA Administrator Charles F. Bolden downplayed fears that this week's final space shuttle launch marks the end of American dominance in space during a speech Friday at the National Press Club. "We are not ending human space flight," he said. "We are recommitting ourselves to it."
NASA Administrator Charles Bolden (left), accompanied by astronaut Capt. Mark Kelly, husband of wounded Arizona Rep. Gabrielle Giffords, speaks at the National Press Club in Washington on July 1, 2011. (Associated Press)
An image made from NASA Television shows the space shuttle Endeavour as it does its fly-around of the International Space Station on Monday, May 30, 2011, before returning home from NASA's penultimate shuttle mission. The shuttle is viewed from the space station as it passes over Australia. (AP Photo/National Aeronautics and Space Administration)
In this image from NASA television astronauts Mike Fincke, left, and Greg Chamitoff, make their way along the P3 Truss on the International Space Station as they make their way back to the quest airlock wrapping up the fourth spacewalk Friday morning, May 27, 2011. (AP Photo/NASA)
This image provided by NASA televsion shows the space shuttle Endeavour's tiles being inspected early Saturday morning May 21, 2011, using both the shuttle's robot arm and the International Space Station's robot arm. (AP Photo/NASA)
This image provided by NASA on Saturday, May 14, 2011, and taken by an Expedition 27 crew member aboard the International Space Station on May 12, 2011, clearly shows the outlines of some heavily flooded agricultural fields on the Missouri side of the Mississippi River. The center point for this frame is just north of Caruthersville, Mo., and west of Ridgely, Tenn. North is toward the lower right corner of the image. (AP Photo/NASA)
This March 28, 2011 image provided by NASA shows composited images from Swift's Ultraviolet/Optical and X-ray telescopes of a gamma-ray explosion designated GRB 110328A. Scientists say this blast is unusual because the effects are long-lasting. More than a week later, they continue to see high-energy radiation spiking and fading at the source. Flaring from such an event usually lasts a couple of hours. (AP Photo/NASA, Swift, Stefan Immler)
This image provided by NASA is the first ever obtained from a spacecraft in orbit about the Solar System's innermost planet, Mercury. The image was captured early this morning, at 5:20 a.m. EDT,Tuesday March 29, 2011. The dominant rayed crater in the upper portion of the image is Debussy. The bottom portion of this image is near Mercury's south pole and includes a region of Mercury's surface not previously seen by spacecraft. On March 17, 2011 (March 18, 2011, UTC), MESSENGER became the first spacecraft to orbit the planet Mercury. (AP Photo/NASA)